Scubaism

Catch and release fishing seems like a win win-situation, with recreational anglers experiencing the thrill of a catch, while their prey can, in theory, swim safely away.

But that’s not always the case, according to a new study that found fish, including sharks, may suffer so much trauma during the event that they could die shortly thereafter. The findings, which will be published in next month’s Journal of Experimental Marine Biology and Ecology, primarily apply to hook and line anglers, since the catches of seine net users rarely died upon release.

“Small sharks are susceptible to predation by larger sharks following release,” lead author Sascha Danylchuk told Discovery News.

Danylchuk, a researcher at the Cape Eleuthera Institute in the Bahamas, added that even if catches survive, they might be less able to reproduce or more susceptible to disease.

Fish that experienced a loss of equilibrium, or an inability to swim away normally, were six times more likely to die than others.”When a loss of equilibrium has occurred, what we as anglers see is a fish rolls on its side or ends up nose diving to the bottom rather than swimming away with some vigor,” Danylchuk said.

During the study, predators, including lemon sharks and great barracuda, quickly nabbed the bonefish that experienced the equilibrium problem. The scientists think traumatized fish may even release stress chemicals, which function like a dinner bell to watchful predators.

Danylchuk also recommend that catch and release fishermen should minimize air exposure, use landing nets without knotted mesh, use barbless hooks to help expedite hook removal, and avoid sunscreen and bug repellent on hands, since Danylchuk said, “these can affect the slime coating on fish.”

“Make sure to get your shot all set up before taking the fish out of the water,” she advised. “When you do take the fish out of the water, try holding your breath. When you need to breathe, the fish probably does too and it’s time to put it back in the water.”