CCAMLR

Commercial trawl fisheries in the modern era started within the Heard Island EEZ in 1997. This paper summarises the fishing activities to date and collates the information on the biology of the species gathered from the fishery and from a series of fishery-independent surveys conducted between 1990 and 2000. Icefish abundance varies widely between years and the fishery is dependent on periodic abundant year classes that can be followed through the population before disappearing in their fifth year. The occurrence of abundant cohorts is not synchronised between the Heard Island Plateau, Shell Bank or the Kerguelen Plateau, nor are the respective spawning seasons. This suggests that the populations in the respective areas are mostly independent of one another.

Interactions between seabirds and longline fishing can cause incidental bird mortality and reduced gear efficiency. The potential for solving these problems by using a bird-scaring streamer line and a line shooter was investigated in commercial longlining in the northern Atlantic off the coast of Norway. We compared the bycatch rate of northern fulmars Fulmarus glacialis, the loss rate of baits to fulmars and the catch rates of fish target species among lines set with either of these mitigation measures, a combination of both and no mitigation measure. A total of 58,420 hooks were set in each of the four treatments. No birds were caught using the bird-scaring line alone and a single fulmar was caught when the bird-scaring line was used in combination with the line shooter. In contrast, 32 fulmars were caught in sets with no mitigation device and thirteen in sets with the line shooter alone. Losses of mackerel bait were reduced when the bird-scaring line was used, but not by using the line shooter alone. Longlines set with the line shooter reached 3 m depth 15% faster then lines set without the line shooter; beyond this depth sinking rates were similar (about 15 cm s-1). Fish catch did not vary significantly among setting methods. These results should also be applicable to the bycatch of Fulmarus spp. in demersal longline fisheries worldwide.