CCAMLR

A revision of the research plan and preliminary results of the Spanish exploratory longline fishery for Dissostichus spp in Divisions 58.4.1 and 58.4.2, submitted to the XXXII-WG-SAM, taking into account the advice made by the Working Group, is presented.

The Spanish vessel Tronio started the research plan in the 2012/13 season using the Spanish bottom longline system. One depletion experiments was completed in each of the SSRU surveyed (58.4.1H and 58.4.1G). Three prospecting-phase clusters of sets did not reach the threshold to start the depletion.

A new prospective estimation of the local biomass (B_LOC) of the two localized areas where the depletion experiments were performed is done as well as an estimation of the biomass of the SSRUs (B_SSRU), maximal and minimal, considering areas with high and low densities, with a better fit of the regression and lower residuals than the previous analysis.   
 
An analysis of relevant sea-ice conditions in the last 11 seasons in these areas along with a summary of the activities and results from the survey is also presented related to the sampling scheme, collected samples and species involved.

Data were collected at Bird Island and King Edward Point, South Georgia, at Signy Island, South Orkneys and at Goudier Island, Antarctic Peninsula for the period April 2012 to March 2013. Surveys of beached marine debris at Bird Island recorded a total of 145 and 134 items during winter (April to September 2012) and summer (October 2012 to March 2013) respectively. Surveys at Signy Island (operational during summer only; 25 November 2012 to 20 March 2013) recorded a total of 13 items of beached marine debris. Entanglements of 13 Antarctic fur seals were observed at Bird Island, 15 at King Edward Point and zero at Signy Island and Goudier Island. In total, 85 items of marine debris were found in association with seabird colonies at Bird Island, most commonly in association with wandering albatrosses (45 items). There were no reports of beached marine debris at Goudier Island, and no incidences of hydrocarbon soiling at any of the four sites during the reporting period. Overall, the occurrence of beached marine debris was below the long-term mean at Bird Island during both summer and winter and was the lowest recorded in 23 years of summer surveys at Signy Island, possibly due to sea-ice coverage at the three survey beaches between November and January. The incidence of marine mammal entanglements was below the long-term mean at Bird Island and Signy Island but above the mean at King Edward Point. Debris associated with seabird colonies was below the mean level for wandering albatrosses, grey-headed albatrosses and giant petrels, but above the mean for black-browed albatrosses.

During the Antarctic krill fishing in the area off the North-Western slope of the South Orkney Islands shelf were caught 5000 kg of Champsocephalus gunnari.
 

This article reviews the adequacy of data and models currently being used to estimate the present and future population sizes of the Antarctic toothfish (Dissostichus mawsoni Norman) in the Ross Sea regional ecosystem. It argues that the current tagging program is unlikely to provide an accurate picture of total population size, and that estimates of both the pre-exploitation spawning stock biomass and the ratio of current to pre-exploitation biomass are unreliable. Many parameters necessary for estimating future population growth or decline have not been measured, and the current objective of a 50% reduction in biomass relative to unexploited biomass may easily fail to prevent a much larger reduction from taking place. The need to guess values of important parameters makes it impossible to set bounds on the potential errors of population forecasts. Current scientific knowledge is far from what is needed to predict the likely effects of food web responses to harvesting of toothfish in the Ross Sea, or to predict the feedback effects of those food web changes on toothfish populations.

In the fishing season 2012/2013 Russian vessel “Yantar-35” worked in the Weddell Sea for the first time since fishery of Dissostichus mawsoni began. It has allowed extending a sampling area on biology of this species. In particular, size-age and growth samples of the Antarctic toothfish were collected in this sea.

According to the stock assessment survey, as well as using CPUE data collected by Russian and South Korean vessels in three Antarctic sectors in 2003-2010, it has been shown that fishery of the Antarctic toothfish is commercially viable not only for countries which are close to the fishing areas. The assessment study was conducted by several researchers using various models designed for the Pacific and Indian sectors of the Antarctic. According to lack of data on the Antarctic toothfish from “zero” SSRUs, it follows that current TAC values are underestimated in all studied areas. Correct estimation of toothfish stock and TAC values in all high-latitude Antarctic seas is necessary.

From data available we suggest that factual stock values of the Antarctic toothfish are considerably underestimated in the Pacific (the Ross Sea) and the Indian sectors (the Dumont d'Urville Sea (SSRU G), the Mawson Sea (SSRU E), the Davis Sea (SSRU C)) resulting in restrictive policy of the Antarctic toothfish fishery.

The Scientific Committee (SC -XXXI, par. 9.30)  focused on distribution pattern of toothfish in SSRU 88.2 A and adjacent SSRUs 88.1 K and L, and discussed a need to carry out background investigations considering insufficient information on this area, and how catch limits used in the Ross Sea can be applied for this SSRU.

Investigations conducted by Russian scientists in SSRU 88.2A in 2010-2012 showed that this unit should be open for shared environmental management. We propose agreement on SSRU 88.2A opened within the scope of the Conservation Measure 41-10.