Incidental catch of seabirds by Taiwanese longline fleets in the Southern Oceans between 2010-2018

In this study, we update the distribution of seabird bycatch of Taiwanese tuna longline vessels from 2010-2018. Furthermore, we explore if seabird bycatch rate varies among fleets, including (1) Taiwanese fleets with different size and targets, and (2) Taiwanese fleet and Japanese fleet. We used observer data collected from 440 Taiwanese tuna longline vessels operating in the southern Ocean (south of 20° S) between 2010 and 2018. For the observed 103,511 hooks, 1,523 seabirds were incidental caught. The mean annual bycatch rate ranges from 0.003-0.037 from 2010-2017. The bycatch rate of seabirds was not significantly different among vessels with different size and targets, when year and operation location were considered. In addition, the mean bycatch rate of seabirds was similar between Taiwanese and Japanese tuna longline vessels, when the operation time period and fishing ground are controlled.