Scientists at the National Marine Fisheries Service have documented a rise in the number of pelagic false killer whales that are killed or seriously injured as a result of interactions with the Hawaiʻi-based longline fishing fleet.
While the separate population of insular false killer whales, listed as endangered, is pretty well protected from interactions with longline vessels, not so the pelagic population. The pelagic animals have not been listed as endangered, but they do have protection under the Marine Mammal Protection Act, and so NMFS is required to establish rules to limit the number of mortalities or serious injuries resulting from fisheries interactions (M/SI) to a number that is at or below the level where the losses do not jeopardize the population’s ability to sustain itself.
For the pelagic false killer whales, that number – the so-called potential biological removal (PBR) – has been set at 33. Yet the most recent average annual take, over the last five years, has been 47.
Last month, a group of four conservation organizations – Center for Biological Diversity, Hawaiʻi Wildlife Fund, Defenders of Wildlife, and the Natural Resources Defense Council – put NMFS on notice that its failure to issue a rule to amend the Take Reduction Plan for false killer whales violates the Marine Mammal Protection Act. In addition, their letter to NMFS officials states, the failure “puts false killer whales at greater risk and undermines one of the MMPA’s primary mandates: that marine mammal mortality and serious injury in commercial fisheries be reduced to insignificant levels approaching zero.”
The letter does not threaten legal action, but it does “urge the agency to promptly issue proposed amendments to the” False Killer Whale Take Reduction Plan.
At its June meeting, the Western Pacific Fishery Management Council discussed the population status of both the pelagic and the insular false killer whale populations. Elena Duke, the coordinator of NMFS’ False Killer Whale Take Reduction Team, outlined measures that the FKW Take Reduction Team (TRT) had considered at its most recent meeting, in March 2023, to discuss the increasing rates of M/SI among the pelagic population. NMFS sought to have the TRT, which includes representatives of the agency, industry, and conservation groups, reach a consensus on changes to the Take Reduction Plan. Agreed-upon recommendations included electronic monitoring, crew training, and acoustic monitoring, among other things, but proposals to cut back on fishing effort or to require controversial changes in fishing gear were not agreed to.
Still, Duke said, even though NMFS has not amended the Take Reduction Plan, it has discussed ways to improve handling of animals, funded a University of Hawaiʻi engineering lab to test various longline gear configurations, and has begun dockside crew training programs.
Meanwhile, the insular population of false killer whales, largely protected from interacting with longline vessels, continues to decline at a rate of about 1.3 percent a year. That population is estimated to number fewer than 150 animals.
At the council meeting, Guam representative Manny Duenas suggested that the decline of the insular population could be because “the females beat up on males.”
Amanda Bradford, a researcher with NMFS’ Pacific Islands Fisheries Science Center, responded, stating, “We do see evidence of fishery interaction. We think they’re occurring with nearshore commercial and recreational fisheries.”
There is more of a female bias, she added. “Females seem to have more scarring. But we don’t really know what’s driving the population decline.
— Patricia Tummons
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