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.

A method of surveying incidental mortality of seabirds during longlining operations and the effectiveness of mitigation measures is described. An alternative design of streamer line for use with the 'Spanish' method of longlining (separate hauling and fishing lines) is described. The results of observations of incidental mortality of seabirds made during the fishing operations of the Korean longliner lhn Sung 66 are presented. Preliminary findings suggest that the phase of daylight during which the longline is set is more important than the use of a streamer line in the mitigation of incidental mortality. The use of a streamer line during setting of longlines during the day reduced the observed rate of bird deaths from snagging and drowning by 79%. More data are required to develop the investigation further.

This paper is a revision of the assessment of the competition between the Japanese krill (Euphausia superba) fishery and penguins (WG-Krill-93/7). Main fishing areas were confined to the slope and shelf to the north of either Livingston or Elephant Islands. In contrast, main foraging areas of penguins are considered to be formed in areas to the north of King George, Nelson and Robert Islands, and around Low, Clarence and Deception Islands. This little overlap between the main fishing and foraging areas is resulted from that large colonies of the dominant penguin (chinstrap penguins, Pygoscelis antarctica) are closely associated with areas where sea-ice disappears earlier in spring, not necessarily with areas of high krill abundance. The overlap between trawling depth and foraging dive depth of penguins was also insignificant. Furthermore, less similarity between krill caught by trawlers and those captured by penguins was observed. The above mentioned results imply a low level of competition between the fishery and penguins. Krill biomass was estimated to be as large as 200-1500 xl03 tonnes within the preferred fishing areas during the breeding season. Compared with the level of biomass (≥200 xl03 tonnes) and its variability (the order of 100 xl03 tonnes/half-month period), the present catch rate (≤13 xl0 3 tonnes/half-month period) is smaller by one or more orders of magnitude within the localized areas. Thus, the present fishery is very unlikely to have an adverse impact on the local krill biomass and hence on penguins,. when catch levels are also taken into account.