Update on flesh-footed shearwater tracking and potential areas of bycatch risk

Fisher JH, Bose S, Taylor G, et al (2023) Update on flesh-footed shearwater tracking and potential areas of bycatch risk. In: WCPFC Scientific Committee 19th Regular Session. WCPFC-SC19-2023/EB-IP-13, Koror, Palau

Flesh-footed shearwaters are one of the many species of seabirds breeding in New Zealand which are known to be vulnerable to bycatch in longline fisheries. Adult fleshfooted shearwaters migrate to the North Pacific during the non-breeding season. Historically, our knowledge on the distribution of flesh-footed shearwaters has been based on tracking of breeding adult birds which, on completion of breeding, migrate rapidly across equatorial waters into the North Pacific mostly north of 23 o North. This information was presented to SC12 during earlier reviews of the WCPFC seabird Conservation and Management Measure. We report initial results from the first successful satellite tracking of juvenile fleshfooted shearwaters during May-June 2023. The results show a striking difference in the behaviour of juvenile birds compared to adults and are consistent with results for earlier attempts to track juvenile birds. The juvenile birds moved rapidly north into equatorial waters but then continued to spend multiple weeks in the equatorial zone. At the time of preparation of this paper none have continued their northwards migrations into more northerly areas of the North Pacific. Based on these initial results, this places these birds in a zone of the WCPFC area where no seabird bycatch mitigation is required under CMM2018-03. This tracking study is ongoing and we plan to present full results, including an assessment of the overlap of juvenile flesh-footed shearwaters with fishing effort, to SC20.