Distribution of mackerel icefish by size-group at South Georgia

The depth distribution of C. gunnari was investigated with data from 9 groundfish surveys between 1986 and 2000 using data from representative, randomly located hauls. The data set for South Georgia (Subarea 48.3) but excluding Shag Rocks comprised between 58 and 61 bottom trawls in each of 8 depth strata with mean depths of 112, 137, 165, 185, 208, 230, 257 and 308 m. Fish were divided into size groups representative of age-classes. Kruskal-Wallis tests on log-transformed median abundance (number of fish km?2) indicated that depth of maximum abundance increased as the size of the fish increased. The size range of all year classes was contained within the sampling depth of the surveys. The results indicate that future surveys should be designed so as to provide a uniform sampling intensity over the depth range from 100 to 300 metres depth.