November 10, 2017 — SEAFOOD NEWS — Light-emitting diodes – LEDs – are proving effective for lowering bycatch in fisheries besides West Coast pink shrimp.

A study by the Pacific States Marine Fisheries Commission and the Northwest Fisheries Science Center shows that LEDs are very effective in directing Chinook salmon to escape windows in Pacific hake trawl nets, according to a statement from the National Marine Fisheries Service. Chinook salmon bycatch in the hake fishery, the largest groundfish fishery on the West Coast, can be an issue; if too many Chinook salmon are caught, management measures may be implemented to conserve salmon stocks.

NMFS requested an Endangered Species Act Section 7 re-consultation on the take of salmon species in the West Coast groundfish fishery in 2013. Now, four years later, the biological opinion or “BiOp” and accompanying incidental take statement is scheduled to be completed in December.

However, avoiding salmon bycatch is an ongoing issue for the whiting fishery and the midwater rockfish fishery. The use of LEDs on the nets, similar to how they are used in the pink shrimp fishery to channel eulachon smelt out escape holes, may prove useful in the future. The LEDs researchers and fishermen used for this project were developed for use on longlines, designed for rugged use in the ocean environment.

The development of efficient, cost-effective LED technology has led to a growing list of innovative residential and industrial applications, according to the statement from NMFS. With NOAA Fisheries’ Bycatch Reduction Engineering Program funding, researchers found LEDs can play an important role in productive and sustainable fisheries as well.

Data show that Chinook salmon are much more likely to exit the nets where lights are placed—86 percent of escaped salmon used the well-lit, LED-framed openings. While further research is underway, the data suggest the LEDs can increase the salmon’s escapement overall, NMFS said.

Mark Lomeli, a researcher at the Pacific States Marine Fisheries Commission, said the challenge was to develop a salmon excluder design to lower incidental salmon bycatch. He and other researchers worked with fishermen to use two sets of large, open escape windows that allowed salmon to swim out.

“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,” Lomeli said in the NMFS report.

The key to keeping hake in and guide Chinook out is fish behavior. Salmon are stronger swimmers and can escape. By the time the whiting get to part of the net where the excluders are positioned, they are too fatigued to swim out.

Researchers said the technology could also be adapted for other fisheries, such as for reducing salmon bycatch in the Alaska pollock fishery.

“Many fishermen are aware of this technology now and use it if they think Chinook bycatch will be an issue,” Lomeli was quoted as saying in the statement. “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. With these research results in hand, the lights are on the shelf for them when they need them. 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.”

This story originally appeared on Seafoodnews.com, a subscription site. It is reprinted with permission.