Fine-scale behaviour and population estimates suggest low exposure but do not exclude high sensitivity to bycatch for Endangered sooty albatrosses

Abstract

Recent developments in assessing species-specific seabird bycatch risks demonstrated that fine-scale approaches are essential tools to quantify interactions with fishing vessels and understand attraction and attendance behaviours. Matching boats movements with birds tracking data specifically allows to investigate seabird-fishery interaction for cryptic species for which on-board information is critically lacking. The sooty albatross (Phoebetria fusca) overlaps with fisheries throughout its range and is known to be vulnerable to incidental bycatch. Combining GPS and behaviour data from individuals from Crozet Islands and boat locations during the incubation period, we investigated interactions of sooty albatrosses with fisheries in the southern Indian Ocean. Individuals foraged mostly in sub-tropical international waters, where they only encountered a small number of boats. The low interaction rate during this period may suggests that sooty albatrosses are not strongly attracted towards fishing vessels. However, this result should be interpreted with caution due to the low sample size and fishing effort during the study period, as these observations may conceal a higher bycatch risk during intense fishing effort and/or energetically demanding periods. The species conservation status requires further data to be collected throughout the annual cycle to provide an accurate assessment of the threat.