Preliminary report on biological observations and exploratory fishing data collected in the South Georgia area during the 1985/86 cruise of MT Carina
A fish survey in South Georgia waters was undertaken from November 1985 to January 1986 as a part of the on-going fish stock monitoring program conducted by the Sea Fisheries Institute, Gdynia. Codends of two mesh sizes (47 and 60 mm) were used with a bottom trawl of 32 m head rope. Catch data were collected in 249 hauls using 60 mm mesh size outside the 12 nautical mile protected zone around South Georgia. Sampling tows, including some tows inside the 12 Nm zone, were made with 47 mm mesh size codends. Fifty six fish samples were taken for biological analysis. Random length measurements and detailed biological analyses were made of five species: Champsocephalus gunnari, Chaenocephalus aceratus, Pseudochaenichthys georgianus, Notothenia gibberifrons and N. rossii marmorata. Scales and otoliths were also collected for age determinations. The total catch with 60 mm mesh size codends was 1305.4 tons with a mean CPUE of 1822 kg/hour. C. gunnari comprised the bulk of the catch (62.5%), C. aceratus, P. georgianus and N. gibberifrons, 7.5 to 14% while N. rossii and D. eleginoides were present only as by-catch. In sampling catches two length groups of C. gunnari were found with modes of 18 and 28 cm. The length range of C. aceratus was 25–72 cm. P. georgianus was represented by three length groups : 20–24, 32–41 and 42–56 cm. N. gibberifrons was also represented by three length groups: 7–22/23, 22–31 and 31–49 cm. Weight/length ratios were calculated for all five species. The fish in samples were at maturity stages II to V with the majority at stage III. Feeding intensity was rather low for all species at the beginning of cruise. A rapid increase in feeding intensity of C. gunnari was observed between the second and third 10-day periods in December, while for P. georgianus and C. aceratus it remained low throughout the whole cruise. Some comparisons of the observed parameters were drawn between this and previous seasons.