Seabird mortality in the Japanese tuna longline fishery around Australia, 1988–1995

摘要: Abstract Large numbers of seabirds are killed each year within the Australian Fishing Zone (AFZ) by Japanese longline vessels targeting tuna. In recent years estimated rate seabird bycatch in AFZ has been order 0.15 birds/1000 hooks, translating to mortalities 1000–3500 birds per year. These estimates absolute minima because not all remain on hooks be observed hauled aboard vessels. The catch varies annually, seasonally and spatially. Most killed: (a) during summer fishing season (October March), even though most effort occurs winter; (b) when longlines set day; (c) waters around southern Australia. Uncertainties rates prevent confident assessment trends, but do appear showing a sustained decrease. process incidental collection data (by observers whose priority is fish sampling tasks) renders inadequate for reliable trends total over time. Sixteen species have identified. include black-browed ( Diomedea melanophris ), shy D. cauta grey-headed chrysostoma yellow-nosed chlororhynchos ) wandering albatrosses exulans flesh-footed shearwaters Puffinus carneipes white-chinned petrels Procellaria aequinoctialis ). Seventy-four cent were composition varied with seasons areas. characterised unequal representation sex age cohorts, these representations consistent between grounds or seasons.