CCAMLR

The diet of grey-headed albatrosses at Diego Ramírez, Chile, was analyzed and compared to that of the sympatric black-browed albatross. Diet composition was inferred from an analysis of prey hard parts present in 103 chick regurgitates obtained during breeding seasons 2000, 2001 and 2002. The squid Martialia hyadesi predominated in the diet samples in 2001 and 2002 (89% and 81% of reconstituted mass), but was absent from the 2000 samples. Reconstituted mean mass per sample in 2000 was significantly lower than in 2001 and 2002. Chick growth rate during 2000 was also the lowest recorded. This suggests that M. hyadesi plays an important role in the breeding performance of grey-headed albatrosses at Diego Ramírez. Low presence of M. hyadesi in grey-headed albatrosses’ diet at South Georgia in 2000, a year with significant low breeding success, suggests ocean-wide processes affecting the availability of this prey to both populations simultaneously. Overlap in diet composition, and inferred feeding areas, between the sympatric albatross species at Diego Ramírez was minimal. Grey-headed albatrosses fed mainly on species associated with the Antarctic Polar Front, whereas black-browed albatrosses consumed benthopelagic species frequently caught in fishing operations in southern Chile.

The legal Patagonian toothfish longline fishery operating in the French ZEE of Crozet (58.6) and Kerguelen (58.5.1) killed 26 668 seabirds, accidentally drowned, during 24 months of fishing between September 2001 and August 2003. Overall, white-chinned petrels Procellaria aequinoctialis were by far the most frequently killed species then grey petrels Procellaria cinerea were incidentally killed in great number. Giant petrels, black-browed and grey-headed albatrosses were also captured over this period. The multivariate analysis contributed to highlight that a combination of variables (environmental and relating to the fishing technicals) have an effect on the observed seabirds incidental capture.

Icefish are a family of species unique among vertebrates in that they possess no haemoglobin. With the exception of one species, icefish live only in the cold – stable and oxygen – rich environment of the Southern Ocean. It is still questionable how old icefish are in evolutionary terms: they may not be older than 6 MA, i.e. they evolved well after the Southern Ocean started to cool down or they are 15 – 20 Ma old and started to evolve some time after the formation of the Antarctic Circumpolar Current. Certain icefish species, such as Chionobathyscus dewitti, have been found down more than 2,000 m. Icefish have been shown to present organ – level adaptations on different levels to compensate for the ‘disadvantages’ of lacking respiratory pigments. Biological features, such as reproduction and growth, are not unique and are comparable to other notothenioids living in the same environment. Icefish produce large yolky eggs which have a diameter of more than 4 mm in most species. Most icefish species do not attain maturity before they are 5 – 8 years old. Spawning period of most icefish species is autumn – winter. The incubation period spans from 2 months in the north of the Southern Ocean to more than 6 months close to the continent. Growth in icefish to the extent it is known is fairly rapid. They grow 6 – 10 cm in length per annum before they reach spawning maturity. Icefish feed primarily on krill and fish. Some icefish species are abundant enough to be exploited by commercial fisheries, primarily in the 1970’s and 1980’s with Champsocephalus gunnari as the main target species. Most stocks of this species had been overexploited by the beginning of the 1990’s.

Information on CCAMLR fisheries of relevance to the work of WG-FSA is summarised. Additional fishery-related information can be found in WG-FSA-04/6, 04/7, 04/8 and 04/9 (summaries of observer data), WG-FSA-SAM-04/4 (Development of Fishery Plans), SC-CAMLR-XXIII/BG/1 (catches in the Convention Area) SC-CAMLR-XXIII/BG/3 (summary of notification for new and exploratory fisheries), SCIC-04/3 (estimates of IUU catches) and CCAMLR-XXIII/BG/8 (implementation of conservation measures) and CCAMLR-XXIII/38 (Monitoring CCAMLR Fisheries).