‘SharkGuard’ reduces bycatch of endangered sharks, sea trials present

For sharks dwelling within the open ocean, longline fishing is the number-one risk, with an estimated 20 million pelagic sharks caught yearly by fishers searching for tuna and different desired species. Now, a brand new research reported in Present Biology on November 21 exhibits {that a} new expertise, often called “SharkGuard,” may enable longline fishing to proceed whereas reversing the dramatic decline of endangered sharks around the globe.

“The primary implication is that business longline fishing could proceed, nevertheless it will not at all times essentially consequence within the mass bycatch of sharks and rays,” stated Robert Enever of Fishtek Marine, Dartington, Devon, United Kingdom. “That is essential in balancing the wants of the fishers with the wants of the surroundings and contributes to nationwide and worldwide biodiversity commitments for long-term sustainability.”

Enever and his colleagues noticed the large must gradual and even reverse the decline in international shark populations based mostly on proof that greater than 100 million sharks, skates, and rays are caught annually by the world’s business fisheries. 1 / 4 of sharks and rays additionally are actually categorized as threatened. They thought that shark deterrents that confirmed promise for safeguarding scuba divers and surfers from sharks would even have software in tuna fisheries to guard sharks from bycatch.

How does it work? SharkGuard emits a small, localized, pulsing electrical area. When connected to the fishing line, it creates an electrical area round a baited hook. The purpose is to discourage sharks and rays, which detect the electrical indicators by way of their electroreceptors, from biting with out getting in the best way of hooking different fish.

To learn how effectively it labored, the researchers ran sea trials in July and August 2021 in southern France. Two fishing vessels fished 22 longlines on 11 separate journeys, deploying a complete of greater than 18,000 hooks. Their findings confirmed that SharkGuard hooks considerably lowered the variety of blue sharks and pelagic stingrays caught compared to normal management hooks. The catch price of those species per unit effort dropped by 91% and 71% for sharks and rays, respectively. Catch charges of bluefin tuna weren’t considerably influenced by the presence of SharkGuard on the hook.

“The sharks don’t take the bait and don’t get (by)caught on the hooks,” Enever stated.

The researchers notice that, compared to catching and releasing bycaught species together with sharks, SharkGuard provides a extra complete resolution. If its use have been scaled as much as the extent of complete fisheries, it might imply a lot lowered interplay between sharks and fishing gear.

For now, nonetheless, the machine does have limitations, together with the necessity for frequent battery adjustments. They’re now working to beat this barrier, so fishers may “match and overlook” it, whereas nonetheless defending sharks and different bycatch species. It is anticipated {that a} full set of induction-charged SharkGuard units for two,000 hooks would price round $20,000 and would final 3 to five years (~$4-7K each year), which they notice is a modest annual price for many business tuna fishing operations.

They now encourage fishers who expertise excessive shark and ray bycatch, in addition to retail corporates who’re intent on bettering the sustainability of their provide chain, to hunt contact with Fishtek Marine early as sea trials and engineering developments are deliberate for commercialization.

“There may be hope!” Enever stated. “In opposition to the relentless backdrop of tales of dramatic declines occurring throughout all species, it is very important do not forget that there are folks working arduous to search out options. SharkGuard is an instance of the place, given the suitable backing, it might be attainable to roll the answer out on a ample scale to reverse the present decline in international shark populations.”

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