Marine Reserves Found to Boost Nearby Fishing Grounds

Bijal P. Trivedi
National Geographic Today
December 4, 2001

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In 1995, the people of the Caribbean island of St. Lucia had grown alarmed by local fish harvests that were so paltry they could barely sustain their families. In a desperate effort to revive the overexploited reefs, they created a marine reserve and banned fishing in 35 percent of their fishing grounds.

Today, the people are reaping the rewards of their gamble as they watch their catch sizes double and triple in waters neighboring the sanctuary.

"When we went there in 1994, the fishermen could spend several hours rowing to a fishing spot—a whole day on the water—and catch barely a handful of fish," said marine conservation biologist Callum Roberts of the University of York in the United Kingdom. "It was hardly worth the effort."

Roberts and his colleagues studied the marine reserve bordering St. Lucia and one in Florida to determine the impacts on neighboring fisheries. The results showed that the creation of marine sanctuaries significantly increased both fish yields and the size of fish in surrounding areas.

The St. Lucians' decision to set aside 35 percent of their fishing grounds—creating the Soufrière Marine Management Area—was locally contentious. But although the first two years were particularly tough, local fishermen are now reaping the benefits of the reserve. With the fisheries replenished, they are enjoying the spillover, with much higher harvests than before the reserve was established even though there are fewer regions to fish, said Roberts.

The increase in fish stocks and habitat recovery within marine reserves has been well documented. Until now, however, the impact of such reserves on surrounding fisheries had not been evaluated. Roberts believes his study, which is published in the November 30 issue of the journal Science, provides this link.

Record Catches

Roberts and his team also studied a marine reserve in Merritt Island National Wildlife Refuge at Cape Canaveral, Florida, which is one of the oldest marine sanctuaries in the United States.

Ironically, the reserve, where fishing and public access have been prohibited since 1962, was established to protect rockets, not fish. Because it is near Kennedy Space Center, access was prohibited for security reasons. The area off limits included estuarine habitats that were particularly rich breeding grounds for several game-fish species—black drum, red drum, spotted sea trout, and common snook.

This area has been undisturbed for nearly 40 years, which gives scientists the opportunity to study how local marine resources have been affected.

One of the biggest payoffs, the scientists found, is that species that grow slowly can reach their full potential. The black drum, whose lifespan may reach 70 years, can grow up to 100 pounds (45 kilograms).

It's better to have fewer big fish rather than many small fish, said Roberts, because big fish produce more eggs. "A single 20-pound grouper can produce more eggs than 93 one-pound groupers," he explained.

The International Game Fish Association, which registers record-breaking fish catches from around the world, has found that the waters within 62 miles (100 kilometers) of the Merritt Island Refuge yield more record-breaking big fish than all other Florida waters combined.

Multiple Benefits

Marine reserves benefit not only fish but also delicate habitats.

Trawling—essentially plowing the ocean bottom to harvest scallops and shrimp—is a particularly destructive method of fishing. "[Marine scientist] Sylvia Earle compared trawling to cutting a forest to catch squirrels," said Roberts.

Marine reserves protect ocean bottom, enabling the undersea environment to recover. Closing off a portion of northeastern fisheries in Georges Bank off the coast of New England to ground fishing has led to the best scallop season in a decade, said Roberts. And flounder, which had been severely overfished, is on the road to recovery as a result of putting some fishing areas off limits.

"Marine reserves are like money in the bank for fishers," said Fiona Gell, also of the University of York and a co-author of the study. "If you want to keep a population going, you have to provide safe havens where fish and their habitats can flourish."

Currently in California, legislators are weighing the benefits of the Marine Life Protection Act, which would establish a string of no-fishing zones along the California coastline. But as in St. Lucia, setting up these reserves is a politically charged and highly emotional issue.

The fishing industries are on the verge of disaster, said fisheries biologist Alec MacCall of the Southwest Fisheries Science Center in Santa Cruz, California. "Fishing quotas have been so low that fishermen are barely able to make a living."

Wave of Resistance

Recognition that habitat loss and overfishing cannot sustain existing fishing levels led to the U.S. 1996 Sustainable Fisheries Act, which limits the size of catches and by-catches, thereby allowing depleted fish stocks to rebound. But fishermen already hurting from low catches and quotas are concerned that creating reserves will deliver a final crippling blow to their livelihood.

Most fishermen agree with the concept of marine reserves, but want them implemented in someone else's area, said MacCall.

"Fishing is almost the last frontier—people can fish just about anywhere and anyhow, but creating marine reserves is like creating fences in the ocean," he said. "It ends a way of life, it ends an era."

MacCall believes that marine reserves are a long-term investment, without which fisheries are likely to experience "boom-bust cycles." He is particularly interested in the effect of such reserves on marine habitats. Nonetheless, he thinks conservationists are overselling the merit of the approach.

"It's a great idea but should not be oversold as a panacea to severely depleted fish stocks," said MacCall. Migratory fish, such as albacore and bluefin tuna, will not be well protected by reserves, for example. On the other hand, orange roughy—which grow slowly, can live up to 150 years, and tend to settle in one location—may be well served by sanctuaries.

"The ocean is a complicated place and you can't predict the population benefits of creating these reserves," said McCall. "It's the sort of thing you just do, and then you wait and see."

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