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.

Long term fisheries observer data were used to analyse the influence of a range of environmental variables and mitigation measures upon catch rates of seabirds in the Japanese pelagic longline fishery. In the Australian Fishing Zone (AFZ) seabirds were most likely to be caught on longlines that were set during summer, in southern areas of the zone, and during daylight hours. However, interpretation of changes in catch rates resulting from the use of mitigation measures or from weather effects were problematic due to the interrelationships between the many measured factors. Interpretation and accurate assessment was further complicated by ongoing changes to fishing practices and equipment, and due to changes of the priority that fisheries observers placed on the collection of seabird data. The data relating to factors affecting seabird bycatch which is currently collected incidentally by fisheries observers are not sufficiently robust to allow confidence in statistical assessments alone to examine the efficacy of mitigation measures. Dedicated observations may allow for more confident determination of the reasons why seabirds were or were not caught, and to what degree mitigation measures are effective. The use of these observations in combination with the analyses suggested seabird bycatch rates may be lowered by the use of bird lines, bait throwing machines and thawed baits. However, appropriate use and deployment of these measures are critical if they are to be effective. Further work is required to better understand the effect of these measures, and their effect upon the catch rate of target and non-target species.

A pilot census of light-mantled sooty albatross Phoebetria palpebrata nests was conducted on western Campbell Island in November 1995. An extrapolation from 292 nests counted on 19 km of coastline, more than 77 seen on offshore islands, and 32 found in four inland areas, suggests that there were at least 1600 nests on the island in 1995-96. Standard vantage points were established for future index counts. Sixty nests were monitored, and 50% were still successfully rearing chick in January-February. Five nests at Beeman Hill and 12 nests at north-west Lyall ridge were monitored closely, and adults banded.

The black petrel (Procellaria parkinsoni) is a vulnerable endemic seabird, which breeds only on Little and Great Barrier Islands, New Zealand. During late January and February 1997, within the main breeding area around the highest point on Great Barrier Island, Kirakimata (Mount Hobson), 100 burrows that had adults present were selected as long-term study burrows. The burrows were either accessible through the entrance or easily excavated to reach their contents. Eighty four of these burrows were used by breeding paris, and the remainder by non-breeding adults. The threee 1600 m2 census areas set up in 1996 around the summit were monitored over the 1997 breeding season. A total of 54 burrows were located within the census grids and 36 were being used by breeding pairs. A preliminary estiate extrapolating from the grid burrows shows the population consists of 4 500 breeding birds and at least 685 non-breeding birds.

During February and March 1998, a 43-day cruise on FV Tierra del Fuego was conducted as part of the New Fisheries Projects developed by Chile, mainly in order to establish presence of Dissostichus spp. in the CCAMLR Statistical Subareas 48.1, 48.2 and 88.3. Industrial longlines Spanish system were used for the operations, with variable quantities of fishhooks (1 440-4 320), No. 9 Mustard Kirby type, mainly between 600 and 2 550 m deep. Sardines (Sardinops sagax) and squids (Illex argentinus) were used as bait. The results of this research indicated that the Antarctic toothfish (D. mawsoni) was registered on the surroundings of Pedro I Island (Latitude 68°49'S), and from the Bellingshausen Sea (Latitude 70038'S) to the Clarence and Elephant Islands (Latitude 61°14'S). While the Patagonian toothfish (D. eleginoides) was captured from King George Island, in the Antarctic-Pacific Ocean (latitude 61°24'S) to the Scottish Sea in the Antarctic-Atlantic (Latitude 58°01'S). The Dissostichus spp. yielded small quantities in the three subareas, with values of only 5.7 g/hook (Subarea 88.3), 19.1 g/hook (Subarea 48.1) and 3.0 g/hook (Subarea 48.2), with a total average of 11.1 g/hook.