False killer whales and Hawaii’s longline fisheries.

Abstract

False killer whales have been implicated in depredation, or removal of catch or bait, from pelagic longline fisheries throughout the Indo‐Pacific. These interactions often result in significant financial loss to the fishing industry, and though uncommon, hooking, or entanglement of false killer whales during depredation often leads to death or serious injury of the whales. False killer whale bycatch in Hawaii’s longline fisheries exceeds allowable limits established under the Marine Mammal Protection Act. In 2010, the National Marine Fisheries Service convened a Take Reduction Team to develop a plan for reducing serious injuries and mortalities of false killer whales caused by such interactions. Means of avoiding or minimizing depredation were an important aspect of the Team’s deliberations. Among other factors, measures of noise produced by fishing vessels or gear and local acoustic propagation may help predict false killer whale‐fishing gear interactions. Acoustics studies are now underway to evaluate noise produced by fishing vessels and the setting, soaking, and hauling of gear, and to evaluate the behavior of false killer whales when they interact with gear. Additional studies on echolocation jamming or acoustically disguising gear were also suggested by the Team.