SharkGuard deters sharks and stingrays from baited hooks

Developed by conservation engineers Fishtek Marine, and tested by researchers at Exeter University, SharkGuard has shown that it can reduce bycatch (accidental catching) of blue sharks by 91 per cent and stingrays by 71 per cent.

The study, carried out on boats fishing for bluefin tuna, found that catch of the target species also appeared to decline. The team said further testing is needed to fully understand the effects of SharkGuard on target species.

"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," said Dr Phil Doherty from the Centre for Ecology and Conservation on Exeter' University’s Penryn Campus in Cornwall. "There is an urgent need to reduce bycatch, which not only kills millions of sharks and rays each year but also costs fishers time and money.”

Dr Doherty continued: "Our study suggests SharkGuard is remarkably effective at keeping blue sharks and pelagic stingrays off fishing hooks."

The team’s results are published in Current Biology.

SharkGuard activates on entering water and works by overstimulating electroreceptors in a shark’s nose and mouth. It does this by emitting an electrical pulse - 30V, lasting 1.5 milliseconds every two seconds - powered by a 3.6V Lithium thionyl chloride battery with a 65-hour life in water.

The device’s electronics are encased in a 100mm x 20mm cylindrical tube and are easily removed from its bespoke polycarbonate housing, which is permanently attached to the branchlines above each hook. SharkGuard is depth rated to 1000m and weighs 46g in seawater. In a statement, Pete Kibel, co-founder and director of Fishtek Marine, said: “When SharkGuard is used, sharks do not take the bait and do not get caught on the hooks, and that gives us a huge sense of hope.

“SharkGuard is an example of where, given the appropriate backing, it is possible to roll the solution out on a sufficient scale to reverse the current decline in global shark populations.”

“On the back of these exciting results, the engineers at Fishtek Marine are modifying SharkGuard so it is smaller and self-charging after every haul,” said Dr Doherty. “Research will continue at Exeter, where we test SharkGuard’s effectiveness at sea across multiple species and fisheries.”