CCAMLR

For recent years Dissostichus eleginoids is the main target species of trawling and long-line fisheries in the vicinity of the Kerguelen Islands. Results of research made by the author on board the fishing vessel "Poltava" in the summer season 1991-1992 were the base for the present paper. Regular direct distribution of size groups D. eleginoides in depth range within the fishing area on the northern slope of shelf was revealed. Difference in feeding spectrum of these groups was noted that in this case characterized quality composition of food supply in different depths. Seasonal (summer) migration of size groups was directed from less depths to greater ones. In April in depths of 550-600 m the group of D. eleginoides was supposed to he which in December-February occurred in depths of 350-400 m. Feeding on fish and squids primarily D. eleginoides under definite conditions might turn to more assessable (Hyperiida), secondary (jelly-like fish) or incidental (bottom crustaceans, octopoda, vessels' wastes) food. Seasonal change in quality composition of D. eleginoides in depths of 500-600 m was revealed, i.e . cold-water jelly fishes (Salpae, Ct,enophora, Scyphomedusae) being the basic food component in December-February were replaced with natal-subtropic species of the squid (Chiroteuthis veranyi) in March-April.

The cephalopods of the Antarctic are supposed to have a very high biomass level However, they have not been fished nor any fishable aggregations of them detected to date in the CCAMLR Convention Area. The squid Moroteuthis ingens has been constantly present in bottom trawl catches on Ob Bank during aimed fishery for Lepidonotothen squamifrons. At maximum, the proportion of squid in the total catches exceeded half of the catch, reaching 1310 kg per hour of trawling. All the squid were in prespawning state. The squid aggregation was apparently composed of mating individuals. At has been concluded that target searching and fishing for Moroteuthis ingens with a midwater trawl over the seamaunts in the sub-Antarctic may be expected to bring forth good commercial yields.
The crabs (craboids) of the Antarctic are now an object of intense interest for the scientific and fishery organizations of the member countries of the CCAMLR, especially in view of the development of experimental fishing by a U.S. vessel on the shelf of South Georgia. The biology and the environmental aspects of the life of craboids in the Antarctic are but insufficiently known. The Anomura faune on Ob Bank is represented by a single species, Paralomis aculeata. The craboids have been constantly found in bottom trawl catches during target fishery for Lepidonotothen squamifrons, the frequency of their occurrence being 25 to 30%. Considering, that a routine bottom trawl was used with the footrope so designed that there was little probability of the benthic animals (craboids included) being captured, a conclusion has been made of the possibile sufficiently high abundance of Paralomis aculeata population on Ob Bank.

Four species of shark have been known to date to occur in the sub-Antarctic waters: Lamna nasus, Somniosus microcephalus, Etmopterus lucifer, E. granulosus. A specimen of Squalus acanthias was captured in February 1995 on the shelf of the Kerguelen Islands from the depth of about 195 m and duly described . Squalus acanthias is believed to be one of the most widespread shark species in the World Ocean. The fact of capturing this species in the Kerguelen waters enlarges by far its range and adds to the list of ichthyofauna of the Antarctic, more particularly to the scanty fauna of cartilaginous fishes. The occurence of Sq. acanthias in the waters of the Kerguelen Islands is thought to suggest natural enlargement of the range of this ecologically plastic species.

AS many as 18 species of benthopelagic fishes belonging to 12 families were caught in trawls during the integrated surveys in December 1977 and in January 1978 on Elan Bank consisting of two sublatitudinal sea-bottom elevations with prevailing depths from 960 to 1350 m. Among these fishes there were found both species inhabiting exclusively in sub-Antarctic and Antarctic waters (endemies) and those having a wider geographical range. The 900-1000 m depth range was characterized by the greatest diversity of fish species, their numbers, however, being the smallest in those particular depths. Sub-Antarctic and Antarctic fish species were the dominant group. The proportion of deep-dwelling fishes increased with depth and they were quite abundant. Most abundant on Elan Bank were Macrourus whitsoni, Antimora rostrata and Alepocephalus sp. cf. antipodiana. The paper contains an annotated list of species and a brief analysis of their vertical distribution by area and depth with the information about their biological state.

Interactions between longliners, fishing for Patagonian toothfish Dissostichus eleginoides in the west of Kerguelen islands during 1995 - 96 cruise, and marine mammals occured with Kerguelen Fur Seals Arctocephalus gazella. They catch 0.75 % of toothfish on long-lines where interaction occured, but 2.2 % were lost alongside the vessel.

By-catch was observed during two successive cruises of longliners fishing for Patagonian toothfish Dissostichus eleginoides in approximately 500m depth along the shelf slope in the west of Kerguelen. By-catch consisted mainly of Rajidae Bathyraja spp. (85 %). The proportion of species taken in the by-catch was low (less than 0.75%) and does not represent a problem at the present level of fishing. The results indicate that longlining therefore is a highly target-specific method of fishing in the patagonian toothfish fishery.

Incidental captures of seabirds were observed during 93/94 to 95/96 longlining fishing campaigns around Kerguelen islands (division 58.5.1). Mean by-catch rate is 0.81 birds / 1.000 hooks. The species mainly affected is the White-chinned Petrel Procellaria aequinoctialis (86 %), because of its diving faculty. The different ways to minimize seabird by-catch proposed by CCAMLR are tested and their effectiveness discussed.

Studies carried out over the past three decades at Crozet and Kerguelen Islands in the Indian Ocean indicate that wandering albatross Diomedea exulans populations declined markedly, but since 1986 have shown slow recovery. The population of the endangered Amsterdam albatross Diomedea amsterdamensis appears to have similarly recovered since 1985, but remains close to extinction. A demographic study of the Crozet population indicates that the earlier decline was mainly the result of increased adult mortality, and secondarily of low recruitment. Satellite tracking studies of breeding birds and band recoveries of non breeding birds indicate that during and outside the breeding season these populations are in contact with long-line fisheries, mainly the pelagic Japanese southern blue-Jin tuna fishery and to a lesser extent the Patagonian tooth-fish fishery operating on the Kerguelen shelf: Decreased fishing effort and a concentration outside the central Indian Ocean by the Japanese fishery during recent years has probably resulted in the slow recovery of these albatross populations as a result of improved adult survival and recruitment. Long-line fisheries still represent a major threat to great albatross populations, most which are still declining in the Southern Ocean. Possible conservation measures to reduce mortality in the fishery and to reduce contacts between fishing units and foraging albatrosses are examined.