CCAMLR

The distribution and diet of juvenile (<750 mm) Patagonian toothfish are described from 4 annual trawl surveys (2003-06) around the island of South Georgia in the Atlantic sector of the Southern Ocean. Recruitment of toothfish varies inter-annually, and a single large cohort dominated during the four years surveyed. Most juveniles were caught on the Shag Rocks shelf to the NW of South Georgia, with fish subsequently dispersing to deeper water around both the South Georgia and Shag Rocks shelves. Mean size of juvenile toothfish increased with depth of capture. Stomach contents analysis was conducted on 795 fish that contained food remains and revealed that juvenile toothfish are essentially piscivorous, with the diet dominated by notothenid fish. The yellow-finned notothen, Patagonotothen guntheri, was the dominant prey at Shag Rocks whilst at South Georgia, where P. guntheri is absent, the dominant prey were Antarctic krill and notothenid fish. The diet changed with size, with an increase in myctophid fish and krill as toothfish grow and disperse. The size of prey also increased with fish size, with a greater range of prey sizes consumed by larger fish.

The distribution, length-frequency and diet of Patagonotothen guntheri are described from 14 bottom trawl surveys conducted on the Shag Rocks and South Georgia shelves in the austral summers from 1986 to 2006. P. guntheri (80-265 mm LT) were caught on the Shag Rocks shelf from depths of 111 to 470 m, but no specimens were caught on the South Georgia shelf. Multiple cohorts were present during each survey and length-frequency analysis of these cohorts suggests that growth is slow (K=0.133). Evidence from stomach contents and acoustic data (2005 & 2006) show that P. guntheri is primarily a pelagic feeder, migrating from the seafloor towards the surface to feed during daylight. The diet of smaller fish (

We describe the process used in the fisheries management system of the Convention for the Conservation of Antarctic Marine Living Resources (CCAMLR) to minimise seabird bycatch, and the risk assessment methodology developed to assist this. We examine the progress of several Regional Fishery Management Organisations in taking steps to address seabird bycatch. CCAMLR has the most advanced system of management among the RFMOS covered in this review, and has made the most demonstrable progress in reducing seabird bycatch levels in its longline fisheries. A combination of proven mitigation measures, extensive monitoring by independent observers, annual expert review of seabird bycatch rates and evolving fishery and mitigation practices have been instrumental in reducing seabird bycatch in CCAMLR fisheries.

The most abundant icefish species observed in catches off the northern tip of the Antarctic Peninsula in the last 25 - 30 years has been the spiny icefish Chaenodraco wilsoni Regan 1914. C. wilsoni has been exploited on a commercial scale from the late 1970’s to the end of the 1980’s off Joinville – D’Urville Islands (CCAMLR Statistical Subarea 48.1) and in the Cosmonauts and Cooperation Seas and Prydz Bay in the Indian Ocean sector (CCAMLR Statistical Division 58.4.2). This paper presents new information on biological features and life history characteristics of C. wilsoni, based on research survey collections along the northern Antarctic Peninsula in 2006 and 2007 and samples taken in the commercial fishery in 1987. Length frequency compositions from the research surveys demonstrated that fish 21 – 34 cm long predominated in the catches. Sexual maturity is attained at 24 – 25 cm. Absolute fecundity and relative fecundity is low (1000 – 2500 eggs; 6 – 12 eggs). Oocyte diameter varied from 4.3 to 4.8 mm very close to spawning. Spawning at the tip of the Antarctic Peninsula is likely to occur in October-November. Remotely Operated Vehicle deployments in the northern Weddell Sea demonstrated that C. wilsoni exhibit parental nest guarding where males protect the eggs. The incubation period is likely to be 8 months long. Fish feed primarily on Antarctic krill (Euphausia superba) in the Antarctic Peninsula region and in the Cosmonauts and Cooperation Seas while fish take ice krill (E. crystallorophias), Pleuragramma antarcticum and myctophids to some extent in other areas. Age determination still awaits validation. Preliminary ageing attempts suggested a maximum age of about 8 – 10 years.

The rocks from stomachs of Dissostichus mawsoni were used as a source of geological information about sea bottom. Authors suggest toothfish picks up stones from the bottom randomly, and these stones may be used for geological description of the closed areas of Antarctic shelf and slope. In this respect, Dissostichus mawsoni may be considered as a «dredge» with a wide area of sampling. Preliminary analyses allow qualitative estimation of geological structure of Antarctic shelf and continental slope in different areas.

This is a preliminary report of the results of the 11th UK South Georgia groundfish survey, the first to be conducted during the austral winter since 1997. Preliminary biomass estimates are provided for C. gunnari whilst new information on the winter distribution and ecology of the demersal fish fauna at South Georgia is provided.

Analysis of recent commercial catch, research survey and larval data for mackerel icefish (Champsocephalus gunnari) recorded from CCAMLR Subarea 48.3 coupled with historical information indicates that they spawn inshore close to the bays and over the shelf to the northeast. There is also evidence that spawning is protracted and occurs from January through to July. The majority of commercial fishing activities for this species take place to the northwest of South Georgia over 12 nautical miles from the coast and do not overlap with important spawning areas. Therefore the current conservation measure restricting the total allowable catch during the assumed spawning period from March-May is unlikely to protect spawning aggregations of C. gunnari but could, inadvertently, increase the risk of brooding seabirds being caught as by-catch.

This document summarises the suggestions made by WG-EMM to address the requests made by the Scientific Committee in relation to Scientific Observer Manual. These are establishment and replacement of protocol for fish-larvae by-catch observation, review of priorities for scientific observation of krill fishery, and other minor revisions on the e-forms. This document also contains examples of the revisions made to the forms and is presented to the Working Group on Fish Stock Assessment for comment.

This paper further develops an integrated assessment for Patagonian toothfish in Division 58.5.2. It updates the model used at WG-FSA in 2006 using data from the 2007 season as well as 2006 data not available for WG-FSA in 2006. It also includes the following refinements: (i) estimation of the coefficient of variation (CV) for length given age, (ii) use of non-informative priors for year class strength parameters, (iii) separate selectivity parameters used for the pre-2006 compared to the 2006-2007 fishing seasons for the main trawl ground, (iv) separate selectivity parameters for the late (within-year) season compared to the combined early (within-year) seasons for the main trawl ground, and (v) the use of an improved method of determining effective sample size for commercial catch-at-length data. The estimated long-term yield was 2500 tonnes with depletion probability of 0.081 and escapement probability of 0.505. As expected, the assessment was sensitive to the inclusion of different datasets and to the choices of parameters used in both the stock assessment and projections. It is concluded that until the difficulties with the use of mark-recapture data are resolved, recruitment surveys provide the best means of establishing current stock status as an absolute index of abundance.