CCAMLR

Two tuna longline fishing hooks have been recovered from beside Wandering Albatross Diomedea exulans nests at Marion Island in the 1990s. No hooks have been found at Gough Island and no birds have been found dead ashore on either island as a result of fishing gear. Recoveries of banded birds at sea suggest Wandering Albatrosses are more at risk to being hooked than are giant petrels Macronectes sp.

Longlining operations for Dissostichus eleginoides around South Georgia were assessed for interactions with sea mammals. Twenty-seven lines were observed and interactions recorded during twenty-five of these. During setting of lines neither mortalities nor interactions were recorded. All interactions occured during hauling operations, both during the day and at night. Killer whales (Orcinus orca)were present during one haul, from which 11 intact fish were taken aboard, compared to a mean of 510 fish/haul for all 27 lines. Sperm whales (Physeter macrocephalus) were also associated with hauling operations and may have been removing fish captured on the lines. Numbers of sperm whales varied with location; some whales with identifying masks were observed over successive lines to the south-west of South Georgia, but were not seen on subsequent operations to the north-west of the island. On two occasions, sperm whales were snagged on the line but were freed. Interviews with fishermen indicated that interactions of killer whales and sperm whales with longlining operations may be common in the South Atlantic and off southern Chile. Fishermen recognized that these interactions were costly in terms of fish and fishing time lost; the development of measures to reduce interactions may help prevent fishermen taking action potentially harmful to cetaceans.

Long-lining operations for Dissostichus eleginoides off South Georgia were assessed for incidental mortality and interactions with seabirds. Twenty-seven lines were observed and ninety-eight mortalities recorded over twenty sets of the line; no mortalities occurred during hauls. The 16 sets made at night contributed 15% of the overall mortality, all of white-chinned petrels: the four day time sets contributed 85% of overall mortality, with giant petrels, grey-headed albatrosses and black-browed albatrosses predominating. Our data suggest that grey-headed albatrosses, whose populations at South Georgia are in serious decline, were disproportionately affected in relation to their numbers in the vicinity of the fishing vessel; giant petrels also may be disproportionately affected, at least in relation to the size of their breeding population at South Georgia when compared to the albatrosses. Average mortality rate for the twenty sets was 0.48 birds/1000 hooks and maximum mortality 3.12 birds/1000 hooks. Mortality and interactions of birds with operations varied with site and time of day, and due to behavioural interactions between birds. Setting only at night would dramatically reduce albatross deaths, but would substantially increase white-chinned petrel mortalities. A streamer line made to CCAMLR specifications may also reduce mortalities but may be less effective during calm weather, intense feeding activity by seabirds, or when incorrectly constructed.