LED lights help guide salmon to openings in trawl nets

Low-cost LED lights can help Chinook salmon escape trawl nets.

A 2020 study by the Pacific States Marine Fisheries Commission and NOAA’s Northwest Fisheries Science Center showed that LEDs are very effective in directing Chinook salmon to escape openings in trawl nets targeting Pacific hake, the largest groundfish fishery on the West Coast that typically takes more than 500 million pounds a year.

The study showed that Chinook are much more likely to exit the nets where lights are placed — 86% of escaped salmon used the LED-framed openings — without fishermen losing the targeted catch.

“Our data and video observations indicate that at deeper, darker depths where trawl nets go, light from the LEDs are enhancing the salmon’s ability to perceive the escape areas and the areas outside the nets,” said Mark Lomeli, lead researcher at the Pacific States Commission.

Lomeli said the lights have also proven effective at reducing bycatch of eulachon (Pacific smelt) and juvenile rockfish and flatfish in the shrimp trawl fishery off Oregon.

“We also think the LEDs could be used in other fisheries — for example, in the pollock midwater trawl fishery in Alaska — to reduce Chinook salmon bycatch,” Lomeli said in a NOAA release about the project.

“Many fishermen are aware of this technology and use it if they think Chinook bycatch will be an issue. It’s easy to use, relatively cheap and widely available. You can easily clip the lights to the webbing of the net around the escape openings. ... We think these LEDs are low-hanging fruit for contributing to the recovery of this species and can also play an important role in the stability of this fishery,” Lomeli said.

Looks to be good year

for federal fisheries

Fisheries are driven by numbers, and there will be more ups than downs in 2022 catches for Alaska fishermen based on poundages set by the North Pacific Fishery Management Council.

The NPFMC is a federal advisory panel that has the herculean task of setting six fishery management plans covering 140-plus species within 47 stocks and stock complexes, including setting annual bycatch limits. Their jurisdiction includes waters from three to 200 miles offshore where more than 60% of Alaska’s fish catches by volume are harvested.

For Pacific cod in the Bering Sea/Aleutian Islands, the catch for next year was increased by 20% to just over 330.5 million pounds.

Cod catches in the Gulf of Alaska got a boost to 61.5 million pounds, a 61% increase over 2021.

Also getting a larger allocation is the so-called “head-and-gut” fleet of 19 Seattle-based bottom trawlers that have been making headlines for their annual takes/tossings of more than four million pounds of halibut bycatch (which comes off the top of all other users). The big boats, which include seven owned by Western Alaska Native groups, target flounders, cod, perch and Atka mackerel. The 2022 catch limit for all but one of those was upped by 20% or more. Their most important catch, yellowfin sole, was increased 25% to 550 million pounds.

The 2022 catches must be approved by the U.S. Commerce Department, which almost always adopts NPFMC recommendations.

Fishermen

enhance science

More than 100 Alaska fishermen signed on for a “skipper science” program that lets them share what they know and see out on the water.

The pilot program started in June and uses a free phone app for logging real-time observations.

“Basically, it worked, and fishermen are very well equipped to be a big part of the science and the research going on so we can better understand and manage our fisheries,” said Lindsey Bloom, director of SalmonState’s Salmon Habitat Information Program (SHIP), which partnered with the St. Paul Island tribal government to run the citizen-scientist project.

The app is an offshoot of an Indigenous Sentinels Network started nearly 20 years ago at St. Paul Island in the Pribilofs to monitor wildlife and environmental conditions in the Bering Sea.

“There is a vast body of deep knowledge that fishermen hold from their experiences on the water, indigenous and non-indigenous fishermen alike, that they're using for decision making and risk evaluation. And we have very much underutilized that knowledge for years and years, especially here in the North Pacific,” said Lauren Divine, director of ecosystem conservation for St. Paul’s tribal government at the launch of the skipper science program.

A report showed that nearly 1,700 fishermen shared their views on ways a changing climate is affecting Alaska’s waters and habitats, and 61% said they are very or somewhat concerned about impacts to fisheries.

“There’s not a fisherman out on the water who has not experienced abruptly changing conditions as a result of a changing climate,” Bloom said. “We have consistently heard that in terms of what people are feeling are the threats to their businesses and bottom lines — climate is in the top two or three.”

Nineteen diverse industry members, processors and fishing groups sponsored the science project and helped get the word out, and Bloom said it has support from fishery managers.

Bloom is hopeful that fishermen might eventually get paid to collect and provide data.

“I think there are incredible efficiencies to be gained. When you have all these small boats out on the water day in and day out, why not use them to measure and report on what’s happening,” she said.

Divine added that local knowledge and experiences enhance the science provided by drones, satellites, ships and other high-tech devices.

More information is available at skipperscience.org.

 

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