CCAMLR

Surveys of all known breeding sites of wandering, black-browed and grey-headed albatrosses were carried out at South Georgia in the 2003/04 breeding season. Wandering albatrosses were censused by ground counts, and black-browed and grey-headed albatrosses mainly by yacht-based digital photography and subsequent counting on computer screen using Adobe Photoshop software. In total, an estimated 1,553 pairs of wandering albatrosses, 75,500 pairs of black-browed albatrosses and 47,800 pairs of grey-headed albatrosses were breeding at South Georgia in the 2003/04 season. Compared to results from a predominantly yacht-based survey of black-browed and grey-headed albatrosses over the whole of South Georgia conducted in the mid 1980s, numbers of these two species appear to have decreased by 26% and 14%, respectively. However, comparison of annual totals for Bird Island, which was censused on both occasions mainly by ground counts, indicate more rapid declines: 4.0% p.a. from 1989/90-2003/04 for black-browed albatrosses, and 2.9% p.a. from 1990/91-2003/04 for grey-headed albatrosses. Due to the lower accuracy of the methods used in the 1980s, it is likely that the Bird Island figures are more indicative of the population trends at South Georgia. The decline in wandering albatrosses is even more pronounced: 30% (1.8% p.a.) since the previous survey in 1984. The magnitude of these population decreases is alarming, given the long time span involved and consistent downward pattern. Of particular concern is the acceleration since 1997 in the rate of decline of wandering albatrosses at Bird Island, which now stands at 4.5% per year. Unless these long-term declines can be halted or reversed, there must be some doubt over the long-term viability of the breeding populations of these species of albatrosses at South Georgia.

Age determinations estimated by means of otoliths and age classes derived from CMIX analysis have been compared in Champsocephalus gunnari using material collected around South Georgia during four Russian surveys in 1988, 1990, 2000 and 2002. Considerable differences in age estimates between the two methods were revealed. A number of suggestions including an Age Determination Worksop to be held in Kaliningrad in 2005 and the exploration of methods in addition to CMIX are made to reconcile some of these differences in the future.

The paper presents the application of the bootstrap method to estimate accuracy of mixture distributions parameters. The method allows to estimate statistical characteristics not only component densities but another parameters: mean length of components, their standard deviations or equation parameters to determine these standard deviations. It is possible to estimate parameters correlation and bias.
The method has been applied to data from UK survey in 2002 that WG-FSA-03 used for toothfish recruitment calculations in S. Georgia area. The accuracy of mean length of component is high (CV~0.04), but total densities have CV~0.3 – 0.5. CV of parameters of linear equation is more then 1.0. It was marked high correlation between some parameters. Standard errors of densities exceed the values calculated by CCAMLR program.
The method can be used to determine the number of trawl stations in a survey to get the recruitment estimates with given accuracy.

This paper presents bycatch information for the Australian fisheries in Divisions 58.5.2, 58.4.2 and 58.4.3, with estimates of total removals by fishing ground for the 2002/2003 and 2003/2004 seasons. Bycatch in the trawl fisheries was low, approximately 1 to 2% of the total catch (target plus bycatch). Bycatch in the longline fisheries was higher, ranging from 8% to 14% of the total catch. Much higher percentage bycatch rates occurred in longlining grounds where the fishing effort and therefore target catch was low. The main bycatch species were skates and grenadiers in the D. eleginoides fishery and skates and C. rhinoceratus in the C. gunnari fishery. The total skate catch in Division 58.5.2 (including those cut from longlines) was 43 tonnes in 2002/2003 and 55 tonnes in 2003/2004. Results from the skate tagging program in Division 58.5.2 indicate that skates move very little between release and recapture, even after extended periods at liberty. The distances travelled ranged between 0.2 to 7 nm with periods at liberty ranging from 208 to 822 days. Growth rates estimated from recaptured skates were 20mm per/year in total length, 21mm per year in disk width and 0.14 kg per year in weight. Recapture rates were 2.5% for B. eatonii and 0.8% for B. murrayi for skates tagged in the trawl fishery and 0.05% for skates tagged in the longline fishery.

During tagging programmes for Dissostichus eleginoides at Heard and Macquarie Islands, fish have been treated with strontium to mark their otoliths for validation of subsequent age estimation. Otoliths from 69 fish that were at liberty for at least 350 days were eventually examined. Results indicate that current methods for ageing D. eleginoides are appropriate: the number of observed annuli on the otoliths after the strontium mark was consistent with the time at liberty of the fish after marking.
Current and future work on age validation is designed to address outstanding problems with age determination in this species: investigating the accuracy of ageing small fish ( 1000 days; and developing techniques to analyse the daily marks at the centre of the otolith in order to pinpoint the position of the first annulus.

The Australian longliner Eldfisk was authorised to conduct an exploratory fishery for Dissostichus sp. in CCAMLR Divisions 58.4.3b (BANZARE Bank) and Division 58.4.2 in the 2003/04 season. The results of the fisheries in Division 58.4.2 and Division 58.4.3b are summarised. Between 12 December 2003 and 23 December 2003, the Australian vessel, Eldfisk undertook exploratory longline fishing in Division 58.4.3b. 19 sets were completed, yielding 447 kg of D. eleginoides and 6345 kg of D. mawsoni. Between 6 and 25 January 2004, the vessel undertook exploratory longline fishing in Division 58.4.2, specifically in SSRUs D and E. 129 kg of D. eleginoides and 19 552 kg of D. mawsoni were caught from 46 sets.
Overall, bycatch was highest at BANZARE Bank with 916 kg of total bycatch, comprising 15% of the total catch weight. Of the two SSRUs in Division 58.4.2, bycatch was highest in SSRU E with 624 kg of total bycatch comprising around 4% of the total catch compared with 247 kg of total bycatch (4%) for SSRU D. In both SSRU’s more bycatch occurred in the research sets than in the commercial sets.

A version of the mixture fitting program CMIX was recompiled to enable it to be run within the DOS emulator of recent versions of the Microsoft Windows operating system. The performance of the recompiled version was compared with that of the original version.
The recompiled version of CMIX produced very similar, though not identical, results to the original version. We attribute this to differences in the minimisation routines of the recompiled version. We conclude that the small differences evident from these tests are unlikely to significantly influence the estimated long-term yield of Dissostichus eleginoides

The Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) has the primary competency for managing fishing south of the Antarctic Polar Front. Despite a relatively long history of scientific research and fisheries, CCAMLR’s fisheries management strategy has often had to address incomplete and uncertain information on affected resources. Fishery-independent studies are difficult and expensive to conduct. In addition, the size of the Convention Area, its remoteness and prevailing inclement weather have complicated matters. Therefore, in addition to the standard catch and effort data supplied by vessels, the collection of data by scientifically qualified observers aboard fishing vessels has assumed prominence in the collection of essential data for fisheries management purposes. The Scheme of International Scientific Observation, adopted by CCAMLR in 1992, is designed to gather and validate fishery-related information essential for assessing target species status as well as the impact of fishing on dependent and related species, including seabirds and marine mammals. The Scheme is limited to scientific observation only and is carefully separated from enforcement aspects falling covered by the CCAMLR System of Inspection. Under the Scheme observers are deployed under bilateral agreements between CCAMLR Members and they operate on vessels under flags other than their own country. This paper outlines the Scheme's history in terms of its logistics, participation and coverage, changes in research priorities, volume of data collected and data usage. The Scheme’s benefits and shortcomings are explored and an attempt is made to evaluate the total annual cost of scientific observer programs.

A new method for estimating illegal fishing effort is put forward. The results from this new method are similar to the Agnew and Kirkwood method and this suggests that the current method is adequate under circumstances of low evasion and for when good knowledge exists that zero observations reflects zero illegal fishing. The new method performs better in the case of zero detections and can potentially better handle the evasion of detection by illegal activity.
Both the new and the current method suffer from the type of observations method used, which directly affects the system. This is the prevention/detection problem, in which the greater the number of detections for a given level of illegal fishing the more often the illegal fishers will curtail their fishing trips. This leads to a negative correlation between the amount of fishing and the estimated amount of fishing, for a given number of illegal vessels.
As the number of illegal vessels increase, both the estimate and the average amount of illegal fishing increases. This gives us some confidence that the method can produce results that have a degree of legitimacy. However, the range of actual fishing (in the simulation data sets) for a given estimated level of fishing is very large. This range of uncertainty increases as the evasion rate increases.
This research suggests that it would be possible to calculate a precautionary assessment of illegal fishing such that the actual number of illegal fishing days is less than or equal to the precautionary estimate with some given level of confidence (for example 80%).

A multi-disciplinary research cruise in the Atlantic sector of the Southern Ocean was conducted during the 2004 austral winter as part of the International Collaborative Expedition to collect and study Fish Indigenous to Sub-antarctic Habitats (ICEFISH). Sampling during the ICEFISH cruise included demersal finfish, benthic invertebrates, and information of seafloor composition. The objectives of the cruise included Antarctic fish and invertebrate biochemical, molecular and physiological, ecological and population genetics research. Trawling was conducted within the CCAMLR Convention area at Shag Rocks, South Georgia, the South Sandwich Islands, and Bouvetoya Island from 5 June to 30 June, 2004. A description of demersal finfish and benthic invertebrate collections, distribution, and composition from each island group is presented, including some preliminary information on the seabed composition of shelf areas. The total number of finfish specimens recorded within the Antarctic convergence during the ICEFISH cruise trawl deployments was 9105 specimens of 29 species.
A wide contrast in finfish and invertebrate species composition between island groups was observed, with the greatest differences between the South Sandwich Islands and Bouvetoya, where the isolation of the latter island likely played a role in the different community structure. Due to mixed gear selectivity and possible avoidance, it was not feasible to make quantitative estimates of finfish abundance. However, using data from the Blake trawl, estimates of benthic invertebrate densities by station were computed and maps generated that provide information on benthic communities.