CCAMLR

Work on finfish in the southern Scotia Arc was restricted to taxonomy until the end of the 1960’s. Commercial exploitation, primarily on mackerel ice fish, Champsocephalus gunnari, and marbled notothenia, Notothenia rossii, started around the South Orkney Islands (60 – 62° / 43 – 47° W) in 1977/78 and close to Elephant Island and the lower South Shetland Islands (60 – 62° S / 54 – 62° W) in 1978/79. The fishery was lucrative for a few seasons only, and was closed in 1989/90.
Stocks of finfish suffered substantial declines during the period the fishery was open. Most fish stocks, with the exception of mackerel ice fish and marbled notothenia, had recovered from exploitation by the end of the 1980’s/beginning of the 1990’s. Since the early 1990’s, most species appeared to have changed little in abundance, and followed primarily fluctuations in year-class strength and the environment. However, stocks of mackerel ice fish, which had formed the backbone of the fishery remained only small proportions of their initial sizes.
Most information on biological parameters of finfish stocks stemmed from Soviet, Polish, German and recent American research in the area. Two elements of the fish fauna overlapped in the southern Scotia Arc region: peri-Antarctic or Lesser Antarctic species and high-Antarctic species. Peri-Antarctic species prevailed in terms of weight and numbers. High-Antarctic species occurred regularly albeit in small numbers, and played a negligible role in terms of biomass. Among the three subareas, the fish fauna around the South Orkney Islands was the least known. Basic biological parameters of fish species, such as vertical and horizontal distribution, reproduction, age and growth, food preferences and feeding (except in the South Orkney Islands) were comparatively well known although some gaps in our knowledge still existed. Age and growth of most species were poorly understood. Major deficiencies were apparent in the understanding of the early life history of many species. Future work should focus on filling in the gaps in the biology of species, intensifying synecological work and better describing the relationships of fish species with each other, predator-prey relationships both with other fish species and seals and birds, the food consumption of fish species, and their interactions with the environment.

Tristan da Cunha and Gough Islands in the central South Atlantic Ocean support globally important seabird populations. Two longline fisheries occur within Tristan’s Exclusive Economic Zone: a pelagic fishery for tunas and a demersal fishery for bluefish and alfoncino. Fishery observers have accompanied all three licensed demersal cruises. Despite attracting considerable numbers of birds and setting lines during the day, only one bird (a Great Sheawater Puffinus gravis) was killed (mortality rate 0.001 birds per 1000 hooks). By comparison, the pelagic fishery for tuna, which exceeds demersal fishing effort, probably has a much greater impact. Observations aboard one vessel in mid-winter suggest a bycatch rate of >1 bird killed per 1000 hooks; this could be even higher in summer when more birds are breeding at the islands. Stricter regulations are required for pelagic vessels, including routine placing of observers on board. The gravest threat posed by longline fishing to Tristan’s seabirds comes from vessels fishing illegally in Tristan waters, as well as vessels in international waters that do not use basic mitigation measures. There is a pressing need for better policing of Tristan’s waters.

The current status of the CCAMLR Website (http://www.ccamlr.org) is described with reference to the work of WG-FSA.

Over the past two years, the CCAMLR Data Centre has undertaken a major overhaul of the research survey database and the routines used for length-density analyses. This overhaul was necessary because of the increasing quantity and diversity of survey data and their importance in the assessments of WG-FSA. Historically, trawl survey data and commercial trawl data were managed as a single dataset. While appropriate in earlier years, this procedure constricted the type of survey data that could be stored in the CCAMLR database and placed limitations of their interpretation. The Data Centre’s extensive overhaul of the survey data has resolved these ‘historical’ difficulties. This paper briefly describes the work done, the structure of the new survey database, and the steps in the length-density analysis. The document should be considered as a working draft, to be added to, and updated, as the database and analyses develop.