There have been a spate of recent papers on the effect of LEDs in reducing bycatch with research showing very strong effects to none in shallow water with sea duck and gill nets. It would appear that the ambient light regime of where the gear is deployed is a key factor in this. In the study reported below LEDs worked best for deeper trawl fishing.
Study shows lit escape holes allow non-target species to get away, protecting populations
Guardian A simple technique to “illuminate the exits” in trawl fishing nets can almost halve the numbers of unwanted catch, new research has found, potentially protecting both the environment and fishermen’s livelihoods. Attaching LED lights to larger holes in nets, intended to allow non-target species to escape, dramatically reduced the numbers killed unnecessarily, a team from Bangor University found. The research, published in Journal of the Marine Biological Association of the United Kingdom, inverts an old fishing technique of shining a light on water to attract fish into a net.