Spatial assessment of albatrosses, commercial fisheries, and bycatch incidents on Canada’s Pacific coast

Abstract

Fisheries bycatch mortality poses a primary threat to the majority of the world’s 22 albatross species, 15 of which are at risk of extinction. Although quantitative estimates of albatross bycatch are often unavailable due to a relative or total absence of monitoring, spatial overlap between fisheries and albatrosses is often used to estimate the extent of interaction, a proxy for exposure to bycatch, and to inform avoidance and mitigation actions. Using comprehensive records of commercial demersal longline and trap fishing and survey information for albatrosses (black-footed albatross Phoebastria nigripes, Laysan albatross P. immutabilis, short-tailed albatross P. albatrus), the extent of spatial potential interaction was estimated in Canada’s Pacific coast waters and examined across breeding and non-breeding seasons. The distributions of albatrosses and longline and trap fisheries were found to substantially overlap, with potential interaction hotspots concentrated along the continental shelf break. Trap fisheries reported 1 albatross bycatch incident, suggesting that these fisheries are responsible for negligible albatross mortalities. In contrast, >80% of recorded albatross bycatch incidents occurred within 10 km of albatross-longline fisheries hotspot locations, providing evidence that longline-albatross potential interaction hotspots represent actual areas of elevated bycatch mortality risk. Indicative of potential conservation concern, 60% of short-tailed albatross sightings occurred within 10 km, and 93% within 30 km, of longline-albatross potential interaction hotspots. By contributing knowledge regarding albatross-fisheries interactions, in addition to undertaking the first evaluation of albatross-fisheries hotspots with recorded bycatch incidents on Canada’s Pacific coast, this study represents a step towards enhancing albatross conservation through bycatch avoidance and mitigation.