Diet composition and observations on reproduction of Champsocephalus gunnari in Subarea 48.3 in March/April 1996, Dr. Eduardo Holmberg Survey

BARRERA-ORO E.; CASAUX R.; MARSCHOFF E.

Workshop; The CCAMLR Fish Stock Assessment Working Group; 1996

The diet composition of the icefish Champsocephalus gunnari caught in the Subarea 48.3 in March/April 1996 was analyzed using frequency of occurrence (F%) and coefficient ?Q? (%) methods.  Krill was by far the main food around South Georgia and Shag Rocks (F= 85%, Q=99%). Other prey items, known as an important alternative food in years of krill scarcity, were ingested only occasionally (Themisto gaudichaudii, F=18%, Q=1% at  SG;  mysids, F=11%, Q=1.1% at SR) or in negligible amounts (Thysanoessa sp.). Many empty stomachs (56%) were found in the sampling area, in levels even higher than those reported for the 1991 and 1994 years of krill shortage. The analysis of the ovarian maturation stages indicated a high proportion of 1996 spawners, a fact which may be related with a large availability of food (=krill). It is suggested that krill was present in the region in levels equivalent to the historical years of high abundance.