Diet composition of Champsocephalus gunnari (Pisces,Channichthyidae)around South Georgia Islands, R/V Dr. Eduardo L.Holmberg survey, February/March 1994.
MetadataShow full item record
The diet composition of the icefish Champsocephalus gunnari caught around the South Georgia Islands and Shag Rocks, Atlantic sector of Antacrtica in February/March 1994 was analyzed using the frequency of occurrence (. ) method. Krill Euphausia superba followed by the hyperiid amphipod Themisto gaudichaudii were the main prey items at South Georgia and Shag Rocks; first were found in thestomachs more frequently than in past seasons around South Georgia,in parallel with the virtual absence of mysids and Thysanoessaspp. Krill was available for fish at the same level than in previous years (e.g. 1985, 1992). However, high proportion of empty stomachs were found at South Georgia and Shag Rocks, close to the values reported for the 1991 year of krill 'shortage'. Besides, the tentative analysis of part of the samples using coefficient Q (. )showed a greater importance of T.gaudichaudii with respect to krill.It is possible that the inconsistencies found between the results obtained by both methods are due to a particular spatial distribution of krill in the area in the period of study, but no previous data are available for comparison. No krill aggregations were found in the region by acoustic methods in the 1994 summer season; a fact that might be related to a significant change in surface temperature observed during the cruise.