A comparative study of diet in three sympatric populations of Patagonotothen species (Pisces: Nototheniidae)
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The diet of three Patagonotothen species was investigated from the bycatch of near-bottom trawls for squid on the southern Falkland Island shelf. Patagonotothen ramsayi had a moderately diverse diet that was mostly zooplankton, especially amphipods, but included benthos and discards from the fishery, especially squid. P. guntheri also had a moderately diverse zooplankton diet, especially copepods, and benthos and squid damaged by the fishery. The diet of P. tessellata was the most diverse and was mainly benthos, including damaged scallops, with some euphausiids and amphipods. Feeding niche overlap of fish between 10 and 20 cm TL for the three species was between 5.8 and 9.2% for each pair of species, indicating relatively little overlap even though all species scavenged on organisms made available by the fishery. Thus the diet of these three Patagonotothen species indicates substantial feeding niche separation, and that the three species are moderately specialised feeders.
KeywordsLinear Discriminant Analysis Niche Breadth Falkland Island Natural Prey Niche Separation
I would like to thank the crew of FV “Sil” for their valuable help during sampling procedures and their hospitality onboard, Dr. A.W. North for his scrupulous revision of the manuscript, Dr. D. Lloris, Dr. A.I. Arkhipkin, P. Brickle and an anonymous referee for valuable comments, and the Director of Fisheries, John Barton, for supporting this work.
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