A SIMPLE technique to “illuminate the exits” in trawl fishing nets can reduce unwanted bycatch by almost 50 per cent, 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 cut 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 to boost the catch.

The study, which was conducted between June and August 2017, tested the impact of lights in reducing the number of haddock and flatfish caught in a queen scallop fishery off the Isle of Man.

It found that while existing bycatch reduction devices were effective at shallower depths of 29 metres to 40 metres deep, in deeper darker waters of 45 metres to 95 metres, they had no impact at all on bycatch numbers.

But once LEDs were added to these “exits” in deep water, haddock bycatch was reduced by 47 per cent and flatfish catch was reduced by 25%.

Bycatch is a problem in fisheries all over the world because it inflicts further damage on often depleted non-target species, and kills mammals and seabirds that become entangled in


It can also be a huge cost to fishermen – under EU law, the Landings Obligation requires fishermen to bring ashore almost everything that they catch, including fish that are not part of their quota.

If they end up catching too much of their non-target species, fishermen can see their fishery “choked” – closed for a period of months to allow vulnerable stocks to recover.

Lucy Southworth, lead author of the study, said: “Traditionally, and this goes back decades and maybe even centuries, fishers used lights to attract fish.

“But now we are turning that on its head to try and manipulate the behavioural responses in fish and other animals to either repel them away from gear or to manipulate their

behaviour so they can escape from them net.”

She added: “In our case we decided to attach the lights to the escape exit to try and guide fish towards it so they would escape out more so than they would do if the lights weren’t there.”

Ms Southworth described the discovery that existing bycatch reduction devices without LEDs cease to work at greater depth or at night “very worrying”.

It means fishermen trying to comply with best practice are still at risk of seeing their fisheries closed early, and potentially causing significant unintended environmental damage.

The research team thinks the LED solution could prove very popular with fishermen because the lights are relatively cheap, easily applied to existing nets and reconfigured for different environments.

Separate research conducted in Peru has already shown LED lights can reduce the numbers of seabirds entangled in gill nets, and is trying to establish if it can help protect turtles.

Anecdotally, the team conducting the research in the Isle of Man found evidence of escapement of shark bycatch and think it could be an area for further research.

It could potentially reduce the numbers of dolphins, whales and porpoises killed in fishing nets in UK waters every year.

The lights might help alert marine mammals to the presence of nets – particularly gill netting, which forms a wall across the seabed – helping them to avoid them.

The study worked with lights supplied by the UK-based start-up SafetyNet Technologies.

Dan Watson, the company’s chief executive, said: “We’d love to keep working with people to progress the science further.”