Thomas, Peter O.,Reeves, Randall R.,Brownell, Robert L.
Status of the world's baleen whales Journal Article
In: Marine Mammal Science, no. 242, 2015, ISBN: 1748-7692.
Abstract | Links | BibTeX | Tags: anthropogenic noise, baleen whales, blue whales, Bycatch, cetaceans, Climate change, Endangered species, Entanglement, IUCN, ocean acidification, Red List, ship strike, status, whaling
@article{,
title = {Status of the world's baleen whales},
author = {Thomas, Peter O.,Reeves, Randall R.,Brownell, Robert L.},
url = {http://dx.doi.org/10.1111/mms.12281},
issn = {1748-7692},
year = {2015},
date = {2015-01-01},
journal = {Marine Mammal Science},
number = {242},
abstract = {No global synthesis of the status of baleen whales has been published since the 2008 IUCN Red List assessments. Many populations remain at low numbers from historical commercial whaling, which had ceased for all but a few by 1989. Fishing gear entanglement and ship strikes are the most severe current threats. The acute and long-term effects of anthropogenic noise and the cumulative effects of multiple stressors are of concern but poorly understood. The looming consequences of climate change and ocean acidification remain difficult to characterize. North Atlantic and North Pacific right whales are among the species listed as Endangered. Southern right, bowhead, and gray whales have been assessed as Least Concern but some subpopulations of these species - western North Pacific gray whales, Chile-Peru right whales, and Svalbard/Barents Sea and Sea of Okhotsk bowhead whales - remain at low levels and are either Endangered or Critically Endangered. Eastern North Pacific blue whales have reportedly recovered, but Antarctic blue whales remain at about 1% of pre-exploitation levels. Small isolated subspecies or subpopulations, such as northern Indian Ocean blue whales, Arabian Sea humpback whales, and Mediterranean Sea fin whales are threatened while most subpopulations of sei, Bryde's, and Omura's whales are inadequately monitored and difficult to assess.},
keywords = {anthropogenic noise, baleen whales, blue whales, Bycatch, cetaceans, Climate change, Endangered species, Entanglement, IUCN, ocean acidification, Red List, ship strike, status, whaling},
pubstate = {published},
tppubtype = {article}
}
No global synthesis of the status of baleen whales has been published since the 2008 IUCN Red List assessments. Many populations remain at low numbers from historical commercial whaling, which had ceased for all but a few by 1989. Fishing gear entanglement and ship strikes are the most severe current threats. The acute and long-term effects of anthropogenic noise and the cumulative effects of multiple stressors are of concern but poorly understood. The looming consequences of climate change and ocean acidification remain difficult to characterize. North Atlantic and North Pacific right whales are among the species listed as Endangered. Southern right, bowhead, and gray whales have been assessed as Least Concern but some subpopulations of these species - western North Pacific gray whales, Chile-Peru right whales, and Svalbard/Barents Sea and Sea of Okhotsk bowhead whales - remain at low levels and are either Endangered or Critically Endangered. Eastern North Pacific blue whales have reportedly recovered, but Antarctic blue whales remain at about 1% of pre-exploitation levels. Small isolated subspecies or subpopulations, such as northern Indian Ocean blue whales, Arabian Sea humpback whales, and Mediterranean Sea fin whales are threatened while most subpopulations of sei, Bryde's, and Omura's whales are inadequately monitored and difficult to assess.
Zemsky,V.A.
Extermination of populations of commercial whale species and its possible biological consequences Technical Report
no. 268, 2005.
Abstract | BibTeX | Tags: Arabian Sea, Atlantic, Atlantic Ocean, baleen whale, baleen whales, biological consequences, cetacean, cetaceans, depletion, extermination, mammals, marine, marine mammal, Marine mammals, oil, population, populations, Southern Hemisphere, Soviet whaling, sperm whale, status, whale, whales, whaling
@techreport{,
title = {Extermination of populations of commercial whale species and its possible biological consequences},
author = {Zemsky,V.A.},
year = {2005},
date = {2005-01-01},
number = {268},
pages = {249-259},
abstract = {Cetaceans inhabit practically all seas and oceans of the world and their role in ocean biocenoses is doubtless. Being the source of nutrition and technical resources - oil, meat, etc., - this numrous group of marine mammals had also substantial meaning for the man's economic activity. In a number of coastal regions, some whales are still an important, if not one, source of protein food. All cetaceans can be subdivided into two conditional categories: those which are caught for commerial needs and those which are not. The first group comprises practically all baleen whales, the size of most of which has no analogous in terrestrial mammals, and the sperm whale - the only one of toothed whales. All other cetaceans can be referred to the second group. They are much smaller in size, but more numerous and play not less important role in biocenoses. Some of them were of commercial value in the past and now have lost it almost completely. This brief review pursues three goals: firstly, to reveal the relationship between the population number of the commercial whales and whaling in a historical aspect; secondly, to determine the significance for the estimation of the current status of the large whales' populations of the materials, pulished in 1995, on the largest falsification of statistical data on the Soviet whaling operations in the Southern Hemisphere and in some regions of the Atlantic Ocean, including the Arabian Sea and equatorial waters; thirdly, to try to reveal possible consequences of the drastic depletion of number of the large commerical whales for the ocean biogeocenoses.},
keywords = {Arabian Sea, Atlantic, Atlantic Ocean, baleen whale, baleen whales, biological consequences, cetacean, cetaceans, depletion, extermination, mammals, marine, marine mammal, Marine mammals, oil, population, populations, Southern Hemisphere, Soviet whaling, sperm whale, status, whale, whales, whaling},
pubstate = {published},
tppubtype = {techreport}
}
Cetaceans inhabit practically all seas and oceans of the world and their role in ocean biocenoses is doubtless. Being the source of nutrition and technical resources - oil, meat, etc., - this numrous group of marine mammals had also substantial meaning for the man's economic activity. In a number of coastal regions, some whales are still an important, if not one, source of protein food. All cetaceans can be subdivided into two conditional categories: those which are caught for commerial needs and those which are not. The first group comprises practically all baleen whales, the size of most of which has no analogous in terrestrial mammals, and the sperm whale - the only one of toothed whales. All other cetaceans can be referred to the second group. They are much smaller in size, but more numerous and play not less important role in biocenoses. Some of them were of commercial value in the past and now have lost it almost completely. This brief review pursues three goals: firstly, to reveal the relationship between the population number of the commercial whales and whaling in a historical aspect; secondly, to determine the significance for the estimation of the current status of the large whales' populations of the materials, pulished in 1995, on the largest falsification of statistical data on the Soviet whaling operations in the Southern Hemisphere and in some regions of the Atlantic Ocean, including the Arabian Sea and equatorial waters; thirdly, to try to reveal possible consequences of the drastic depletion of number of the large commerical whales for the ocean biogeocenoses.
Mehta,A.V.
How important are baleen whales as prey for killer whales (Orcinus orca) in high-latitude waters? PhD Thesis
2004.
Abstract | BibTeX | Tags: Alaska, Antarctic, Atlantic, Australia, baleen whales, Blue whale, blue whales, Gulf of Maine, Humpback Whale, humpback whales, killer whale, killer whales, New Caledonia, New Zealand, North Atlantic, North Atlantic right whale, North Pacific, Oman, Orca, Orcinus orca, population, prey, pygmy blue whale, Pygmy blue whales, right whale, right whales, whale, whales, whaling
@phdthesis{,
title = {How important are baleen whales as prey for killer whales (Orcinus orca) in high-latitude waters?},
author = {Mehta,A.V.},
year = {2004},
date = {2004-01-01},
number = {403},
pages = {1-15},
publisher = {Boston University},
abstract = {Data on humpback whales were collected from twenty-one regions: eleven in the North Atlantic and three in the North Pacific, as well as American Samoa, Vava'u (Tonga), New Zealand, New Caledonia, western Australia, the Antarctic Peninsula, and Oman. The other species and subspecies included in this project were sampled from a single population each (Fig. 1): North Atlantic right whales, blue whales off southeastern Australia, and pygmy blue whales (Balaenoptera musculus brevicauda) off western Australia. The proportion of whales in different sampling regions bearing rake marks ranged from 0% to over 40%. The Gulf of Maine population had a scarring rate of 9.9-11%, while SW Alaska had a rate of 21.1 to 21.9%. Oman had a rate of 9.1% (3 of 33 animals). The highest rate of scarring was the "Mexico" population with a scarring rate of over 40%. Of those scarred animals with multi-year sighting histories, 82.8% to 100% had those scars the first time they were sighted. Of the total number of whales sampled from these regions, 0% to only 4.8% acquired new or additional rake marks after their first sighting, supporting the hypothesis that most whales aquire their scars as calves, and that adult baleen whales do not constitute a major prey source for killer whales.Overall, the present study suggests that the hypothesis presented by Springer et al. (2003) - that killer whales in the North Pacific were forced by industrial whaling to switch prey from baleen whales to pinnipeds and sea otters - is untenable.},
keywords = {Alaska, Antarctic, Atlantic, Australia, baleen whales, Blue whale, blue whales, Gulf of Maine, Humpback Whale, humpback whales, killer whale, killer whales, New Caledonia, New Zealand, North Atlantic, North Atlantic right whale, North Pacific, Oman, Orca, Orcinus orca, population, prey, pygmy blue whale, Pygmy blue whales, right whale, right whales, whale, whales, whaling},
pubstate = {published},
tppubtype = {phdthesis}
}
Data on humpback whales were collected from twenty-one regions: eleven in the North Atlantic and three in the North Pacific, as well as American Samoa, Vava'u (Tonga), New Zealand, New Caledonia, western Australia, the Antarctic Peninsula, and Oman. The other species and subspecies included in this project were sampled from a single population each (Fig. 1): North Atlantic right whales, blue whales off southeastern Australia, and pygmy blue whales (Balaenoptera musculus brevicauda) off western Australia. The proportion of whales in different sampling regions bearing rake marks ranged from 0% to over 40%. The Gulf of Maine population had a scarring rate of 9.9-11%, while SW Alaska had a rate of 21.1 to 21.9%. Oman had a rate of 9.1% (3 of 33 animals). The highest rate of scarring was the "Mexico" population with a scarring rate of over 40%. Of those scarred animals with multi-year sighting histories, 82.8% to 100% had those scars the first time they were sighted. Of the total number of whales sampled from these regions, 0% to only 4.8% acquired new or additional rake marks after their first sighting, supporting the hypothesis that most whales aquire their scars as calves, and that adult baleen whales do not constitute a major prey source for killer whales.Overall, the present study suggests that the hypothesis presented by Springer et al. (2003) - that killer whales in the North Pacific were forced by industrial whaling to switch prey from baleen whales to pinnipeds and sea otters - is untenable.
Phillip Clapham, Sharon Young, Robert L. Brownell Jr
Baleen whales: conservation issues and the status of the most endangered populations Journal Article
In: Mammal Review, vol. 29 , no. 69, pp. 35-60, 1999.
Abstract | Links | BibTeX | Tags: 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 = {Phillip Clapham, Sharon Young, Robert L. Brownell Jr},
doi = {https://doi.org/10.1046/j.1365-2907.1999.00035.x},
year = {1999},
date = {1999-01-01},
urldate = {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.
Lento,G.M.,Dalebout,M.L.,Baker,C.S.
Species and individual identification of whale and dolphin products for sale in Japan by mtDNA sequences and nuclear microsatellite profiles Technical Report
no. 399, 1998.
Abstract | BibTeX | Tags: Atlantic, baleen whale, baleen whales, beaked whales, developing, DNA, dolphin, dolphins, fin whale, Japan, Microsatellite, minke whale, mtDNA, North Atlantic, Oman, population, Porpoise, pygmy sperm whale, Southern Hemisphere, sperm whale, stocks, survey, whale, whales, whaling
@techreport{,
title = {Species and individual identification of whale and dolphin products for sale in Japan by mtDNA sequences and nuclear microsatellite profiles },
author = {Lento,G.M.,Dalebout,M.L.,Baker,C.S.},
year = {1998},
date = {1998-01-01},
volume = {SC/50/O8},
number = {399},
pages = {1-12},
abstract = {We report on species and individual identification of whale and dolphin products available on commercial markets of Japan in 1997/98 based on analysis of mitochondria) DNA (mtDNA) sequences and microsatellite variation. The total sample of 74 products included four species of baleen whales, the fin (n=4), sei (n=1), northern minke (n=15) and southern minke (n=39) whales. The remaining 15 samples included dolphins (n = 8; at least four species), Baird's beaked whales (n=5), a porpoise (n=1), and a pygmy sperm whale (n=1), all sold as "kujira" in Japan. It is noted that two new species, the sei whale, and the pygmy sperm whale, appeared for the first time in this series of market surveys. With the inclusion of the sei whale, a total of eight species of baleen whale have been found for sale in post-moratorium surveys of markets in Korea and Japan. Comparison of the sei whale mtDNA to reference sequences from the North Atlantic and Southern Hemisphere suggested that this product originated from the Southern Hemisphere. The last legal hunting of this population was in 1979-80. To investigate the stock origins of northern minke whale products sold in Japan, in 1997-98, the mtDNA haplotypes of these products were compared to those found previously in Korea, 1994-97 (Lento et al. 1998). This comparison revealed that four (33%) of the 12 haplotypes among the Japanese products were identical to those from Korea. This is not consistent with the hypothesis that northern minke whale products sold in Japan originate exclusively from the scientific hunting of a stock that is genetically distinct from the Korean coastal bycatch. Instead, these findings could suggest that whales from both stocks are being hunted illegally or that whale products are being smuggled between the two countries. To further investigate the possibility of smuggling and to estimate the total number of individual whales represented in commercial products, we are developing protocols for DNA profiling using microsatellite loci. Based on preliminary analysis of three loci, the four fin whale products, representing three mtDNA haplotypes, were shown to have originated from four individuals. The 15 northern minke whale products found in 1997-98, representing 12 mtDNA haplotypes, were shown to have originated from a minimum of 14 individuals. One of these products that shared a haplotype with a 1997 product, was also shown to be unique.},
keywords = {Atlantic, baleen whale, baleen whales, beaked whales, developing, DNA, dolphin, dolphins, fin whale, Japan, Microsatellite, minke whale, mtDNA, North Atlantic, Oman, population, Porpoise, pygmy sperm whale, Southern Hemisphere, sperm whale, stocks, survey, whale, whales, whaling},
pubstate = {published},
tppubtype = {techreport}
}
We report on species and individual identification of whale and dolphin products available on commercial markets of Japan in 1997/98 based on analysis of mitochondria) DNA (mtDNA) sequences and microsatellite variation. The total sample of 74 products included four species of baleen whales, the fin (n=4), sei (n=1), northern minke (n=15) and southern minke (n=39) whales. The remaining 15 samples included dolphins (n = 8; at least four species), Baird's beaked whales (n=5), a porpoise (n=1), and a pygmy sperm whale (n=1), all sold as "kujira" in Japan. It is noted that two new species, the sei whale, and the pygmy sperm whale, appeared for the first time in this series of market surveys. With the inclusion of the sei whale, a total of eight species of baleen whale have been found for sale in post-moratorium surveys of markets in Korea and Japan. Comparison of the sei whale mtDNA to reference sequences from the North Atlantic and Southern Hemisphere suggested that this product originated from the Southern Hemisphere. The last legal hunting of this population was in 1979-80. To investigate the stock origins of northern minke whale products sold in Japan, in 1997-98, the mtDNA haplotypes of these products were compared to those found previously in Korea, 1994-97 (Lento et al. 1998). This comparison revealed that four (33%) of the 12 haplotypes among the Japanese products were identical to those from Korea. This is not consistent with the hypothesis that northern minke whale products sold in Japan originate exclusively from the scientific hunting of a stock that is genetically distinct from the Korean coastal bycatch. Instead, these findings could suggest that whales from both stocks are being hunted illegally or that whale products are being smuggled between the two countries. To further investigate the possibility of smuggling and to estimate the total number of individual whales represented in commercial products, we are developing protocols for DNA profiling using microsatellite loci. Based on preliminary analysis of three loci, the four fin whale products, representing three mtDNA haplotypes, were shown to have originated from four individuals. The 15 northern minke whale products found in 1997-98, representing 12 mtDNA haplotypes, were shown to have originated from a minimum of 14 individuals. One of these products that shared a haplotype with a 1997 product, was also shown to be unique.
Mikhalev,Y.A.
Sperm whales of the Arabian Sea Technical Report
no. 155, 1998.
Abstract | BibTeX | Tags: Arabian Sea, baleen whale, baleen whales, Blue whale, blue whales, Bryde's whale, cetacean, Humpback Whale, humpback whales, Indian Ocean, IWC, pygmy blue whale, Pygmy blue whales, Slava, Soviet whaling, sperm whale, sperm whales, whale, whales, whaling
@techreport{,
title = {Sperm whales of the Arabian Sea},
author = {Mikhalev,Y.A.},
year = {1998},
date = {1998-01-01},
journal = {Report presented to the Scientific Committee of the Internaitonal Whaling Commission},
volume = {SC/50/CAWS40},
number = {155},
pages = {1-7},
publisher = {Internaitonal Whaling Commission},
abstract = {This article is part of the ongoing publication of materials about true whale catches by Soviet whaling fleets (Yablokov, 1994, Tormosov, 1995; Zemsky, et al, 1995, 1995a, 1996; Mikhalev 1995, 1997, 1997a). The goal of this article is to provide real quantitative characteristics, as well as size and sexual composition, of the sperm whales taken by the fleets Slava and Sovietskaya Ukraina in the Arabian Sea during the period 1963 to 1967. While the catching of baleen whales - pygmy blue whales, Bryde's whales, and humpback whales - in the northwestern Indian Ocean (Mikhalev, 1995, 1997) was absolutely prohibited and thus was a most serious violation of IWC rules, the sperm whale catches in the region had a more masked character. Harvesting of this species was not restricted to areas south of the 40øS, but rather by date and animal size. The first information about sperm whales met in this region by Soviet whalers became known through Yukhov (1969) His article reported that the stock was mixed, including both barren and lactating females as well as young males. Such detailed information about the sperm whales' stock structure should have indicated that the author's primary material was not based on visual observation, but on the results of catches. After the disintegration of the Soviet Union, cetacean research laboratories were liquidated and a portion of their primary materials disappeared. Other portions ended up distributed among various former Soviet republics, now independent states, and in private archives. Nonetheless, it was possible to recover with a high level of confidence data on the biological composition, especially the quantitative and size characteristics, of whales taken in the Arabian Sea.},
keywords = {Arabian Sea, baleen whale, baleen whales, Blue whale, blue whales, Bryde's whale, cetacean, Humpback Whale, humpback whales, Indian Ocean, IWC, pygmy blue whale, Pygmy blue whales, Slava, Soviet whaling, sperm whale, sperm whales, whale, whales, whaling},
pubstate = {published},
tppubtype = {techreport}
}
This article is part of the ongoing publication of materials about true whale catches by Soviet whaling fleets (Yablokov, 1994, Tormosov, 1995; Zemsky, et al, 1995, 1995a, 1996; Mikhalev 1995, 1997, 1997a). The goal of this article is to provide real quantitative characteristics, as well as size and sexual composition, of the sperm whales taken by the fleets Slava and Sovietskaya Ukraina in the Arabian Sea during the period 1963 to 1967. While the catching of baleen whales - pygmy blue whales, Bryde's whales, and humpback whales - in the northwestern Indian Ocean (Mikhalev, 1995, 1997) was absolutely prohibited and thus was a most serious violation of IWC rules, the sperm whale catches in the region had a more masked character. Harvesting of this species was not restricted to areas south of the 40øS, but rather by date and animal size. The first information about sperm whales met in this region by Soviet whalers became known through Yukhov (1969) His article reported that the stock was mixed, including both barren and lactating females as well as young males. Such detailed information about the sperm whales' stock structure should have indicated that the author's primary material was not based on visual observation, but on the results of catches. After the disintegration of the Soviet Union, cetacean research laboratories were liquidated and a portion of their primary materials disappeared. Other portions ended up distributed among various former Soviet republics, now independent states, and in private archives. Nonetheless, it was possible to recover with a high level of confidence data on the biological composition, especially the quantitative and size characteristics, of whales taken in the Arabian Sea.
Best,P.B.
Increase rates in severely depleted stocks of baleen whales Journal Article
In: ICES Journal of Marine Science, vol. 50, no. 43, pp. 169-186, 1993.
Abstract | BibTeX | Tags: abundance, Arabian Sea, baleen whales, historical whaling, population estimates, Stock identity, whaling
@article{,
title = {Increase rates in severely depleted stocks of baleen whales},
author = {Best,P.B.},
year = {1993},
date = {1993-01-01},
journal = {ICES Journal of Marine Science},
volume = {50},
number = {43},
pages = {169-186},
abstract = {The paper tries to examine the status of all known stocks of baleen whales that were depleted to an estimated 10% of their original abundance. Of 44 such stocks, 18 are classified as not feasible to monitor (including Arabian Sea humpbacks), 12 have been or are being monitored (at the time of writing), and increase rates have been demonstrated for 10 of those. The author concludes that more depleted stocks show higher rates of increase than less depleted stocks, and that most populations are reaching a size which would allow harvesting (a minimum of 60% of their pre-exploitation numbers according to the IWC). The paper points out some interesting problems with the use of historical whaling data and mark-recapture in estimating fecundity rates. It also suggests that population increases were not detected in the years immediately following protection for two reasons: 1) commercial catches were underreported and initial post-whaling population estimates were too high, 2) following population decreases, whales may condense their ranges, leaving some historical feeding or breeding sites to form concentration areas, some of which were only recently discovered.},
keywords = {abundance, Arabian Sea, baleen whales, historical whaling, population estimates, Stock identity, whaling},
pubstate = {published},
tppubtype = {article}
}
The paper tries to examine the status of all known stocks of baleen whales that were depleted to an estimated 10% of their original abundance. Of 44 such stocks, 18 are classified as not feasible to monitor (including Arabian Sea humpbacks), 12 have been or are being monitored (at the time of writing), and increase rates have been demonstrated for 10 of those. The author concludes that more depleted stocks show higher rates of increase than less depleted stocks, and that most populations are reaching a size which would allow harvesting (a minimum of 60% of their pre-exploitation numbers according to the IWC). The paper points out some interesting problems with the use of historical whaling data and mark-recapture in estimating fecundity rates. It also suggests that population increases were not detected in the years immediately following protection for two reasons: 1) commercial catches were underreported and initial post-whaling population estimates were too high, 2) following population decreases, whales may condense their ranges, leaving some historical feeding or breeding sites to form concentration areas, some of which were only recently discovered.
Brown,S.G.
Whales observed in the Indian Ocean: notes on their distribution Journal Article
In: The Marine Observer, vol. 27, no. 339, pp. 157-165, 1957.
Abstract | BibTeX | Tags: Antarctic, Arabian Sea, Australia, baleen whales, Central Indian Ocean, cetacean, density, Distribution, Gulf of Aden, Humpback Whale, humpback whales, India, Indian Ocean, Oman, population, South Africa, Southern Hemisphere, sperm whale, sperm whales, whale, whales
@article{,
title = {Whales observed in the Indian Ocean: notes on their distribution},
author = {Brown,S.G.},
year = {1957},
date = {1957-01-01},
journal = {The Marine Observer},
volume = {27},
number = {339},
pages = {157-165},
abstract = {The paper provides a summary of the results of a questionnaire put to merchant ships and other vessels, 80 of which provided their track data. These vessels apparently had someone on watch during all daylight hours and reported all their cetacean sightings. The authors feel confident that while some sightings could not be identified to species level, a distinction could be drawn between sperm, humpback and "rorqual" whales. The "search effort" and sightings of the ships are plotted in the paper, with the majority of search effort and a high concentration of sightings occurring in the Gulf of Aden and S coast of Oman. Only two humpback whale sightings are recorded for the Northern Arabian sea - one near the horn of Africa/Somalia, and one near Sharbitat/Likbe. An additional string 4 of humpback whale sightings are recorded off the SW coast of India in the region of the Laccadive Islands.The author himself concludes: "There is apparently no great difference in the overall density of the large whale populations per unit area north and south of the equator. The highest concentrations of whales in the Indian Ocean occur in the Gulf of Aden and its approaches, the Arabian Sea and in the zone between South Africa and Australia. The least concentration is found in the Central Indian Ocean. In summer the concentration of baleen whales in the Antarctic is very many times greater than in the Indian Ocean but there is much less difference in winter . The number of sperm whales in the ocean as a whole seems not to outnumber that of the different species of baleen whales combined. Humpback whales and rorquals are found unexpectedly far north, on the supposition that they all belong to the southern hemisphere populations. Rorquals have been observed right across the 30ø to 40ø S. zone between South Africa and Australia where ships might be expected to intercept them occasionally during their migrations."},
keywords = {Antarctic, Arabian Sea, Australia, baleen whales, Central Indian Ocean, cetacean, density, Distribution, Gulf of Aden, Humpback Whale, humpback whales, India, Indian Ocean, Oman, population, South Africa, Southern Hemisphere, sperm whale, sperm whales, whale, whales},
pubstate = {published},
tppubtype = {article}
}
The paper provides a summary of the results of a questionnaire put to merchant ships and other vessels, 80 of which provided their track data. These vessels apparently had someone on watch during all daylight hours and reported all their cetacean sightings. The authors feel confident that while some sightings could not be identified to species level, a distinction could be drawn between sperm, humpback and "rorqual" whales. The "search effort" and sightings of the ships are plotted in the paper, with the majority of search effort and a high concentration of sightings occurring in the Gulf of Aden and S coast of Oman. Only two humpback whale sightings are recorded for the Northern Arabian sea - one near the horn of Africa/Somalia, and one near Sharbitat/Likbe. An additional string 4 of humpback whale sightings are recorded off the SW coast of India in the region of the Laccadive Islands.The author himself concludes: "There is apparently no great difference in the overall density of the large whale populations per unit area north and south of the equator. The highest concentrations of whales in the Indian Ocean occur in the Gulf of Aden and its approaches, the Arabian Sea and in the zone between South Africa and Australia. The least concentration is found in the Central Indian Ocean. In summer the concentration of baleen whales in the Antarctic is very many times greater than in the Indian Ocean but there is much less difference in winter . The number of sperm whales in the ocean as a whole seems not to outnumber that of the different species of baleen whales combined. Humpback whales and rorquals are found unexpectedly far north, on the supposition that they all belong to the southern hemisphere populations. Rorquals have been observed right across the 30ø to 40ø S. zone between South Africa and Australia where ships might be expected to intercept them occasionally during their migrations."