CCAMLR

The description of a design of longline of the "spanish type" on European hake (Merluccius merluccius) fishery in the coastal and deep waters of the North Atlantic and its modifications used on fishery of Antarctic toothfish (D. mawsoni) and Patagonian toothfish (D. eleginoides) in waters of the Antarctic Region is given. The operational experience by the longline of the «spanish type» by two vessels under the Russian flag ("Yantar" and "Volna") in Antarctic waters (seasons 2004/05-2005/06) is described.

Information on CCAMLR fisheries of relevance to the work of WG-FSA is summarised, and where possible, in a format suitable for importing directly to the Fishery Reports. Additional fishery-related information can be found in WG-FSA-06/36, 06/37, 06/38 (summaries of observer data), SC-CAMLR-XXV/BG/1 rev.1 (catches in the Convention Area) CCAMLR-XXV/16 (summary of notification for new and exploratory fisheries), WG-FSA-06/11 (estimates of IUU catches) and CCAMLR-XXV/BG/3 (implementation of conservation measures).

Life-history theory predicts that adults of long-lived species such as seabirds should optimally balance investment in current and future offspring. However, when trying to optimize investment in offspring provisioning, the most energetically costly component of seabird parental care, adults need to contend with large interannual fluctuations in prey availability and hence the cost of chick provisioning. Adults faced with this uncertainty can mechanistically balance parental care by adopting a strategy somewhere along the continuum between maintaining constant investment in foraging effort between years and letting chick provisioning fluctuate or holding chick provisioning constant and varying investment in foraging effort. Using ship-based hydroacoustic assessment of prey, time-depth recorders attached to penguins and land-based observations at the breeding colony, we examined how foraging and reproductive effort in breeding chinstrap penguins Pygoscelis antarctica responded to interannual variation in the abundance of Antarctic krill Euphausia superba in the vicinity of Seal Island, South Shetland Islands, 1990–1992. Regional measures of krill density varied by a factor of 2.5 (47.0, 23.8 and 61.2 gm–2 in 1990, 1991 and 1992, respectively) and was correlated with annual measures of breeding adult body weight and reproductive performance (breeding population size, duration of chick rearing, chick growth, breeding success and fledgling weight). In contrast, measures of penguin foraging effort (dive depth, dive duration, number of trips day–1, trip duration, number of dives trip–1 and dive rate) did not differ between years. We conclude that chinstrap penguins reduce reproductive success rather than increase foraging effort in response to decreases in prey abundance in a manner consistent with predictions of life-history strategies for long-lived seabirds.

The spatial and temporal variability in the fish component of the diet of Antarctic fur seals Arctocephalus gazella (Peters 1975) in the Atlantic sector of the Southern Ocean was examined using diet data from ten sites in the region including a 13 year time-series from South Georgia. The fish species composition in the diet at each site showed a strong relationship with the local marine habitat/topography. The absence of formerly harvested fish species indicates a lack of recovery of stocks of Notothenia rossii (Richardson 1844) at South Georgia and Champsocephalus gunnari (Lönnberg 1905) at the South Orkney Islands. At South Georgia Protomyctophum choriodon (Hulley 1981), Lepidonotothen larseni (Lönnberg 1905) and C.gunnari were the most important species in the diet between 1991 and 2004. Variability in the occurrence of the C. gunnari was driven mainly by annual scale processes, particularly those that influence the availability of Antarctic krill Euphausia superba (Dana 1852). The occurrence of the pelagic P. choriodon was primarily influenced by shorter-term water mass changes within the foraging range of the seals. The fish composition in the diet reflects differences in marine habitat/topography as well as variability at a range of time-scales that reflect environmental variability and harvesting.