Biology and distribution of South Georgia icefish (Pseudochaenichthys georgianus) around South Georgia and Shag Rocks

Pseudochaenichthys georgianus is a member of the unique Channichthyidae family, which lack haemoglobin. The distribution, length-frequency and summer diet are described from 14 bottom trawl surveys undertaken in the austral summers between 1986 and 2006. P. georgianus (50-590 mm Total Length) were caught throughout the South Georgia shelf from depths of 76 to 370 m, but very few specimens (<1%) were caught on the Shag Rocks shelf. Multiple cohorts were present during each survey and length-frequency analysis of these cohorts suggests that growth is fast during the first 3-4 years. Stomach contents analysis (2005 & 2006) indicate that P. georgianus is a pelagic or semi pelagic predator, with the summer diet dominated by Antarctic krill (Euphausia superba). Fish (channichthyids and notothenids) were also taken, but were a relatively minor part of the diet.