WG-FSA-00

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

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 Read More
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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 Read More
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The dynamics of daily vertical migrations of icefish Champsocephalus gunnari was studied and some quantitative estimates were obtained by results of analysis of more than 150 fragments of echograms obtained with the use of an echograph of the "Priboi-101" echo sounder during the directed fishery for icefish in the subarea 48.3 in December 1999 – January 2000. The commercial concentrations of Read More
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In the period from 11 December 1999 to 31 January 2000 Russian trawler "Zakhar Sorokin" carried out fishing the icefish Champsocephalus gunnari feeding consent rations in the western shelf of the South Georgia Island. Icefish 26-40 cm in length, with the average size of 30.3 cm made up the bulk of the catches. Length-frequency distribution was characterized by bimodality, with frequency peaks Read More
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A survey was conducted by the UK around South Georgia and Shag Rocks, Subarea 48.3, from 11 January to 2 February 2000, using the FV Argos Galicia. The design followed similar surveys by the UK conducted throughout the late 1980s and 1990s. The swept area estimates of the standing stock of Champsocephalus gunnari were about 24,800 t. Estimates for other major species are given.

Morphological information is given on specimens of Raja georgiana that were caught during a demersal trawl survey in Subarea 48.3, South Georgia. It is concluded that, in spite of allometric growth, proportional measurements are best referenced to total length rather than disc width. Additional biological information is given: total mass=0.00000646x(total length)3.06. Based on data from male Read More
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During the period March to May 2000, the UK undertook trials of a pot fishing method to catch D. eleginoides around South Georgia (Sub-area 48.3). This method has the potential to minimise, or eliminate, incidental bird mortality when compared to the standard longline method. This paper describes the trial, the results, and discusses the commercial viability of this fishing method for Read More
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Trials of a method of fishing for toothfish using pots were undertaken by FV Argos Georgia from March to May 2000. A significant bycatch of crabs was encountered. Paralomis spinosissima occurred in shallow water, generally shallower than 800m. P. anamerae, which has not been reported for this area previously, had an intermediate depth distribution from 400 – 800m. P. formosa was present in Read More
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To undertake the 'ecosystem approach' to fisheries management recommended by CCAMLR, an understanding of the trophic relationships of exploited species is vital. Toothfish, (Dissostichus eleginoides), represents an important target species for fisheries not only in the study area around South Georgia (CCAMLR Sub-area 48.3), but also in other CCAMLR areas. To improve the knowledge on the Read More
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A tagging programme for toothfish (Dissostichus eleginoides)w as undertaken around South Georgia during early 2000. Details of the programme are given. A total of 359 toothfish were tagged during a trawl survey on the Shag Rocks shelf and a further 135 were tagged on the continental slope around South Georgia and Shag Rocks. The programme has been advertised widely amongst industrial fishermen Read More
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Historical information is assessed on the distribution of spawning and larval mackerel icefish within subarea 48.3 (South Georgia). This is considered alongside other new data from commercial fisheries and research surveys. It is concluded that there is strong evidence for inshore spawning during April within and close to the bays on the north side of the island. Some spawning at much lower Read More
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We tested the efficacy of a Mustad underwater setting funnel to reduce seabird bycatch in a demersal longline fishery for Patagonian toothfish Dissostichus eleginoides. The funnel, which deploys the longline 1-2 m beneath the sea surface, was used on 52% of 1714 sets (total effort 5.12 million hooks) over a two-year period. There was no evidence for lower catches or significantly higher bait Read More
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This paper summarises seabird bycatch during the fourth year (July 1999-June 2000) of sanctioned longline fishing for Patagonian toothfish Dissostichus eleginoides in the Exclusive Economic Zone around South Africa's Prince Edward Islands. Data were obtained from fishery observers aboard all 11 sanctioned fishing trips. Fishing effort was 7.4 million hooks, a 45% increase on the number of Read More
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An attempt has been made to study icefish as an object of acoustic survey basing on the acoustic and biological data obtained by Russian RN ATLANTIDA in the area of South Georgia Island (January-February 2000). Estimation of possible target strength values was made by a comparison to TS of other fish species having similar body structure and morphological characters, as well as taking into Read More
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Biostatistic data obtained by Soviet research and commercial vessels in 1970 to 1991 have been used to study length-age composition of Champsocephalus gunnari from different locations of South Georgia Island Subarea. An analysis of Ch.gunnari length-age groups spatial distribution over Eastern, Northern, Western, Southern Island Shelf and near Shag Rocks allowed for revealing similarity of Ch. Read More
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A brief description of hawl-by-hawl data sets from Ukrainian commercial vessels fishing tooth-fish in Subdivision 48.3 during 1986-199 1 is presented. The fishery was mainly carried out in summer months off the eastern South Georgia and at Shag Rocks. The length frequency modes amounted to 95-100 cm, which exceeded modes for the latest years of fishery. Using the generalized additive model the Read More
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Fish Heaven is a simple spatially explicit age structured fish model, containing the basic features of standard fish modeling with a number of optional extras. It was designed within an object oriented framework to allow for the possible extension in a number of directions. In particular it was designed with the view of testing the efficacy of different statistical sampling regimes given Read More
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For the last 3 years, WG-FSA has accorded high priority to development of a method to integrate different indicators of stock status into assessments using the generalised yield model (GYM). In this paper, we propose a method, based on use of the sampling/importance-resampling algorithm, for incorporating information on trends in standardised CPUEs into GYM assessments. The use of the method Read More
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A random stratified trawl survey was conducted in May 2000 to assess the abundance of icefish, Champsocephalus gunnari, and juvenile pre-recruit toothfish, Dissostichus eleginoides, on the Heard Island Plateau and Shell Bank. Abundances and length density plots of these species plus two principal bycatch species Lepidonotothen squamifrons and Channichthys rhinoceratus are given for each Read More
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A recent 2000 survey of mackerel icefish in the vicinity of Heard Island enabled a revised estimate of yield for the coming 2 seasons. While the biomass of icefish appears lower than in previous years, it is dominated by a strong age 2 year class. Estimates of yield for the Heard Island Plateau population using the short-term assessment are 1150 tonnes for 2000/01 and 1000 tonnes for 2001/02 Read More
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The recent fish survey at in the vicinity of Heard Island in 2000 has provided estimates of recruitment for at least one new cohort (1996) and another estimate of the 1995 cohort. The older cohorts are likely to be distributed more widely than the shallow part of the Heard Plateau, consistent with the observations from 1999. A reanalysis of all survey data from the region has shown that Read More
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This paper presents an assessment of the harvested population of Patagonian toothfish at Macquarie Island based on data from a tag-recapture experiment initiated during the 1995/96 fishing season. Population models that include dynamics of tagged and un-tagged fish, daily releases, catches, recaptures, natural mortality, and annual net recruitment are used to assess the population of one of Read More
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The unusually effective fishery on mackerel icefish (C.gunnari) in the South Georgia Island subarea (48.3), when during 1.5 months two fishing vessels (Russia and Chile) caught more than 4 thousand tons, and the followed bottom trawl surveys by Russia and Great Britain in December 1999 - February 2000 showed clearly a necessity to revise the methods of icefish (which is near-bottom and pelagic Read More
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In February 2000 the bottom trawling survey was carried out in Subdivision of South Georgia (48.3) to assess the main commercial and promising near-bottom and bottom fish species. The data on distribution, biology, minimal (relative) biomass and abundance of fishes were obtained.

The results of mackerel icefish (Champsocephalus gunnari) trawling survey carried out by Russia at R/V Atlantida in February 2000 in Subarea 48.3 are presented. During that period C.gunnari were feeding. In all parts of the Subarea, except the North-Western one, C. gunnari of 22-28 cm in length and 2-3 years old predominated. Fish biomass distributed near the bottom estimated with different Read More
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Estimates of natural mortality are currently unavailable for Patagonian toothfish. Such estimates are needed for estimating recruitments and for use in assessing yield. This paper proposes a method for jointly estimating natural mortality and cohort strength at age 4 using a negative log-likelihood function based on one or more cohorts for which their abundance has been estimated in two or Read More
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Two previously recorded species, Raja georgiana and Bathyraja meridionalis were recorded as-bycatch on one vessel in the South Georgia toothfish fishery, 2000. One further species could not be identified and was referred to as R. species 1. R. georgiana occurred in shallow water, the other two in deep water. The average catch rate was 0.23 rajids/1000 hooks. Distribution and length at maturity Read More
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A total of 1103 inshore notothenioid fish were caught by means of trammel-nets in four sites surrounding Cierva Point (Moss Island 1; Moss Island 2; Sterneck Island and Leopardo Island), Danco Coast, West Antarctic Peninsula, in the summer season of 2000. The families Nototheniidae, Channichthyidae and Bathydraconidae were represented being Notothenia coriiceps the dominant fish of the area. Read More
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