CCAMLR

Sea-birds taking baits during longline setting occationally become caught and are killed, while the associated bait loss may have serious impact on longlining efficiency and profitability. Two different setting methods were tested as a solution to this problem; lines were set either through a setting funnel that guided the baited line beneath the sea surface or when using a sea-bird scaring device. Bait loss and the catches of target species and sea birds were compared with those of lines set without using such devices. Accidental catches of birds were reduced by both methods, most effectively by the sea-bird scarer. Losses of mackerel bait were also significantly reduced by using the scarer, but not by using the setting funnel. No increase in the catches of target species was demonstrated by using either of the setting methods. However, bait loss caused by sea birds was regarded as a minor problem in this fishing experiment. Suggestions on how to improve the efficiency of the two methods tested were discussed.

CCAMLR has been using the total catch of krill taken within 100 km of penguin colonies in their breeding season (December to March) as an index of overlap between the potential foraging areas of penguins and the distribution of the krill fishery in Subarea 48.1 (South Shetland Islands). As this index has proven unsuitable for a number of reasons, an alternative method of calculating an index of fishery-predator interaction has been developed. The new index reflects the functional interaction between these two utilisers of the krill resource and is based on a detailed model of penguin foraging patterns combined with catch positions. This analysis shows that the overlap between the fishery and chinstrap penguins is much greater than for other penguins, and that this overlap has been decreasing since 1988.