Spare the Fish, Save the Reefs

June 18, 2009

A new study says that banning certain types of fishing gear can help save coral reefs from the damaging effects of climate change, by protecting key fish populations that help stressed reefs recover.

As embattled coral reefs cope with rising sea temperatures and increasing storms, scientists point to a powerful ally as key to their protection: fish. Wildlife Conservation Society researchers are calling for bans or restrictions on certain types of fishing gear in order to help reefs survive the onslaughts of climate change.

Their study, conducted in partnership with the ARC Centre of Excellence for Coral Reef Studies at James Cook University and other groups, appears in the latest issue of the Journal of Applied Ecology.

Research carried out in Kenya and Papua New Guinea has shown that certain types of fishing gear, particularly spear guns, fish traps, and beach seine nets, are more damaging to corals and the fish that depend on them. Some of the targeted fish species can help reefs recover from storm damage or “bleaching”—a sickness that occurs when corals discharge the beneficial algae that live within their tissues during prolonged periods of surface warming. When populations of key reef fish crash, decline of the reef may accelerate.

“This is creating a double jeopardy for both the corals and certain types of reef fish. They are already on the edge because of overfishing, and the additional impact caused by a bleaching can push them over,” the study’s lead author, Dr. Josh Cinner explains.

Co-author Dr. Tim McClanahan of WCS says that while the best response to bleaching from an ecological perspective may be to completely ban reef fishing, that solution is not feasible everywhere, especially for impoverished fishers in developing countries. “In areas where fishery closures are impractical,” he says, “managers don’t have many options and haven’t been able to do much but watch the reef die.”

Cinner suggests that selectively restricting gear can offer both reef managers and fishers a middle ground, reducing pressure on the reef and its fish while they are in the recovery phase, while also providing fishers with some livelihood options. This solution is also more likely to garner support among fishers, who typically use several types of gear, so even if one type is banned, they can continue to earn a living.

The team investigated the impacts of five types of fishing gear, including spear guns—a popular choice among the poorest fishers in developing countries, due to their low cost and high yield. The researchers found the spear guns to be the most damaging to key species like parrotfish, surgeonfish, and triggerfish, which help damaged reefs recover. The grazing preferences of these fish help keep seaweed and urchins in check while corals re-grow.

Spear guns also cause the most direct damage to the corals themselves. When a fish is shot, it often hides in the reef, which can lead some fishers to break the corals in an attempt to make their catch.

Fish traps also targeted the most susceptible reef fish and the ones most involved in reef recovery. Beach seine nets didn’t target as many key fish species as gill nets, traps, or spear guns, but caused direct damage to corals and took large amounts of juvenile fish.

Despite these known harmful effects, co-author Dr. Shaun Wilson of the Western Australian Department of Environment and Conservation cautions against arbitrary bans on spear guns or other gear. “You need to consider issues like compensation, other fishing options, or alternative livelihoods for the affected fishers,” he says. “One key issue may be educating fishers about the importance of reef habitat and the species that help to maintain reef quality—and the need to be selective in what they shoot. This would mean fishers could still use this cheap and effective fishing tool without necessarily damaging habitat and reef resilience.”

The study authors agree that where the conditions are right, managers and fishers should impose preventative gear bans, rather than wait for a bleaching event to occur. Increasingly, fishing communities around the world are making their own decisions about how to protect their reefs. Temporary bans or permanent restrictions on the use of various types of gear can apply to virtually any coral reef management—whether in the developing world or in developed countries such as Australia.

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