Fish selectivity in eight top predators at the South Orkney Islands, Antarctica.

BERTOLIN M.; CASAUX R,

Buenos Aires

Congreso; Scientific Committee on Antarctic Research Open Science Conference; 2010

Scientific Committee on Antarctic Research

Information from two trawl surveys carried out during the 1987 and the 1999 summerseasons and on diet composition gathered from 1993 to 1999 was considered to determinethe degree of fish prey selectivity in eight top predators at the South Orkney Islands. Overall,specimens from the families Nototheniidae, Myctophidae and Channichthyidae predominatedin both trawl and diet samples. Krill-feeders such us penguins, fur seals and Cape Petrelsshowed a positive selectivity on myctophids (mainly Electrona antarctica andGymnoscopelus nicholsi) whereas benthic feeders (e.g. Weddell Seal, Antarctic Shag)positively selected nototheniid species (predominantly Trematomus newnesi andLepidonotothen nudifrons). The Antarctic fur seal presented the widest prey spectrum andthe highest number of positively selected fish species which evidence its ecological flexibilityin terms of food consumption.