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.
Butler,M.,Bollens,S.M.,Burghalter,B.,Madin,L.P.,Horgan,E.
Mesopelagic fishes of the Arabian Sea: distribution, abundance and diet of Journal Article
In: Deep-Sea Research Part II, vol. 48, no. 61, pp. 1369-1383, 2001.
Abstract | BibTeX | Tags: abundance, Arabian Sea, diel, diet, diets, Distribution, ecology, feeding, migration, oxygen minimum, population, populations, predation, south
@article{,
title = {Mesopelagic fishes of the Arabian Sea: distribution, abundance and diet of },
author = {Butler,M.,Bollens,S.M.,Burghalter,B.,Madin,L.P.,Horgan,E.},
year = {2001},
date = {2001-01-01},
journal = {Deep-Sea Research Part II},
volume = {48},
number = {61},
pages = {1369-1383},
abstract = {Four species of predatory fishes - Chauliodus pammelas, Chauliodus sloani, Stomias afffnis and Stomias nebulosus - were collected on two cruises to the Arabian Sea during 1995. We present data on the abundances, horizontal and vertical distributions, and diet of these fishes. We also discuss briefly the importance of the oxygen minimum zone and predation on myctophid fishes to the ecology of these mesopelagic predators. Chauliodus pammelas and C. sloani appear to have only partially overlapping horizontal distributions in the Arabian Sea, with C. pammelas more common to the north and C. sloani more common to the south. Our data support previous results suggesting that diel vertical migration is the norm for these species, with smaller individuals usually nearer to the surface and larger individuals tending to stay deeper. In contrast to Chauliodus, Stomias affinis and S. nebulosus appear to have largely overlapping horizontal distributions in the Arabian Sea. However, they may have slightly di!erent vertical distributions, with S. affinis living slightly shallower (especially at night) than S. nebulosus. All four species spend most of their time in the oxygen minimum zone, entering the surface oxygenated waters (100-150 m) only at night (if at all). The diets of C. pammelas, C. sloani, and S. affinis consisted mainly of lantern fishes, Myctophidae, and other fishes. In contrast, S. nebulosus, the smaller of the two Stomias species, ate mostly copepods and other crustaceans. This differential feeding may allow the two Stomias species to co-occur. Three of these four stomiids appear to play an important role in predation on myctophid fish populations in the Arabian Sea.},
keywords = {abundance, Arabian Sea, diel, diet, diets, Distribution, ecology, feeding, migration, oxygen minimum, population, populations, predation, south},
pubstate = {published},
tppubtype = {article}
}
Four species of predatory fishes - Chauliodus pammelas, Chauliodus sloani, Stomias afffnis and Stomias nebulosus - were collected on two cruises to the Arabian Sea during 1995. We present data on the abundances, horizontal and vertical distributions, and diet of these fishes. We also discuss briefly the importance of the oxygen minimum zone and predation on myctophid fishes to the ecology of these mesopelagic predators. Chauliodus pammelas and C. sloani appear to have only partially overlapping horizontal distributions in the Arabian Sea, with C. pammelas more common to the north and C. sloani more common to the south. Our data support previous results suggesting that diel vertical migration is the norm for these species, with smaller individuals usually nearer to the surface and larger individuals tending to stay deeper. In contrast to Chauliodus, Stomias affinis and S. nebulosus appear to have largely overlapping horizontal distributions in the Arabian Sea. However, they may have slightly di!erent vertical distributions, with S. affinis living slightly shallower (especially at night) than S. nebulosus. All four species spend most of their time in the oxygen minimum zone, entering the surface oxygenated waters (100-150 m) only at night (if at all). The diets of C. pammelas, C. sloani, and S. affinis consisted mainly of lantern fishes, Myctophidae, and other fishes. In contrast, S. nebulosus, the smaller of the two Stomias species, ate mostly copepods and other crustaceans. This differential feeding may allow the two Stomias species to co-occur. Three of these four stomiids appear to play an important role in predation on myctophid fish populations in the Arabian Sea.
Weigmann,R.
On the ecology and feeding habits of the euphausiids (Crustacea) in the Arabian Sea (Zur Okologie und Eranhrungsbiologie der Euphausiaceen (Crustacea) im Arabischen Meer) Journal Article
In: Meteor Forschungsergeb., vol. 5, no. 498, pp. 11-52, 1970.
Abstract | BibTeX | Tags: Arabian Sea, biology, density, diet, Distribution, ecology, Euphausiid, feeding, Gulf of Aden, Gulf of Oman, marine, Oman, population, populations, predation, Red Sea, Upwelling, zooplankton
@article{,
title = {On the ecology and feeding habits of the euphausiids (Crustacea) in the Arabian Sea (Zur Okologie und Eranhrungsbiologie der Euphausiaceen (Crustacea) im Arabischen Meer)},
author = {Weigmann,R.},
year = {1970},
date = {1970-01-01},
journal = {Meteor Forschungsergeb.},
volume = {5},
number = {498},
pages = {11-52},
abstract = {In the present paper, the ecology and feeding habits of euphausiids are described. The samples were taken at the time of the NE-monsoon (1964/65) by R. V. 'Meteor' in the Arabian Sea and adjacent waters. 24 spp were determined. According to distribution of the spp, the following marine areas can be distinguished: Arabian Sea: 24 spp, dominant are Euphausia diomedeae, E. tenera, E. distinguenda, Stylocheiron carinatum. Gulf of Aden: 1 0 spp, dominant are Euphausia diomedeae, E. distinguenda. Red Sea: 6 spp, dominant are Euphausia diomedeae, E. distinguena. Gulf of Oman: 5 spp, dominant are Euphausia distinguenda, Pseudeuphausia latifrons. Persian Gulf: 1 sp- Pseudeuphausia latifrons. The total number of euphausiids indicate the biomass of this group. High densities of euphausiids (200-299 and > 300 individuals/l00 m super(3)) occur in the innermost part of the Gulf of Aden, in the area south of the Euqator near the African east coast, near Karachi (Indian west coast) and in the Persian Gulf. Comparison with data relating to production biology confirms that these are eutrophic zones which coincide with areas in which upwelling occurs at the time of the NE-monsoon. The central part of the Arabian Sea differs from adjacent waters by virtue of less dense euphasiid populations (>199 individuals/lOO m super(3)). Measurements relating to production biology demonstrate a relatively low concentration of primary food sources. Food material was ascertained by analysis of stomach content. The following omnivorous species were examined: Euphausia diomedeae, E. distinguenda, E. tenera, Pseudeuphausia latifronts and Thysanopoda tricuspidata. Apart from crustacean remains large numbers of Foraminifera, Radiolaria, tintinnids, dinoflagellates were found in the stomachs. Quantitatively crustaceans form the most important item in the diet. Food selection on the basis of size an form appears to be restricted to certain genera of tintinnids. The genera Stylocheiron and Nematoscelis are predators. Only crustacean remains were found in the stomachs of Stylocheiron abbreviatum, whereas Radiolaria, Foraminifera and tintinnids occurred to some extent in Nematoscelis sp. Different euphauisiids occupy different positions in the food chain in the Arabian Sea. In omnivorous species the position is variable, since they not only feed by filtering autotrophic and heterotrophic Protista, but also by predation on zooplankton. Carnivorous spp without filtering apparatus feed exclusively on zooolankton of the size of copepods. Only these spp are well established as occupying a higher position in food chain. The parasrtlc protozoan Thalassomyces fagei was found on Euphausia diomedeae, E. tenera, E. distinguenda and E. sanzoi.},
keywords = {Arabian Sea, biology, density, diet, Distribution, ecology, Euphausiid, feeding, Gulf of Aden, Gulf of Oman, marine, Oman, population, populations, predation, Red Sea, Upwelling, zooplankton},
pubstate = {published},
tppubtype = {article}
}
In the present paper, the ecology and feeding habits of euphausiids are described. The samples were taken at the time of the NE-monsoon (1964/65) by R. V. 'Meteor' in the Arabian Sea and adjacent waters. 24 spp were determined. According to distribution of the spp, the following marine areas can be distinguished: Arabian Sea: 24 spp, dominant are Euphausia diomedeae, E. tenera, E. distinguenda, Stylocheiron carinatum. Gulf of Aden: 1 0 spp, dominant are Euphausia diomedeae, E. distinguenda. Red Sea: 6 spp, dominant are Euphausia diomedeae, E. distinguena. Gulf of Oman: 5 spp, dominant are Euphausia distinguenda, Pseudeuphausia latifrons. Persian Gulf: 1 sp- Pseudeuphausia latifrons. The total number of euphausiids indicate the biomass of this group. High densities of euphausiids (200-299 and > 300 individuals/l00 m super(3)) occur in the innermost part of the Gulf of Aden, in the area south of the Euqator near the African east coast, near Karachi (Indian west coast) and in the Persian Gulf. Comparison with data relating to production biology confirms that these are eutrophic zones which coincide with areas in which upwelling occurs at the time of the NE-monsoon. The central part of the Arabian Sea differs from adjacent waters by virtue of less dense euphasiid populations (>199 individuals/lOO m super(3)). Measurements relating to production biology demonstrate a relatively low concentration of primary food sources. Food material was ascertained by analysis of stomach content. The following omnivorous species were examined: Euphausia diomedeae, E. distinguenda, E. tenera, Pseudeuphausia latifronts and Thysanopoda tricuspidata. Apart from crustacean remains large numbers of Foraminifera, Radiolaria, tintinnids, dinoflagellates were found in the stomachs. Quantitatively crustaceans form the most important item in the diet. Food selection on the basis of size an form appears to be restricted to certain genera of tintinnids. The genera Stylocheiron and Nematoscelis are predators. Only crustacean remains were found in the stomachs of Stylocheiron abbreviatum, whereas Radiolaria, Foraminifera and tintinnids occurred to some extent in Nematoscelis sp. Different euphauisiids occupy different positions in the food chain in the Arabian Sea. In omnivorous species the position is variable, since they not only feed by filtering autotrophic and heterotrophic Protista, but also by predation on zooplankton. Carnivorous spp without filtering apparatus feed exclusively on zooolankton of the size of copepods. Only these spp are well established as occupying a higher position in food chain. The parasrtlc protozoan Thalassomyces fagei was found on Euphausia diomedeae, E. tenera, E. distinguenda and E. sanzoi.