Seabird mortality on factory trawlers in the Falkland Islands and beyond

Abstract

Specifically tasked seabird observers were placed onboard demersal (bottom) finfish trawlers operating in the Falkland Islands in 2002/2003 to investigate the level of seabird mortality caused by the fleet. The observers were tasked to record seabird interactions during shooting, trawling and hauling operations during 157 days of coverage. It is estimated that >1500 seabirds, predominantly Black-browed albatross ( Thalassarche melanophris), were killed by finfish trawlers during this period. Significant levels of mortality were also recorded on the Patagonian Shelf, north of the islands. Birds were killed after being dragged underwater by the warp cable while feeding on factory discharge at the stern of the vessel. An unknown proportion of these birds slide down the cable and become impaled on a splice in the cable, which was situated on average at 90 ± 40 m from the waters surface, and are subsequently hauled onboard. The incidence of mortality caused by the many large trawling fleets around the world that discharge factory waste and attract large bodied seabirds (e.g. albatross and large petrels) requires immediate investigation.