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The killer whale (Orcinus orca) behavior termed "depredation" is a major issue negatively affecting fisheries worldwide. Information on killer whale depredation in the northwestern Pacific Ocean is limited. The goal of this work was to assess the extent of killer whale depredation on the groundfish fisheries in the western Bering Sea and the Sea of Okhotsk. Observations of killer whale depredation were conducted on 8 of the 42 (19%) longline fishing vessels between October 2018 and September 2019. Killer whales depredated during 2.0% of vessel days in the western Bering Sea and 18.6% of vessel days in the Sea of Okhotsk, taking exclusively Greenland turbot (Reinhardtius hippoglossoides). Seventy-one killer whales were identified depredating on longlines in the Sea of Okhotsk, with the best estimation for the total number of killer whales depredating about 139 individuals. Results suggest that killer whale depredation is an issue for Greenland turbot longline fisheries in the northwestern Pacific. There is a strong need for mitigation measures, as this has an economic impact on the fisheries and also affects the killer whale population and associated ecosystems. [ABSTRACT FROM AUTHOR]

The article presents a study which examines the seasonal selection behavior of sea ice landscape of bowhead whales or Balaena mysticetus based on satellite tracking data of the whales across Eastern Canada-West Greenland. The study investigates the movement of the whales and their habitat selection throughout summer and winter seasons, and employs resource selection functions to evaluate their habitat selection behavior. The results show that bowhead whales preferred areas with low ice coverage, thin ice and small floe size during winter, while areas with high ice coverage, thick ice and large floe size during summer.