Bycatch – the accidental capture of non-target species in fishing nets and gear – is the single biggest killer of whales and dolphins around the globe, according to the wildlife charity Whale and Dolphin Conservation (WDC), with hundreds of thousands dying as a result of it every year. Sharks, rays, turtles and many other sea creatures are also subject to bycatch.
Now, two brothers from Totnes in South England are using AI to try and combat the issue.
In the 1990’s, the Kibel brothers, Pete (a fisheries biologist) and Ben (an engineer) were determined to see if they could use their understanding of behavioural ecology and engineering to reduce net deaths.
Since then they have been utilising light to protect turtles, sound to protect porpoises and electro pulses to protect sharks. It all sounds a bit science fiction, but the results have been impressive enough to land them a nomination for the 2024 Earthshot Prize.
Using AI to reduce bycatch
"It has always struck me how full of life the local waters here in Devon and Cornwall are," says Pete. "So much so that they have supported a healthy inshore fishing industry for centuries.
"So, it is easy to understand why generation after generation of fishers have boarded their boats to see what they can catch by net, line or pot."
But they aren’t the only ones hunting for fish in these waters. Accidental entanglement of marine life is a recognised problem around the UK coastline and can impact survival of local whale and dolphin populations, says WDC.
"It is a problem for the fishers too," says Pete. "It is upsetting for them to deal with and can result in expensive repairs to their gear. It can also lead to increased risk for fishers themselves."
The banana pinger
To counter this, Pete, Ben and their team at Fishtek Marine developed the banana pinger.
These small acoustic alarms attached at intervals along a fishing net emit a repeated audible signal which alerts individual harbour porpoises to the presence and location of the nets, significantly reducing the likelihood of them becoming entangled.
Tests in Cornish waters revealed that this method was also effective in reducing the accidental capture of several dolphin and whale species.
Saving sharks with pulse
Bycatch has had a huge impact on shark populations too – an estimated 100 million sharks are accidentally caught in commercial fisheries each year. Oceanic shark populations have undergone an average 71% decline over the last century, says Fishtek.
Most bycatch of sharks comes from open ocean fishing fleets that target fish such as tuna using longlines, says the wildlife charity. With European funding, a prototype, low-cost device named SharkGuard was developed.
Attached to the longline, the device takes advantage of the a shark’s sensitivities to electric fields by emitting a tiny electro pulse. The shark is deterred from the hooked line as it approaches.
Results from tests at sea in the UK, Australia and France waters were stunning. Working in a commercial bluefin tuna fishery off the Mediterranean coast of France, trials in conjunction with Exeter University researchers showed reduced average catch rates of blue shark by 91%, and catch rates of pelagic stingray by 71%.
Alerting turtles with light
The success of SharkGuard has spurred Pete and the Fishtek team on – this time to helping turtles in Cyprus. The results have been equally as impressive or, to be more accurate, illuminating.
Every year an estimated 40,000 green and loggerhead turtles are killed after being accidentally caught in fishing nets throughout the Mediterranean, according to Fishtek. Pete wanted to shed light on this issue – literally.
Working with university scientists, the Society for Protection of Turtles and fishers in Cyprus having been using a simple device to illuminate nets, significantly reducing the number of turtles getting caught in them.
Named NetLight, the tiny, long-lasting, curve-shaped light is powered by two AA batteries and attaches to the ropes on fishing nets to alert turtles to the danger.
"Around Cyprus, over 2,800 sea turtles die in nets every year," says Robin Snape, a researcher at Bluedot Associates and associate researcher at the University of Exeter’s Centre for Ecology and Conservation.
"Our trials with NetLight have shown that this can be significantly reduced." Testing with Cypriot fishermen showed a fall in the number of sea turtles being trapped by 42%.
"We need a healthy ocean," says Pete. "It provides every other breath we take and is key in the fight against climate breakdown. And we need to grow dolphin, porpoise, whale, shark and turtle populations to keep the ocean healthy. We have shown that the solutions to issues like bycatch can be developed. Now we just need to fund them and scale up their global roll out."
Words: Danny Groves
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