A monitoring program of demersal fish in inshore sites of the South Shetland Islands has continued in Potter Cove from 1991 to 1998, covering a continuous sampling period of 15 years and in Harmony Cove, Nelson Island, in the austral summer 1995/96. The decline in trammel net catches of fjord fishes of the species Notothenia rossii and Gobionotothen gibberifrons in relation to the non commercially fished Notothenia coriiceps, which was already reported for the period 1983-1990 in a previous study, is still evident. These results are supported by our knowledge on the diet of the piscivorous Antarctic shag Phalacrocorax bransfieldensis in the South Shetland/Antarctic Peninsula area in this decade. The most likely explanation for the decrease in recruitment to the inshore sub-populations of N. rossii and G. gibberifrons in the last 15 years is the effect of the offshore commercial fishery in the area in the late 1970s. This interpretation is consistent with the information on the historical offshore commercial fishing and with the results of scientific surveys in the area.

During the 1 997198 season, one vessel, Chilean registered stern trawler Betanzos, fished commercially for mackerel icefish at South Georgia (Subarea 48.3) using a midwater trawl for ten days between 25 December 1997 and 5 January 1998. The total catch of C. gunnari was 5.04 tonnes in 34 hauls. 67% of this catch was taken in just two hauls, confirming the patchy distribution of this species. Most of the catch was made up of fish between 22 and 30 cm long. Fish of this size range have previously been shown to be ages two and three. The catch of species other than C. gunnari amounted to only 0.21 tonnes. The vessel's fishing master had no experience of fishing for icefish and was not well briefed before the short trip to South Georgia. It is unclear whether the poor catches by the FV Betanzos were due to a low standing stock of the target species, or the inexperience of the fishing master.

Longline sink rates were investigated using Time Depth Recorders on a bottom autoline vessel F.V. San Aotea in New Zealand. The objective of the project was to determine line sink rate, and the effect that adding weights to the line had on its sink rate. The vessel used Mustad autoline equipment that is designed to sink without weights, so non-weighted longline line sink rate data were collected initially to give an information baseline. Further trials were then conducted using added weights as would be used in normal fishing operations to test the effectiveness of weighting the longline as a method of accelerating line sink rate and thus avoiding incidental capture of seabirds. A new rapid attachment method for Time Depth Recorders was also developed and is documented. The study found the middle of an unweighted longline of this design sinks to 10m in a mean time of 63.0 seconds (n = 11, c.v. 16.7%), compared with the start of the longline which takes a mean time 31.1 seconds (n = 11, c.v. 30.4%) to reach 10m. The tori line aerial section covered the longline for a mean time of 26.3 seconds (n = 25, c.v.13.6%). The longline weighting trials indicate that the weighting regime used had no detectable effect on the overall line sink rate. However, observation indicated that the weighting regime did have quite noticeable effects on line sink rate for 20 - 40 m either side of the attached weight. Given the data collected on line sink times and tori line coverage it would seem that we need quicker sink rates to substantially decrease the incidental mortality of seabirds during auto line fishing.