Bigeye Fishery Struggles to Avoid Whale Hookings, Serious Injuries

posted in: Fisheries, July 2018 | 0

While the Hawai`i longline swordfish fishery has closed because of its incidental take of endangered sea turtles, deep-set longliners targeting bigeye tuna are facing the closure of a huge portion of their fishing grounds due to their recent uptick in false killer whale (FKW) hookings.

In late June, the National Marine Fisheries Service (NMFS) determined that all three of the false killer whales that were hooked by the fishery in late May and early June were seriously injured (meaning there is a greater than 50 percent change the injury will lead to the animal’s death). Under the current FKW take reduction plan, this will force NMFS to close a 112,575-square-nautical-mile swath of ocean south of the Main Hawaiian Islands.

(NMFS has not yet published notice of the closure in the Federal Register, but when the notice is published, it will specify when the exclusion will take effect. That will not be earlier than seven days after the notice is published, but will not be later than 15 days.)

At the Western Pacific Fishery Management Council’s meeting last month, council staff suggested that NMFS’s own policies might actually be endangering the whales.

Whether a FKW is released with just a hook in its mouth, or a hook with more than a meter of fishing gear trailing behind it (as in the three recent interactions), NMFS would consider the injury to the whale to be serious in either case under its current policy, council staffer Asuka Ishizaki said. She argued that this policy provides no incentive for fishermen to try to release hooked whales with as little fishing gear as possible.

The council ultimately recommended that NMFS review its serious injury determination policy for FKWs and support research into post-hooking mortality “to inform revision of the policy.”

“Ninety percent of interactions in this fishery do result in animals released alive, but do get classified as a serious injury. … Common sense would tell you the more gear you can remove off the animal, you would be able to improve the survival of the animal,” Ishizaki said.

How to do that safely is another question. Under the take reduction plan, the fleet must use weak hooks that are supposed to straighten under the weight of a FKW, allowing the animal to swim free without any gear attached. Instead of trying to keep the line taut or manipulating it to try to free hooked whales, however, some crews have chosen to cut lines with their wire leaders attached to prevent the gear from whipping back at them.

The council’s Scientific and Statistical Committee, which also met last month, found that the weak hook requirement was not only ineffective, but also dangerous to fishermen. “It strongly supported development of modified gear requirements and release procedures to improve the success rate of hooks straightening so as to allow safe release of false killer whales without trailing gear,” a council press release stated.

Federal fisheries scientists worked with longliners on a study in 2016 testing various contraptions — cages, pods, and chains — that might deter depredation of bait or catch by FKW, and therefore deter incidental hookings. “Spoiler alert: there’s no magic silver bullet here,” said David Itano, one of the scientists involved, at a FKW take reduction team meeting in April. While the pod seemed to perform the best, Itano noted that at $6 to $10 apiece, any of the gear tested would be expensive to employ. Ishizaki added that a summary of the study results were presented to the Hawai`i Longline Association (HLA) and “the interest has been lukewarm, I think, in general.”

Crew Training

Trevor Ryder, a team member representing the longline industry, told the team that in any case, “the quickest bang for the buck would be training of crew on line cutting, not cutting the line. Statistically, we could see a bigger return on crew training.”

But training them to do what is one question. The HLA-recommended method is to tie the line of a hooked whale to the boat to maintain tension and, hopefully, straighten the hook. But data has shown that using “active tension” or the “fighting line method” may be the most successful in straightening the hooks. That could be because it’s used 80 percent of the time.

Whether or not active tension is really the most effective way to de-hook whales, it may be safer for both the animals and the crew. NMFS protected species workshop instructor Colby Grady told the team that the HLA method could be “too immediate” and cause a hook to rip through a whale’s jaw bone, or gear to come flying back on deck, or both.

How the crew members will be trained, when so many of them are foreigners who can’t legally set foot on U.S. soil, is another question. Ryder said he’s taken the three-hour protected species training classes 15 times and shares what he learns with his crew. He added that the federal observers on board some of the vessels also try to instruct crew members on what to do when protected species are incidentally hooked. That said, he added, “I can’t speak for all other captains and all the other crew.”

In the case of the FKW hooked on May 23, NMFS reports that the observer on board asked the crew to get the captain, “but the crew did not speak English and did not appear to understand the request. … The crew was unable to keep holding the line, so it was cut releasing the animal with the hook …, weight (45 g), leader (0.5 m of 2.0 mm diameter wire leader), and branchline (approximately 5 m of 2.0 mm diameter monofilament).”

According to NMFS data, since 2016, vessel captains were absent during the handling of hooked or entangled FKWs more than a third of the time. For now, however, crew training across the entire 145-vessel fleet appears unlikely.

“There is no funding available to go down and train someone on the boat,” Grady said. Whether U.S. Customs and Border Protection would allow some foreign crew members to obtain the same kind of protected species interaction training that their captains do — on land, and in a language they can understand — remains to be seen.

–Teresa Dawson

 

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