CCAMLR

A new fishery was declared for Dissostichus spp in Division 58.4.3 for the 1996197 season. Results of a brief survey by an Australian vessel are presented, but catches were very low. A new proposal for an exploratory fishery in Division 58.4.3 is presented. This involves a random stratified trawl survey to be undertaken in parallel with commercial exploration, and the collection of a comprehensive data set from both the survey and commercial operations.

This paper provides an assessment of the long-term annual yield for three species caught as by-catch in the commercial trawl fisheries in the Heard Island area (Statistical SubArea 58.5.2): Channichthys rhinoceratus, Lepidonotothen squamifrons and skates (Bathyraja spp.). These assessments were undertaken with the aim of examining the potential for the commercial trawl fisheries to significantly affect the spawning biomass of these stocks in the longer term. The long-term annual yield for each of the three species were estimated using the generalised yield model developed for WG-FSA, based on survey data obtained from the region in 1990-1993. Values for missing input parameters were obtained from the literature. The second part of the analysis examined the amount of each species caught in the commercial operations, the nature of the trawl operations in which they were caught and the effectiveness of current by-catch provisions in CCAMLR to ensure the status of these species is not affected by these fisheries. The estimates of long term annual yields for Channichthys rhinoceratus, Lepidonotothen squamifrons and skates were 69-97 tonnes (average 80 t), 7-91 1 tonnes (average 325 t) and 50-210 tonnes (average 120 t) respectively. Notably, the by-catch in 1997 did not exceed the lowest estimates of yield for each species. The results indicate that the current commercial trawl fisheries around Heard Island are unlikely to be negatively affecting these stocks. Notably, the large majority of infringements of the 5% by-catch rule in CCAMLR were caused by very small amounts of by-catch. This occurs, especially in prospecting mode, when the catch of target species is low, and hence the amount of by-catch necessary to trigger the 5% rule is also very low. Most infringements were caused by less than l00kg of by-catch. While the basic role of the by-catch provisions is to protect the by-catch species from over-exploitation combined with protection them from being targetted by commercial operations, the current 5% by-catch rule excludes many areas from prospecting. In order to enable prospecting for commercial aggregations of icefish or toothfish while protecting the by-catch species from excessive fishing effort, the by-catch rule could be modified for the Heard Island area to allow catches of by-catch species of up to 100 kg in any one haul. However, if this level is exceeded by any one of the by-catch species then the 5% rule should be enforced.

Assessments of the abundance and potential yield of mackerel icefish (Champsocephalus gunnari) populations at Heard Island are developed from the results of four scientific surveys conducted in 1990, 1992, 1993 and 1997. The assessments include estimates of all the parameters required, based on the data collected during the surveys, including growth curves, natural mortality, ages and sizes of maturity and a weight length relationship. The results show that characteristics of icefish populations on the Heard plateau are sufficiently different from those on Shell Bank for them to be managed separately. Precautionary catch limits calculated using the Generalised Yield model are found to be 180 tonnes for the plateau and 18 tonnes for Shell Bank. An assessment based on the results of a survey conducted at the end of the 1997 fishing season would allow for a catch limit on the Heard plateau of 900 tonnes in the 1997/98 season and 600 tonnes in 1998/99.

The population and conservation status of the world's albatrosses are reviewed within the framework of recent taxonomic changes. The latest estimates of size of breeding populations (pairs) at all known localities of each of the 24 proposed species are presented; population trends are assessed where sufficient data are available. Despite increased efforts in population monitoring, the status (i.e.. population trends) of two-thirds of the world's ca. 150 albatross populations remain unknown. For those that are known, almost half are decreasing. The threats currently facing each species are briefly reviewed. The best available evidence indicates that longline fishing is the most serious threat facing albatrosses today. Twenty-one of the 24 species are known to be killed on longline hooks, including rare and endangered species. Widespread implementation of appropriate mitigation measures is urgently required.

Finfish stocks in the Antarctic Peninsula region (CCAMLR Statistical Subarea 48.1) have been exploited from 1978179 to 1988189 with most of the commercial harvesting taking place in the first two years of the fishery. Results of bottom trawl surveys conducted by Germany in the vicinity of Elephant Island in the 1980s showed that stocks of Champsocephalus gunnari, Notothenia rossii, Gobionotothen gibberifrons, Chaenocephalus aceratus have been considerably affected by fishing. Stocks of G. gibberifrons and C. aceratus had apparently recovered to a large extent by the second half of the 1980s. C. gunnari remained at a low level. The status of N. rossii is still unclear, although some recovery was apparent from length compositions obtained in the 1980s. The Antarctic Peninsula region was closed for finfishing from 1989190 onwards. Results of the first bottom trawl survey carried out after the closure of the area in November-December 1996 suggested that the fish standing stock biomass had further declined. Given the low abundance of C. gunnari and other species and the difficulties in managing fisheries which exploit mixed-species assemblages there appears to be little prospect at present in re-opening the fishery around Elephant Island.

The incidental mortality of birds in the fishery of Dissostichus eleginoides was analyzed for the Chilean fleet at Subarea 48.3 during 1996 to 1997. In 1996, 533 birds were killed and 478 in 1997. The most vulnerable species was Diomedea melanophrys representing 41,% of the total bird killed in both years, followed by Procellaria aequincotialis with 10% and 33% respectively. For 1995, 1996 and 1997 the BPUE (Birds killed per 1000 set hooks) was calculated, existing no significantly differences among fishing seasons.