NOAA Endangered and Threatened Species; Identification of 14 Distinct Population Segments of the Humpback Whale (Megaptera novaeangliae) and Revision of Species-wide Listing 2016. Abstract | BibTeX | Keywords: Arabian Sea, breeding grounds, conservation status, feeding grounds, Humpback Whale, marine mammal, megaptera novaeangliae, population status, USA @{, title = {Endangered and Threatened Species; Identification of 14 Distinct Population Segments of the Humpback Whale (Megaptera novaeangliae) and Revision of Species-wide Listing}, author = {NOAA}, issn = {Docket No. 130708594-6598-03}, year = {2016}, date = {2016-01-01}, number = {183}, pages = {247}, publisher = {Department of Commerce}, abstract = {We, NMFS, issue a final determination to revise the listing status of the humpback whale (Megaptera novaeangliae) under the Endangered Species Act (ESA). We divide the globally listed endangered species into 14 distinct population segments (DPS), remove the current species-level listing, and in its place list four DPSs as endangered and one DPS as threatened. Based on their current statuses, the remaining nine DPSs do not warrant listing. At this time, we find that critical habitat is not determinable for the three listed DPSs that occur in U.S. waters (Western North Pacific, Mexico, Central America); we will consider designating critical habitat for these three DPSs in a separate rulemaking. }, keywords = {Arabian Sea, breeding grounds, conservation status, feeding grounds, Humpback Whale, marine mammal, megaptera novaeangliae, population status, USA}, pubstate = {published}, tppubtype = {} } We, NMFS, issue a final determination to revise the listing status of the humpback whale (Megaptera novaeangliae) under the Endangered Species Act (ESA). We divide the globally listed endangered species into 14 distinct population segments (DPS), remove the current species-level listing, and in its place list four DPSs as endangered and one DPS as threatened. Based on their current statuses, the remaining nine DPSs do not warrant listing. At this time, we find that critical habitat is not determinable for the three listed DPSs that occur in U.S. waters (Western North Pacific, Mexico, Central America); we will consider designating critical habitat for these three DPSs in a separate rulemaking. |
Ministry of Agriculture; Fisheries Ministerial Decree 4/94: Marine Fishing and Living-Aquatic-Resources Protection law 1994. Abstract | BibTeX | Keywords: fishing gear, mammals, marine, marine mammal, Marine mammals, regulations, turtles @{, title = {Ministerial Decree 4/94: Marine Fishing and Living-Aquatic-Resources Protection law}, author = {Ministry of Agriculture and Fisheries}, year = {1994}, date = {1994-01-01}, volume = {4/94}, number = {371}, abstract = {Ministerial Decision 4/94, issued by the Ministry of Agriculture and Fisheries, updates Royal Decree No. 53/81, the Marine Fishing and Living Aquatic Resources Protection Law. In addition to prohibiting the hunting of marine mammals (see above) this legislation contains articles pertaining to the licensing of fishermen, fishing vessels, restrictions on certain types of fishing gear and seasonal closures for certain species of fish. A few pertinent articles include:ù A prohibition on capturing any marine resources during their reproductive season (resulting in seasonal closers for lobster and abalone fisheries, and a justification for other seasonal closures on pelagic or demersal species pending research results);ù A prohibition on the use of string nets, monofilament gill nets or the setting of nets at high tide on beaches or lagoons to trap fish on outgoing tides;ù A prohibition on foreign fishing vessels in Omani waters operating without official permit from the MAF;ù A prohibition on the use of foreign/expatriate workers on fishing vessels licensed to conduct artisanal/traditional fishing;ù A prohibition for fishermen to 1) sail into areas allocated to other fishermen with the intent to fish; or 2) to place fishing gear in areas not specifically allocated to them by licence;ù The right of the MAF to require fishermen and dealers to collect and provide any data requested or required by the MAF;ù The right of the MAF to prohibit fishing of certain species, or fishing in certain regions or seasons.}, keywords = {fishing gear, mammals, marine, marine mammal, Marine mammals, regulations, turtles}, pubstate = {published}, tppubtype = {} } Ministerial Decision 4/94, issued by the Ministry of Agriculture and Fisheries, updates Royal Decree No. 53/81, the Marine Fishing and Living Aquatic Resources Protection Law. In addition to prohibiting the hunting of marine mammals (see above) this legislation contains articles pertaining to the licensing of fishermen, fishing vessels, restrictions on certain types of fishing gear and seasonal closures for certain species of fish. A few pertinent articles include:ù A prohibition on capturing any marine resources during their reproductive season (resulting in seasonal closers for lobster and abalone fisheries, and a justification for other seasonal closures on pelagic or demersal species pending research results);ù A prohibition on the use of string nets, monofilament gill nets or the setting of nets at high tide on beaches or lagoons to trap fish on outgoing tides;ù A prohibition on foreign fishing vessels in Omani waters operating without official permit from the MAF;ù A prohibition on the use of foreign/expatriate workers on fishing vessels licensed to conduct artisanal/traditional fishing;ù A prohibition for fishermen to 1) sail into areas allocated to other fishermen with the intent to fish; or 2) to place fishing gear in areas not specifically allocated to them by licence;ù The right of the MAF to require fishermen and dealers to collect and provide any data requested or required by the MAF;ù The right of the MAF to prohibit fishing of certain species, or fishing in certain regions or seasons. |
Environment Society of Oman Oman Cetacean Database 2019. BibTeX | Keywords: data analysis, Distribution, diversity, Oman @{, title = {Oman Cetacean Database}, author = {Environment Society of Oman}, year = {2019}, date = {2019-01-01}, number = {422}, keywords = {data analysis, Distribution, diversity, Oman}, pubstate = {published}, tppubtype = {} } |
Vaidya, S. Oman launches high-speed ferry 2008. Abstract | BibTeX | Keywords: high speed ferry, Oman, Threats, vessel collision, vessel traffic @{, title = {Oman launches high-speed ferry}, author = {Vaidya, S.}, year = {2008}, date = {2008-01-01}, journal = {Gulf News}, number = {488}, pages = {http://gulfnews.com/news/gulf/oman/oman-}, abstract = {Muscat: Oman on Saturday unveiled the world's fastest diesel-powered passenger ferry that would link capital Muscat with Khasab in Musandam Peninsula from Wednesday. "The high-speed ferries have been introduced on this route basically to promote remote areas, providing services and easing movement of equipment without going through borders," Mehdi Al Abduwani, Chairman of the National Ferry Company (NFC), told media on board 65-metre-long catamaran - Shinas - on Saturday during its soft launch. He also revealed that NFC would overall run five such ferries. "There would be two ferries in the north (linking Khasab with Muscat), two in the South (linking Halniyat Island with Salalah) and the third ferry would link Masirah Island with Shannah in the east. Khimji Ramdas Shipping Division have been given the rights to market the services. Al Abduwani stressed that the ferry service would be made available to all categories of passengers, including Omani citizens, expatriate residents as well as tourists. He said the ferries to Khasab would be operated from Shinas, which is located 250 km north of Muscat, from mid-2009. "The jetty at Shinas is not yet ready but once it is ready to take the ferries, it would be operated daily between Shinas and Khasab," Al Abduwani informed. "It would be then discontinued from Muscat," he added. "For the time being the ferries - Shinas and Hormuz - would be operated between Port Qaboos in Muscat and Khasab Port," he added. The Australian-make catamaran, Shinas, launched yesterday would be joined by another vessel Hormuz. "Hormuz is slightly faster than Shinas and is expected to come here in the first week of September," he revealed. Facilities According to him Shinas has clocked a top cruise speed of 51 knots (100km/h) while Hormuz clocked world-record 56 knots during a practice run in Australia recently. "The ferry service, he pointed out, would encourage tourist travel to remote picturesque areas of the Musandam peninsula," he said. Passengers on board these ferries will be able to travel in comfort across two classes - Tourist Class and First Class. "There's a small VIP class with eight seats only," he added. High quality seating and catering facilities on board these ferries are all located on a single deck while a helicopter landing pad on the bridge deck can accommodate a medium-class helicopter. The vessels are built at an estimated cost of $70 million by Australia-based Austal, who are the world's largest builder of fast ferries. Features: No UAE visa needed The Musandam region, due to its geographical position and mountainous terrain, is isolated from the rest of Oman and separated by the UAE. Thus, every resident has to travel through the UAE to come to Muscat or any other part of the Sultanate by road. Each time an expatriate, travelling from Khasab to any other part of Oman, has to procure a UAE visa to cross from their territories and this has proved to be very cumbersome. The ferry eliminates this need. The road travel from Muscat to Khasab is over seven hours, including time spent at the border check points. The ferry between Muscat and Khasab would take around six hours. The ferry, which is the fastest diesel-operated vessel in the world, will operate twice a week between Muscat and Khasab. Each ferry can accommodate 208 passengers and 56 cars.}, keywords = {high speed ferry, Oman, Threats, vessel collision, vessel traffic}, pubstate = {published}, tppubtype = {} } Muscat: Oman on Saturday unveiled the world's fastest diesel-powered passenger ferry that would link capital Muscat with Khasab in Musandam Peninsula from Wednesday. "The high-speed ferries have been introduced on this route basically to promote remote areas, providing services and easing movement of equipment without going through borders," Mehdi Al Abduwani, Chairman of the National Ferry Company (NFC), told media on board 65-metre-long catamaran - Shinas - on Saturday during its soft launch. He also revealed that NFC would overall run five such ferries. "There would be two ferries in the north (linking Khasab with Muscat), two in the South (linking Halniyat Island with Salalah) and the third ferry would link Masirah Island with Shannah in the east. Khimji Ramdas Shipping Division have been given the rights to market the services. Al Abduwani stressed that the ferry service would be made available to all categories of passengers, including Omani citizens, expatriate residents as well as tourists. He said the ferries to Khasab would be operated from Shinas, which is located 250 km north of Muscat, from mid-2009. "The jetty at Shinas is not yet ready but once it is ready to take the ferries, it would be operated daily between Shinas and Khasab," Al Abduwani informed. "It would be then discontinued from Muscat," he added. "For the time being the ferries - Shinas and Hormuz - would be operated between Port Qaboos in Muscat and Khasab Port," he added. The Australian-make catamaran, Shinas, launched yesterday would be joined by another vessel Hormuz. "Hormuz is slightly faster than Shinas and is expected to come here in the first week of September," he revealed. Facilities According to him Shinas has clocked a top cruise speed of 51 knots (100km/h) while Hormuz clocked world-record 56 knots during a practice run in Australia recently. "The ferry service, he pointed out, would encourage tourist travel to remote picturesque areas of the Musandam peninsula," he said. Passengers on board these ferries will be able to travel in comfort across two classes - Tourist Class and First Class. "There's a small VIP class with eight seats only," he added. High quality seating and catering facilities on board these ferries are all located on a single deck while a helicopter landing pad on the bridge deck can accommodate a medium-class helicopter. The vessels are built at an estimated cost of $70 million by Australia-based Austal, who are the world's largest builder of fast ferries. Features: No UAE visa needed The Musandam region, due to its geographical position and mountainous terrain, is isolated from the rest of Oman and separated by the UAE. Thus, every resident has to travel through the UAE to come to Muscat or any other part of the Sultanate by road. Each time an expatriate, travelling from Khasab to any other part of Oman, has to procure a UAE visa to cross from their territories and this has proved to be very cumbersome. The ferry eliminates this need. The road travel from Muscat to Khasab is over seven hours, including time spent at the border check points. The ferry between Muscat and Khasab would take around six hours. The ferry, which is the fastest diesel-operated vessel in the world, will operate twice a week between Muscat and Khasab. Each ferry can accommodate 208 passengers and 56 cars. |
HM Sultan Qaboos Bin Said Royal Decree 6/2003: Issuing the Law of Natural Protected Areas (NPAs) and Conservation of Wildlife 2003. Abstract | BibTeX | Keywords: conservation, protected areas @{, title = {Royal Decree 6/2003: Issuing the Law of Natural Protected Areas (NPAs) and Conservation of Wildlife}, author = {HM Sultan Qaboos Bin Said}, year = {2003}, date = {2003-01-01}, volume = {6/2003}, number = {217}, abstract = {Royal Decree 6/2003, Issuing the law of Natural Protected Areas and Conservation of Wildlife, specifies that it is illegal to hunt, confine, breed or transfer any protected animal or its products in, or to collect samples from or possess any wildlife or its products inside or outside protected areas. The decree contains a listing of "Appendix 1" and "Appendix 2" protected species, which include Arabian Oryx, Arabian Leopard, and all four species of sea turtle, among other species. Proposals to include a number of cetacean species on these lists were rejected for unknown reasons.}, keywords = {conservation, protected areas}, pubstate = {published}, tppubtype = {} } Royal Decree 6/2003, Issuing the law of Natural Protected Areas and Conservation of Wildlife, specifies that it is illegal to hunt, confine, breed or transfer any protected animal or its products in, or to collect samples from or possess any wildlife or its products inside or outside protected areas. The decree contains a listing of "Appendix 1" and "Appendix 2" protected species, which include Arabian Oryx, Arabian Leopard, and all four species of sea turtle, among other species. Proposals to include a number of cetacean species on these lists were rejected for unknown reasons. |
Latasa, Mikel.,Bidigare, Robert. R. A comparison of phytoplankton populations of the Arabian Sea during the Spring Intermonsoon and Southwest Monsoon of 1995 as described by HPLC-analyzed pigments Journal Article Deep-Sea Research II, 45 (141), pp. 2133-2170, 1998. BibTeX | Keywords: Arabia, Arabian Sea, Iran, Pakistan, Phytoplankton, Upwelling @article{, title = {A comparison of phytoplankton populations of the Arabian Sea during the Spring Intermonsoon and Southwest Monsoon of 1995 as described by HPLC-analyzed pigments}, author = {Latasa, Mikel.,Bidigare, Robert. R.}, year = {1998}, date = {1998-01-01}, journal = {Deep-Sea Research II}, volume = {45}, number = {141}, pages = {2133-2170}, keywords = {Arabia, Arabian Sea, Iran, Pakistan, Phytoplankton, Upwelling}, pubstate = {published}, tppubtype = {article} } |
Baldwin, Robert.,Barwani, M. A Leviathan Rescue Journal Article Arabian Wildlife, 2 (304), pp. 2, 2001. BibTeX | Keywords: Entanglement, Humpback Whale, Oman, Popular Article @article{, title = {A Leviathan Rescue}, author = {Baldwin, Robert.,Barwani, M.}, year = {2001}, date = {2001-01-01}, journal = {Arabian Wildlife}, volume = {2}, number = {304}, pages = {2}, keywords = {Entanglement, Humpback Whale, Oman, Popular Article}, pubstate = {published}, tppubtype = {article} } |
Afsal, V.V.,Yousuf, K.M.M.,Anoop, B.,Anoop, A. K.,Kannan, P.,Rajagopalan, M.,Vivekanandan, E. A note on cetacean distribution in the Indian EEZ and contiguous seas during 2003-07 Journal Article Journal of Cetacean Research and Management, 10 (2), pp. 209-215, 2008. BibTeX | Keywords: Arabian Sea, Bay of Bengal, Distribution, India, Indian Ocean @article{, title = {A note on cetacean distribution in the Indian EEZ and contiguous seas during 2003-07}, author = {Afsal, V.V.,Yousuf, K.M.M.,Anoop, B.,Anoop, A. K.,Kannan, P.,Rajagopalan, M.,Vivekanandan, E.}, year = {2008}, date = {2008-01-01}, journal = {Journal of Cetacean Research and Management}, volume = {10}, number = {2}, pages = {209-215}, keywords = {Arabian Sea, Bay of Bengal, Distribution, India, Indian Ocean}, pubstate = {published}, tppubtype = {article} } |
Baldwin, Robert. A note on sightings of sperm whales off the coasts of the Sultanate of Oman and the United Arab Emirates, October 1994 to October 1997 Journal Article International Whaling Commission Scientific Committee Document SC/50/CAWS22. Cambridge, UK., (301), 1998. BibTeX | Keywords: Arabian Gulf, Arabian Sea, Oman, Persian Gulf, sperm whales, UAE @article{, title = {A note on sightings of sperm whales off the coasts of the Sultanate of Oman and the United Arab Emirates, October 1994 to October 1997}, author = {Baldwin, Robert.}, year = {1998}, date = {1998-01-01}, journal = {International Whaling Commission Scientific Committee Document SC/50/CAWS22. Cambridge, UK.}, number = {301}, keywords = {Arabian Gulf, Arabian Sea, Oman, Persian Gulf, sperm whales, UAE}, pubstate = {published}, tppubtype = {article} } |
Minton,G.,Cherchio, S.,Collins,T.J.Q.,Ersts, P.J.,Findlay,K.P.,Pomilla, C.,Bennett, D.,Meyer, M.,Razafindrakoto, Y.,Kotze, D.,Oosthuizen, H.,Leslie, M.,Andrianarivelo, N.,Baldwin,R.M.,Ponnampalam, L.,Rosenbaum, H.C. A note on the comparison of humpback whale tail fluke catalogues from the Sultanate of Oman with Madagascar and the East African Mainland Journal Article Journal of Cetacean Research and Management, 11 (408), pp. 65-68, 2010. Abstract | BibTeX | Keywords: Arabian Sea, Humpback Whale, humpback whales, Indian Ocean, Madagascar, megaptera novaeangliae, Mozambique, Northern Hemisphere, Oman, photo-ID, population identity, South Africa @article{, title = {A note on the comparison of humpback whale tail fluke catalogues from the Sultanate of Oman with Madagascar and the East African Mainland}, author = {Minton,G.,Cherchio, S.,Collins,T.J.Q.,Ersts, P.J.,Findlay,K.P.,Pomilla, C.,Bennett, D.,Meyer, M.,Razafindrakoto, Y.,Kotze, D.,Oosthuizen, H.,Leslie, M.,Andrianarivelo, N.,Baldwin,R.M.,Ponnampalam, L.,Rosenbaum, H.C.}, year = {2010}, date = {2010-01-01}, journal = {Journal of Cetacean Research and Management}, volume = {11}, number = {408}, pages = {65-68}, abstract = {The photo-identification catalogue of humpback whale tail flukes from Oman was compared with those from Antongil Bay, Madagascar and study sites in South Africa and Mozambique collectively termed the ‘East African Mainland’. No matches were found, supporting other lines of evidence that the humpback whales studied off the coast of Oman form part of a discrete Arabian Sea population, which adheres to a Northern Hemisphere breeding cycle, and has little or no ongoing exchange with the nearest neighbouring populations in the southern Indian Ocean.While the sample size from Oman is small, and low levels of ongoing exchange might not be detected in this type of catalogue comparison, the study nonetheless emphasises the need to pursue research and conservation efforts in the known and suspected range of the Endangered Arabian Sea humpback whale population.}, keywords = {Arabian Sea, Humpback Whale, humpback whales, Indian Ocean, Madagascar, megaptera novaeangliae, Mozambique, Northern Hemisphere, Oman, photo-ID, population identity, South Africa}, pubstate = {published}, tppubtype = {article} } The photo-identification catalogue of humpback whale tail flukes from Oman was compared with those from Antongil Bay, Madagascar and study sites in South Africa and Mozambique collectively termed the ‘East African Mainland’. No matches were found, supporting other lines of evidence that the humpback whales studied off the coast of Oman form part of a discrete Arabian Sea population, which adheres to a Northern Hemisphere breeding cycle, and has little or no ongoing exchange with the nearest neighbouring populations in the southern Indian Ocean.While the sample size from Oman is small, and low levels of ongoing exchange might not be detected in this type of catalogue comparison, the study nonetheless emphasises the need to pursue research and conservation efforts in the known and suspected range of the Endangered Arabian Sea humpback whale population. |
Collins, T.,Minton, G.,Baldwin, R.,Van Waerebeek, K.,Hywel-Davies, A.,Cockcroft, V. A preliminary assessment of the frequency, distribution and causes of moratlity of beach cast cetaceans in the Sultanate of Oman, January 1999 to February 2002 Journal Article Document presented to the 54th meeting of the International Whaling Commission. SC/54/O4, (350), pp. 1 - 13, 2002. @article{, title = {A preliminary assessment of the frequency, distribution and causes of moratlity of beach cast cetaceans in the Sultanate of Oman, January 1999 to February 2002}, author = {Collins, T.,Minton, G.,Baldwin, R.,Van Waerebeek, K.,Hywel-Davies, A.,Cockcroft, V.}, year = {2002}, date = {2002-01-01}, journal = {Document presented to the 54th meeting of the International Whaling Commission. SC/54/O4}, number = {350}, pages = {1 - 13}, abstract = {Data are presented on beach cast cetaceans recorded in central and southern Oman between January 1999 and February 2000 during systematic beach surveys. Crude encounters rates of cetacean specimens are comparable with previous published data and indicate relatively high levels of mortality of Tursiops sp. and Sousa plumbea. Over two-thirds of specimens are recorded as stranding state V with cause of mortality unknown. Of the remaining specimens, empirical and circumstantial evidence for cause of death is suggestive of interactions with fisheries activities in the majority of cases. Direct evidence of interactions between cetaceans and fisheries, including information on incidental catch, is also presented. Other possible causes of mortality are hypothesised. Two mass strandings of small cetaceans are also discussed. Given the high numbers (725 records) and diversity (18 spp.) of beach cast cetaceans recorded in Oman, and the value of specimens to scientific study and conservation and fisheries management, recommendations are made to expand the scope of research and application of data.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Data are presented on beach cast cetaceans recorded in central and southern Oman between January 1999 and February 2000 during systematic beach surveys. Crude encounters rates of cetacean specimens are comparable with previous published data and indicate relatively high levels of mortality of Tursiops sp. and Sousa plumbea. Over two-thirds of specimens are recorded as stranding state V with cause of mortality unknown. Of the remaining specimens, empirical and circumstantial evidence for cause of death is suggestive of interactions with fisheries activities in the majority of cases. Direct evidence of interactions between cetaceans and fisheries, including information on incidental catch, is also presented. Other possible causes of mortality are hypothesised. Two mass strandings of small cetaceans are also discussed. Given the high numbers (725 records) and diversity (18 spp.) of beach cast cetaceans recorded in Oman, and the value of specimens to scientific study and conservation and fisheries management, recommendations are made to expand the scope of research and application of data. |
Wilson-Diaz,D.,Mariano,A.J.,Evans,R.H.,Luther,M.E. A principal component analysis of sea-surface temperature in the Arabian Sea Journal Article Deep-Sea Research Part II, 48 (263), pp. 1097-1114, 2001. Abstract | BibTeX | Keywords: Arabian Sea, Indian monsoon, Indian Ocean, temperature, Upwelling @article{, title = {A principal component analysis of sea-surface temperature in the Arabian Sea}, author = {Wilson-Diaz,D.,Mariano,A.J.,Evans,R.H.,Luther,M.E.}, year = {2001}, date = {2001-01-01}, journal = {Deep-Sea Research Part II}, volume = {48 }, number = {263}, pages = {1097-1114}, abstract = {Spatial and temporal variability in sea-surface temperature (SST) is analyzed by the method of principal component analysis (PCA). Variability of satellite-derived SST from the NOAA/NASA Advanced Very High Resolution Radiometer (AVHRR) Pathfinder data over the Arabian Sea is compared to the PCA of the mixed-layer temperature fields from two different Indian Ocean models. Climatological model output is compared to Pathfinder's "averaged" year using data from 1987 to 1990. A 5-year analysis with data and model output (from 1985 to 1989) is also done. The first mode in all the studies accounts for 58.2-95.8% of the SST variability, and is identified with the seasonal warming and cooling associated with the Indian Monsoon. The second mode accounts for 20.6-31.1% and corresponds to the radiative heating of the basin. Time series of the basin's mean SST shows that the models lag Pathfinder SST by approximately one month. The climatological models fail to reproduce the SST variability, in both space and time, of the Arabian Sea. The Luther-Ji model, forced by interannual monthly winds, does much better. The main discrepancies are likely due to the models' forcing fields underestimating the strength of the monsoon, and the vertical thermal structure not being adequate to represent the real ocean, especially in upwelling areas.}, keywords = {Arabian Sea, Indian monsoon, Indian Ocean, temperature, Upwelling}, pubstate = {published}, tppubtype = {article} } Spatial and temporal variability in sea-surface temperature (SST) is analyzed by the method of principal component analysis (PCA). Variability of satellite-derived SST from the NOAA/NASA Advanced Very High Resolution Radiometer (AVHRR) Pathfinder data over the Arabian Sea is compared to the PCA of the mixed-layer temperature fields from two different Indian Ocean models. Climatological model output is compared to Pathfinder's "averaged" year using data from 1987 to 1990. A 5-year analysis with data and model output (from 1985 to 1989) is also done. The first mode in all the studies accounts for 58.2-95.8% of the SST variability, and is identified with the seasonal warming and cooling associated with the Indian Monsoon. The second mode accounts for 20.6-31.1% and corresponds to the radiative heating of the basin. Time series of the basin's mean SST shows that the models lag Pathfinder SST by approximately one month. The climatological models fail to reproduce the SST variability, in both space and time, of the Arabian Sea. The Luther-Ji model, forced by interannual monthly winds, does much better. The main discrepancies are likely due to the models' forcing fields underestimating the strength of the monsoon, and the vertical thermal structure not being adequate to represent the real ocean, especially in upwelling areas. |
Braulik, G.,Savadkouhi, O.S.,Fadakar, S.,Mohammadi, H.,Brownell Jr, R.L.,Reeves, R. R.,Nabavi, M.B.,Fernandez, A. A retropsective investigation of two dolphin mass mortality events in Iran, autumn 2007 Journal Article Zoology in the Middle East, 49 (335), pp. 13-26, 2010. Abstract | BibTeX | Keywords: Arabian Gulf, cetaceans, Gulf of Oman, Iran, mass mortality, Spinner dolphin, Stenella longirostris, stranding @article{, title = {A retropsective investigation of two dolphin mass mortality events in Iran, autumn 2007}, author = {Braulik, G.,Savadkouhi, O.S.,Fadakar, S.,Mohammadi, H.,Brownell Jr, R.L.,Reeves, R. R.,Nabavi, M.B.,Fernandez, A.}, year = {2010}, date = {2010-01-01}, journal = {Zoology in the Middle East}, volume = {49}, number = {335}, pages = {13-26}, abstract = {During the autumn of 2007, two mass mortality events involving at least 152 small cetaceans were reported from southern Iran. Both events occurred on the Gulf of Oman coast near the town of Bandar Jask, and were separated by a month in time and more than 170 km in distance. The first event, on 20 September 2007, involved 79 animals, probably all spinner dolphins (Stenella longirostris). Dead animals, all exhibiting a similar degree of decomposition, drifted to shore along 13 km of coastline over a period of approximately 24 hours. These circumstances suggest that the mortality was caused by a single acute event at sea. Several carcasses had evidence of traumatic injuries, the stranding event was spatially and temporally coincident with an active fishing ground, and other potentially bycaught and discarded species were found on the beach. This pattern is generally consistent with the hypothesis that the dolphin mortality was caused by fishing operations, although the available data are insufficient to confirm that hypothesis unequivocally. On 24 October 2007 there was a mass stranding of 73 live striped dolphins (Stenella coeruleoalba). The striped dolphin is a pelagic species believed to be rare in the Gulf of Oman. The most likely explanation for this mass stranding is that the dolphin group was trapped by a falling tide among the complex sandbanks of the Kangan estuary. Striped dolphins are not normally found in shallow water or near shore, and their occurrence in this area is considered unusual. The factor or factors that caused them to enter this atypical habitat remain unknown. The two mass mortality events involved different species and exhibited many different characteristics; there is no evidence to suggest that they were linked. As the cetacean fauna of Iran is little known, it is hoped that the great national and international interest generated by these events will enhance Iran’s capacity and motivation for research and conservation of marine mammals.}, keywords = {Arabian Gulf, cetaceans, Gulf of Oman, Iran, mass mortality, Spinner dolphin, Stenella longirostris, stranding}, pubstate = {published}, tppubtype = {article} } During the autumn of 2007, two mass mortality events involving at least 152 small cetaceans were reported from southern Iran. Both events occurred on the Gulf of Oman coast near the town of Bandar Jask, and were separated by a month in time and more than 170 km in distance. The first event, on 20 September 2007, involved 79 animals, probably all spinner dolphins (Stenella longirostris). Dead animals, all exhibiting a similar degree of decomposition, drifted to shore along 13 km of coastline over a period of approximately 24 hours. These circumstances suggest that the mortality was caused by a single acute event at sea. Several carcasses had evidence of traumatic injuries, the stranding event was spatially and temporally coincident with an active fishing ground, and other potentially bycaught and discarded species were found on the beach. This pattern is generally consistent with the hypothesis that the dolphin mortality was caused by fishing operations, although the available data are insufficient to confirm that hypothesis unequivocally. On 24 October 2007 there was a mass stranding of 73 live striped dolphins (Stenella coeruleoalba). The striped dolphin is a pelagic species believed to be rare in the Gulf of Oman. The most likely explanation for this mass stranding is that the dolphin group was trapped by a falling tide among the complex sandbanks of the Kangan estuary. Striped dolphins are not normally found in shallow water or near shore, and their occurrence in this area is considered unusual. The factor or factors that caused them to enter this atypical habitat remain unknown. The two mass mortality events involved different species and exhibited many different characteristics; there is no evidence to suggest that they were linked. As the cetacean fauna of Iran is little known, it is hoped that the great national and international interest generated by these events will enhance Iran’s capacity and motivation for research and conservation of marine mammals. |
Savidge,G.,Lennon,J.,Matthews,A.J. A shore-based survey of upwelling along the coast of Dhofar region, southern Oman Journal Article Continental Shelf Research, 10 (471), pp. 259-275, 1990. Abstract | BibTeX | Keywords: bathymetry, chlorophyll, Oman, salinity, survey, temperature, Upwelling @article{, title = {A shore-based survey of upwelling along the coast of Dhofar region, southern Oman}, author = {Savidge,G.,Lennon,J.,Matthews,A.J.}, year = {1990}, date = {1990-01-01}, journal = {Continental Shelf Research}, volume = {10}, number = {471}, pages = {259-275}, abstract = {A shore-based survey of hydrographic variables along the southern Oman coast between 16ø55'N, 53ø55'E and 170Z3'N, 55ø17.5'E was carried out between August and November 1985 during the southwest monsoon season and the succeeding period marked by the onset of the northeast winds. During the monsoon season strong evidence of upwelling based on temperature and nutrient data was apparent for the eastern half of the survey area which was distinguished by severe coastal relief and a steeply shelving bathymetry. The upwelled water appeared to be advected westwards into the shallower waters of Salalah Bay which comprised the western part of the survey area. Maximum stratification as inferred from increased temperatures and decreased nutrient concentrations was recorded at the western end of Salalah Bay. Marked increases in chlorophyll a were apparent within the Bay at the boundary between the stratified and upwelled water but concentrations were low within the main bodies of the two water types. The upwelling process was discontinuous in time but the intensity of the upwelling was not apparently related to variation in wind strength; only minimal variations in the velocity of the prevailing southwest wind were recorded during the major part of the survey period. Regular diurnal changes of variable amplitude were observed for all properties sampled with the exception of salinity.}, keywords = {bathymetry, chlorophyll, Oman, salinity, survey, temperature, Upwelling}, pubstate = {published}, tppubtype = {article} } A shore-based survey of hydrographic variables along the southern Oman coast between 16ø55'N, 53ø55'E and 170Z3'N, 55ø17.5'E was carried out between August and November 1985 during the southwest monsoon season and the succeeding period marked by the onset of the northeast winds. During the monsoon season strong evidence of upwelling based on temperature and nutrient data was apparent for the eastern half of the survey area which was distinguished by severe coastal relief and a steeply shelving bathymetry. The upwelled water appeared to be advected westwards into the shallower waters of Salalah Bay which comprised the western part of the survey area. Maximum stratification as inferred from increased temperatures and decreased nutrient concentrations was recorded at the western end of Salalah Bay. Marked increases in chlorophyll a were apparent within the Bay at the boundary between the stratified and upwelled water but concentrations were low within the main bodies of the two water types. The upwelling process was discontinuous in time but the intensity of the upwelling was not apparently related to variation in wind strength; only minimal variations in the velocity of the prevailing southwest wind were recorded during the major part of the survey period. Regular diurnal changes of variable amplitude were observed for all properties sampled with the exception of salinity. |
Brock,J.C.,McClain,C.R.,Hay,W.W. A southwest monsoon hydrographic climatology for the northwestern Arabian Sea Journal Article Journal of Geophysical Research, 97 (337), pp. 9455-9465, 1992. Abstract | BibTeX | Keywords: Antarctic, Arabian Sea, depth, oceanography, Oman, salinity, temperature, thermocline, Upwelling @article{, title = {A southwest monsoon hydrographic climatology for the northwestern Arabian Sea}, author = {Brock,J.C.,McClain,C.R.,Hay,W.W.}, year = {1992}, date = {1992-01-01}, journal = {Journal of Geophysical Research}, volume = {97}, number = {337}, pages = {9455-9465}, abstract = {This paper provides a detailed hydrographic climatology for the shallow northwestern Arabian Sea prior to and during the southwest monsoon, presented as multiple-year composite vertical hydrographic sections based on National Oceanographic Data Center historical ocean station data, Temperature and salinity measurements are used to infer the water masses present in the upper 500 m. The hydrographic evolution depicted on bimonthly sections is inferred to result from wind-driven physical processes. In the northwestern Arabian Sea the water mass in the upper 50 m is the Arabian Sea Surface Water. Waters from 50 to 500 m are formed by mixing of Arabian Sea Surface Water with Antarctic and Indonesian intermediate waters. The inflow of Persian Gulf Water does not significantly influence the hydrography of the northwestern Arabian Sea along the Omani coast. Nitrate has a high inverse correlation with temperature and oxygen in the premonsoon thermocline in the depth interval 5(}-150 m. During the southwest monsoon coastal upwelling off Oman and adjacent offshore upward Ekman pumping alter the shallow hydrography.}, keywords = {Antarctic, Arabian Sea, depth, oceanography, Oman, salinity, temperature, thermocline, Upwelling}, pubstate = {published}, tppubtype = {article} } This paper provides a detailed hydrographic climatology for the shallow northwestern Arabian Sea prior to and during the southwest monsoon, presented as multiple-year composite vertical hydrographic sections based on National Oceanographic Data Center historical ocean station data, Temperature and salinity measurements are used to infer the water masses present in the upper 500 m. The hydrographic evolution depicted on bimonthly sections is inferred to result from wind-driven physical processes. In the northwestern Arabian Sea the water mass in the upper 50 m is the Arabian Sea Surface Water. Waters from 50 to 500 m are formed by mixing of Arabian Sea Surface Water with Antarctic and Indonesian intermediate waters. The inflow of Persian Gulf Water does not significantly influence the hydrography of the northwestern Arabian Sea along the Omani coast. Nitrate has a high inverse correlation with temperature and oxygen in the premonsoon thermocline in the depth interval 5(}-150 m. During the southwest monsoon coastal upwelling off Oman and adjacent offshore upward Ekman pumping alter the shallow hydrography. |
Aneesh Kumar, K. V.,Baby, Sibi T.,Dhaneesh, K. V.,Manjebrayakath, Hashim,Saravanane, N.,Sudhakar, M. A Stranding Record of Dwarf Sperm Whale Kogia sima in Lakshadweep Archipelago, India and its Genetic Analogy by Molecular Phylogeny Journal Article Thalassas: An International Journal of Marine Sciences, 35 (13), pp. 239-245, 2019, ISBN: 2366-1674. Abstract | Links | BibTeX | Keywords: Arabian Sea, India, Indian Ocean, kogia, kogia simus, stranding @article{, title = {A Stranding Record of Dwarf Sperm Whale Kogia sima in Lakshadweep Archipelago, India and its Genetic Analogy by Molecular Phylogeny}, author = {Aneesh Kumar, K. V.,Baby, Sibi T.,Dhaneesh, K. V.,Manjebrayakath, Hashim,Saravanane, N.,Sudhakar, M.}, url = {https://doi.org/10.1007/s41208-018-0115-9}, issn = {2366-1674}, year = {2019}, date = {2019-01-01}, journal = {Thalassas: An International Journal of Marine Sciences}, volume = {35}, number = {13}, pages = {239-245}, abstract = {The distribution of Kogiid whales from the Indian Ocean waters, especially Indian waters are poorly known. It is extremely difficult to differentiate the two species (Kogia sima and K. breviceps) based on their morphological characteristics alone. Our study presents the first confirmed record of dwarf sperm whale Kogia sima from the Indian waters using morphological examinations, skull morphology and molecular identification. The study is based on the stranded animal found in the west coast of Agatti Island in Lakshadweep Archipelago belongs to the Indian EEZ. K. sima showed intra-species genetic variability which confirms the isolation of the species in oceans as the tropical nature of the species restricts its movement.}, keywords = {Arabian Sea, India, Indian Ocean, kogia, kogia simus, stranding}, pubstate = {published}, tppubtype = {article} } The distribution of Kogiid whales from the Indian Ocean waters, especially Indian waters are poorly known. It is extremely difficult to differentiate the two species (Kogia sima and K. breviceps) based on their morphological characteristics alone. Our study presents the first confirmed record of dwarf sperm whale Kogia sima from the Indian waters using morphological examinations, skull morphology and molecular identification. The study is based on the stranded animal found in the west coast of Agatti Island in Lakshadweep Archipelago belongs to the Indian EEZ. K. sima showed intra-species genetic variability which confirms the isolation of the species in oceans as the tropical nature of the species restricts its movement. |
Clapham, P.J.,Ivashcenko, Y.V. A whale of a deception Journal Article Marine Fisheries Review, 71 (347), pp. 44-52, 2009. Abstract | BibTeX | Keywords: Humpback Whale, IWC, Soviet whaling @article{, title = {A whale of a deception}, author = {Clapham, P.J.,Ivashcenko, Y.V.}, year = {2009}, date = {2009-01-01}, journal = {Marine Fisheries Review}, volume = {71}, number = {347}, pages = {44-52}, abstract = {A whaling fleet engaged in the practice of whaling is hardly cause for comment. What made these catches unusual, however, was that almost all of them were illegal. Over the next two weeks, the vessels of the Soviet fleet swept the northwestern Indian Ocean. Their search for whales took them from Oman to the Gulf of Kutch off Pakistan, through offshore waters west of the Indian city of Bombay, and south to the Maldive Islands. By the time Sovetskaya Ukraina finally resumed her course for the Antarctic on November 21st, her catcher boats had delivered more than three hundred whales to the huge floating factory for processing. Most of the animals had been either humpbacks, Megaptera novaeangliae, or blue whales, Balaenoptera musculus, two species that were officially considered “protected” under the international regulations that governed commercial whaling. When the Soviet fleet reached the Antarctic, the pattern was repeated. Already-depleted and supposedly protected stocks of whales were plundered for several months until the onset of the austral winter. Finally, as the weather turned increasingly foul, the factory ship and her catchers began the long journey home.}, keywords = {Humpback Whale, IWC, Soviet whaling}, pubstate = {published}, tppubtype = {article} } A whaling fleet engaged in the practice of whaling is hardly cause for comment. What made these catches unusual, however, was that almost all of them were illegal. Over the next two weeks, the vessels of the Soviet fleet swept the northwestern Indian Ocean. Their search for whales took them from Oman to the Gulf of Kutch off Pakistan, through offshore waters west of the Indian city of Bombay, and south to the Maldive Islands. By the time Sovetskaya Ukraina finally resumed her course for the Antarctic on November 21st, her catcher boats had delivered more than three hundred whales to the huge floating factory for processing. Most of the animals had been either humpbacks, Megaptera novaeangliae, or blue whales, Balaenoptera musculus, two species that were officially considered “protected” under the international regulations that governed commercial whaling. When the Soviet fleet reached the Antarctic, the pattern was repeated. Already-depleted and supposedly protected stocks of whales were plundered for several months until the onset of the austral winter. Finally, as the weather turned increasingly foul, the factory ship and her catchers began the long journey home. |
Dennett,M.R.,Caron,D.A.,Murzov,S.A.,Polikarpov,I.G.,Gavrilova,N.A.,Georgieva,L.V.,Kuzmenko,L.V. Abundance and biomass of nano- and microplankton during the 1995 Northeast Monsoon and Spring Intermonsoon in the Arabian Sea Journal Article Deep-Sea Research Part II, 46 (87), pp. 1691-1717, 1999. Abstract | BibTeX | Keywords: abundance, Arabian Sea, ecosystem, Oceanic, oxygen minimum, plankton @article{, title = {Abundance and biomass of nano- and microplankton during the 1995 Northeast Monsoon and Spring Intermonsoon in the Arabian Sea}, author = {Dennett,M.R.,Caron,D.A.,Murzov,S.A.,Polikarpov,I.G.,Gavrilova,N.A.,Georgieva,L.V.,Kuzmenko,L.V.}, year = {1999}, date = {1999-01-01}, journal = {Deep-Sea Research Part II}, volume = {46}, number = {87}, pages = {1691-1717}, abstract = {Phototrophic and heterotrophic nanoplankton (PNAN, HNAN; 2-20 æm protists) and microplankton (PMIC, HMIC; 20-200 æm protists and micrometazoa) are major components of the producer and consumer assemblages in oceanic plankton communities. Abundances and biomasses of these microorganisms were determined from samples collected along two transects during the Northeast Monsoon and Spring Intermonsoon process cruises of the US JGOFS Arabian Sea Program in 1995. Vertical profiles of these assemblages were strongly affected by the presence of a subsurface oxygen minimum layer. Abundances of all four assemblages decreased dramatically below the top of this layer. Depth-integrated (0-160 m) abundances and biomasses of nanoplankton and microplankton were of similar magnitude for most samples. Exceptions to this rule were primarily due to PMIC (mostly diatom) species which dominated phytoplankton assemblages at a few stations during each season. Depth-integrated biomasses for the combined nano- and microplankton averaged over all stations for each cruise were surprisingly similar for the Northeast Monsoon and Spring Intermonsoon seasons in this ecosystem (2.0 and 1.8 g C m-2 [170 and 150 m moles C m-2] for the two seasons, respectively). Nano- and microplankton biomass for these two time periods constituted a significant portion of the total amount of the particulate organic carbon (POC) in the water column. Summed over all stations, these assemblages constituted approximately 25-35% of the POC in the top 160 m of the northern Arabian Sea.}, keywords = {abundance, Arabian Sea, ecosystem, Oceanic, oxygen minimum, plankton}, pubstate = {published}, tppubtype = {article} } Phototrophic and heterotrophic nanoplankton (PNAN, HNAN; 2-20 æm protists) and microplankton (PMIC, HMIC; 20-200 æm protists and micrometazoa) are major components of the producer and consumer assemblages in oceanic plankton communities. Abundances and biomasses of these microorganisms were determined from samples collected along two transects during the Northeast Monsoon and Spring Intermonsoon process cruises of the US JGOFS Arabian Sea Program in 1995. Vertical profiles of these assemblages were strongly affected by the presence of a subsurface oxygen minimum layer. Abundances of all four assemblages decreased dramatically below the top of this layer. Depth-integrated (0-160 m) abundances and biomasses of nanoplankton and microplankton were of similar magnitude for most samples. Exceptions to this rule were primarily due to PMIC (mostly diatom) species which dominated phytoplankton assemblages at a few stations during each season. Depth-integrated biomasses for the combined nano- and microplankton averaged over all stations for each cruise were surprisingly similar for the Northeast Monsoon and Spring Intermonsoon seasons in this ecosystem (2.0 and 1.8 g C m-2 [170 and 150 m moles C m-2] for the two seasons, respectively). Nano- and microplankton biomass for these two time periods constituted a significant portion of the total amount of the particulate organic carbon (POC) in the water column. Summed over all stations, these assemblages constituted approximately 25-35% of the POC in the top 160 m of the northern Arabian Sea. |
Clift, Peter.,Gaedicke, Christoph. Accelerated mass flux to the Arabian Sea during the middle to late Miocene Journal Article Geology, 30 (70), pp. 207-210, 2002. Abstract | BibTeX | Keywords: history, Indus River, palaeogeography @article{, title = {Accelerated mass flux to the Arabian Sea during the middle to late Miocene}, author = {Clift, Peter.,Gaedicke, Christoph.}, year = {2002}, date = {2002-01-01}, journal = {Geology}, volume = {30}, number = {70}, pages = {207-210}, abstract = {only}, keywords = {history, Indus River, palaeogeography}, pubstate = {published}, tppubtype = {article} } only |
Tindale,N.W.,Pease,P.P. Aerosols over the Arabian Sea: Atmospheric transport pathways and concentrations of dust and sea salt Journal Article Deep-Sea Research Part II, 46 (485), pp. 1577-1595, 1999. Abstract | BibTeX | Keywords: Arabian Sea, Gulf of Oman, Oceanic, Oman @article{, title = {Aerosols over the Arabian Sea: Atmospheric transport pathways and concentrations of dust and sea salt}, author = {Tindale,N.W.,Pease,P.P.}, year = {1999}, date = {1999-01-01}, journal = {Deep-Sea Research Part II}, volume = {46 }, number = {485}, pages = {1577-1595}, abstract = {This paper provides an overview of dust transport pathways and concentrations over the Arabian Sea during 1995. Results indicate that the transport and input of dust to the region is complex, being affected by both temporally and spatially important processes. Highest values of dust were found off the Omani coast and in the entrance to the Gulf of Oman. Dust levels were generally lower in summer than the other seasons, although still relatively high compared to other oceanic regions. The Findlater jet, rather than acting as a source of dust from Africa, appears to block the direct transport of dust to the open Arabian Sea from desert dust source regions in the Middle East and Iran/Pakistan. Dust transport aloft, above the jet, rather than at the surface, may be more important during summer. In an opposite pattern to dust, sea salt levels were exceedingly high during the summer monsoon, presumably due to the sustained strong surface winds. The high sea salt aerosols during the summer months may be impacting on the strong aerosol reflectance and absorbance signals over the Arabian Sea that are detected by satellite each year}, keywords = {Arabian Sea, Gulf of Oman, Oceanic, Oman}, pubstate = {published}, tppubtype = {article} } This paper provides an overview of dust transport pathways and concentrations over the Arabian Sea during 1995. Results indicate that the transport and input of dust to the region is complex, being affected by both temporally and spatially important processes. Highest values of dust were found off the Omani coast and in the entrance to the Gulf of Oman. Dust levels were generally lower in summer than the other seasons, although still relatively high compared to other oceanic regions. The Findlater jet, rather than acting as a source of dust from Africa, appears to block the direct transport of dust to the open Arabian Sea from desert dust source regions in the Middle East and Iran/Pakistan. Dust transport aloft, above the jet, rather than at the surface, may be more important during summer. In an opposite pattern to dust, sea salt levels were exceedingly high during the summer monsoon, presumably due to the sustained strong surface winds. The high sea salt aerosols during the summer months may be impacting on the strong aerosol reflectance and absorbance signals over the Arabian Sea that are detected by satellite each year |
Kinkade,C.S.,Marra,J.,Dickey,T.D.,Weller,R. An annual cycle of phytoplankton biomass in the Arabian Sea, 1994-1995, as determined by moored optical sensors Journal Article Deep-Sea Research Part II, 48 (137), pp. 1285-1301, 2001. Abstract | BibTeX | Keywords: Arabian Sea, chlorophyll, depth @article{, title = {An annual cycle of phytoplankton biomass in the Arabian Sea, 1994-1995, as determined by moored optical sensors}, author = {Kinkade,C.S.,Marra,J.,Dickey,T.D.,Weller,R.}, year = {2001}, date = {2001-01-01}, journal = {Deep-Sea Research Part II}, volume = {48}, number = {137}, pages = {1285-1301}, abstract = {A surface-to-bottom mooring in the central Arabian Sea (15.5§N, 61.5§E) deployed from October 1994 to October 1995, included fluorometers, PAR irradiance sensors, Lu683 sensors, and a spectral radiometer. An annual cycle of phytoplankton biomass was determined by transforming signals from the optical sensors into chlorophyll a (chl a). Half-yearly phytoplankton blooms with water-column stratification were observed near the end of each monsoon, as well as biomass increases in response to mesoscale #ow features. During the Northeast Monsoon, the integrate water-column chl a rose from 15 to 25mg m-2, while during the Southwest Monsoon, chl a increased from 15 to a maximum >40mg m-2. We present an empirical relationship between the ratio of downwelling Ed443/Ed550 (blue to green wavelength ratio) and integral euphotic zone chl a determined by moored fluorometers (r2 = 0.73). There is a more significant relationship between Ed443/Ed550 measured at one depth in the water column (65 m) and the average vertical attenuation cofficient for PAR (KPAR) between 0 and 65m (r2 = 0.845). Because biofouling was a significant problem at times, data return from any one sensor was incomplete. However, optical sensor/data intercomparison helped fill gaps while permitting investigation of the temporal variability in observed phytoplankton biomass. }, keywords = {Arabian Sea, chlorophyll, depth}, pubstate = {published}, tppubtype = {article} } A surface-to-bottom mooring in the central Arabian Sea (15.5§N, 61.5§E) deployed from October 1994 to October 1995, included fluorometers, PAR irradiance sensors, Lu683 sensors, and a spectral radiometer. An annual cycle of phytoplankton biomass was determined by transforming signals from the optical sensors into chlorophyll a (chl a). Half-yearly phytoplankton blooms with water-column stratification were observed near the end of each monsoon, as well as biomass increases in response to mesoscale #ow features. During the Northeast Monsoon, the integrate water-column chl a rose from 15 to 25mg m-2, while during the Southwest Monsoon, chl a increased from 15 to a maximum >40mg m-2. We present an empirical relationship between the ratio of downwelling Ed443/Ed550 (blue to green wavelength ratio) and integral euphotic zone chl a determined by moored fluorometers (r2 = 0.73). There is a more significant relationship between Ed443/Ed550 measured at one depth in the water column (65 m) and the average vertical attenuation cofficient for PAR (KPAR) between 0 and 65m (r2 = 0.845). Because biofouling was a significant problem at times, data return from any one sensor was incomplete. However, optical sensor/data intercomparison helped fill gaps while permitting investigation of the temporal variability in observed phytoplankton biomass. |
Sarma, VVSS An evaluation of physical and biogeochemical processes regulating perennial suboxic conditions in the water column of the Arabian Sea Journal Article Global Biogeochemical Cycles, 16 (220), 2002, ISBN: 1944-9224. Abstract | BibTeX | Keywords: Arabian Sea, oceanography, suboxic @article{, title = {An evaluation of physical and biogeochemical processes regulating perennial suboxic conditions in the water column of the Arabian Sea}, author = {Sarma, VVSS}, issn = {1944-9224}, year = {2002}, date = {2002-01-01}, journal = {Global Biogeochemical Cycles}, volume = {16}, number = {220}, abstract = {Monthly oxygen budgets for the subsurface Arabian Sea (100–1000 m) are constructed on the basis of Modular Ocean Model and recently collected oxygen data. The model results are in agreement with the observed pattern. The model results revealed that oxygen minimum zone (OMZ) in the Arabian Sea is regulated largely by physical processes in association with biogeochemical cycling of oxygen. This results in perennial suboxic conditions in the water column with no significant seasonal variability. Maintenance of OMZ during nonmonsoon seasons, when oligotrophic conditions prevail in surface layers, occurs through low supply of oxygen by physical pump aided by continued oxygen consumption in the oxidation of organic matter produced during monsoons. On the other hand, formation of anoxic conditions during monsoons, when higher sinking fluxes of carbon occur, is prevented by higher flux of oxygen by the physical pump. Hence, suboxic conditions in the Arabian Sea are maintained by physical pump with moderation from monsoonal biological pump. The residence time of the Arabian Sea intermediate waters (100–1000 m) was computed to be 6.5 years with rapid replacement during monsoons. The oxygen consumption rates are also high during monsoons compared with nonmonsoon seasons. The carbon regeneration rates computed based on the water mass-mixing model, bacterial carbon demand, and electron transport system activity in the subsurface layers are in agreement with oxygen consumption rates estimated based on this model.}, keywords = {Arabian Sea, oceanography, suboxic}, pubstate = {published}, tppubtype = {article} } Monthly oxygen budgets for the subsurface Arabian Sea (100–1000 m) are constructed on the basis of Modular Ocean Model and recently collected oxygen data. The model results are in agreement with the observed pattern. The model results revealed that oxygen minimum zone (OMZ) in the Arabian Sea is regulated largely by physical processes in association with biogeochemical cycling of oxygen. This results in perennial suboxic conditions in the water column with no significant seasonal variability. Maintenance of OMZ during nonmonsoon seasons, when oligotrophic conditions prevail in surface layers, occurs through low supply of oxygen by physical pump aided by continued oxygen consumption in the oxidation of organic matter produced during monsoons. On the other hand, formation of anoxic conditions during monsoons, when higher sinking fluxes of carbon occur, is prevented by higher flux of oxygen by the physical pump. Hence, suboxic conditions in the Arabian Sea are maintained by physical pump with moderation from monsoonal biological pump. The residence time of the Arabian Sea intermediate waters (100–1000 m) was computed to be 6.5 years with rapid replacement during monsoons. The oxygen consumption rates are also high during monsoons compared with nonmonsoon seasons. The carbon regeneration rates computed based on the water mass-mixing model, bacterial carbon demand, and electron transport system activity in the subsurface layers are in agreement with oxygen consumption rates estimated based on this model. |
Mahanty, Madan M,Latha, G,Thirunavukkarasu, A Analysis of humpback whale sounds in shallow waters of the Southeastern Arabian Sea: An indication of breeding habitat Journal Article Journal of biosciences, 40 (148), pp. 407-417, 2015, ISBN: 0250-5991. Abstract | BibTeX | Keywords: Arabian Sea, behaviour, breeding grounds, Humpback Whale, India, megaptera novaeangliae, song @article{, title = {Analysis of humpback whale sounds in shallow waters of the Southeastern Arabian Sea: An indication of breeding habitat}, author = {Mahanty, Madan M,Latha, G,Thirunavukkarasu, A}, issn = {0250-5991}, year = {2015}, date = {2015-01-01}, journal = {Journal of biosciences}, volume = {40}, number = {148}, pages = {407-417}, abstract = {The primary objective of this work was to present the acoustical identification of humpback whales, detected by using an autonomous ambient noise measurement system, deployed in the shallow waters of the Southeastern Arabian Sea (SEAS) during the period January to May 2011. Seven types of sounds were detected. These were characteristically upsweeps and downsweeps along with harmonics. Sounds produced repeatedly in a specific pattern were referred to as phrases (PQRS and ABC). Repeated phrases in a particular pattern were referred to as themes, and from the spectrographic analysis, two themes (I and II) were identified. The variation in the acoustic characteristics such as fundamental frequency, range, duration of the sound unit, and the structure of the phrases and themes are discussed. Sound units were recorded from mid-January to mid-March, with a peak in February, when the mean SST is ~28°C, and no presence was recorded after mid-March. The temporal and thematic structures strongly determine the functions of the humpback whale song form. Given the use of song in the SEAS, this area is possibly used as an active breeding habitat by humpback whales during the winter season.}, keywords = {Arabian Sea, behaviour, breeding grounds, Humpback Whale, India, megaptera novaeangliae, song}, pubstate = {published}, tppubtype = {article} } The primary objective of this work was to present the acoustical identification of humpback whales, detected by using an autonomous ambient noise measurement system, deployed in the shallow waters of the Southeastern Arabian Sea (SEAS) during the period January to May 2011. Seven types of sounds were detected. These were characteristically upsweeps and downsweeps along with harmonics. Sounds produced repeatedly in a specific pattern were referred to as phrases (PQRS and ABC). Repeated phrases in a particular pattern were referred to as themes, and from the spectrographic analysis, two themes (I and II) were identified. The variation in the acoustic characteristics such as fundamental frequency, range, duration of the sound unit, and the structure of the phrases and themes are discussed. Sound units were recorded from mid-January to mid-March, with a peak in February, when the mean SST is ~28°C, and no presence was recorded after mid-March. The temporal and thematic structures strongly determine the functions of the humpback whale song form. Given the use of song in the SEAS, this area is possibly used as an active breeding habitat by humpback whales during the winter season. |
Prahl,F.G.,Dymond,J.,Sparrow,M.A. Annual biomarker record for export production in the central Arabian Sea Journal Article Deep-Sea Research Part II, 47 (200), pp. 1581-1604, 2000. Abstract | BibTeX | Keywords: Arabian Sea, depletion, marine, plankton, productivity, trap @article{, title = {Annual biomarker record for export production in the central Arabian Sea}, author = {Prahl,F.G.,Dymond,J.,Sparrow,M.A.}, year = {2000}, date = {2000-01-01}, journal = {Deep-Sea Research Part II}, volume = {47}, number = {200}, pages = {1581-1604}, abstract = {The record for plankton biomarkers in sediment trap samples from a one-year experiment in the central Arabian Sea (AS4: 15§59'N 61§30'E) shows variations that reflect changing biological conditions in surface waters. Particulate fluxes of C37-39 alkenones, highly branched C25 isoprenoids (HBI), dinosterol, nC28 12-hydroxy fatty acid, 24-ethylcholesterol, and C30-34 series of pentacyclic triterpanols all displayed distinct maxima at the start and stop of the Northeast (NE) and Southwest (SW) Monsoons. Surface mixing conditions changed rapidly at these times, altering light and nutrient availability, thereby triggering these biomarker signals of export production. Temporal offsets noted in individual biomarker concentrations (per g total organic carbon) at the start of the SW Monsoon suggest succession occurs in the phytoplankton community contributing to organic matter export. Comparable offsets were neither apparent at the start of the less dynamic NE Monsoon nor at the end of the NE or SW Monsoons. Broad concentration maxima for HBI also were observed at the beginning and end of the time-series during the relatively quiescent Fall Intermonsoon period when such features were conspicuously absent for other biomarkers. HBI are reputed biomarkers of Rhizoselenia and Haslea spp., two recognized dominants of diatom biomass in the Arabian Sea. These peaks in biomarker concentration could reflect either changes in the relative proportion of specific organisms that contribute to the upper ocean productivity or enhanced preservation of the biomarkers during times of high export production. In either case, the biomarker record in sediment traps reflects important changes in the biological condition of the upper ocean. All biomarkers except HBI were measurable in surface sediments deposited beneath the trap site. Comparison with concentrations in average sediment trap particles showed each was sensitive to significant ( ~ 99%) degradation, displaying depletion factors relative to TOC of ò4. Clearly, consequences of such high levels of early diagenetic recycling must be considered carefully when conclusions about changes in export production from surface waters in past oceans are drawn from stratigraphic analysis of biomarkers in marine sediments. }, keywords = {Arabian Sea, depletion, marine, plankton, productivity, trap}, pubstate = {published}, tppubtype = {article} } The record for plankton biomarkers in sediment trap samples from a one-year experiment in the central Arabian Sea (AS4: 15§59'N 61§30'E) shows variations that reflect changing biological conditions in surface waters. Particulate fluxes of C37-39 alkenones, highly branched C25 isoprenoids (HBI), dinosterol, nC28 12-hydroxy fatty acid, 24-ethylcholesterol, and C30-34 series of pentacyclic triterpanols all displayed distinct maxima at the start and stop of the Northeast (NE) and Southwest (SW) Monsoons. Surface mixing conditions changed rapidly at these times, altering light and nutrient availability, thereby triggering these biomarker signals of export production. Temporal offsets noted in individual biomarker concentrations (per g total organic carbon) at the start of the SW Monsoon suggest succession occurs in the phytoplankton community contributing to organic matter export. Comparable offsets were neither apparent at the start of the less dynamic NE Monsoon nor at the end of the NE or SW Monsoons. Broad concentration maxima for HBI also were observed at the beginning and end of the time-series during the relatively quiescent Fall Intermonsoon period when such features were conspicuously absent for other biomarkers. HBI are reputed biomarkers of Rhizoselenia and Haslea spp., two recognized dominants of diatom biomass in the Arabian Sea. These peaks in biomarker concentration could reflect either changes in the relative proportion of specific organisms that contribute to the upper ocean productivity or enhanced preservation of the biomarkers during times of high export production. In either case, the biomarker record in sediment traps reflects important changes in the biological condition of the upper ocean. All biomarkers except HBI were measurable in surface sediments deposited beneath the trap site. Comparison with concentrations in average sediment trap particles showed each was sensitive to significant ( ~ 99%) degradation, displaying depletion factors relative to TOC of ò4. Clearly, consequences of such high levels of early diagenetic recycling must be considered carefully when conclusions about changes in export production from surface waters in past oceans are drawn from stratigraphic analysis of biomarkers in marine sediments. |
Romano, T.A.,Keogh, M.J.,Kelly, C.,Feng, P.,Berk, L.,Schlundt, C.E.,Carder, D.A.,Finneran, J. J. Anthropogenic sound and marine mammal health: measures of the nervous and immune systems before and after intense sound exposure Journal Article Canadian Journal of Fisheries and Aquatic Science, 61 (454), pp. 1124-1134, 2004. BibTeX | Keywords: health, noise, stress @article{, title = {Anthropogenic sound and marine mammal health: measures of the nervous and immune systems before and after intense sound exposure}, author = {Romano, T.A.,Keogh, M.J.,Kelly, C.,Feng, P.,Berk, L.,Schlundt, C.E.,Carder, D.A.,Finneran, J. J.}, year = {2004}, date = {2004-01-01}, journal = {Canadian Journal of Fisheries and Aquatic Science}, volume = {61}, number = {454}, pages = {1124-1134}, keywords = {health, noise, stress}, pubstate = {published}, tppubtype = {article} } |
Burkill,P.H. Arabesque: An overview Journal Article Deep-Sea Research Part II, 46 (340), pp. 529-547, 1999. Abstract | BibTeX | Keywords: Arabian Sea, Gulf of Oman, length, Oceanic, oceanography, Oman, Upwelling @article{, title = {Arabesque: An overview}, author = {Burkill,P.H.}, year = {1999}, date = {1999-01-01}, journal = {Deep-Sea Research Part II}, volume = {46}, number = {340}, pages = {529-547}, abstract = {This special issue reports the results of ARABESQUE, a UK-led, international programme of upper-ocean biogeochemistry in the Arabian Sea region, conducted during two contrasting seasons. The seasons studied here were the waning of the southwest monsoon in August/September and the intermonsoon-northeast monsoon transition in November/December 1994. Biogeochemical studies were carried out along three transects in the Gulf of Oman and the Arabian Sea. the main ARABESQUE transect, 1590km in length, lay orthagonal to the southern Oman coast and spanned a range of conditions that encompassed coastal seasonal upwelling through to oceanic aseasonal oligotrophy of the central Arabian Sea. Surface mixed-layer hydrography, PAR, wind speed and direction fields and research results obtained during two seasonal studies are summarised in this paper which also serves and an introductory overview to ARABESQUE.}, keywords = {Arabian Sea, Gulf of Oman, length, Oceanic, oceanography, Oman, Upwelling}, pubstate = {published}, tppubtype = {article} } This special issue reports the results of ARABESQUE, a UK-led, international programme of upper-ocean biogeochemistry in the Arabian Sea region, conducted during two contrasting seasons. The seasons studied here were the waning of the southwest monsoon in August/September and the intermonsoon-northeast monsoon transition in November/December 1994. Biogeochemical studies were carried out along three transects in the Gulf of Oman and the Arabian Sea. the main ARABESQUE transect, 1590km in length, lay orthagonal to the southern Oman coast and spanned a range of conditions that encompassed coastal seasonal upwelling through to oceanic aseasonal oligotrophy of the central Arabian Sea. Surface mixed-layer hydrography, PAR, wind speed and direction fields and research results obtained during two seasonal studies are summarised in this paper which also serves and an introductory overview to ARABESQUE. |
Baldwin, R.,Collins, T.J.Q.,Minton, G.,Willson, A.,Corkeron, P. Arabian Sea humpback whales 2011 update: resights, bubble feeding and hotspots Journal Article Document presented to the Scientific Committee of the International Whaling Commission, SC/54/O4 (23), pp. 5, 2011. Abstract | BibTeX | Keywords: Arabian Sea, blue whales, breeding, feeding, Humpback Whale, megaptera novaeangliae, photo identification, sperm whales @article{, title = {Arabian Sea humpback whales 2011 update: resights, bubble feeding and hotspots}, author = {Baldwin, R.,Collins, T.J.Q.,Minton, G.,Willson, A.,Corkeron, P.}, year = {2011}, date = {2011-01-01}, journal = {Document presented to the Scientific Committee of the International Whaling Commission}, volume = {SC/54/O4}, number = {23}, pages = {5}, abstract = {The 2010 report of the Scientific Committee (IWC/62/Rep 1) expressed grave concern for the resident ‘Arabian Sea humpback whale population’. The Committee made strong recommendations for additional research to monitor the status of this Endangered population which has a restricted range, is reproductively isolated, has a very small population size (n=82 (95% CI=60-111)) and is known to interact with humans with negative consequences. A survey during March 2011 resulted in 47 sightings of humpback whales representing approximately12 individuals. Sightings included a mother-calf pair, observation of competitive behaviour and frequent feeding including use of ‘bubble cloud’ and ‘bubble net’ structures, all of which have been rarely witnessed in Oman on previous surveys. At least three known individuals were identified, among them those that have been re-sighted as many as four times previously and those that have been previously photographed at the same location. Song was recorded on numerous occasions from the survey vessel and one Cornell MARU was deployed resulting in acquisition of over 20 days of continuous recordings which are undergoing analysis. Threats from fishing activity, coastal development and vessel traffic were documented, and an apparent attack on a humpback whale by false killer whales was witnessed. Numerous other cetacean species were recorded, including other large whales (blue whales, Bryde’s whales and sperm whales – all with calves – and numerous small cetaceans). The majority of sightings were clustered around Ras Hasik and all feeding behaviour, including that by humpback, blue and Bryde’s whales occurred within 2-3 kilometers of this apparent ‘hotspot’. Further research is recommended which may be best determined via the Conservation Management Planning process.}, keywords = {Arabian Sea, blue whales, breeding, feeding, Humpback Whale, megaptera novaeangliae, photo identification, sperm whales}, pubstate = {published}, tppubtype = {article} } The 2010 report of the Scientific Committee (IWC/62/Rep 1) expressed grave concern for the resident ‘Arabian Sea humpback whale population’. The Committee made strong recommendations for additional research to monitor the status of this Endangered population which has a restricted range, is reproductively isolated, has a very small population size (n=82 (95% CI=60-111)) and is known to interact with humans with negative consequences. A survey during March 2011 resulted in 47 sightings of humpback whales representing approximately12 individuals. Sightings included a mother-calf pair, observation of competitive behaviour and frequent feeding including use of ‘bubble cloud’ and ‘bubble net’ structures, all of which have been rarely witnessed in Oman on previous surveys. At least three known individuals were identified, among them those that have been re-sighted as many as four times previously and those that have been previously photographed at the same location. Song was recorded on numerous occasions from the survey vessel and one Cornell MARU was deployed resulting in acquisition of over 20 days of continuous recordings which are undergoing analysis. Threats from fishing activity, coastal development and vessel traffic were documented, and an apparent attack on a humpback whale by false killer whales was witnessed. Numerous other cetacean species were recorded, including other large whales (blue whales, Bryde’s whales and sperm whales – all with calves – and numerous small cetaceans). The majority of sightings were clustered around Ras Hasik and all feeding behaviour, including that by humpback, blue and Bryde’s whales occurred within 2-3 kilometers of this apparent ‘hotspot’. Further research is recommended which may be best determined via the Conservation Management Planning process. |
Baldwin, R.,Collins, T.,Minton, G.,Findlay, K.,Corkeron, P.,Willson, A.,Van Bressem, M.F. Arabian Sea Humpback Whales: Canaries for the Northern Indian Ocean? Journal Article Document presented to the 62nd meeting of the Scientific Committee of the International Whaling Commission. SC/62/SH20, (305), pp. 1-5, 2010. Abstract | BibTeX | Keywords: Arabian Sea, Humpback Whale, megaptera novaeangliae, mitigation, Oman, Threats @article{, title = {Arabian Sea Humpback Whales: Canaries for the Northern Indian Ocean?}, author = {Baldwin, R.,Collins, T.,Minton, G.,Findlay, K.,Corkeron, P.,Willson, A.,Van Bressem, M.F.}, year = {2010}, date = {2010-01-01}, journal = {Document presented to the 62nd meeting of the Scientific Committee of the International Whaling Commission. SC/62/SH20}, number = {305}, pages = {1-5}, abstract = {Both historic whaling data and recent field research confirm the presence of a resident sub-population of humpback whales in the western Arabian Sea (Breeding Stock X). This endangered population is geographically, demographically and genetically isolated and is thought to have been greatly reduced in size by Soviet whaling in 1966; it likely remains severely depleted. Current threats to this population, including incidental capture in fishing gear, coastal development and hydrocarbon exploration have increased in recent years and, coupled with possible underlying health issues, raise significant concerns about this population’s viability. When compared with effort and resources aimed at other whale stocks, Breeding Stock X receives disproportionately meagre support for its research and conservation, whilst its status, health and the precautionary principle, imply that it merits at least the same level of concern.}, keywords = {Arabian Sea, Humpback Whale, megaptera novaeangliae, mitigation, Oman, Threats}, pubstate = {published}, tppubtype = {article} } Both historic whaling data and recent field research confirm the presence of a resident sub-population of humpback whales in the western Arabian Sea (Breeding Stock X). This endangered population is geographically, demographically and genetically isolated and is thought to have been greatly reduced in size by Soviet whaling in 1966; it likely remains severely depleted. Current threats to this population, including incidental capture in fishing gear, coastal development and hydrocarbon exploration have increased in recent years and, coupled with possible underlying health issues, raise significant concerns about this population’s viability. When compared with effort and resources aimed at other whale stocks, Breeding Stock X receives disproportionately meagre support for its research and conservation, whilst its status, health and the precautionary principle, imply that it merits at least the same level of concern. |
Shalapyonok,A.,Olson,R.J.,Shalapyonok,L.S. Arabian Sea phytoplankton during Southwest and Northeast Monsoons 1995: composition, size structure and biomass from individual cell properties measured by flow cytometry Journal Article Deep-Sea Research Part II, 48 (221), pp. 1231-1261, 2001. Abstract | BibTeX | Keywords: abundance, Arabian Sea, diel, Distribution, location, surface temperature, temperature, Upwelling @article{, title = {Arabian Sea phytoplankton during Southwest and Northeast Monsoons 1995: composition, size structure and biomass from individual cell properties measured by flow cytometry}, author = {Shalapyonok,A.,Olson,R.J.,Shalapyonok,L.S.}, year = {2001}, date = {2001-01-01}, journal = {Deep-Sea Research Part II}, volume = {48 }, number = {221}, pages = {1231-1261}, abstract = {As part of the US JGOFS Arabian Sea Process Study, we determined the abundance, size distributions and carbon biomass of autotrophic phytoplankton in the Arabian Sea during summer Southwest and fall Northeast Monsoon seasons of 1995 (R/V Thomas G. Thompson cruises TN 049 and TN 053). Flowcytometry of 60-ml samples was used to enumerate and determine scattering and fluorescence properties of Prochlorococcus sp., Synechococcus sp., and eukaryotic phytoplankton with cell equivalent spherical diameter up to 40 æm. Cellular forward light scattering was calibrated against Coulter size using 22 phytoplankton cultures spanning the size range 0.8-40 æm, grown exponentially in natural sunlight. The phytoplankton community structure was strongly linked to water-mass characteristics, and was affected by both intense monsoon-related environmental forcing and widespread and dynamic mesoscale structures; the magnitude of spatial variability was similar to that between seasons for all three phytoplankton groups. Prochlorococcus was numerically dominant in the more oligotrophic, stratified areas with surface nitrate concentrations below 0.1 æM and surface temperatures above 27§C. Its abundance was significantly greater during the NE Monsoon and was inversely correlated with the abundance of the two other groups. Synechococcus and eukaryotic phytoplankton cell concentrations covaried at most locations, were highest in areas of intense, monsoon-related mixing, and changed less between seasons than Prochlorococcus. The bulk of biomass of all three groups was located within the mixed layer. Only eukaryotes formed notable subsurface maxima at several offshore locations where Prochlorococcus dominated the mixed layer. Dramatically elevated eukaryotic phytoplankton concentrations in the nutrient-rich upwelling areas were due to the blooming of smaller (<3 æm) cells. Surprisingly, stratified, offshore, nutrient-depleted areas had concentrations of 10-40 æm phytoplankton cells similar to or even higher than upwelling areas. Thus, the mean eukaryotic cell size and the relative contribution of large nanoeukaryotes to the phytoplankton biomass were highest in offshore waters. Eukaryotes accounted for most of the phytoplankton carbon biomass - from about 50 to 80% on average during both seasons. Both Prochlorococcus and large (10 æm) nanoeukaryotes reached their greatest biomass contributions - up to 40% each - in the offshore oligotrophic locations. For the SW and NE Monsoon cruises, flow cytometrically-measured phytoplankton was estimated at 1.1 and 2.2 gCm-2 on average and comprised 33 and 38% of POC, respectively. Diel variability in cellular carbon content accounted for 52% of the observed variability in cellular carbon content for Prochlorococcus, 26% for Synechococcus, and 14% for eukaryotic phytoplankton cells at the surface.}, keywords = {abundance, Arabian Sea, diel, Distribution, location, surface temperature, temperature, Upwelling}, pubstate = {published}, tppubtype = {article} } As part of the US JGOFS Arabian Sea Process Study, we determined the abundance, size distributions and carbon biomass of autotrophic phytoplankton in the Arabian Sea during summer Southwest and fall Northeast Monsoon seasons of 1995 (R/V Thomas G. Thompson cruises TN 049 and TN 053). Flowcytometry of 60-ml samples was used to enumerate and determine scattering and fluorescence properties of Prochlorococcus sp., Synechococcus sp., and eukaryotic phytoplankton with cell equivalent spherical diameter up to 40 æm. Cellular forward light scattering was calibrated against Coulter size using 22 phytoplankton cultures spanning the size range 0.8-40 æm, grown exponentially in natural sunlight. The phytoplankton community structure was strongly linked to water-mass characteristics, and was affected by both intense monsoon-related environmental forcing and widespread and dynamic mesoscale structures; the magnitude of spatial variability was similar to that between seasons for all three phytoplankton groups. Prochlorococcus was numerically dominant in the more oligotrophic, stratified areas with surface nitrate concentrations below 0.1 æM and surface temperatures above 27§C. Its abundance was significantly greater during the NE Monsoon and was inversely correlated with the abundance of the two other groups. Synechococcus and eukaryotic phytoplankton cell concentrations covaried at most locations, were highest in areas of intense, monsoon-related mixing, and changed less between seasons than Prochlorococcus. The bulk of biomass of all three groups was located within the mixed layer. Only eukaryotes formed notable subsurface maxima at several offshore locations where Prochlorococcus dominated the mixed layer. Dramatically elevated eukaryotic phytoplankton concentrations in the nutrient-rich upwelling areas were due to the blooming of smaller (<3 æm) cells. Surprisingly, stratified, offshore, nutrient-depleted areas had concentrations of 10-40 æm phytoplankton cells similar to or even higher than upwelling areas. Thus, the mean eukaryotic cell size and the relative contribution of large nanoeukaryotes to the phytoplankton biomass were highest in offshore waters. Eukaryotes accounted for most of the phytoplankton carbon biomass - from about 50 to 80% on average during both seasons. Both Prochlorococcus and large (10 æm) nanoeukaryotes reached their greatest biomass contributions - up to 40% each - in the offshore oligotrophic locations. For the SW and NE Monsoon cruises, flow cytometrically-measured phytoplankton was estimated at 1.1 and 2.2 gCm-2 on average and comprised 33 and 38% of POC, respectively. Diel variability in cellular carbon content accounted for 52% of the observed variability in cellular carbon content for Prochlorococcus, 26% for Synechococcus, and 14% for eukaryotic phytoplankton cells at the surface. |
Gore, M. A.,Culloch, R,Gray, H.,Hoelzel, A. R.,Lockyer, C.,Kiani, M. S.,Waqas, U,Hussain, B,Rahim, Abdul,Shah, A.,Ormond, R. F. Assessment of beach-cast cetaceans in Pakistan: implications for conservation and management Journal Article Journal of Cetacean Research and Management, 16 (104), pp. 1-7, 2017. Abstract | BibTeX | Keywords: aging, Arabian Sea, balaenoptera edeni, beach survey, Bryde’s whale, carcass analysis, genetics, Pakistan, stranding @article{, title = {Assessment of beach-cast cetaceans in Pakistan: implications for conservation and management}, author = {Gore, M. A.,Culloch, R,Gray, H.,Hoelzel, A. R.,Lockyer, C.,Kiani, M. S.,Waqas, U,Hussain, B,Rahim, Abdul,Shah, A.,Ormond, R. F.}, year = {2017}, date = {2017-01-01}, journal = {Journal of Cetacean Research and Management}, volume = {16}, number = {104}, pages = {1-7}, abstract = {Until recently, little was known about the distribution and species occurrence of marine cetaceans in Pakistani waters, an area which needed to be addressed exigently given its inclusion in the Indian Ocean Whale Sanctuary. Boat-based surveys (2005–09) carried out along the coast of Pakistan identified 12 species of cetaceans. Although these surveys can be very useful for providing information on species presence and distribution, estimates of the age and sex of these groups can be more uncertain. Consequently, this present study undertook complementary beach-based surveys over the same period across all accessible regions of the Pakistani coast and created a community reporting scheme for stranded and beach-cast remains of cetaceans. Tissue samples and/or skeletal material were collected over three years from 37 individual specimens, with DNA successfully extracted from 24. Using molecular techniques, a total of seven species were identified and there was an indication that the majority of the samples were from males. An analysis of teeth collected from 12 beach-cast odontocetes showed an age range between neonatal and 17 years. The results of this study corroborate the presence of species observed during the boat-based surveys and identified a further three species. The data also provide additional information on age and sex. A comparison with similar studies suggests that the stranding rate is low in Pakistan. No mass strandings occurred during the seven year monitoring period. The results indicate that beach-based surveys are effective for gathering data on species presence in regions where resources are limited, the terrain is harsh and availability of data is low. Ultimately, the results of this work will help with assessing the conservation status and management requirements of the region’s cetaceans, both locally and internationally with respect to the Indian Ocean Whale Sanctuary. Species identified were 4 bottlenose dolphins (Tursiops sp.), 6 long-beaked common dolphins, 1 spinner dolphin, 4 Indian Ocean humpback dolphins, 1 pantropical spotted dolphin (Stenella attenuata) and 5 Bryde’s whales}, keywords = {aging, Arabian Sea, balaenoptera edeni, beach survey, Bryde’s whale, carcass analysis, genetics, Pakistan, stranding}, pubstate = {published}, tppubtype = {article} } Until recently, little was known about the distribution and species occurrence of marine cetaceans in Pakistani waters, an area which needed to be addressed exigently given its inclusion in the Indian Ocean Whale Sanctuary. Boat-based surveys (2005–09) carried out along the coast of Pakistan identified 12 species of cetaceans. Although these surveys can be very useful for providing information on species presence and distribution, estimates of the age and sex of these groups can be more uncertain. Consequently, this present study undertook complementary beach-based surveys over the same period across all accessible regions of the Pakistani coast and created a community reporting scheme for stranded and beach-cast remains of cetaceans. Tissue samples and/or skeletal material were collected over three years from 37 individual specimens, with DNA successfully extracted from 24. Using molecular techniques, a total of seven species were identified and there was an indication that the majority of the samples were from males. An analysis of teeth collected from 12 beach-cast odontocetes showed an age range between neonatal and 17 years. The results of this study corroborate the presence of species observed during the boat-based surveys and identified a further three species. The data also provide additional information on age and sex. A comparison with similar studies suggests that the stranding rate is low in Pakistan. No mass strandings occurred during the seven year monitoring period. The results indicate that beach-based surveys are effective for gathering data on species presence in regions where resources are limited, the terrain is harsh and availability of data is low. Ultimately, the results of this work will help with assessing the conservation status and management requirements of the region’s cetaceans, both locally and internationally with respect to the Indian Ocean Whale Sanctuary. Species identified were 4 bottlenose dolphins (Tursiops sp.), 6 long-beaked common dolphins, 1 spinner dolphin, 4 Indian Ocean humpback dolphins, 1 pantropical spotted dolphin (Stenella attenuata) and 5 Bryde’s whales |
Riemann,L.,Steward,G.F.,Fandino,L.B.,Campbell,L.,Landry,M.R.,Azam,F. Bacterial community composition during two consecutive NE Monsoon periods in the Arabian Sea studied by denaturing gradient gel electrophoresis (DGGE) of rRNA genes Journal Article Deep-Sea Research Part II, 46 (205), pp. 1791-1811, 1999. Abstract | BibTeX | Keywords: Arabian Sea, depth, DNA, dominance, Oceanic, PCR @article{, title = {Bacterial community composition during two consecutive NE Monsoon periods in the Arabian Sea studied by denaturing gradient gel electrophoresis (DGGE) of rRNA genes}, author = {Riemann,L.,Steward,G.F.,Fandino,L.B.,Campbell,L.,Landry,M.R.,Azam,F.}, year = {1999}, date = {1999-01-01}, journal = {Deep-Sea Research Part II}, volume = {46}, number = {205}, pages = {1791-1811}, abstract = {Horizontal and vertical variations in bacterial community composition were examined in samples collected during two Joint Global Ocean Flux Study (JGOFS) Arabian Sea cruises in 1995. The cruises, 11 months apart, took place during two consecutive NE Monsoon periods (January and December). Bacteria were harvested by filtration from samples collected in the mixed layer, mid-water, and deep sea at stations across the study area. Total bacterial community genomic DNA was analyzed by PCR amplification of 16S rRNA gene fragments, followed by denaturing gradient gel electrophoresis (DGGE). In total, 20 DGGE bands reflecting unique or varying phylotypes were excised, cloned and sequenced. Amplicons were dominated by bacterial groups commonly found in oceanic waters (e.g., the SAR11 cluster of a-Proteobacteria and cyanobacteria), but surprisingly none of the sequenced amplicons were related to c-Proteobacteria or to members of the Cytophaga-Flavobacter-Bacteroides phylum. Amplicons related to magnetotactic bacteria were found for the first time in pelagic oceanic waters. The DGGE banding patterns revealed a dominance of ÷ 15 distinguishable amplicons in all samples. In the mixed layer the bacterial community was dominated by the same ÷ 15 phylotypes at all stations, but unique phylotypes were found with increasing depth. Except for cyanobacteria, comparison of the bacterial community composition in surface waters from January and December 1995 showed only minor differences, despite significant differences in environmental parameters. These data suggest a horizontal homogeneity and some degree of seasonal predictability of bacterial community composition in the Arabian Sea.}, keywords = {Arabian Sea, depth, DNA, dominance, Oceanic, PCR}, pubstate = {published}, tppubtype = {article} } Horizontal and vertical variations in bacterial community composition were examined in samples collected during two Joint Global Ocean Flux Study (JGOFS) Arabian Sea cruises in 1995. The cruises, 11 months apart, took place during two consecutive NE Monsoon periods (January and December). Bacteria were harvested by filtration from samples collected in the mixed layer, mid-water, and deep sea at stations across the study area. Total bacterial community genomic DNA was analyzed by PCR amplification of 16S rRNA gene fragments, followed by denaturing gradient gel electrophoresis (DGGE). In total, 20 DGGE bands reflecting unique or varying phylotypes were excised, cloned and sequenced. Amplicons were dominated by bacterial groups commonly found in oceanic waters (e.g., the SAR11 cluster of a-Proteobacteria and cyanobacteria), but surprisingly none of the sequenced amplicons were related to c-Proteobacteria or to members of the Cytophaga-Flavobacter-Bacteroides phylum. Amplicons related to magnetotactic bacteria were found for the first time in pelagic oceanic waters. The DGGE banding patterns revealed a dominance of ÷ 15 distinguishable amplicons in all samples. In the mixed layer the bacterial community was dominated by the same ÷ 15 phylotypes at all stations, but unique phylotypes were found with increasing depth. Except for cyanobacteria, comparison of the bacterial community composition in surface waters from January and December 1995 showed only minor differences, despite significant differences in environmental parameters. These data suggest a horizontal homogeneity and some degree of seasonal predictability of bacterial community composition in the Arabian Sea. |
Clapham,P.J.,Young,S.B.,Brownell Jr,R.L. Baleen whales: conservation issues and the status of the most endangered populations Journal Article Mammal Review, 29 (69), pp. 35-60, 1999. Abstract | BibTeX | Keywords: abundance, Arabian Sea, Arctic, Balaena mysticetus, baleen whale, baleen whales, Blue whale, bowhead whale, bowhead whales, conservation, contaminants, disease, endangered, Entanglement, Eubalaena glacialis, fishing gear, gray whales, habitat degradation, Humpback Whale, humpback whales, mortality, Okhotsk Sea, population, populations, right whale, right whales, ship-strike, southern right whales, status, stocks, whale, whales, whaling @article{, title = {Baleen whales: conservation issues and the status of the most endangered populations }, author = {Clapham,P.J.,Young,S.B.,Brownell Jr,R.L.}, year = {1999}, date = {1999-01-01}, journal = {Mammal Review}, volume = {29 }, number = {69}, pages = {35-60}, abstract = {Most species of baleen whales were subject to intensive overexploitation by commercial whaling in this and previous centuries, and many populations were reduced to small fractions of their original sizes. Here, we review the status of baleen whale stocks, with an emphasis on those that are known or thought to be critically endangered. Current data suggest that, of the various threats potentially affecting baleen whales, only entanglement in fishing gear and ship strikes may be significant at the population level, and then only in those populations which are already at critically low abundance. The impact of some problems (vessel harassment, and commercial or aboriginal whaling) is at present probably minor. For others (contaminants, habitat degradation, disease), existing data either indicate no immediate cause for concern, or are insufficient to permit an assessment. While the prospect for many baleen whales appears good, there are notable exceptions: populations that are of greatest concern are those suffering from low abundance and associated problems, including (in some cases) anthropogenic mortality. These include: all Northern Right N hales Eubalaena glacialis. Bowhead Whales Balaena mysticetus of the Okhotsk Sea and various eastern Arctic populations. western Gray Whales Eschrichtius robustus, and probably many Blue Whale Balaenoptera musculus populations. We review the status of these populations and. where known, the issues potentially affecting their recovery. Although Humpback Whales Megaptera novaeangliae and Southern Right Whales Eubalaena australis were also heavily exploited by whaling. existing data indicate strong recovery in most studied populations of these species.}, keywords = {abundance, Arabian Sea, Arctic, Balaena mysticetus, baleen whale, baleen whales, Blue whale, bowhead whale, bowhead whales, conservation, contaminants, disease, endangered, Entanglement, Eubalaena glacialis, fishing gear, gray whales, habitat degradation, Humpback Whale, humpback whales, mortality, Okhotsk Sea, population, populations, right whale, right whales, ship-strike, southern right whales, status, stocks, whale, whales, whaling}, pubstate = {published}, tppubtype = {article} } Most species of baleen whales were subject to intensive overexploitation by commercial whaling in this and previous centuries, and many populations were reduced to small fractions of their original sizes. Here, we review the status of baleen whale stocks, with an emphasis on those that are known or thought to be critically endangered. Current data suggest that, of the various threats potentially affecting baleen whales, only entanglement in fishing gear and ship strikes may be significant at the population level, and then only in those populations which are already at critically low abundance. The impact of some problems (vessel harassment, and commercial or aboriginal whaling) is at present probably minor. For others (contaminants, habitat degradation, disease), existing data either indicate no immediate cause for concern, or are insufficient to permit an assessment. While the prospect for many baleen whales appears good, there are notable exceptions: populations that are of greatest concern are those suffering from low abundance and associated problems, including (in some cases) anthropogenic mortality. These include: all Northern Right N hales Eubalaena glacialis. Bowhead Whales Balaena mysticetus of the Okhotsk Sea and various eastern Arctic populations. western Gray Whales Eschrichtius robustus, and probably many Blue Whale Balaenoptera musculus populations. We review the status of these populations and. where known, the issues potentially affecting their recovery. Although Humpback Whales Megaptera novaeangliae and Southern Right Whales Eubalaena australis were also heavily exploited by whaling. existing data indicate strong recovery in most studied populations of these species. |
Sajikumar, Kurichithara K.,Ragesh, Nadakkal,Mohamed, Kolliyil S. Behaviour of Short-finned Pilot Whales Journal Article Journal of Threatened Taxa, 6 (218), pp. 6488-6492, 0000, ISBN: 0974-7907. Abstract | Links | BibTeX | Keywords: Arabian Sea, Globicephala macrorhynchus, India, short-finned pilot whale @article{, title = {Behaviour of Short-finned Pilot Whales}, author = {Sajikumar, Kurichithara K.,Ragesh, Nadakkal,Mohamed, Kolliyil S.}, url = {https://threatenedtaxa.org/index.php/JoTT/article/view/1626}, issn = {0974-7907}, journal = {Journal of Threatened Taxa}, volume = {6}, number = {218}, pages = {6488-6492}, abstract = {We report the presence and behaviour of a pod of short-finned pilot whale Globicephala macrorhynchus in the southeastern Arabian Sea. The pod was observed in the southeastern side of Minicoy Island, in the Nine degree channel (09°219′23′′N;74°39′529′′E) on 03.02.2013. Later, on 06.02.2013,the same pod of pilot whales were observed near Kalpeni Island (10°02′402′′N; 73°39′579′′E) 130 km northwest of the previous location. The average length of the whales was estimated as 550 cm and weight as approximately 1200 kg. They were travelling in a northwesterly direction. The pod size of the whales sighted was twelve and several species specific behaviour such as side rolling, spyhopping, lobtailing, peduncle arching and movement patterns such as synchronous travelling and logging could be observed. The occurrence of scars and injuries on the body of four whales in the pod are also reported.}, keywords = {Arabian Sea, Globicephala macrorhynchus, India, short-finned pilot whale}, pubstate = {published}, tppubtype = {article} } We report the presence and behaviour of a pod of short-finned pilot whale Globicephala macrorhynchus in the southeastern Arabian Sea. The pod was observed in the southeastern side of Minicoy Island, in the Nine degree channel (09°219′23′′N;74°39′529′′E) on 03.02.2013. Later, on 06.02.2013,the same pod of pilot whales were observed near Kalpeni Island (10°02′402′′N; 73°39′579′′E) 130 km northwest of the previous location. The average length of the whales was estimated as 550 cm and weight as approximately 1200 kg. They were travelling in a northwesterly direction. The pod size of the whales sighted was twelve and several species specific behaviour such as side rolling, spyhopping, lobtailing, peduncle arching and movement patterns such as synchronous travelling and logging could be observed. The occurrence of scars and injuries on the body of four whales in the pod are also reported. |
Rees, A. F.,Al Saady, S.,Broderick, A. C.,Coyne, M. S.,Papathanasopoulou, N.,Godley, B. J. Behavioural polymorphism in one of the world’s largest populations of loggerhead sea turtles Caretta caretta Journal Article Marine Ecology Progress Series, 418 (442), pp. 201-212, 2010. Abstract | Links | BibTeX | Keywords: caretta caretta, Gulf of Masirah, Loggerhead, marine turtle, Oman, Satellite telemetry, turtles @article{, title = {Behavioural polymorphism in one of the world’s largest populations of loggerhead sea turtles Caretta caretta}, author = {Rees, A. F.,Al Saady, S.,Broderick, A. C.,Coyne, M. S.,Papathanasopoulou, N.,Godley, B. J.}, url = {http://www.int-res.com/abstracts/meps/v418/p201-212/}, year = {2010}, date = {2010-01-01}, journal = {Marine Ecology Progress Series}, volume = {418}, number = {442}, pages = {201-212}, abstract = {ABSTRACT: To aid management and conservation of widely distributed marine vertebrate species, it is necessary to have a knowledge and understanding of their spatial ecology. We tracked 10 adult female loggerhead turtles \textit{Caretta caretta} from Masirah Island, Sultanate of Oman, which hosts one of the world’s largest breeding aggregations. Transmitters were specifically deployed early in the nesting season to enable tracking throughout the internesting and post-nesting habitats. Turtles displayed a dichotomy in behaviour during the internesting period, with 6 remaining close to Masirah Island and the others undertaking circuitous oceanic loops, hundreds of kilometres in length. This behaviour did not appear to be related to body size. Tracking-derived minimum clutch frequency was on average (± SD) 4.8 ± 1.2 nests (n = 8 ind.). Post-nesting migrations revealed a propensity towards long-term utilisation of oceanic habitats in the region between Socotra Island (Yemen) and the mainland of Yemen/Oman, with 76 ± 15.4% of time spent in oceanic habitat (n = 8 ind.). The spatial footprint of our tracked turtles was found to be far less than that of a similar number of turtles that were tagged later in the same season (from a separate unpublished study) and from long-distance returns of flipper tags. The spatial and temporal sub-structuring of the population highlights the need for more comprehensive tracking projects, with deployments across the breeding season in multiple years, in order to obtain reliable estimations of high-use foraging habitats of widely dispersed marine vertebrates. Variation in behaviour patterns suggests the need for diverse conservation measures.}, keywords = {caretta caretta, Gulf of Masirah, Loggerhead, marine turtle, Oman, Satellite telemetry, turtles}, pubstate = {published}, tppubtype = {article} } ABSTRACT: To aid management and conservation of widely distributed marine vertebrate species, it is necessary to have a knowledge and understanding of their spatial ecology. We tracked 10 adult female loggerhead turtles Caretta caretta from Masirah Island, Sultanate of Oman, which hosts one of the world’s largest breeding aggregations. Transmitters were specifically deployed early in the nesting season to enable tracking throughout the internesting and post-nesting habitats. Turtles displayed a dichotomy in behaviour during the internesting period, with 6 remaining close to Masirah Island and the others undertaking circuitous oceanic loops, hundreds of kilometres in length. This behaviour did not appear to be related to body size. Tracking-derived minimum clutch frequency was on average (± SD) 4.8 ± 1.2 nests (n = 8 ind.). Post-nesting migrations revealed a propensity towards long-term utilisation of oceanic habitats in the region between Socotra Island (Yemen) and the mainland of Yemen/Oman, with 76 ± 15.4% of time spent in oceanic habitat (n = 8 ind.). The spatial footprint of our tracked turtles was found to be far less than that of a similar number of turtles that were tagged later in the same season (from a separate unpublished study) and from long-distance returns of flipper tags. The spatial and temporal sub-structuring of the population highlights the need for more comprehensive tracking projects, with deployments across the breeding season in multiple years, in order to obtain reliable estimations of high-use foraging habitats of widely dispersed marine vertebrates. Variation in behaviour patterns suggests the need for diverse conservation measures. |
Brock,J.C.,Sathyendranath,S.,Platt,T. Biohydro-optical classification of the northwestern Indian Ocean Journal Article Marine Ecology Progress Series, 165 (338), pp. 1-15, 1998. Abstract | BibTeX | Keywords: Arabian Sea, chlorophyll, ecosystem, Gulf of Masirah, Indian Ocean, Oman, plankton, Upwelling @article{, title = {Biohydro-optical classification of the northwestern Indian Ocean}, author = {Brock,J.C.,Sathyendranath,S.,Platt,T.}, year = {1998}, date = {1998-01-01}, journal = {Marine Ecology Progress Series}, volume = {165}, number = {338}, pages = {1-15}, abstract = {An approach to a partial solution to the general problem of defining biogeochemical provinces for the accurate estimation of global-ocean primary production and realistic structuring of epipelagic plankton ecosystem models is presented for the northwestern Indian Ocean. This is accomplished through use of a new technique, biohydro-optical classification, that applies a rudimentary submarine light budget incorporating climatologies of incident light, mixed layer thickness, and chlorophyll to recognize fundamental modes of tropical plankton ecosystems. The three types of biohydro-optical classes found in the Arabian Sea, Typical Tropical, Mixed-Layer Bloom, and Transitional, are shown to evolve thorough the spring intermonsoon (March through May) summer southwest monsoon (June thorough August), and fall intermonsoon (Sep through Nov) under climatic forcing and in response to the resulting biological variability. Virtually all of the open Arabian Sea is within the Typical Tropical Class at the close of the spring intermonsoon. This class type is intended to identify the maximum (DCM) maintained by active algal growth, and light-rich oligotrophic shallow zone containing phytoplankton association which depends largely on regenerated nutrients. At the close of the southwest monsoon in August, a mixed layer bloom province covers much of the northern Arabian Sea. This province class corresponds to the ecosystem mode represented by tropical regions undergoing marginal or mid-ocean upwelling and greatly simplifies regional extrapolation of the local primary production algorithm. At the onset of the fall intermonsoon, the mixed layer algal bloom province in the northern and western Arabian Sea is superseded by a transitional province, which persists through the fall intermonsoon. We interpret the upper layer of the fall intermonsoon transitional province in the Arabian Sea as a special case of the shallow regenerative plankton ecosystem of oligotrophic ocean areas, where rates of zooplankton-driven nutrient regeneration and recycled production, key processes in the upper layer of the classic 2-layer euphotic zone or oligotrophic low-latitude oceans, reach extreme values.Note on diagrams/maps in paper:Of all the regions of the nw Arabian Sea, the coastal areas off Oman and Yemen are most often in the Transitional or Mixed layer bloom classes. The Gulf of Masirah maintains a mixed layer bloom class thorughout the year, even when other coastal areas of Oman switch to a Transitional class.}, keywords = {Arabian Sea, chlorophyll, ecosystem, Gulf of Masirah, Indian Ocean, Oman, plankton, Upwelling}, pubstate = {published}, tppubtype = {article} } An approach to a partial solution to the general problem of defining biogeochemical provinces for the accurate estimation of global-ocean primary production and realistic structuring of epipelagic plankton ecosystem models is presented for the northwestern Indian Ocean. This is accomplished through use of a new technique, biohydro-optical classification, that applies a rudimentary submarine light budget incorporating climatologies of incident light, mixed layer thickness, and chlorophyll to recognize fundamental modes of tropical plankton ecosystems. The three types of biohydro-optical classes found in the Arabian Sea, Typical Tropical, Mixed-Layer Bloom, and Transitional, are shown to evolve thorough the spring intermonsoon (March through May) summer southwest monsoon (June thorough August), and fall intermonsoon (Sep through Nov) under climatic forcing and in response to the resulting biological variability. Virtually all of the open Arabian Sea is within the Typical Tropical Class at the close of the spring intermonsoon. This class type is intended to identify the maximum (DCM) maintained by active algal growth, and light-rich oligotrophic shallow zone containing phytoplankton association which depends largely on regenerated nutrients. At the close of the southwest monsoon in August, a mixed layer bloom province covers much of the northern Arabian Sea. This province class corresponds to the ecosystem mode represented by tropical regions undergoing marginal or mid-ocean upwelling and greatly simplifies regional extrapolation of the local primary production algorithm. At the onset of the fall intermonsoon, the mixed layer algal bloom province in the northern and western Arabian Sea is superseded by a transitional province, which persists through the fall intermonsoon. We interpret the upper layer of the fall intermonsoon transitional province in the Arabian Sea as a special case of the shallow regenerative plankton ecosystem of oligotrophic ocean areas, where rates of zooplankton-driven nutrient regeneration and recycled production, key processes in the upper layer of the classic 2-layer euphotic zone or oligotrophic low-latitude oceans, reach extreme values.Note on diagrams/maps in paper:Of all the regions of the nw Arabian Sea, the coastal areas off Oman and Yemen are most often in the Transitional or Mixed layer bloom classes. The Gulf of Masirah maintains a mixed layer bloom class thorughout the year, even when other coastal areas of Oman switch to a Transitional class. |
Stewart, J. R.,Aspinall, S.,Beech, M.,Fenberg, P.,Hellyer, P.,Larkin, N.,Lokier, S. W.,Marx, F. G.,Meyer, M.,Miller, R.,Rainbow, P. S.,Taylor, J. D.,Whittaker, J. E.,Al-Mehsin, K.,Strohmenger, C. J. Quaternary Science Reviews, 30 (238), pp. 3675-3690, 2011, ISBN: 0277-3791. Abstract | Links | BibTeX | Keywords: Arabian Gulf, Arabian Sea, Humpback Whale, megaptera novaeangliae, United Arab Emirates @article{, title = {Biotically constrained palaeoenvironmental conditions of a mid-Holocene intertidal lagoon on the southern shore of the Arabian Gulf: evidence associated with a whale skeleton at Musaffah, Abu Dhabi, UAE}, author = {Stewart, J. R.,Aspinall, S.,Beech, M.,Fenberg, P.,Hellyer, P.,Larkin, N.,Lokier, S. W.,Marx, F. G.,Meyer, M.,Miller, R.,Rainbow, P. S.,Taylor, J. D.,Whittaker, J. E.,Al-Mehsin, K.,Strohmenger, C. J.}, url = {http://www.sciencedirect.com/science/article/pii/S0277379111002836}, issn = {0277-3791}, year = {2011}, date = {2011-01-01}, journal = {Quaternary Science Reviews}, volume = {30}, number = {238}, pages = {3675-3690}, abstract = {Whale remains (a left and right mandible, scapula, humerus and fragmentary radius and ulna as well as parts of the cranium and rostrum) belonging to a probable humpback whale (Megaptera cf. novaeangliae) were found in the well-described sabkha sequence exposed in the Musaffah Industrial Channel, Abu Dhabi, United Arab Emirates. More precisely, the whale remains were found in a series of sediments representing a range of lagoonal facies. The sediments surrounding the whale bones were age-dated at approximately 5200 14C yrsBP and are therefore interpreted to correspond to the previously documented late Flandrian sea-level peak, preceding a fall in sea-level which culminated in the supratidal sabkha overprint of the carbonates. Associated with the whale remains is an assemblage of molluscs, foraminifera and ostracods. Together with the inferred presence of sea grass and algae, these facies are interpreted to indicate a very shallow subtidal to intertidal lagoonal environment. Cirripede remains found associated with the skeleton were identified as those of the whale barnacle Coronula diadema and hence had their origins with the whale. Significantly, the low species diversity of microfossils suggests that higher salinities existed in the mid-Holocene lagoon than are present in modern counterparts. This is here inferred to be related to the onset of continental aridity in Arabia during the mid-Holocene.}, keywords = {Arabian Gulf, Arabian Sea, Humpback Whale, megaptera novaeangliae, United Arab Emirates}, pubstate = {published}, tppubtype = {article} } Whale remains (a left and right mandible, scapula, humerus and fragmentary radius and ulna as well as parts of the cranium and rostrum) belonging to a probable humpback whale (Megaptera cf. novaeangliae) were found in the well-described sabkha sequence exposed in the Musaffah Industrial Channel, Abu Dhabi, United Arab Emirates. More precisely, the whale remains were found in a series of sediments representing a range of lagoonal facies. The sediments surrounding the whale bones were age-dated at approximately 5200 14C yrsBP and are therefore interpreted to correspond to the previously documented late Flandrian sea-level peak, preceding a fall in sea-level which culminated in the supratidal sabkha overprint of the carbonates. Associated with the whale remains is an assemblage of molluscs, foraminifera and ostracods. Together with the inferred presence of sea grass and algae, these facies are interpreted to indicate a very shallow subtidal to intertidal lagoonal environment. Cirripede remains found associated with the skeleton were identified as those of the whale barnacle Coronula diadema and hence had their origins with the whale. Significantly, the low species diversity of microfossils suggests that higher salinities existed in the mid-Holocene lagoon than are present in modern counterparts. This is here inferred to be related to the onset of continental aridity in Arabia during the mid-Holocene. |
Anon. Bloom of jellyfish (Crambionela orisini) in the Oman Sea and the Persian Gulf Journal Article Iranian Fisheries Research Organisation Newsletter, 35 (297), pp. 1, 2003. BibTeX | Keywords: Invertebrates, Jellyfish, Oman Sea, Persian Gulf @article{, title = {Bloom of jellyfish (Crambionela orisini) in the Oman Sea and the Persian Gulf}, author = {Anon.}, year = {2003}, date = {2003-01-01}, journal = {Iranian Fisheries Research Organisation Newsletter}, volume = {35}, number = {297}, pages = {1}, keywords = {Invertebrates, Jellyfish, Oman Sea, Persian Gulf}, pubstate = {published}, tppubtype = {article} } |
Romanov, Evgeny V Bycatch in the tuna purse-seine fisheries of the western Indian Ocean Journal Article Fishery Bulletin, 100 (455), pp. 90-105, 2002, ISBN: 0090-0656. Abstract | BibTeX | Keywords: balaenoptera, Bryde’s whale, Bycatch, Indian Ocean, purse-Seine, tuna fishery @article{, title = {Bycatch in the tuna purse-seine fisheries of the western Indian Ocean}, author = {Romanov, Evgeny V}, issn = {0090-0656}, year = {2002}, date = {2002-01-01}, journal = {Fishery Bulletin}, volume = {100}, number = {455}, pages = {90-105}, abstract = {Bycatch taken by the tuna purse-seine fishery from the Indian Ocean pelagic ecosystem was estimated from data collected by scientific observers aboard Soviet purse seiners in the western Indian Ocean (WIO) during 1986–92. A total of 494 sets on free-swimming schools, whale-shark-associated schools, whale-associated schools, and log-associated schools were analyzed. More than 40 fish species and other marine animals were recorded. Among them only two species, yellow-fin and skipjack tunas, were target species. Average levels of bycatch were 0.518 metric tons (t) per set, and 27.1 t per 1000 t of target species. The total annual purse-seine catch of yellowfin and skipjack tunas by principal fishing nations in the WIO during 1985–94 was 118,000–277,000 t. Nonrecorded annual bycatch for this period was estimated at 944–2270 t of pelagic oceanic sharks, 720–1877 t of rainbow runners, 705–1836 t of dolphinfishes, 507–1322 t of triggerfishes, 113–294 t of wahoo, 104–251 t of billfishes, 53–112 t of mobulas and mantas, 35–89 t of mackerel scad, 9–24 t of barracudas, and 67–174 t of other fishes. In addition, turtle bycatch and whale mortalities may have occurred. Because the bycatches were not recorded by some purse-seine vessels, it was not possible to assess the full impact of the fisheries on the pelagic ecosystem of the Indian Ocean. The first step to solving this problem is for the Indian Ocean Tuna Commission to establish a pro-gram in which scientific observers are placed on board tuna purse-seine and longline vessels fishing in the WIO.}, keywords = {balaenoptera, Bryde’s whale, Bycatch, Indian Ocean, purse-Seine, tuna fishery}, pubstate = {published}, tppubtype = {article} } Bycatch taken by the tuna purse-seine fishery from the Indian Ocean pelagic ecosystem was estimated from data collected by scientific observers aboard Soviet purse seiners in the western Indian Ocean (WIO) during 1986–92. A total of 494 sets on free-swimming schools, whale-shark-associated schools, whale-associated schools, and log-associated schools were analyzed. More than 40 fish species and other marine animals were recorded. Among them only two species, yellow-fin and skipjack tunas, were target species. Average levels of bycatch were 0.518 metric tons (t) per set, and 27.1 t per 1000 t of target species. The total annual purse-seine catch of yellowfin and skipjack tunas by principal fishing nations in the WIO during 1985–94 was 118,000–277,000 t. Nonrecorded annual bycatch for this period was estimated at 944–2270 t of pelagic oceanic sharks, 720–1877 t of rainbow runners, 705–1836 t of dolphinfishes, 507–1322 t of triggerfishes, 113–294 t of wahoo, 104–251 t of billfishes, 53–112 t of mobulas and mantas, 35–89 t of mackerel scad, 9–24 t of barracudas, and 67–174 t of other fishes. In addition, turtle bycatch and whale mortalities may have occurred. Because the bycatches were not recorded by some purse-seine vessels, it was not possible to assess the full impact of the fisheries on the pelagic ecosystem of the Indian Ocean. The first step to solving this problem is for the Indian Ocean Tuna Commission to establish a pro-gram in which scientific observers are placed on board tuna purse-seine and longline vessels fishing in the WIO. |
Nanayakkara, Ranil P,Kusuminda, Tharaka,Jefferson, Thomas A Can the Indian Ocean Humpback Dolphin ( Journal Article Aquatic Mammals, 40 (182), pp. 398, 2014, ISBN: 0167-5427. Abstract | BibTeX | Keywords: Arabian Sea, humpback dolphin, Indian Ocean, photo identification, population status, sousa, Sousa plumbea, Sri Lanka, Threat assessment @article{, title = {Can the Indian Ocean Humpback Dolphin (}, author = {Nanayakkara, Ranil P,Kusuminda, Tharaka,Jefferson, Thomas A}, issn = {0167-5427}, year = {2014}, date = {2014-01-01}, journal = {Aquatic Mammals}, volume = {40}, number = {182}, pages = {398}, abstract = { Until the last few years, the only records of Indian Ocean humpback dolphins (Sousa plumbea) in Sri Lanka were a small number of older stranding records and one unconfirmed sighting, but repeated verified sightings have been made since the early 2000s in the Puttalam Lagoon area of northwestern Sri Lanka. To determine dolphin status and distribution patterns, we conducted monthly surveys of the lagoon from July 2010 to June 2011 and sighted humpback dolphins in the lagoon in every month of the year. Repeated sightings of the same six individuals were made; and in March 2011, one of these humpback dolphins was killed by dynamite fishing. It appears that the population is very small, possibly now consisting only of these five individuals, and is resident in the lagoon. Although it is likely the species was more widespread and abundant in the past, it appears that Puttalam Lagoon may be the only location where this species persists in Sri Lanka at present. Additional research is needed to investigate possible mixing with populations in India, and urgent conservation measures are recommended to ensure the long-term survival of this enigmatic species in Sri Lanka.}, keywords = {Arabian Sea, humpback dolphin, Indian Ocean, photo identification, population status, sousa, Sousa plumbea, Sri Lanka, Threat assessment}, pubstate = {published}, tppubtype = {article} } Until the last few years, the only records of Indian Ocean humpback dolphins (Sousa plumbea) in Sri Lanka were a small number of older stranding records and one unconfirmed sighting, but repeated verified sightings have been made since the early 2000s in the Puttalam Lagoon area of northwestern Sri Lanka. To determine dolphin status and distribution patterns, we conducted monthly surveys of the lagoon from July 2010 to June 2011 and sighted humpback dolphins in the lagoon in every month of the year. Repeated sightings of the same six individuals were made; and in March 2011, one of these humpback dolphins was killed by dynamite fishing. It appears that the population is very small, possibly now consisting only of these five individuals, and is resident in the lagoon. Although it is likely the species was more widespread and abundant in the past, it appears that Puttalam Lagoon may be the only location where this species persists in Sri Lanka at present. Additional research is needed to investigate possible mixing with populations in India, and urgent conservation measures are recommended to ensure the long-term survival of this enigmatic species in Sri Lanka. |
Nanayakkara, Ranil,Kusuminda, Tharaka,Jefferson, Thomas Can the Indian Ocean Humpback Dolphin ( Journal Article Aquatic Mammals, 40 (178), pp. 398-406, 2014. Abstract | BibTeX | Keywords: Arabian Sea, Distribution, humpback dolphin, Indian Ocean, Indian Ocean humpback dolphin, Individual identification, photo identification, population, Sousa plumbea, Sri Lanka @article{, title = {Can the Indian Ocean Humpback Dolphin (}, author = {Nanayakkara, Ranil,Kusuminda, Tharaka,Jefferson, Thomas}, year = {2014}, date = {2014-01-01}, journal = {Aquatic Mammals}, volume = {40}, number = {178}, pages = {398-406}, abstract = {Until the last few years, the only records of Indian Ocean humpback dolphins (Sousa plumbea) in Sri Lanka were a small number of older stranding records and one unconfirmed sighting, but repeated verified sightings have been made since the early 2000s in the Puttalam Lagoon area of northwestern Sri Lanka. To determine dolphin status and distribution patterns, we conducted monthly surveys of the lagoon from July 2010 to June 2011 and sighted humpback dolphins in the lagoon in every month of the year. Repeated sightings of the same six individuals were made; and in March 2011, one of these humpback dolphins was killed by dynamite fishing. It appears that the population is very small, possibly now consisting only of these five individuals, and is resident in the lagoon. Although it is likely the species was more widespread and abundant in the past, it appears that Puttalam Lagoon may be the only location where this species persists in Sri Lanka at present. Additional research is needed to investigate possible mixing with populations in India, and urgent conservation measures are recommended to ensure the long-term survival of this enigmatic species in Sri Lanka.}, keywords = {Arabian Sea, Distribution, humpback dolphin, Indian Ocean, Indian Ocean humpback dolphin, Individual identification, photo identification, population, Sousa plumbea, Sri Lanka}, pubstate = {published}, tppubtype = {article} } Until the last few years, the only records of Indian Ocean humpback dolphins (Sousa plumbea) in Sri Lanka were a small number of older stranding records and one unconfirmed sighting, but repeated verified sightings have been made since the early 2000s in the Puttalam Lagoon area of northwestern Sri Lanka. To determine dolphin status and distribution patterns, we conducted monthly surveys of the lagoon from July 2010 to June 2011 and sighted humpback dolphins in the lagoon in every month of the year. Repeated sightings of the same six individuals were made; and in March 2011, one of these humpback dolphins was killed by dynamite fishing. It appears that the population is very small, possibly now consisting only of these five individuals, and is resident in the lagoon. Although it is likely the species was more widespread and abundant in the past, it appears that Puttalam Lagoon may be the only location where this species persists in Sri Lanka at present. Additional research is needed to investigate possible mixing with populations in India, and urgent conservation measures are recommended to ensure the long-term survival of this enigmatic species in Sri Lanka. |
Laws,E.A.,Landry,M.R.,Barber,R.T.,Campbell,L.,Dickson,M-L.,Marra,J. Carbon cycling in primary production bottle incubations: inferences from grazing experiments and photosynthetic studies using 14C and 18O in the Arabian Sea Journal Article Deep-Sea Research Part II, 47 (142), pp. 1339-1352, 2000. Abstract | BibTeX | Keywords: Arabian Sea, respiration @article{, title = {Carbon cycling in primary production bottle incubations: inferences from grazing experiments and photosynthetic studies using 14C and 18O in the Arabian Sea}, author = {Laws,E.A.,Landry,M.R.,Barber,R.T.,Campbell,L.,Dickson,M-L.,Marra,J.}, year = {2000}, date = {2000-01-01}, journal = {Deep-Sea Research Part II}, volume = {47}, number = {142}, pages = {1339-1352}, abstract = {Estimates of photosynthesis based on the incorporation of 14C-labeled inorganic carbon into particulate carbon were compared to estimates of gross photosynthesis based on net O2 production and the production of 18O2 from H218O during the US Joint Global Ocean Flux Study (US JGOFS) Arabian Sea process cruises. For samples incubated below the surface and at optical depths <3, the 14C uptake : gross photosynthesis ratio averaged 0.45 ñ 0.1. This result is in accord with theoretical considerations of the combined effects of the Mehler reaction, photorespiration, dark respiration, excretion, and grazing e!ects on the two estimates of photosynthesis. The 14C uptake : gross photosynthesis ratio was distinctly higher (0.62) for samples incubated at the surface. This result is likely due to UV light e!ects, since the O2 and 14C incubations were done in quartz and polysulfone bottles, respectively. The 14C uptake : gross photosynthesis ratio was lower (0.31) for bottles incubated at optical depths >3. This result probably reflects an increase in the ratio of dark respiration to net photosynthesis in the vicinity of the compensation light level }, keywords = {Arabian Sea, respiration}, pubstate = {published}, tppubtype = {article} } Estimates of photosynthesis based on the incorporation of 14C-labeled inorganic carbon into particulate carbon were compared to estimates of gross photosynthesis based on net O2 production and the production of 18O2 from H218O during the US Joint Global Ocean Flux Study (US JGOFS) Arabian Sea process cruises. For samples incubated below the surface and at optical depths <3, the 14C uptake : gross photosynthesis ratio averaged 0.45 ñ 0.1. This result is in accord with theoretical considerations of the combined effects of the Mehler reaction, photorespiration, dark respiration, excretion, and grazing e!ects on the two estimates of photosynthesis. The 14C uptake : gross photosynthesis ratio was distinctly higher (0.62) for samples incubated at the surface. This result is likely due to UV light e!ects, since the O2 and 14C incubations were done in quartz and polysulfone bottles, respectively. The 14C uptake : gross photosynthesis ratio was lower (0.31) for bottles incubated at optical depths >3. This result probably reflects an increase in the ratio of dark respiration to net photosynthesis in the vicinity of the compensation light level |
Al-Masroori, H.,Al-Oufi, H.,McIlwain, J.L.,McLean, E. Catches of lost fish traps (ghost fishing) from fishing grounds near Muscat, Sultanate of Oman Journal Article Fisheries Research, 69 (282), pp. 407-414, 2004. Abstract | Links | BibTeX | Keywords: @article{, title = {Catches of lost fish traps (ghost fishing) from fishing grounds near Muscat, Sultanate of Oman}, author = {Al-Masroori, H.,Al-Oufi, H.,McIlwain, J.L.,McLean, E.}, url = {http://www.sciencedirect.com/science/article/B6T6N-4DCDD2N-2/2/ee1df9c8cbf9ba5b2439df10fe0f9550}, year = {2004}, date = {2004-01-01}, journal = {Fisheries Research}, volume = {69}, number = {282}, pages = {407-414}, abstract = {A field study was undertaken to quantify the catch rate of simulated lost fish traps at five traditional fishing grounds near Muscat and Mutrah, Sultanate of Oman. Twenty-five traps were set at depths between 16 and 36 m during the period late November 2000 to mid-July 2001. Ghost fishing mortality was estimated at 1.34 kg/trap per day, decreasing over time. An exponential model, to estimate trap ghost fishing mortality, predicted a mortality rate of 67.27 and 78.36 kg/trap during 3 and 6 months respectively, with trapped fish having a value of 55.565 RO/trap ([not, vert, similar]US$145) and 64.725 RO/trap ([not, vert, similar]US$168) respectively.1 To reduce the negative impacts of ghost trap fishing here and elsewhere, it is recommended that future traps be better marked, equipped with timed-release or degradable sections or panels, and that openings be included in the traps to release undersized animals.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A field study was undertaken to quantify the catch rate of simulated lost fish traps at five traditional fishing grounds near Muscat and Mutrah, Sultanate of Oman. Twenty-five traps were set at depths between 16 and 36 m during the period late November 2000 to mid-July 2001. Ghost fishing mortality was estimated at 1.34 kg/trap per day, decreasing over time. An exponential model, to estimate trap ghost fishing mortality, predicted a mortality rate of 67.27 and 78.36 kg/trap during 3 and 6 months respectively, with trapped fish having a value of 55.565 RO/trap ([not, vert, similar]US$145) and 64.725 RO/trap ([not, vert, similar]US$168) respectively.1 To reduce the negative impacts of ghost trap fishing here and elsewhere, it is recommended that future traps be better marked, equipped with timed-release or degradable sections or panels, and that openings be included in the traps to release undersized animals. |
Anderson, Charles,Herrera, Miguel,Ilangakoon, Anoukchika,Koya, KM,Moazzam, M,Mustika, Putu L,Sutaria, Dipani N Cetacean bycatch in Indian Ocean tuna gillnet fisheries Journal Article Endangered Species Research, 41 (292), pp. 39-53, 2020, ISSN: 1863-5407. Abstract | Links | BibTeX | Keywords: Bycatch, Estimates, Extrapolation, Gill net, gillnet, Indian Ocean, mortality, Observer programmes, Oman, Pakistan, Sri Lanka, Trends, tuna fishery @article{, title = {Cetacean bycatch in Indian Ocean tuna gillnet fisheries}, author = {Anderson, Charles,Herrera, Miguel,Ilangakoon, Anoukchika,Koya, KM,Moazzam, M,Mustika, Putu L,Sutaria, Dipani N}, url = {https://www.int-res.com/prepress/n01008.html}, doi = {https://doi.org/10.3354/esr01008}, issn = {1863-5407}, year = {2020}, date = {2020-01-01}, journal = {Endangered Species Research}, volume = {41}, number = {292}, pages = {39-53}, abstract = {Pelagic gillnet (driftnet) fisheries account for some 34% of Indian Ocean tuna catches. We combine published results from 10 bycatch sampling programmes (1981–2016) in Australia, Sri Lanka, India and Pakistan to estimate bycatch rates for cetaceans across all Indian Ocean tuna gillnet fisheries. Estimated cetacean bycatch peaked at almost 100,000 individuals yr–1 during 2004–2006, but has declined by over 15% since then, despite an increase in tuna gillnet fishing effort. These fisheries caught an estimated cumulative total of 4.1 million small cetaceans between 1950 and 2018. These bycatch estimates take little or no account of cetaceans caught by gillnet but not landed, of delayed mortality or sub-lethal impacts on cetaceans (especially whales) that escape from gillnets, of mortality associated with ghost nets, of harpoon catches made from gillnetters, nor of mortality from other tuna fisheries. Total cetacean mortality from Indian Ocean tuna fisheries may therefore be substantially higher than estimated here. Declining cetacean bycatch rates suggest that such levels of mortality are not sustainable. Indeed, mean small cetacean abundance may currently be 13% of pre-fishery levels. None of these estimates are precise, but they do demonstrate the likely order of magnitude of the issue. Countries with the largest current gillnet catches of tuna, and thus the ones likely to have the largest cetacean bycatch are (in order): Iran, Indonesia, India, Sri Lanka, Pakistan, Oman, Yemen, UAE and Tanzania. These 9 countries together may account for roughly 96% of all cetacean bycatch from tuna gillnet fisheries across the Indian Ocean. }, keywords = {Bycatch, Estimates, Extrapolation, Gill net, gillnet, Indian Ocean, mortality, Observer programmes, Oman, Pakistan, Sri Lanka, Trends, tuna fishery}, pubstate = {published}, tppubtype = {article} } Pelagic gillnet (driftnet) fisheries account for some 34% of Indian Ocean tuna catches. We combine published results from 10 bycatch sampling programmes (1981–2016) in Australia, Sri Lanka, India and Pakistan to estimate bycatch rates for cetaceans across all Indian Ocean tuna gillnet fisheries. Estimated cetacean bycatch peaked at almost 100,000 individuals yr–1 during 2004–2006, but has declined by over 15% since then, despite an increase in tuna gillnet fishing effort. These fisheries caught an estimated cumulative total of 4.1 million small cetaceans between 1950 and 2018. These bycatch estimates take little or no account of cetaceans caught by gillnet but not landed, of delayed mortality or sub-lethal impacts on cetaceans (especially whales) that escape from gillnets, of mortality associated with ghost nets, of harpoon catches made from gillnetters, nor of mortality from other tuna fisheries. Total cetacean mortality from Indian Ocean tuna fisheries may therefore be substantially higher than estimated here. Declining cetacean bycatch rates suggest that such levels of mortality are not sustainable. Indeed, mean small cetacean abundance may currently be 13% of pre-fishery levels. None of these estimates are precise, but they do demonstrate the likely order of magnitude of the issue. Countries with the largest current gillnet catches of tuna, and thus the ones likely to have the largest cetacean bycatch are (in order): Iran, Indonesia, India, Sri Lanka, Pakistan, Oman, Yemen, UAE and Tanzania. These 9 countries together may account for roughly 96% of all cetacean bycatch from tuna gillnet fisheries across the Indian Ocean. |
Minton, Gianna.,Collins, Tim.,Findlay, K.,Baldwin, R. Cetacean distribution in the coastal waters of the Sultanate of Oman Journal Article Journal of Cetacean Research and Management, 11 (410), pp. 301-313, 2010. BibTeX | Keywords: @article{, title = {Cetacean distribution in the coastal waters of the Sultanate of Oman}, author = {Minton, Gianna.,Collins, Tim.,Findlay, K.,Baldwin, R.}, year = {2010}, date = {2010-01-01}, journal = {Journal of Cetacean Research and Management}, volume = {11}, number = {410}, pages = {301-313}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Small,J.A..,Small,G.J. Cetacean observations from the Somali Democratic Republic, September 1985 through May 1987 Journal Article CEtaceans and Cetacean Research in the Indian Ocean Sanctuary: UNEP - Marine Mammal Technical Report No.3, (476), pp. 179-210, 1991. Abstract | BibTeX | Keywords: Antarctic, Blue whale, bottlenose dolphin, Bryde's whale, cetacean, cetaceans, Common dolphin, dolphin, false killer whale, Gulf of Aden, Humpback Whale, humpback whales, Indian Ocean, killer whale, location, marine, megaptera novaeangliae, melon-headed whale, migration, occurrence, Oman, Pacific Ocean, Risso's dolphin, sanctuaries, Southern Hemisphere, sperm whale, Spinner dolphin, spotted dolphin, stocks, Striped dolphin, survey, trend, Upwelling, whale, whales, whaling @article{, title = {Cetacean observations from the Somali Democratic Republic, September 1985 through May 1987}, author = {Small,J.A..,Small,G.J.}, year = {1991}, date = {1991-01-01}, journal = {CEtaceans and Cetacean Research in the Indian Ocean Sanctuary: UNEP - Marine Mammal Technical Report No.3}, number = {476}, pages = {179-210}, abstract = {Two vessels operated along the Gulf of Aden and northern Indian Ocean coasts of Somalia from Aug. 1985 through May 1987. Their fishing activities carried them on a routine basis from Djibouti to the Horn of Africa and, on many cruises, into the Indian Ocean as far south as 8øN. The frequent and regular presence of these vessels afforded a unique opportunity for research since few previous surveys along the Somalian coast were transitory and/or of short duration. There were 398 sightings of cetaceans representing at least 14 species: blue whale, Bryde's whale, sperm whale, melon-headed whale, false killer whale, killer whale, short-finned pilot whale, Indo-Pacific humpback dolphin, common dolphin, bottlenose dolphin, Risso's dolphin, spotted dolphin, striped dolphin and spinner dolphin (NO humpback whales!!). Sightings locations and related environmental data are discussed. Some trends between years were seen in the occurrence and location of blue, killer and short-finned pilot whales.}, keywords = {Antarctic, Blue whale, bottlenose dolphin, Bryde's whale, cetacean, cetaceans, Common dolphin, dolphin, false killer whale, Gulf of Aden, Humpback Whale, humpback whales, Indian Ocean, killer whale, location, marine, megaptera novaeangliae, melon-headed whale, migration, occurrence, Oman, Pacific Ocean, Risso's dolphin, sanctuaries, Southern Hemisphere, sperm whale, Spinner dolphin, spotted dolphin, stocks, Striped dolphin, survey, trend, Upwelling, whale, whales, whaling}, pubstate = {published}, tppubtype = {article} } Two vessels operated along the Gulf of Aden and northern Indian Ocean coasts of Somalia from Aug. 1985 through May 1987. Their fishing activities carried them on a routine basis from Djibouti to the Horn of Africa and, on many cruises, into the Indian Ocean as far south as 8øN. The frequent and regular presence of these vessels afforded a unique opportunity for research since few previous surveys along the Somalian coast were transitory and/or of short duration. There were 398 sightings of cetaceans representing at least 14 species: blue whale, Bryde's whale, sperm whale, melon-headed whale, false killer whale, killer whale, short-finned pilot whale, Indo-Pacific humpback dolphin, common dolphin, bottlenose dolphin, Risso's dolphin, spotted dolphin, striped dolphin and spinner dolphin (NO humpback whales!!). Sightings locations and related environmental data are discussed. Some trends between years were seen in the occurrence and location of blue, killer and short-finned pilot whales. |
Nanayakkara, Ranil P.,Herath, Jayampathi,de Mel, Ruvinda K. Cetacean Presence in the Trincomalee Bay and Adjacent Waters, Sri Lanka Journal Article Journal of Marine Biology, 2014 (180), pp. 819263, 2014, ISBN: 2633-4666. Abstract | Links | BibTeX | Keywords: Arabian Sea, balaenoptera edeni, balaenoptera musculus, Blue whale, Bryde’s whale, Distribution, diversity, Indian Ocean, Physeter macrocephalus, sperm whale, Spinner dolphin, Sri Lanka, Stenella longirostris @article{, title = {Cetacean Presence in the Trincomalee Bay and Adjacent Waters, Sri Lanka}, author = {Nanayakkara, Ranil P.,Herath, Jayampathi,de Mel, Ruvinda K.}, url = {https://doi.org/10.1155/2014/819263}, issn = {2633-4666}, year = {2014}, date = {2014-01-01}, journal = {Journal of Marine Biology}, volume = {2014}, number = {180}, pages = {819263}, publisher = {Hindawi Publishing Corporation}, abstract = {In Sri Lanka thirty species of cetaceans have been recorded to date. The canyon at Trincomalee bay is a multiple submarine canyon complex and anecdotal reports suggest that the Trincomalee bay and its adjacent waters are utilised by a number of cetacean species. Though Cetaceans are known to be abundant in the waters off Trincomalee there is a dearth of research and data pertaining to the abundance and species frequenting the Trincomalee bay and its adjacent waters. As such the current study was initiated, to get a consensus of the abundance and occurrences of species in Trincomalee Bay and its adjacent waters. Field surveys were carried out for 19 months and the research platform was a 35-foot commercial fishing vessel. 177 cetacean encounters were recorded on 67 of the 75 field days. Remarkably a total of 11 species of cetaceans which composed of two species of Baleen Whales and nine species of Toothed Whales were recorded. Delphinidae was the most common family recorded, followed by Balaenopteridae, Ziphiidae, Physeteridae, and Kogiidae. Spinner Dolphins were the most abundant cetacean owing to the large pods observed and the regularity of the sightings. They were the only species seen feeding/traveling with birds and fish (tuna). Sperm Whales, Blue Whales, and Bryde’s Whales were also relatively common. Two records of interspecific association between cetaceans were recorded. The increase in the human population in the study area has resulted in the overexploitation of marine resources which has dire repercussions on the marine mammal communities found in these waters.}, keywords = {Arabian Sea, balaenoptera edeni, balaenoptera musculus, Blue whale, Bryde’s whale, Distribution, diversity, Indian Ocean, Physeter macrocephalus, sperm whale, Spinner dolphin, Sri Lanka, Stenella longirostris}, pubstate = {published}, tppubtype = {article} } In Sri Lanka thirty species of cetaceans have been recorded to date. The canyon at Trincomalee bay is a multiple submarine canyon complex and anecdotal reports suggest that the Trincomalee bay and its adjacent waters are utilised by a number of cetacean species. Though Cetaceans are known to be abundant in the waters off Trincomalee there is a dearth of research and data pertaining to the abundance and species frequenting the Trincomalee bay and its adjacent waters. As such the current study was initiated, to get a consensus of the abundance and occurrences of species in Trincomalee Bay and its adjacent waters. Field surveys were carried out for 19 months and the research platform was a 35-foot commercial fishing vessel. 177 cetacean encounters were recorded on 67 of the 75 field days. Remarkably a total of 11 species of cetaceans which composed of two species of Baleen Whales and nine species of Toothed Whales were recorded. Delphinidae was the most common family recorded, followed by Balaenopteridae, Ziphiidae, Physeteridae, and Kogiidae. Spinner Dolphins were the most abundant cetacean owing to the large pods observed and the regularity of the sightings. They were the only species seen feeding/traveling with birds and fish (tuna). Sperm Whales, Blue Whales, and Bryde’s Whales were also relatively common. Two records of interspecific association between cetaceans were recorded. The increase in the human population in the study area has resulted in the overexploitation of marine resources which has dire repercussions on the marine mammal communities found in these waters. |
De Silva,P.H.D.H.. Cetaceans (whales, dolphins and porpoises) recorded off Sri Lanka, India, from the Arabian Sea and Gulf, Gulf of Aden and from the Red Sea Journal Article Journal of the Bombay Natural History Society, 84 (357), pp. 505-525, 1987. Abstract | BibTeX | Keywords: Antarctic, Arabia, Arabian Gulf, Arabian Sea, behaviour, Blue whale, cetacea, cetacean, cetaceans, Delphinus tropicalis, dolphin, dolphins, fin whale, Gulf of Aden, Gulf of Oman, Humpback Whale, India, Indian Ocean, mammals, marine, migration, Neophocaena phocaenoides, Oceanic, Oman, Pakistan, Porpoise, Red Sea, sanctuaries, skull, Sri Lanka, stranding, Strandings, survey, whale, whales @article{, title = {Cetaceans (whales, dolphins and porpoises) recorded off Sri Lanka, India, from the Arabian Sea and Gulf, Gulf of Aden and from the Red Sea }, author = {De Silva,P.H.D.H..}, year = {1987}, date = {1987-01-01}, journal = {Journal of the Bombay Natural History Society}, volume = {84 }, number = {357}, pages = {505-525}, abstract = {Cetacea is a highly specialized oceanic group of mammals with several of its species undertaking long migrations, often exceeding thousand miles during a single journey. During these migrations from cold polar and subpolar seas to warmer tropical and subtropical waters and their return to polar seas in summer both individual and mass strandings have very often occurred in many parts of the world, including Sri Lanka, India and the Arabian Gulf. The Cetacean records dealt with in this paper are of countries which lie at the extreme southern margin of the vast land mass of Asia with no land other than a few islands and vast stretches of the Indian Ocean between them and the Antarctica. Sri Lanka, in view of her geographic position at the southern extremity of this vast land mass (5ø 55' and 9§51'N latitude and 79§41' and 81§ 54' E longitude) has become a passing point in the movement of oceanic species including the larger whales. It has been suggested by Deraniyagala (1945, 1960b) that the movement of larger species towards the tropics from the southern temperate zone is partly associated with the periodic influx of Antarctic water toward the tropics. It is however, now fairly established that several larger species such as the Blue whale, the Fin whale and the Humpback whale show a regular migratory cycle. The majority of strandings recorded in this paper deal with individual strandings. Nevertheless there have been instances of both mass stranding and of apparent suicidal behaviour. This paper deals with 30 Cetacean species from the region. Of these records, records from Sri Lanka total 23 species, from India 24 species, from Pakistan 17 species, from the Gulf of Oman 10 species, from the Arabian Gulf 9 species, from the Gulf of Aden 6 species and from the Red Sea 7 species. Reference is also made to a skull of Delphinus tropicalis van Bree in the Colombo Museum (Skull No. 15 B) which appears to be its first record from Sri Lanka. Mention is also made of a specimen of Neophocaena phocaenoides (G. Cuvier) collected from the Wadge Bank by the Smithsonian Carangid Survey Team in March 1970 and of two incomplete skeletons of Balaenoptera physalus (Linn‚) (probably mother and calf) in the Zoological Museum, King Saud University, Riyadh, Saudi Arabia. All these specimens were identified by me. It is evident from this study that our present knowledge of the Cetacean fauna of the Indian Ocean is far from complete and that much could be accomplished by scientific institutions in the countries in the region by diligently maintaining proper records of sightings and strandings (with photographs) and by undertaking joint study surveys. It is gratifying to note that Sri Lanka, in recent years has been making much headway in this regard. During the last few years the Tulip Expedition led by Dr. Hal Whitehead has been studying the larger whales, especially the larger whales off the east coast and Dr. Stephen Leatherwood Of Hubbs-Sea World Research Institute (Marine Science), San Diego, California has recently published (1985) a summary of available information on the Cetacea of the Indian Ocean Cetacean Sanctuary on behalf of the National Aquatic Resources Agency for Sri Lanka. It is hoped that the present paper will further stimulate interest among the scientific institutions in the region and help to increase our knowledge of a group of remarkable animals at least as far as the species which inhabit and visit our seas.has become a passing point in the movement of oceanic species including the larger whales. It has been suggested by Deraniyagala (1945, 1960b) that the movement of larger species towards the tropics from the southern temperate zone is partly associated with the periodic influx of Antarctic water toward the tropics. It is however, now fairly established that several larger species such as the Blue whale, the Fin whale and the Humpback whale show a regular migratory cycle. The majority of strandings recorded in this paper deal with individual strandings. Nevertheless there have been instances of both mass stranding and of apparent suicidal behaviour. This paper deals with 30 Cetacean species from the region. Of these records, records from Sri Lanka total 23 species, from India 24 species, from Pakistan 17 species, from the Gulf of Oman 10 species, from the Arabian Gulf 9 species, from the Gulf of Aden 6 species and from the Red Sea 7 species. Reference is also made to a skull of Delphinus tropicalis van Bree in the Colombo Museum (Skull No. 15 B) which appears to be its first record from Sri Lanka. Mention is also made of a specimen of Neophocaena phocaenoides (G. Cuvier) collected from the Wadge Bank by the Smithsonian Carangid Survey Team in March 1970 and of two incomplete skeletons of Balaenoptera physalus (Linn‚) (probably mother and calf) in the Zoological Museum, King Saud University, Riyadh, Saudi Arabia. All these specimens were identified by me. It is evident from this study that our present knowledge of the Cetacean fauna of the Indian Ocean is far from complete and that much could be accomplished by scientific institutions in the countries in the region by diligently maintaining proper records of sightings and strandings (with photographs) and by undertaking joint study surveys. It is gratifying to note that Sri Lanka, in recent years has been making much headway in this regard. During the last few years the Tulip Expedition led by Dr. Hal Whitehead has been studying the larger whales, especially the larger whales off the east coast and Dr. Stephen Leatherwood Of Hubbs-Sea World Research Institute (Marine Science), San Diego, California has recently published (1985) a summary of available information on the Cetacea of the Indian Ocean Cetacean Sanctuary on behalf of the National Aquatic Resources Agency for Sri Lanka. It is hoped that the present paper will further stimulate interest among the scientific institutions in the region and help to increase our knowledge of a group of remarkable animals at least as far as the species which inhabit and visit our seas. A key to the identification of the species recorded from the region is given in Appendix. }, keywords = {Antarctic, Arabia, Arabian Gulf, Arabian Sea, behaviour, Blue whale, cetacea, cetacean, cetaceans, Delphinus tropicalis, dolphin, dolphins, fin whale, Gulf of Aden, Gulf of Oman, Humpback Whale, India, Indian Ocean, mammals, marine, migration, Neophocaena phocaenoides, Oceanic, Oman, Pakistan, Porpoise, Red Sea, sanctuaries, skull, Sri Lanka, stranding, Strandings, survey, whale, whales}, pubstate = {published}, tppubtype = {article} } Cetacea is a highly specialized oceanic group of mammals with several of its species undertaking long migrations, often exceeding thousand miles during a single journey. During these migrations from cold polar and subpolar seas to warmer tropical and subtropical waters and their return to polar seas in summer both individual and mass strandings have very often occurred in many parts of the world, including Sri Lanka, India and the Arabian Gulf. The Cetacean records dealt with in this paper are of countries which lie at the extreme southern margin of the vast land mass of Asia with no land other than a few islands and vast stretches of the Indian Ocean between them and the Antarctica. Sri Lanka, in view of her geographic position at the southern extremity of this vast land mass (5ø 55' and 9§51'N latitude and 79§41' and 81§ 54' E longitude) has become a passing point in the movement of oceanic species including the larger whales. It has been suggested by Deraniyagala (1945, 1960b) that the movement of larger species towards the tropics from the southern temperate zone is partly associated with the periodic influx of Antarctic water toward the tropics. It is however, now fairly established that several larger species such as the Blue whale, the Fin whale and the Humpback whale show a regular migratory cycle. The majority of strandings recorded in this paper deal with individual strandings. Nevertheless there have been instances of both mass stranding and of apparent suicidal behaviour. This paper deals with 30 Cetacean species from the region. Of these records, records from Sri Lanka total 23 species, from India 24 species, from Pakistan 17 species, from the Gulf of Oman 10 species, from the Arabian Gulf 9 species, from the Gulf of Aden 6 species and from the Red Sea 7 species. Reference is also made to a skull of Delphinus tropicalis van Bree in the Colombo Museum (Skull No. 15 B) which appears to be its first record from Sri Lanka. Mention is also made of a specimen of Neophocaena phocaenoides (G. Cuvier) collected from the Wadge Bank by the Smithsonian Carangid Survey Team in March 1970 and of two incomplete skeletons of Balaenoptera physalus (Linn‚) (probably mother and calf) in the Zoological Museum, King Saud University, Riyadh, Saudi Arabia. All these specimens were identified by me. It is evident from this study that our present knowledge of the Cetacean fauna of the Indian Ocean is far from complete and that much could be accomplished by scientific institutions in the countries in the region by diligently maintaining proper records of sightings and strandings (with photographs) and by undertaking joint study surveys. It is gratifying to note that Sri Lanka, in recent years has been making much headway in this regard. During the last few years the Tulip Expedition led by Dr. Hal Whitehead has been studying the larger whales, especially the larger whales off the east coast and Dr. Stephen Leatherwood Of Hubbs-Sea World Research Institute (Marine Science), San Diego, California has recently published (1985) a summary of available information on the Cetacea of the Indian Ocean Cetacean Sanctuary on behalf of the National Aquatic Resources Agency for Sri Lanka. It is hoped that the present paper will further stimulate interest among the scientific institutions in the region and help to increase our knowledge of a group of remarkable animals at least as far as the species which inhabit and visit our seas.has become a passing point in the movement of oceanic species including the larger whales. It has been suggested by Deraniyagala (1945, 1960b) that the movement of larger species towards the tropics from the southern temperate zone is partly associated with the periodic influx of Antarctic water toward the tropics. It is however, now fairly established that several larger species such as the Blue whale, the Fin whale and the Humpback whale show a regular migratory cycle. The majority of strandings recorded in this paper deal with individual strandings. Nevertheless there have been instances of both mass stranding and of apparent suicidal behaviour. This paper deals with 30 Cetacean species from the region. Of these records, records from Sri Lanka total 23 species, from India 24 species, from Pakistan 17 species, from the Gulf of Oman 10 species, from the Arabian Gulf 9 species, from the Gulf of Aden 6 species and from the Red Sea 7 species. Reference is also made to a skull of Delphinus tropicalis van Bree in the Colombo Museum (Skull No. 15 B) which appears to be its first record from Sri Lanka. Mention is also made of a specimen of Neophocaena phocaenoides (G. Cuvier) collected from the Wadge Bank by the Smithsonian Carangid Survey Team in March 1970 and of two incomplete skeletons of Balaenoptera physalus (Linn‚) (probably mother and calf) in the Zoological Museum, King Saud University, Riyadh, Saudi Arabia. All these specimens were identified by me. It is evident from this study that our present knowledge of the Cetacean fauna of the Indian Ocean is far from complete and that much could be accomplished by scientific institutions in the countries in the region by diligently maintaining proper records of sightings and strandings (with photographs) and by undertaking joint study surveys. It is gratifying to note that Sri Lanka, in recent years has been making much headway in this regard. During the last few years the Tulip Expedition led by Dr. Hal Whitehead has been studying the larger whales, especially the larger whales off the east coast and Dr. Stephen Leatherwood Of Hubbs-Sea World Research Institute (Marine Science), San Diego, California has recently published (1985) a summary of available information on the Cetacea of the Indian Ocean Cetacean Sanctuary on behalf of the National Aquatic Resources Agency for Sri Lanka. It is hoped that the present paper will further stimulate interest among the scientific institutions in the region and help to increase our knowledge of a group of remarkable animals at least as far as the species which inhabit and visit our seas. A key to the identification of the species recorded from the region is given in Appendix. |
Anderson, R Charles Cetaceans and tuna fisheries in the Western and Central Indian Ocean Journal Article International Pole and Line Federation Technical Report, 2 (10), pp. 133, 2014. Abstract | Links | BibTeX | Keywords: Arabian Sea, Bycatch, cetaceans, Fisheries, Gill net, mitigation, Northern Indian Ocean, Regional management units, Tuna @article{, title = {Cetaceans and tuna fisheries in the Western and Central Indian Ocean}, author = {Anderson, R Charles}, url = {http://www.fao.org/3/a-bg252e.pdf}, year = {2014}, date = {2014-01-01}, journal = {International Pole and Line Federation Technical Report}, volume = {2}, number = {10}, pages = {133}, abstract = {This report reviews information on interactions between cetaceans (whales and dolphins) and tuna fisheries in the western and central Indian Ocean. The average annual catch of tuna and related species in the Indian Ocean was just over 1.5 million tonnes during 2008-12. Of this, almost 1.1 million tonnes (71%) came from the western and central Indian Ocean. The main fisheries for tuna and tuna-like species in the region are gillnet (40% of reported catch during 2008-12), purse seine (26%), longline (12%), handline and troll (11%) and pole-and-line (9%). Major gillnet fishing nations include Iran, India, Sri Lanka, Pakistan, Oman and Yemen. Cetacean bycatch must be large, but is poorly documented. A rough estimation, based on the limited published information available, suggests that something in excess of 60,000 small cetaceans might be taken as bycatch each year. There is an urgent need for monitoring and management of these fisheries including the development of mitigation methods to reduce cetacean bycatch. Large-scale gillnetting on the high seas (using nets in excess of 2.5km length) is banned by both UN convention and IOTC resolution, but is being carried out by Iran, Pakistan and possibly also other countries; compliance is required. More generally, the large and still expanding gillnet capacity within the region needs to be assessed, and if appropriate either capped or reduced. Purse seining in the western and central Indian Ocean is dominated by French and Spanish fleets. An increasing proportion of sets is made on drifting fish aggregating devices (FADs) but there has been, and continues to be, a considerable number of sets made on free schools (i.e. non-FAD-associated tuna schools). Most cetaceans do not regularly associate with FADs and the major potential cetacean interactions are with free school sets. During 1981-1999, 9.6% of all sets were reported to have been made in association with baleen whales, probably Bryde’s whales (Balaenoptera brydei). When encircled, most whales are reported to escape by breaking through the net. Mortality is unknown, but may have been of the order of 10s annually. The association of free schools of large yellowfin tuna with dolphins (mostly spotted dolphins Stenella attenuata and spinner dolphins Stenella longrostris) is more contentious. This association (which is common in the Eastern Tropical Pacific and is exploited by the purse seine fishery there) has always been reported to be rare in the western Indian Ocean. However, the tuna-dolphin association is common in many coastal areas of the region and widespread in the high seas of the western Indian Ocean north of 10°S. Setting on dolphin schools has been also reported to be rare, but its true scale is questioned. Setting on cetaceans has recently been banned by EU regulation (2007) and IOTC resolution (2013), so cetacean bycatch and mortality should be much reduced in the future. 100% coverage by international observers would be ideal. Longline fisheries were dominated for several decades by East Asian nations, but now increasing catches are made by coastal countries, notably India, Sri Lanka and Seychelles. A major issue for longliners is depredation – removal of bait and damage of hooked fish by sharks and cetaceans. Several species of cetacean have been implicated, but the main one appears to be the false killer whale (Pseudorca crassidens). There is also some entanglement of cetaceans in longlines (likely following attempts at depredation). Development of mitigation measures is on-going and needs to be continued. It is possible that some longline fishermen are deliberately killing cetaceans. Several coastal countries have handline fisheries for large yellowfin tuna, which fishermen locate by their association with dolphins (mainly spotted and spinner dolphins). There is anecdotal evidence that some dolphins are hooked. Although they invariably break free or are released, the scale of any post-release mortality or of sub-lethal impacts is unknown. From the Maldivian pole-and-line fishery, there are reports of dolphins (probably Indo-pacific bottlenose dolphins, Tursiops aduncus) taking fish attracted by the lights used during night bait fishing. The scale and potential impacts of these interactions require assessment. There has been a widespread failure to monitor and manage cetacean bycatch in Indian Ocean tuna fisheries, and to develop and implement mitigation measures. The enormous, and still growing, gillnet capacity in the region should be of particular concern. There is a need for increased observer coverage of all fisheries, supplemented by electronic monitoring. Fishery-independent surveys of cetacean distribution and abundance in the western Indian Ocean are also required to inform management.}, keywords = {Arabian Sea, Bycatch, cetaceans, Fisheries, Gill net, mitigation, Northern Indian Ocean, Regional management units, Tuna}, pubstate = {published}, tppubtype = {article} } This report reviews information on interactions between cetaceans (whales and dolphins) and tuna fisheries in the western and central Indian Ocean. The average annual catch of tuna and related species in the Indian Ocean was just over 1.5 million tonnes during 2008-12. Of this, almost 1.1 million tonnes (71%) came from the western and central Indian Ocean. The main fisheries for tuna and tuna-like species in the region are gillnet (40% of reported catch during 2008-12), purse seine (26%), longline (12%), handline and troll (11%) and pole-and-line (9%). Major gillnet fishing nations include Iran, India, Sri Lanka, Pakistan, Oman and Yemen. Cetacean bycatch must be large, but is poorly documented. A rough estimation, based on the limited published information available, suggests that something in excess of 60,000 small cetaceans might be taken as bycatch each year. There is an urgent need for monitoring and management of these fisheries including the development of mitigation methods to reduce cetacean bycatch. Large-scale gillnetting on the high seas (using nets in excess of 2.5km length) is banned by both UN convention and IOTC resolution, but is being carried out by Iran, Pakistan and possibly also other countries; compliance is required. More generally, the large and still expanding gillnet capacity within the region needs to be assessed, and if appropriate either capped or reduced. Purse seining in the western and central Indian Ocean is dominated by French and Spanish fleets. An increasing proportion of sets is made on drifting fish aggregating devices (FADs) but there has been, and continues to be, a considerable number of sets made on free schools (i.e. non-FAD-associated tuna schools). Most cetaceans do not regularly associate with FADs and the major potential cetacean interactions are with free school sets. During 1981-1999, 9.6% of all sets were reported to have been made in association with baleen whales, probably Bryde’s whales (Balaenoptera brydei). When encircled, most whales are reported to escape by breaking through the net. Mortality is unknown, but may have been of the order of 10s annually. The association of free schools of large yellowfin tuna with dolphins (mostly spotted dolphins Stenella attenuata and spinner dolphins Stenella longrostris) is more contentious. This association (which is common in the Eastern Tropical Pacific and is exploited by the purse seine fishery there) has always been reported to be rare in the western Indian Ocean. However, the tuna-dolphin association is common in many coastal areas of the region and widespread in the high seas of the western Indian Ocean north of 10°S. Setting on dolphin schools has been also reported to be rare, but its true scale is questioned. Setting on cetaceans has recently been banned by EU regulation (2007) and IOTC resolution (2013), so cetacean bycatch and mortality should be much reduced in the future. 100% coverage by international observers would be ideal. Longline fisheries were dominated for several decades by East Asian nations, but now increasing catches are made by coastal countries, notably India, Sri Lanka and Seychelles. A major issue for longliners is depredation – removal of bait and damage of hooked fish by sharks and cetaceans. Several species of cetacean have been implicated, but the main one appears to be the false killer whale (Pseudorca crassidens). There is also some entanglement of cetaceans in longlines (likely following attempts at depredation). Development of mitigation measures is on-going and needs to be continued. It is possible that some longline fishermen are deliberately killing cetaceans. Several coastal countries have handline fisheries for large yellowfin tuna, which fishermen locate by their association with dolphins (mainly spotted and spinner dolphins). There is anecdotal evidence that some dolphins are hooked. Although they invariably break free or are released, the scale of any post-release mortality or of sub-lethal impacts is unknown. From the Maldivian pole-and-line fishery, there are reports of dolphins (probably Indo-pacific bottlenose dolphins, Tursiops aduncus) taking fish attracted by the lights used during night bait fishing. The scale and potential impacts of these interactions require assessment. There has been a widespread failure to monitor and manage cetacean bycatch in Indian Ocean tuna fisheries, and to develop and implement mitigation measures. The enormous, and still growing, gillnet capacity in the region should be of particular concern. There is a need for increased observer coverage of all fisheries, supplemented by electronic monitoring. Fishery-independent surveys of cetacean distribution and abundance in the western Indian Ocean are also required to inform management. |
Escalle, L.,Capietto, A.,Chavance, P.,Dubroca, L.,Delgado De Molina, A.,Murua, H.,Gaertner, D.,Romanov, E.,Spitz, J.,Kiszka, J. J.,Floch, L.,Damiano, A.,Merigot, B. Cetaceans and tuna purse seine fisheries in the Atlantic and Indian Oceans: interactions but few mortalities Journal Article Marine Ecology Progress Series, 522 (370), pp. 255-268, 2015. Abstract | Links | BibTeX | Keywords: Atlantic, Bycatch, cetaceans, Humpback Whale, Indian Ocean, megaptera novaeangliae, purse-Seine, tuna fishery @article{, title = {Cetaceans and tuna purse seine fisheries in the Atlantic and Indian Oceans: interactions but few mortalities}, author = {Escalle, L.,Capietto, A.,Chavance, P.,Dubroca, L.,Delgado De Molina, A.,Murua, H.,Gaertner, D.,Romanov, E.,Spitz, J.,Kiszka, J. J.,Floch, L.,Damiano, A.,Merigot, B.}, url = {http://www.int-res.com/abstracts/meps/v522/p255-268/}, year = {2015}, date = {2015-01-01}, journal = {Marine Ecology Progress Series}, volume = {522}, number = {370}, pages = {255-268}, abstract = {ABSTRACT: Fisheries bycatch is considered to be one of the most significant causes of mortality for many marine species, including vulnerable megafauna. In the open ocean, tuna purse seiners are known to use several cetacean species to detect tuna schools. This exposes the cetaceans to encirclement which can lead to incidental injury or death. While interactions between fishers and cetaceans have been well documented in the eastern tropical Pacific Ocean, little is known about these interactions and potential mortalities in the tropical Atlantic and Indian Oceans. Here, we provide the first quantification of these interactions in both oceans by analyzing a large database of captain’s logbooks (1980 to 2011) and observations collected by onboard scientific observers (1995 to 2011). Distribution maps of sightings per unit effort highlighted main areas of relatively high co-occurrence: east of the Seychelles (December to March), the Mozambique Channel (April to May) and the offshore waters of Gabon (April to September). The percentage of cetacean-associated fishing sets was around 3% in both oceans and datasets whereas 0.6% of sets had cetaceans encircled. Of the 194 cetaceans encircled in a purse seine net (122 baleen whales, 72 delphinids), immediate apparent survival rates were high (Atlantic: 92%, Indian: 100%). Among recorded mortalities, 8 involved pantropical spotted dolphins \textit{Stenella attenuata} and 3 involved humpback whales \textit{Megaptera novaeangliae}. These high survival rates suggest that setting nets close to cetaceans has a low immediate apparent impact on the species involved. Our findings will contribute to the development of an ecosystem approach to managing fisheries and accurate cetacean conservation measures.}, keywords = {Atlantic, Bycatch, cetaceans, Humpback Whale, Indian Ocean, megaptera novaeangliae, purse-Seine, tuna fishery}, pubstate = {published}, tppubtype = {article} } ABSTRACT: Fisheries bycatch is considered to be one of the most significant causes of mortality for many marine species, including vulnerable megafauna. In the open ocean, tuna purse seiners are known to use several cetacean species to detect tuna schools. This exposes the cetaceans to encirclement which can lead to incidental injury or death. While interactions between fishers and cetaceans have been well documented in the eastern tropical Pacific Ocean, little is known about these interactions and potential mortalities in the tropical Atlantic and Indian Oceans. Here, we provide the first quantification of these interactions in both oceans by analyzing a large database of captain’s logbooks (1980 to 2011) and observations collected by onboard scientific observers (1995 to 2011). Distribution maps of sightings per unit effort highlighted main areas of relatively high co-occurrence: east of the Seychelles (December to March), the Mozambique Channel (April to May) and the offshore waters of Gabon (April to September). The percentage of cetacean-associated fishing sets was around 3% in both oceans and datasets whereas 0.6% of sets had cetaceans encircled. Of the 194 cetaceans encircled in a purse seine net (122 baleen whales, 72 delphinids), immediate apparent survival rates were high (Atlantic: 92%, Indian: 100%). Among recorded mortalities, 8 involved pantropical spotted dolphins Stenella attenuata and 3 involved humpback whales Megaptera novaeangliae. These high survival rates suggest that setting nets close to cetaceans has a low immediate apparent impact on the species involved. Our findings will contribute to the development of an ecosystem approach to managing fisheries and accurate cetacean conservation measures. |
Ballance,L.T,Pitman,R.L. Cetaceans of the Western Tropical Indian Ocean: Distribution, Relative Abundance, and comparisons with Cetacean Communities of Two other Tropical Ecosystems Journal Article Marine Mammal Science, 14 (321), pp. 429-459, 1998. Abstract | BibTeX | Keywords: abundance, cetacean, cetaceans, Distribution, dolphin, dolphins, Gulf of Mexico, habitat preference, Indian Ocean, Maldives, Mexico, Oman, relative abundance, seabirds, survey, whale @article{, title = {Cetaceans of the Western Tropical Indian Ocean: Distribution, Relative Abundance, and comparisons with Cetacean Communities of Two other Tropical Ecosystems}, author = {Ballance,L.T,Pitman,R.L.}, year = {1998}, date = {1998-01-01}, journal = {Marine Mammal Science}, volume = {14}, number = {321}, pages = {429-459}, abstract = {We conducted a cetacean survey in the pelagic western tropical Indian Ocean (WTIO) aboard an 85-m research vessel from March to July 1995, covering 9,784 linear km. Using 25x binoculars and line-transect methods, we recorded 589 sightings of 21 species. Stenella longirostris was the most abundant cetacean, in terms of number of individuals sighted, by an order of magnitude above any other species, while Physeter macrocephalus was the most frequently sighted, in terms of number of schools. Twelve species were widespread, seven were rare, and two were localized; our sightings include new distributional records for 12 species. Significant observations included the following: (1) Delphinus cf. tropicalis was abundant off the coast of Oman (16 sightings) and readily distinguishable in the field from D. delphis and D. capensis, (2) Balaenoptera musculus was fairly common and localized in the area of the Maldives (17 sightings), and (3) three sightings were made of an unidentified bottlenose whale tentatively referred to as Indopacetus (i.e., Mesoplodon) pacificus. We recorded 26 mixed-species cetacean schools, 43 schools with which seabirds associated, and 17 schools associated with tuna. Notable among these were mixed aggregations of Stenella attenuata, S. longirostris, yellowfin tuna, and seabirds. The cetacean community of the WTIO was similar to that of the eastern tropical Pacific (ETP) and the Gulf of Mexico (GM) in several respects. First, differences in abundance rank of individual species were small, with the result that common species were common and rare species were rare, regardless of ocean. Second, these differences in abundance were due primarily to differences in encounter rate, which varied with ocean by as much as 3,000%, and less so to school size, which generally varied less than 100%. Third, regardless of ocean, three species comprised the majority of cetaceans in the community, Stenella attenuata, S. longirostris, and S. coeruleoalba, representing 62%-82% of all individuals for all species. However, the rank order of abundance for these three species differed with ocean. Most notably, S. attenuata was abundant in the ETP and GM (abundance rank = 2 and 1, respectively) but much less common in the WTIO (abundance rank = 6). Although habitat preferences for S. attenuata appear to overlap considerably with those of S. longirostris in the ETP, our results suggest there may actually be significant differences between these two species. Detailed analysis of oceanographic correlates of distribution will be necessary in order to understand fully the habitat requirements of these pelagic dolphins, often the most conspicuous elements of tropical cetacean communities around the world.}, keywords = {abundance, cetacean, cetaceans, Distribution, dolphin, dolphins, Gulf of Mexico, habitat preference, Indian Ocean, Maldives, Mexico, Oman, relative abundance, seabirds, survey, whale}, pubstate = {published}, tppubtype = {article} } We conducted a cetacean survey in the pelagic western tropical Indian Ocean (WTIO) aboard an 85-m research vessel from March to July 1995, covering 9,784 linear km. Using 25x binoculars and line-transect methods, we recorded 589 sightings of 21 species. Stenella longirostris was the most abundant cetacean, in terms of number of individuals sighted, by an order of magnitude above any other species, while Physeter macrocephalus was the most frequently sighted, in terms of number of schools. Twelve species were widespread, seven were rare, and two were localized; our sightings include new distributional records for 12 species. Significant observations included the following: (1) Delphinus cf. tropicalis was abundant off the coast of Oman (16 sightings) and readily distinguishable in the field from D. delphis and D. capensis, (2) Balaenoptera musculus was fairly common and localized in the area of the Maldives (17 sightings), and (3) three sightings were made of an unidentified bottlenose whale tentatively referred to as Indopacetus (i.e., Mesoplodon) pacificus. We recorded 26 mixed-species cetacean schools, 43 schools with which seabirds associated, and 17 schools associated with tuna. Notable among these were mixed aggregations of Stenella attenuata, S. longirostris, yellowfin tuna, and seabirds. The cetacean community of the WTIO was similar to that of the eastern tropical Pacific (ETP) and the Gulf of Mexico (GM) in several respects. First, differences in abundance rank of individual species were small, with the result that common species were common and rare species were rare, regardless of ocean. Second, these differences in abundance were due primarily to differences in encounter rate, which varied with ocean by as much as 3,000%, and less so to school size, which generally varied less than 100%. Third, regardless of ocean, three species comprised the majority of cetaceans in the community, Stenella attenuata, S. longirostris, and S. coeruleoalba, representing 62%-82% of all individuals for all species. However, the rank order of abundance for these three species differed with ocean. Most notably, S. attenuata was abundant in the ETP and GM (abundance rank = 2 and 1, respectively) but much less common in the WTIO (abundance rank = 6). Although habitat preferences for S. attenuata appear to overlap considerably with those of S. longirostris in the ETP, our results suggest there may actually be significant differences between these two species. Detailed analysis of oceanographic correlates of distribution will be necessary in order to understand fully the habitat requirements of these pelagic dolphins, often the most conspicuous elements of tropical cetacean communities around the world. |
Searchable database of publications
Endangered and Threatened Species; Identification of 14 Distinct Population Segments of the Humpback Whale (Megaptera novaeangliae) and Revision of Species-wide Listing 2016. |
Ministerial Decree 4/94: Marine Fishing and Living-Aquatic-Resources Protection law 1994. |
Oman Cetacean Database 2019. |
Oman launches high-speed ferry 2008. |
Royal Decree 6/2003: Issuing the Law of Natural Protected Areas (NPAs) and Conservation of Wildlife 2003. |
A comparison of phytoplankton populations of the Arabian Sea during the Spring Intermonsoon and Southwest Monsoon of 1995 as described by HPLC-analyzed pigments Journal Article Deep-Sea Research II, 45 (141), pp. 2133-2170, 1998. |
A Leviathan Rescue Journal Article Arabian Wildlife, 2 (304), pp. 2, 2001. |
A note on cetacean distribution in the Indian EEZ and contiguous seas during 2003-07 Journal Article Journal of Cetacean Research and Management, 10 (2), pp. 209-215, 2008. |
A note on sightings of sperm whales off the coasts of the Sultanate of Oman and the United Arab Emirates, October 1994 to October 1997 Journal Article International Whaling Commission Scientific Committee Document SC/50/CAWS22. Cambridge, UK., (301), 1998. |
A note on the comparison of humpback whale tail fluke catalogues from the Sultanate of Oman with Madagascar and the East African Mainland Journal Article Journal of Cetacean Research and Management, 11 (408), pp. 65-68, 2010. |
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