A simple device that emits electrical pulses could save the lives of more than 50 million sharks and rays that are killed each year as a result of bycatch.
SharkGuard is a cylindrical device that attaches to longline fishing rigs and generates an electrical field surrounding the baited hook to repel sharks.
The pulse overexcites the sharks and rays, preventing them from engaging with the baited hook.
According to studies conducted on tuna-fishing vessels in France, lines equipped with the device reduced the incidental capture of blue sharks by 91% and stingrays by 71%.
Currently, SharkGuard requires frequent battery recharges, which is inconvenient for most fishing vessels, and a set of 2,000 costs approximately $20,000.
SharkGuard was created by conservation engineers from Fishtek Marine and evaluated by scientists from the University of Exeter.
SharkGuard, which is powered by a small battery, targets the ampullae of Lorenzini, which are electrical sensors located around the shark’s nose and mouth.
These sensory organs are overstimulated by the device’s electric field, causing the sharks to avoid the risk posed by the baited fishing hooks.
Dr. Phil Doherty of the Centre for Ecology and Conservation on Exeter’s Penryn Campus in Cornwall issued the following statement: ‘Many shark and ray populations are declining due to overfishing – particularly oceanic species such as blue sharks and pelagic stingrays that are commonly caught on longlines globally.
There is an urgent need to eliminate bycatch, which annually kills millions of sharks and rays and costs fishermen both time and money.
To test the system, researchers dispatched two fishing vessels on 11 trips off the coast of southern France, during which fishermen deployed 22 longlines with more than 18,000 hooks.
The SharkGuard was positioned 10 centimeters above the hook’s eye to prevent sharks from seizing the bait.
While the catch of sharks and rays decreased, the catch of bluefin tuna decreased by 42 percent, according to the study.
Doherty reported that the total quantity of fish caught during the test period – on lines with and without SharkGuard – was low, necessitating more tests.
Engineers are currently redesigning the device to make it smaller and self-charge after each trip, he noted.
Pete Kibel, co-founder and director of Fishtek Marine, stated, “When SharkGuard is utilized, sharks do not take the bait and do not become entangled on the hooks, which offers us a great deal of hope.
‘Against the unrelenting backdrop of reports of significant population decreases affecting all of our marine species, it is vital to remember that individuals are working diligently to discover answers.
SharkGuard is an example of a solution that, with proper support, may be implemented on a large enough scale to reverse the current fall in global shark populations.
Professor Brendan Godley, who oversees the Exeter Marine research group, stated that the gadget has “the potential to be a global game-changer for longline fishing’s sustainability.”
