Predicting albatross bycatch hotspots across the North Pacific Ocean

Bycatch threatens many seabird populations and remains a barrier to fisheries sustainability. Albatrosses are particularly vulnerable to bycatch in longline and trawl fisheries across the North Pacific due to their wide-ranging movements and attraction to fishing vessels. Identifying when, where and with which fisheries bycatch risk is greatest is crucial to prioritize monitoring and recommend targeted management interventions. Here, we collated >1,200 albatross tracks from eleven populations of three species (Short-tailed, Laysan, and Black-footed) in the North Pacific to provide an ocean-basin-scale assessment of bycatch risk. We overlaid species distribution model predictions of bird densities for each population and breeding stage with Automatic Identification Systems data on longline and trawl effort. Models were high-performing (mean [range] area under receiver operating characteristic curve: 0.91 [0.75-0.98]), and bycatch risk hotspots were identified from pelagic longline fisheries in the central and northwest subtropical Pacific and from demersal longline and trawl fisheries across the Pacific Rim from Japan to California. Risk also varied seasonally and occurred mostly during breeding (winter-spring) from pelagic longline fisheries and during non-breeding (summer-fall) from demersal longline and trawl fisheries. Considerable (88%) overlap with pelagic longline fisheries occurred in the High Seas where observer coverage is extremely low (5%) and use of bycatch mitigation is variable. Four flag states (Japan, USA, Taiwan, and Russia) were responsible for >95% of overall risk. Overall, our results indicate that improved monitoring in the identified fleets and increased adoption of and compliance with best-practice mitigation measures, would reduce future conflicts between fisheries and albatrosses. RECOMMENDATIONS That the SBWG and PaCSWG urge the Advisory Committee to encourage the following actions by RFMOs and Range States: 1. The Western & Central Pacific Fisheries Commission (WCPFC) mandates higher observer coverage of seabird bycatch in pelagic longline fleets of Japan (particularly the small offshore fleet) and Taiwan. 2. The WCPFC mandates best-practice mitigation measures in all pelagic longline fleets; as a minimum, that streamer lines are used by the entire US Hawai’i deep-set fishery, given the high risk to birds in the Central Pacific. 3. More comprehensive monitoring of data on seabird-bycatch rates is carried out by the Japanese coastal pelagic longline fleet, Japanese and Russian demersal longline and Russian trawl fleets, and that these data are made available for assessments. 4. Improved data on fishing effort and seabird-bycatch rates are collected for small coastal longline vessels in Mexico and Japan, to better understand risk associated with small-scale fisheries.