Ponnampalam,Louisa S.,Collins,Tim J.Q.,Minton,Gianna,Schulz,Isabelle,Gray,Howard,Ormond,Rupert F. G.,Baldwin,Robert M.
Stomach contents of small cetaceans stranded along the Sea of Oman and Arabian Sea coasts of the Sultanate of Oman Journal Article
In: Journal of the Marine Biological Association of the United Kingdom, vol. 92, no. 436, pp. 1699-1710, 2012, ISBN: 0025-3154.
Abstract | Links | BibTeX | Tags: Arabian Sea, diet, Fisheries, Gulf of Oman, habitat partitioning, Oman, prey, stomach contents
@article{,
title = {Stomach contents of small cetaceans stranded along the Sea of Oman and Arabian Sea coasts of the Sultanate of Oman},
author = {Ponnampalam,Louisa S.,Collins,Tim J.Q.,Minton,Gianna,Schulz,Isabelle,Gray,Howard,Ormond,Rupert F. G.,Baldwin,Robert M.},
url = {http://dx.doi.org/10.1017/S0025315411002104},
issn = {0025-3154},
year = {2012},
date = {2012-01-01},
journal = {Journal of the Marine Biological Association of the United Kingdom},
volume = {92},
number = {436},
pages = {1699-1710},
abstract = {This study examined the stomach contents of 11 bottlenose dolphins (Tursiops sp.), five Indo-Pacific humpback dolphins (Sousa chinensis) and two spinner dolphins (Stenella longirostris) that were found stranded along the Omani coastline. Across the three species examined, a total of 4796 fish otoliths and 214 cephalopod beaks were found, representing at least 33 species in 22 families. Prey item importance was calculated using the percentage by number and percentage by frequency of occurrence methods, and a modified index of relative importance. The fish families Apogonidae, Carangidae and Scombridae were the most numerically important prey of the bottlenose dolphins. Sciaenidae was the most numerically important fish family for the Indo-Pacific humpback dolphins. The myctophid Benthosema pterotum formed the majority of the prey items of spinner dolphins. Cephalopod remains found in the stomach samples were represented by the families Sepiidae, Loliginidae and Onychoteuthidae. The known depth distribution of prey items of bottlenose dolphins indicated that the animals fed in a wide variety of habitats. Indo-Pacific humpback dolphin prey items indicated feeding in shallow coastal areas. Spinner dolphins appear to have exploited the upper 200 m of the water column for food, where their vertically migrating mesopelagic prey are found at night. Most prey species found in the stomach contents do not appear to be of current commercial importance in Oman. However, the findings here indicated that all three species of dolphins were feeding in areas where artisanal and/or commercial fishing occurs and has conservation implications.},
keywords = {Arabian Sea, diet, Fisheries, Gulf of Oman, habitat partitioning, Oman, prey, stomach contents},
pubstate = {published},
tppubtype = {article}
}
This study examined the stomach contents of 11 bottlenose dolphins (Tursiops sp.), five Indo-Pacific humpback dolphins (Sousa chinensis) and two spinner dolphins (Stenella longirostris) that were found stranded along the Omani coastline. Across the three species examined, a total of 4796 fish otoliths and 214 cephalopod beaks were found, representing at least 33 species in 22 families. Prey item importance was calculated using the percentage by number and percentage by frequency of occurrence methods, and a modified index of relative importance. The fish families Apogonidae, Carangidae and Scombridae were the most numerically important prey of the bottlenose dolphins. Sciaenidae was the most numerically important fish family for the Indo-Pacific humpback dolphins. The myctophid Benthosema pterotum formed the majority of the prey items of spinner dolphins. Cephalopod remains found in the stomach samples were represented by the families Sepiidae, Loliginidae and Onychoteuthidae. The known depth distribution of prey items of bottlenose dolphins indicated that the animals fed in a wide variety of habitats. Indo-Pacific humpback dolphin prey items indicated feeding in shallow coastal areas. Spinner dolphins appear to have exploited the upper 200 m of the water column for food, where their vertically migrating mesopelagic prey are found at night. Most prey species found in the stomach contents do not appear to be of current commercial importance in Oman. However, the findings here indicated that all three species of dolphins were feeding in areas where artisanal and/or commercial fishing occurs and has conservation implications.
Ponnampalam, L. S.
Ecological studies and conservation of small cetaceans in the Sultanate of Oman, with special reference to spinner dolphins, PhD Thesis
2009.
Abstract | BibTeX | Tags: Arabian Sea, diet, dolphin watching, Fisheries, Gulf of Oman, Oman, Spinner dolphin, Stenella longirostris, stomach contents, tourism, Whale watching
@phdthesis{,
title = {Ecological studies and conservation of small cetaceans in the Sultanate of Oman, with special reference to spinner dolphins, },
author = {Ponnampalam, L. S.},
year = {2009},
date = {2009-01-01},
journal = {University Marine Biological Station, Millport},
number = {434},
pages = {347},
publisher = {University of London},
abstract = {Small boat surveys were conducted in two main areas in Oman from 2004 to 2006: (1) the
Muscat capital area and (2) the Gulf of Masirah. Thirteen cetacean species were sighted during
surveys, comprising three species of mysticetes and ten species of odontocetes. Analyses of
sightings data relative to bathymetric and environmental variables revealed habitat trends in the
five most frequently encountered species. A previously undocumented calving ground for
Bryde’s whales was also revealed in the Gulf of Masirah.
Spinner dolphins in the Muscat capital area were consistently present nearshore in the mornings,
but moved offshore as the day progressed. ‘Resting’ behaviour occurred in the morning, although
‘resting’ probably also occurred during long periods of ‘slow travel’. ‘Feeding’ was confined to
the late afternoon, over deeper waters. Stomach contents of bottlenose, Indo-Pacific humpback
and spinner dolphins revealed a highly piscivorous diet. Bottlenose dolphin diet comprised prey
from a wide variety of habitats. Stomach contents of humpback dolphins concurred with their
shallow water, turbid habitats, while stomach contents of spinner dolphins indicated that their
movements offshore were to feed on organisms of the mesopelagic layer.
Spinner dolphins rested less and ‘milled’ significantly more when boat numbers around them
increased. While 82.8% of questionnaire respondents stated that the boat driver maintained a
good distance from the dolphins, only 25.4% were aware of legal guidelines. Most respondents
felt that legal guidelines should be in use and would have opted to join tours with companies
accredited as ‘responsible operators’. Omani fishermen around Muscat said that spinner dolphins
were the most frequent cetacean species in bycatch, usually in gillnets. Interviews also revealed
that fishermen elsewhere targeted dolphins for shark bait.
Scientific research, monitoring and cooperation between scientists, stakeholders and
governmental bodies is necessary to ensure proper conservation and management of cetaceans in
Oman.},
keywords = {Arabian Sea, diet, dolphin watching, Fisheries, Gulf of Oman, Oman, Spinner dolphin, Stenella longirostris, stomach contents, tourism, Whale watching},
pubstate = {published},
tppubtype = {phdthesis}
}
Small boat surveys were conducted in two main areas in Oman from 2004 to 2006: (1) the
Muscat capital area and (2) the Gulf of Masirah. Thirteen cetacean species were sighted during
surveys, comprising three species of mysticetes and ten species of odontocetes. Analyses of
sightings data relative to bathymetric and environmental variables revealed habitat trends in the
five most frequently encountered species. A previously undocumented calving ground for
Bryde’s whales was also revealed in the Gulf of Masirah.
Spinner dolphins in the Muscat capital area were consistently present nearshore in the mornings,
but moved offshore as the day progressed. ‘Resting’ behaviour occurred in the morning, although
‘resting’ probably also occurred during long periods of ‘slow travel’. ‘Feeding’ was confined to
the late afternoon, over deeper waters. Stomach contents of bottlenose, Indo-Pacific humpback
and spinner dolphins revealed a highly piscivorous diet. Bottlenose dolphin diet comprised prey
from a wide variety of habitats. Stomach contents of humpback dolphins concurred with their
shallow water, turbid habitats, while stomach contents of spinner dolphins indicated that their
movements offshore were to feed on organisms of the mesopelagic layer.
Spinner dolphins rested less and ‘milled’ significantly more when boat numbers around them
increased. While 82.8% of questionnaire respondents stated that the boat driver maintained a
good distance from the dolphins, only 25.4% were aware of legal guidelines. Most respondents
felt that legal guidelines should be in use and would have opted to join tours with companies
accredited as ‘responsible operators’. Omani fishermen around Muscat said that spinner dolphins
were the most frequent cetacean species in bycatch, usually in gillnets. Interviews also revealed
that fishermen elsewhere targeted dolphins for shark bait.
Scientific research, monitoring and cooperation between scientists, stakeholders and
governmental bodies is necessary to ensure proper conservation and management of cetaceans in
Oman.
Muscat capital area and (2) the Gulf of Masirah. Thirteen cetacean species were sighted during
surveys, comprising three species of mysticetes and ten species of odontocetes. Analyses of
sightings data relative to bathymetric and environmental variables revealed habitat trends in the
five most frequently encountered species. A previously undocumented calving ground for
Bryde’s whales was also revealed in the Gulf of Masirah.
Spinner dolphins in the Muscat capital area were consistently present nearshore in the mornings,
but moved offshore as the day progressed. ‘Resting’ behaviour occurred in the morning, although
‘resting’ probably also occurred during long periods of ‘slow travel’. ‘Feeding’ was confined to
the late afternoon, over deeper waters. Stomach contents of bottlenose, Indo-Pacific humpback
and spinner dolphins revealed a highly piscivorous diet. Bottlenose dolphin diet comprised prey
from a wide variety of habitats. Stomach contents of humpback dolphins concurred with their
shallow water, turbid habitats, while stomach contents of spinner dolphins indicated that their
movements offshore were to feed on organisms of the mesopelagic layer.
Spinner dolphins rested less and ‘milled’ significantly more when boat numbers around them
increased. While 82.8% of questionnaire respondents stated that the boat driver maintained a
good distance from the dolphins, only 25.4% were aware of legal guidelines. Most respondents
felt that legal guidelines should be in use and would have opted to join tours with companies
accredited as ‘responsible operators’. Omani fishermen around Muscat said that spinner dolphins
were the most frequent cetacean species in bycatch, usually in gillnets. Interviews also revealed
that fishermen elsewhere targeted dolphins for shark bait.
Scientific research, monitoring and cooperation between scientists, stakeholders and
governmental bodies is necessary to ensure proper conservation and management of cetaceans in
Oman.
Ponnampalam,L.,Collins,T.J.Q.,Minton,G.,Baldwin,R
Feeding ecology of small cetaceans in the Sultanate of Oman Journal Article
In: Poster presented at the 17th meeting of the Society for Marine Mammals in Cape Town, no. 433, 2007.
Abstract | BibTeX | Tags: bottlenose dolphin, bottlenose dolphins, cephalopod, cetacean, cetaceans, conservation, diet, Distribution, dolphin, dolphins, ecology, feeding, feeding ecology, fish, habitat, humpback dolphins, occurrence, Oman, prey, Spinner dolphin, Stenella longirostris, stomach contents, survey, tursiops
@article{,
title = {Feeding ecology of small cetaceans in the Sultanate of Oman},
author = {Ponnampalam,L.,Collins,T.J.Q.,Minton,G.,Baldwin,R},
year = {2007},
date = {2007-01-01},
journal = {Poster presented at the 17th meeting of the Society for Marine Mammals in Cape Town},
number = {433},
abstract = {Beach surveys were conducted along the coast of Oman between 2000 and 2006 to locate and examine cetacean remains. This study examines the stomach contents of 11 bottlenose dolphins (Tursiops sp.), 5 Indo-Pacific humpback dolphins (Sousa chinensis) and 2 spinner dolphins (Stenella longirostris) that were found beach-cast along the Omani coastline. Across the three species examined, a total of 4796 fish otoliths and 214 cephalopod beaks were found, representing 36 species in 23 families. No crustacean remains were found. Prey item importance was calculated using the percentage by number (%N), and percentage by frequency of occurrence (%FO) methods, and a modified index of relative importance (IRI). Percentage similarity was also calculated to examine interspecific and intraspecific dietary overlap. All three species of dolphins examined here ate mainly fish. The fish families Apogonidae and Carangidae were the most numerically important prey in the diet of bottlenose dolphins. Sciaenidae was the most numerically important fish family for humpback dolphins. Mesopelagic fishes comprised the diet of spinner dolphins, with the myctophid Benthosema pterotum forming the bulk of the prey items. The cephalopod preys found in the stomach samples were represented by the families Sepiidae, Loliginidae and Onychoteuthidae. The frequency distribution of prey items indicate that the bottlenose dolphins fed in a wide variety of habitats, and may reflect the occurrence of at least two species or ecotypes of Tursiops in Oman. The humpback dolphin prey items indicate feeding in coastal, nearshore areas with soft substrate. Spinner dolphins appeared to feed in the upper 200m of the water column on nocturnal vertically migrating prey. Although most of the prey species do not appear to be of commercial importance, the findings of this study indicated that all three species of dolphins were feeding in areas where fishing occurs and this is likely to have conservation implications. },
keywords = {bottlenose dolphin, bottlenose dolphins, cephalopod, cetacean, cetaceans, conservation, diet, Distribution, dolphin, dolphins, ecology, feeding, feeding ecology, fish, habitat, humpback dolphins, occurrence, Oman, prey, Spinner dolphin, Stenella longirostris, stomach contents, survey, tursiops},
pubstate = {published},
tppubtype = {article}
}
Beach surveys were conducted along the coast of Oman between 2000 and 2006 to locate and examine cetacean remains. This study examines the stomach contents of 11 bottlenose dolphins (Tursiops sp.), 5 Indo-Pacific humpback dolphins (Sousa chinensis) and 2 spinner dolphins (Stenella longirostris) that were found beach-cast along the Omani coastline. Across the three species examined, a total of 4796 fish otoliths and 214 cephalopod beaks were found, representing 36 species in 23 families. No crustacean remains were found. Prey item importance was calculated using the percentage by number (%N), and percentage by frequency of occurrence (%FO) methods, and a modified index of relative importance (IRI). Percentage similarity was also calculated to examine interspecific and intraspecific dietary overlap. All three species of dolphins examined here ate mainly fish. The fish families Apogonidae and Carangidae were the most numerically important prey in the diet of bottlenose dolphins. Sciaenidae was the most numerically important fish family for humpback dolphins. Mesopelagic fishes comprised the diet of spinner dolphins, with the myctophid Benthosema pterotum forming the bulk of the prey items. The cephalopod preys found in the stomach samples were represented by the families Sepiidae, Loliginidae and Onychoteuthidae. The frequency distribution of prey items indicate that the bottlenose dolphins fed in a wide variety of habitats, and may reflect the occurrence of at least two species or ecotypes of Tursiops in Oman. The humpback dolphin prey items indicate feeding in coastal, nearshore areas with soft substrate. Spinner dolphins appeared to feed in the upper 200m of the water column on nocturnal vertically migrating prey. Although most of the prey species do not appear to be of commercial importance, the findings of this study indicated that all three species of dolphins were feeding in areas where fishing occurs and this is likely to have conservation implications.
Mikhalev,Y.A.
Bryde's whales of the Arabian Sea and adjacent waters Technical Report
no. 157, 2002, ISBN: SC/49/035.
Abstract | BibTeX | Tags: Arabian Sea, Blue whale, blue whales, Bryde's whale, Distribution, IWC, marine, Soviet whaling, stomach contents, whale, whales, whaling
@techreport{,
title = {Bryde's whales of the Arabian Sea and adjacent waters},
author = {Mikhalev,Y.A.},
issn = {SC/49/035},
year = {2002},
date = {2002-01-01},
journal = {Report presented to the Scientific Committee of the Internaitonal Whaling Commission},
volume = {SC/49/035},
number = {157},
pages = {1-10},
abstract = {Zemsky and Sazhinov (1982) reported that the Soviet Union continued to take blue whales long after they were protected by the IWC. It became possible to pulish the data about this illegal whaling only after the disintegration of the Soviet Union (Tormosov 1993 - Report on 10th Biennial Meeting of the Society of Marine Mammalogy in Galveston, Texas; Yablokov 1994; Doroshenko 1996; Mikhalev 1997). The most complete available data on Soviet whaling were presented at the 45th and 46th meetings of the IWC and were discussed by the Scientific Committee (Zemsky et al 1995; Tormosov 1995; Zemsky et al 1996). A more detailed comparison between the accurate data and falsified data, which were submitted to the IWC by Soviet whaling fleets, for the period from 1947 to 1972 was published in a separate volume (Zemsky et al 1995, 1996). As a continuation of the recent publication of actual Soviet whaling data, this report presents data on illegal catches of Bryde's whales in the Arabian Sea and adjacent waters up to 5§ - 10§S. Data are presented on sex, size, distribution, stomach contents of whales taken as well as the reproductive state of females and the sizes of fetuses.},
keywords = {Arabian Sea, Blue whale, blue whales, Bryde's whale, Distribution, IWC, marine, Soviet whaling, stomach contents, whale, whales, whaling},
pubstate = {published},
tppubtype = {techreport}
}
Zemsky and Sazhinov (1982) reported that the Soviet Union continued to take blue whales long after they were protected by the IWC. It became possible to pulish the data about this illegal whaling only after the disintegration of the Soviet Union (Tormosov 1993 - Report on 10th Biennial Meeting of the Society of Marine Mammalogy in Galveston, Texas; Yablokov 1994; Doroshenko 1996; Mikhalev 1997). The most complete available data on Soviet whaling were presented at the 45th and 46th meetings of the IWC and were discussed by the Scientific Committee (Zemsky et al 1995; Tormosov 1995; Zemsky et al 1996). A more detailed comparison between the accurate data and falsified data, which were submitted to the IWC by Soviet whaling fleets, for the period from 1947 to 1972 was published in a separate volume (Zemsky et al 1995, 1996). As a continuation of the recent publication of actual Soviet whaling data, this report presents data on illegal catches of Bryde's whales in the Arabian Sea and adjacent waters up to 5§ - 10§S. Data are presented on sex, size, distribution, stomach contents of whales taken as well as the reproductive state of females and the sizes of fetuses.
Alling,A.
A preliminary report of marine mammal fisheries in Djibouti, Oman and Sri Lanka Technical Report
no. 280, 1992.
Abstract | BibTeX | Tags: Arctic, cetacean, cetaceans, dolphin, dolphins, Fisheries, habitat, Indian Ocean, marine, marine mammal, North Pacific, Oman, Porpoise, sanctuaries, skull, skulls, Sri Lanka, status, stomach contents, whale, whales
@techreport{,
title = {A preliminary report of marine mammal fisheries in Djibouti, Oman and Sri Lanka },
author = {Alling,A.},
year = {1992},
date = {1992-01-01},
volume = {694 },
number = {280},
pages = {1-10},
abstract = {INTRODUCTION During the 1982 and 1983 field seasons on Tulip, an effort was made to assess the status of small whale fisheries in Djibouti, Oman and Sri Lanka. In lieu of the fact that the World Wildlife Funds Indian Ocean Whale study still has one more year of field work, this preliminary report will only summarise our findings as of April, 1983. Officials and fisherman were contacted during port calls in 1982 to obtain information about local hunting and entrapment of cetaceans and members of the Tulip crew travelled to 9 harbours in Sri Lanka to interview fishermen. Dolphins seen in fish markets were measured, identified, stomach contents taken, and skulls collected for positive identification. In 1982 one fisherman on the west coast of Sri Lanka was asked to keep a daily log of all cetaceans entrapped or harpooned for a duration of one year. In 1983 we increased the number of harbours Monitored and four additional fishermen, three on the east coast and one on the west coast, were asked to keep these journals. A constant watch was kept at sea for all cetacean sightings. Species seen were identified using three identification guides: Whales, Dolphins and Porpoises of the Eastern North Pacific and Adjacent Arctic Waters (Leatherwood et al., 1982), Sea Guide to, Whales of the World (Watson, 1982), and A Field Guide to Whales and Dolphins (Captain Morzer Bruyns, 1971). When the identification was questionable, animals were photographed for confirmation of identity at a later date. },
keywords = {Arctic, cetacean, cetaceans, dolphin, dolphins, Fisheries, habitat, Indian Ocean, marine, marine mammal, North Pacific, Oman, Porpoise, sanctuaries, skull, skulls, Sri Lanka, status, stomach contents, whale, whales},
pubstate = {published},
tppubtype = {techreport}
}
INTRODUCTION During the 1982 and 1983 field seasons on Tulip, an effort was made to assess the status of small whale fisheries in Djibouti, Oman and Sri Lanka. In lieu of the fact that the World Wildlife Funds Indian Ocean Whale study still has one more year of field work, this preliminary report will only summarise our findings as of April, 1983. Officials and fisherman were contacted during port calls in 1982 to obtain information about local hunting and entrapment of cetaceans and members of the Tulip crew travelled to 9 harbours in Sri Lanka to interview fishermen. Dolphins seen in fish markets were measured, identified, stomach contents taken, and skulls collected for positive identification. In 1982 one fisherman on the west coast of Sri Lanka was asked to keep a daily log of all cetaceans entrapped or harpooned for a duration of one year. In 1983 we increased the number of harbours Monitored and four additional fishermen, three on the east coast and one on the west coast, were asked to keep these journals. A constant watch was kept at sea for all cetacean sightings. Species seen were identified using three identification guides: Whales, Dolphins and Porpoises of the Eastern North Pacific and Adjacent Arctic Waters (Leatherwood et al., 1982), Sea Guide to, Whales of the World (Watson, 1982), and A Field Guide to Whales and Dolphins (Captain Morzer Bruyns, 1971). When the identification was questionable, animals were photographed for confirmation of identity at a later date.