Sharkguard trials result in a 90% decrease of the blue shark bycatch rate in the Atlantic bluefin tuna pelagic longline fishery.

Pelagic longline fisheries set thousands of baited hooks at a time on a main line targeting valuable commercial fish species; mostly tunas, swordfish, and mahi mahi. However, sharks are also attracted to the baited hooks and are commonly caught incidentally. In some fisheries, like the bluefin tuna fishery, shark bycatch is a larger component of the catch composition than even the target species.

The SharkGuard is a small device attached near the baited hook that attempts to interfere with shark and ray electroreceptors (ampullae of Lorenzini) near their mouth resulting in a decrease in hook interactions. The SharkGuard works by emitting regular electric pulses that are unpleasant to sharks and rays. The SharkGuard was trialed in the bluefin tuna longline fishery in the Mediterranean Sea and led to a greater than 90% decrease in the catch of blue sharks, the most commonly caught species in the longline fishery. It also led to a 70% decrease in the catch of pelagic rays, another common bycatch component. However, there is indication that it also led to a decrease in the catch of bluefin tuna.

This mitigation device shows has shown promise but needs additional testing to better understand effects on target species and decrease it’s current cost. If you are interested in implementing SharkGuard in your seafood supply chain contact FishTek directly for planning and pricing information.