FILE – Blacktip reef sharks (Carcharhinus melanopterus) developing below the surface in Moorea Lagoon, January 24, 2021, French Polynesia, Pacific Ocean. PHOTO BY ALEXIS ROSENFELD/GETTY IMAGES“>
Using a novel electrically pulsed device could prevent millions of sharks from getting caught on fishing hooks.
SharkGuard is a device that attaches to fishing longlines and creates an electric field around a baited hook. Sharks and rays pick up these signals with their electroreceptors and are discouraged from biting.
Tests have shown that it can reduce bycatch of these animals by 91 percent in sharks and 71 percent in rays. The inventors say this technology could reverse the dramatic decline in endangered sharks around the world.
“The main message is that commercial longline fishing will continue, but will not always result in mass bycatch of sharks and rays,” said Dr. Robert Enever from conservation company Fishtek Marine.
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“This is important to balance the needs of fishermen with the needs of the environment and contributes to national and international biodiversity commitments for long-term sustainability.”
Longline fishing is the number one threat to sharks living in the open ocean, with more than 20 million pelagic sharks caught each year by fishermen in search of tuna and other species.
Enever and his colleagues thought that shark repellents that worked to protect divers and surfers could also be used in tuna fisheries to protect sharks from bycatch.
The team conducted sea trials of their device in southern France in July and August 2021 and published their findings in the journal Current Biology.
Two fishing vessels fished 22 longlines on 11 separate trips, employing more than 18,000 hooks in total. Researchers found that SharkGuard hooks significantly reduced the number of blue sharks and pelagic stingrays caught compared to standard control hooks.
Catch rates per unit effort for these species decreased by 91 percent and 71 percent for sharks and rays, respectively, while bluefin tuna catch rates were not significantly affected by the presence of SharkGuard on the hook.
“The sharks don’t take the bait and don’t get caught on the hooks,” Enever said.
The researchers also said that expanding SharkGuard’s use to whole fishery levels would mean far fewer sharks would be caught with fishing gear. It could therefore help slow the dramatic decline in shark populations around the world.
Currently, more than 100 million sharks, rays and rays are caught by the world’s commercial fisheries each year and a quarter of sharks and rays are now classified as threatened.
However, the device has limitations, including the need for frequent battery changes.
Enever and colleagues said they are now working to break that barrier so fishermen can “fit and forget” while protecting sharks and other bycatch species.
A full set of inductively charged SharkGuard devices for 2,000 hooks would cost around $20,000 (£16,790) and last three to five years (£3,360 to £5,880 per year), which the researchers say is a modest annual cost for most commercial tuna fisheries.
They are now encouraging fishermen experiencing high levels of shark and ray bycatch, as well as retailers looking to improve the sustainability of their supply chains, to engage early with Fishtek Marine as sea trials and technical developments are planned for commercialization.
“There is hope! Against the relentless backdrop of stories of dramatic declines in all species, it’s important to remember that there are people working hard to find solutions,” Enever said.
“SharkGuard is an example where, with appropriate support, it would be possible to roll out the solution on a sufficient scale to reverse the current decline in global shark populations.”
Produced in collaboration with SWNS talker.
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https://www.westernjournal.com/zg-a-new-device-may-prevent-the-hooking-of-millions-of-sharks/ A New Device May Prevent The Hooking Of Millions Of Sharks