The Hawaii Longline Association announced this week it’s making key changes to its fleet’s fishing equipment to help the imperiled oceanic whitetip shark stave off extinction.

Specifically, by July, crews aboard the fleet’s 140 or so vessels plan to replace the steel wire fishing leaders at the ends of their fishing lines with ones made from less-lethal nylon, or monofilament, according to HLA Executive Director Eric Kingma.

The move should at least somewhat help the endangered and overfished sharks, local fishing officials and industry watchdogs say, because they can bite through the nylon more easily and free themselves when they’re inadvertently caught.

It’s a much-welcomed change to aid a species that was abundant in the central and western Pacific Ocean before commercial fishing and demand for shark fins decimated their numbers, ocean conservationists say.

But to truly save the oceanic whitetip from extinction, the numerous fishing fleets from other nations operating in the Pacific will have to follow suit, officials added.

Nakachi Shark Kahu Mano
An oceanic whitetip shark swims in Hawaiian waters in a photo by Kaikea Nakachi, part of an extensive database he’s collected for his research and practice emulating his family’s legacy as kahu mano, or “shark keepers.” Courtesy: Kaikea Nakachi

The industry-led initiative comes as the Western Pacific Regional Fishery Management Council, or Wespac, which oversees commercial fishing in a broad swath of federal waters, conducts its own study on how to protect oceanic whitetips. The council is expected to make recommendations for federally required methods next year.

“We think this is the most cost-effective way to reduce our impact,” Kingma said of the advance step HLA took this week.

Making the switch to monofilament should reduce the fleet’s number of shark catches by at least half, he said. Plus, it puts protective measures in effect earlier than if the fleet waited for those federal requirements, he added.

The Hawaii longline fleet’s primary target is bigeye tuna, known as ahi in Hawaii. It also pursues swordfish. The council voted this week to urge the international tuna commission that oversees the Western and Central Pacific to nearly double the Hawaii longliners’ bigeye tuna quota from about 3,500 metric tons to 6,554 metric tons. Quota negotiations before the Western and Central Pacific Fisheries Commission will take place next week when delegates for numerous countries hold their annual weeklong meeting.

Those familiar with the oceanic whitetip describe it as a “cruiser” — a pelagic shark that covers vast ocean distances, conserving energy with its large pectoral fin and swooping in fast on fish prey near the sea surface.

But the evolutionary traits that made the once-abundant species such an impressive predator are the same ones leading it toward extinction.

Only a fraction of the thousands of oceanic whitetip sharks that get caught in Pacific fishing gear — many of them fatally — do so on HLA hooks and lines. The vast majority gets caught on gear from the combined fleets based in China, Japan, South Korea and other nations with Pacific fishing operations, officials say.

According to Kingma, about 1,500 oceanic whitetips get caught in HLA gear each year, representing about 4% of all the whitetip catches in the Pacific. Some 30% to 40% of those sharks die after getting caught, he said.

Meanwhile, a report from the National Marine Fisheries Service found that 53,500 oceanic whitetip sharks were caught by western and central Pacific fishing fleets each year on average from 2013 to 2017. That included some 1,700 catches a year by Hawaii’s deep-set longline vessels.

Just The First Fleet?

KerriLynn Miller, an officer for the Pew Charitable Trust’s international fisheries program, said that HLA’s estimates on its own impacts to the shark species sound reasonable.

Furthermore, she hopes the HLA’s changes to its fishing gear will spur other fleets that fish the Pacific to do the same.

Australian fishing representatives already have proposed prohibiting the wire leaders before the Western and Central Pacific Fisheries Commission, Miller said. That’s the same international body overseeing fishing practices that Wespac is lobbying. The Australians’ idea was shut down, Miller added.

She said she hopes that the idea could gain support at the commission’s meeting next year, after the HLA’s wire leaders get replaced.

“They’re taking a big leadership role for shark conservation and we are hopeful that this action will spark a broader commitment within the Pacific,” Miller said.

fishing leaders Wespac
The HLA fleet will be replacing its wire fishing leaders (top) with nylon monofilament ones (bottom) that will be easier for sharks to bite through and free themselves. WESPAC

That international commission conducted its own stock assessment of oceanic whitetips in 2019 that showed the shark was being overfished and that if the current mortality rates didn’t subside they’ll go extinct.

Kingma said that more accurate, reliable catch data from the foreign fleets could help spur the foreign fleets to join in on the changes. That data would be more reliable, he said, if more observers are required to be on board the fishing vessels when they’re out at sea.

Currently, foreign vessels are subject to about 5% observer monitoring, whereas HLA vessels are subject to about 20%, he said.

“It’s really hard, it’s going be tough, but we’ve got to get the data right,” Kingma said Wednesday.

Kingma said that HLA doesn’t know the full financial cost or economic impact of switching out the leaders, but the group doesn’t expect them to be that significant.

The fleet has been using the more durable wire leaders for about 20 years to help prevent “flyback,” where tension on a hooked line can cause it to recoil and whip back dangerously at the vessel.

As the boats switch to monofilament leaders, the crews will also clip weights onto the line to help prevent flyback, Kingma said. The leaders are also required to be weighted down into the water so they stay out of seabirds’ foraging depth.

The switch could potentially help protect some striped marlin as well, which fishing fleets are also required to do, but HLA didn’t consider that in making the change to monofilament, Kingma said. Unlike a shark you don’t always know when you’ve got a marlin caught on the line, he added, so “the science behind it can get a bit convoluted.”

Instead, the move was chiefly about the sharks, Kingma said.

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