Fine‐scale interactions between boats and large albatrosses indicate variable susceptibility to bycatch risk according to species and populations

Citation
Corbeau A, Collet J, Orgeret F, et al (2021) Fine‐scale interactions between boats and large albatrosses indicate variable susceptibility to bycatch risk according to species and populations. Anim Conserv acv.12676. https://doi.org/10.1111/acv.12676
Abstract

Many seabirds are attracted to fishing boats where they exploit foraging opportunities , often involving bycatch-related mortality. Bycatch risk is generally estimated by overlapping seabirds foraging ranges with coarse-scale monthly maps of fishing efforts, but a more direct estimation would be the time birds actually spend attending fishing boats. Here we matched data from Automatic Identification Systems from all declared boats in the Southern Ocean, with 143 simultaneous foraging trips from all populations of large albatrosses (Diomedea amsterdamensis and Dio-medea exulans) breeding in the Indian Ocean (Marion, Crozet, Kerguelen, Amster-dam islands). We quantified and compared real-time co-occurrence between boats and albatrosses, at different scales (100, 30 and 5 km). We also examined to what extent co-occurrence at a large-scale (5x5°grid cell) predicted fine-scale attendance (5 km). Albatrosses on average spent about 3 h per trip attending fishing boats (90% of declared fishing boat attendances occurred within Economic Exclusive Zones (EEZ) where bycatch mitigation measures are enforced. Outside EEZs, birds from all populations to a large extent also attended non-fishing boats. Fishing boat density at a large scale (5x5°, 100 km) was a poor predictor of time spent attending fishing boats (