Proposed Plan to Reduce False Killer Whale Bycatch in the Hawaii-Based Longline Fisheries

Under the Marine Mammal Protection Act (MMPA), NOAA Fisheries Service is required to develop and implement take reduction plans designed to assist in the recovery or prevent the depletion of strategic marine mammal stocks that interact with MMPA Category I or II fisheries, (those with frequent or occasional mortality or serious injury of marine mammals). NOAA Fisheries Service established the False Killer Whale Take Reduction Team (TRT) on January 19, 2010, to address the bycatch of three stocks of false killer whales (Pseudorca crassidens) in the Hawaii-based deep-set (tuna target) and shallow-set (swordfish target) longline fisheries. The TRT is an advisory group consisting of 19 appointed members representing a variety of stakeholders, including the longline fishing industry, conservation organizations, research and academic institutions, the State of Hawaii, the Marine Mammal Commission, and the Western Pacific Fishery Management Council. The TRT met four times between February and July 2010, and submitted consensus recommendations to NOAA Fisheries Service on July 19, 2010.

NOAA Fisheries Service, in collaboration with the longline fishing industry, conducted two field-based experiments in the tuna fishery to support the TRT’s deliberations. First, a variety of devices (wire loops, nails, etc.) attached to the hook were tested to determine whether marine mammal depredation of bait was altered. Preliminary results from 39 sets suggested the experimental gear provided no appreciable increase in bait retention and may have reduced target catch rates. Accordingly, this gear modification was not further considered by the TRT. Second, “weak” circle hooks, designed to straighten under the strain of a hooked marine mammal, were tested. Analysis of the data from 127 sets is underway. If target species catch rates are not substantially affected by the use of weak circle hooks, NMFS may propose their required use in the deep-set longline fishery.

The TRT recommended a package of regulatory and non-regulatory measures, informed by the research results, that included gear requirements, spatial management (including closed areas), marine mammal handling and release training, and a prioritized list of 35 research recommendations. Based on the TRT's recommendations, NMFS is currently developing a proposed Take Reduction Plan which will be published in the Federal Register in 2011.