WG-FSA-90

Chaenocephalus aceratus and Pseudochaenichthys georgianus have been exploited in Subarea 48.3 since 1977 but have never been fully assessed by the Working Group on Fish Stock Assessment because of a lack of reliable biological and catch data. This paper attempts to reconstruct the fishery for these two species by assuming that 75% of the ‘unidentified fish’ caught by the Soviet Union in the Read More
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Whole otoliths and scales were used for a simultaneous age determination of juvenile Notothenia rossii marmorata specimens collected at Potter Cove, King George/25 de Mayo Island, South Shetland Islands. Results from the analysis of both structures agreed in 95.5%. Likewise, the examination of otolith cross sections of chosen specimens confirmed in all the cases the age readings obtained from Read More
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The use of allozymes as a tool in stock structure analysis was examined in the commercially-exploited mackerel icefish, Champsocephalus gunnari, together with a preliminary assessment of stock separation among samples in South Georgia waters.
Four samples (116 individuals) of icefish were collected from South Georgia waters, incorporating Shag Rocks, during January 1990, and subjected to Read More
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A declining trend observed in the abundance of fjord fish of the species Notothenia rossii marmorata and Notothenia gibberifrons from two localities of South Shetland Islands, is analyzed by a nested ANOVA and demonstrated as significant. The material studied was obtained with trammel nets at Potter Cove, King George/25 de Mayo I., from 1983 to 1990 and in waters around Half-Moon I., Moon Bay Read More
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Based on a tentative adjustment of catches of Notothenia gibberifrons previously reported as ‘Pisces nei’ an attempt is made to reconstruct the fishery on that species between 1977/78 and 1985/86. Stock size until the mid 1980s seemed to be more reduced than previously assumed. The current state of the stock is unknown.

Catches of Champsocephalus gunnari from the Kerguelen Shelf and Skiff Bank stocks were re-calculated from those used by the Working Group on Fish Stock Assessment in 1989 using length-frequency data for the years 1981 to 1990. Cohort analysis yielded a Stock Biomass of 22 711 tonnes in 1988 for the Age 2 Kerguelen Shelf stock, an order of magnitude lower than that calculated from a biomass Read More
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In the summer-autumn period E. carlsbergi fed mainly on copepods. Daily food intake measured using various methods ranged from 3.7 to 5.6 % of fish body weight. The amount of food consumed by E. carlsbergi during the year in the southern regions of the Antarctic Convergence is about 15 times its own weight.

Acoustic surveys carried out in summer and autumn periods of 1987-1989 estimated the biomass of myctophids in the Atlantic sector of the Southern Ocean over the region between 48° and 56°S and from 8° to 48W at about 1.7 mill.t. Over the larger part of the surveyed area the fish were sparse, their dense concentrations composed predominantly of one myctophid species Electrona carlsbergi Read More
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A subject of the present study is Electrona carlsbergi from the Atlantic sector of the Southern Ocean. Results from histological examination of gonads are presented. From materials available it has been ascertained that Electrona carlsbergi breeds in the notal zone. The ripening of females begins at body length of 76-78 mm. Vitellogenesis is asynchronous. Vitelline eggs have a diameter from Read More
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Some biological peculiarities of E. carlsbergi from the Antarctic and notal areas of the Southern Ocean Atlantic sector have been studied on the basis of the data for 1987-1989. Mean length of fish from the Antarctic area increased while drifting eastward in the Antarctic circumpolar current waters. Fish specimens from 62 to 97 mm long were registered in catches. About 95% of specimens Read More
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This paper discusses the impact bottom trawling may have on Antarctic benthos. This problem has not been dealt with neither by the Antarctic Treaty System nor by CCAMLR so far.

An outline is provided on data and analyses which would be required to improve the knowledge of the stocks and improve the Scientific Committee’s ability to provide less controversial management advoice. However, a level of uncertainty higher than in fish stock assessment in other parts of the World Ocean (e.g. the North Atlantic) has to be accepted and to be taken into account for fisheries Read More
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The paper “The state of Dissostichus eleginoides stock and TAC for it for 1990/91 season in S.Georgia area (48.3)” presents the data on main biological characteristics of this species (Patagonien Toothfish), caught using long-line bishing in shelf waters of Shag Rocks and S.Georgia. While determining growth rate, size and age composition, natural mortality and catch statistics an attempt was Read More
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According to the results of the registered trawling surveys carried out during the joint Soviet-French expeditions (1987-1988), more precise evaluations of the main commercial species biomass in the Kerguelen Islands area are given below. When evaluating the fish stocks, a special attention has been paid to the registration of hurricane samples zones and to the construction of their content Read More
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From the field material collected on the YugNIRO integrated expedition in the Indian Ocean sector of the Antarctic in the season of 1989-1990, information is presented in this paper on ichthyofauna, size–weight composition and main parameters of the biological state of the more abundant fishes taken on the shelf of Antarctica, at Ob and Lena Seamounts (referred to as Banks in the Russian usage Read More
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In reference to the YugNIRO antarctic expedition in the season of 1989/90, information on the areas covered by oceanographic observations from the expedition’s vessels, on the scope of those observations and the preliminary results thereof are presented in this paper.
It is shows that both ice and hydrometeorolegical conditions determinig the production processes and the formation of krill Read More
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Population structure and dynamics of the abundance of Notothenia rossii rossii on the Kerguelen Island shelf from the beginning of the fishery to 1984 has been examined.Total and commercial stocks of this species have been determined proceeding from data of inventory trawl survey and calculation by mathematical modelling.Comparative estimates of the abundance and recruitment-remainder ratio Read More
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