Progress report of collaborative study on the migration pattern of blue shark (Prionace glauca) in the central North Pacific Ocean
A collaborative study to investigate the migration patterns of blue shark (Prionace glauca) in the central North Pacific Ocean was launched between Japan and the US in 2020. Ten pop-up satellite archival tags (PSATs) provided by Japan were distributed to US longline observers onboard commercial Hawaiian longline fishery vessels between 2020 and 2021 in association with US scientists. As of the end of October 2021, all PSATs had been successfully attached to blue sharks. Among the ten PSATs, three had troubles with their depth sensor and/or archival of data, and two had no data transmissions after the preset pop-off date. We obtained data from one adult female consisting of 226 days-at-liberty, this female exhibited a clockwise movement pattern (from the southwestern waters off Hawaii towards the US mainland) between January and August 2021 with spatiotemporal variation of vertical behavior. The remaining four PSATs currently still attached to sharks are programmed to detach from February -June of 2022.