WG-FSA-92

A total of 8 inventory trawling surveys of the bottom fish were made on South Georgia shelf. Ch.gunnari distribution pattern markedly varied by year which can be attributed to differing survey dates.
Most dense Ch.gunnari aggregations observed were mainly in the northern, north-western and north-eastern parts of the island shelf. Near Shag Rocks they could be seen in separate years. Year Read More
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Catch and length/age composition data for Notothenia squamifrons from Ob and Lena Banks, Division 58.4.4, are presented for the period from 1978 to 1990 split years. These data were used in VPA analyses made for each bank separately. The CCAMLR VPA program, version 4.1 was used. The resulted biomass estimates for 1990 are 10.2 x 103 tonnes for Ob Bank and 20.7 x 103 tonnes for Lena Bank. These Read More
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AtlantNIRO had conducted in 1982-1990 a series of juvenile fish trawl surveys of abundant species around South Georgia Is. Results of these survey were summarised and compared with published data. Juveniles of Champsocephalus gunnari were found to be distributed from the surface to 500 m depth with a maximum density observed at depth between 100 and 200 m. High catches of C. gunnari juveniles Read More
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There is a lack of information regarding the abundance of exploitable finfish in Subarea 48.1. A comprehensive, bottom trawl survey offish stocks in Subarea 48.1 would make it easier for the Working Group on Fish Stock Assessment to assess the stocks in this region and assist the Scientific Committee in giving management advice to the Commission. A stratified random survey is proposed; the Read More
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Results of length-age composition studies of the Patagonian toothfish, Dissostichus eleginoides, from various fishing grounds of the shelf and continental slope areas of the Kerguelen Islands are presented and discussed in the paper. Detailed results of these studies are compiled in tables such as age-length keys, mean fish length by age, length and age frequency distributions in catches. Read More
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Biological data and fishery statistics collected in 1984-1992 were used for stock size and TAC estimation of the Patagonian toothfish, Dissostichus eleginoides, from the Kerguelen shelf area. Method of R. Jones (1964) was used for estimating population size and TAC. Calculations were done for the 1984/85 and 1991/92 seasons where directed fishery for the species took place. Population size of Read More
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Studies of by-catch of juvenile fish in krill catches by research vessels were conducted during 1985-1988 in the Kosmonavtov and Sodruzhestva seas (Antarctic Indian Ocean sector). Isaacs-Kidd trawl with an opening area of 6.0 m2 was used. Trawls were taken in the 0-200 m surface layer over the bottom depth range from 100 to 5000 m. In 1988, studies included catches taken by a commercial krill Read More
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The Antarctic silver fish (Pleuragramma antarcticum) is one of the most numerous species in the outer waters of Antarctica. In the Indian sector of the Southern Ocean there are at least three relatively isolated groups. Fish aged from 0+ to 3+ years live in the epi- mesopelagic zone where there are macro aggregations of plankton, while fish aged from 3+ to 12+ years form near-bottom, pelagic Read More
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Samples gathered from research expeditions of the longliners Medvezhy (April-June 1986) as well as Maksheevo and Mirgorod (June-July 1992) have produced new data on the biology of the reproductive part of the Dissostichus eleginoides population in Subarea 48.3. Analysis and synthesis of these data have established the bathymetric distribution patterns for different size-groups of toothfish Read More
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With samples originated in the Chilean longline fishery of Dissostichus eleginoides of subarea 48.3 (N=7848) after Sparre (1990) the natural mortality was calculated . The Von Bertalanffy parameters obtained independently by three authors were used and considering as variables: fishing site, fishing depth and hook type.
It was determined that there was no significative differences, in M Read More
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Traditional calculation of catch age composition estimate requires that the age-length data and random length frecuency be sampled from the same population, in other case an age-length key is capable of providing biased estimates of age distribution. By using the iteration algorithm is possible to overcome this limitation.
The catch age composition for Dissostichus eleginoides was Read More
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This study analyses fisheries activities carried out by the Chilean longline fishery targeting the Patagonian toothfish (Dissostichus eleginoides) in CCAMLR Statistical Subarea 48.3 (South Georgia Island). From the end of December 1991 until the closing of the fishery on the 10th March 1992, the fleet caught around 80% of the TAC set for this subarea. The catch and effort data and the Read More
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The diet composition and feeding intensity of mackerel icefish (Champsocephalus gunnari) around Shag Rocks and the mainland of South Georgia was investigated in January/February 1985, January/February 1991 and January 1992 by analyzing appr. 9,000 stomachs. Main prey items were krill (Euphausia superba), the hyperiid Themisto gaudichaudii, mysids and in 1985 also Thysanoessa species. The Read More
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Following on from the apparent failure to satisfactorily assess the status of the C. gunnari population in Subarea 48.3 at WG-FSA-91 using VPA, attempts were made to re-work the analysis using Laurec-Shepherd and ADAPT tuning techniques, from 1991 back to 1977. The predicted age structure, dominated in recent years by the 1987 year class (1 year olds in 1988), was quite robust, despite the use Read More
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During the 1990/91 and 1991/92 fishing seasons, two longliners carried out exploratory fishing over the western shelf break of the Kerguelen shelf (Division 58.5.1). Scientific monitoring of fishing carried out by one of these longliners has allowed a description of fishing methods to be made. Bottom longlines are generally used at depths of 400 to 600 m. The mainline (1 to 2 miles long) Read More
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