December 5, 2022


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Tens of hundreds of thousands of sharks are caught yearly as bycatch — a time period that refers back to the seize of non-target species. There are only some fisheries that don’t catch sharks as bycatch, in keeping with the UN, and a few truly catch extra sharks than their focused species. Nevertheless, a brand new gadget may supply a doable answer.

Picture credit score: Fishtek.

SharkGuard is a small battery-powered gadget. The gadget is connected to a baited hook on a line, producing a small, pulsing electrical subject. When used, it dissuades sharks from taking the bait, whereas not affecting different focused fish.

SharkGuard was in a position to cut back the variety of blue sharks (Prionace glauca) unintentionally caught by business fishing gear in a French longline tuna fishery by 91% — and as an added bonus, it additionally decreased the stingray bycatch by 71%, in keeping with a brand new research.

“The principle implication is that business longline fishing might proceed, however it received’t all the time essentially consequence within the mass bycatch of sharks and rays,” Robert Enever, research writer, mentioned in a press release, “That is essential in balancing the wants of the fishers with the wants of the setting and contributes to biodiversity commitments.”

Testing the gadget

To learn the way effectively the gadget labored, Enever and the group of researchers did a set of sea trials between July and August 2021 in southern France. Two fishing vessels fished 22 longlines on 11 journeys, deploying over 18,000 hooks. The findings present SharkGuard considerably reduces the variety of bycatches in blue sharks and stingrays.

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Catch charges of bluefin tuna weren’t considerably influenced by the presence of SharkGuard on the hook, the research confirmed. The gadget gives a extra complete answer than catching and releasing bycaught species. If scaled as much as the extent of complete fisheries, it could cut back interplay between sharks and fishing gear, the researchers argued.

Nevertheless, SharkGuard additionally comes with limitations, equivalent to the necessity for frequent battery adjustments. The researchers are working to beat this, so fishers can deploy it and neglect about it whereas defending species from bycatch. A full set of SharkGuard gadgets for two,000 hooks would price about $20,000 and final from three to 5 years.

The researchers hope the gadget might be commercially obtainable by 2024. In addition to engaged on the batteries, they want to make it smaller so it may be operationally viable for fishermen. Based mostly on the outcomes obtained within the trial, they’ve excessive hopes the SharkGuard could make an enormous distinction in decreasing shark bycatch as soon as deployed.

“Towards the relentless backdrop of tales of dramatic declines occurring throughout all species, it is very important do not forget that there are individuals working onerous to search out options,” Enever mentioned in a press release. “SharkGuard is an instance of the place, given the suitable backing, it could be doable to roll the answer out on a enough scale.”

The research was revealed within the journal Present Biology.