Spawning Opportunities

Belize transformed its fishing economy into an ecotourism boom. But a Texas A&M researcher wondered: Could the influx of amateur divers threaten the ecology they came to admire?


Advance-spawningThousands of divers visit the small Central American nation of Belize each year to witness one of nature’s most spectacular underwater shows. They travel here to observe the silvery cubera snappers and Nassau groupers that spawn in the waters of the Caribbean and to swim with the massive but docile whale sharks that feed on the tiny eggs that the fish produce.

Yet the boom in ecotourism appeared to present a dilemma for Belize. Environmentalists were concerned that diving tourists in particular would upset the natural rhythms of the spawning grounds. Will Heyman, an associate professor of geography in Texas A&M’s College of Geosciences, has worked in Belize for more than a decade studying the region’s cultural, geological and ecological systems. He and others have contributed to Belize’s transition from a country with an economy based on farming and fishing to a major ecotourism destination.

Located along the barrier reef, Gladden Spit and Silk Cayes Marine Reserve now generate more than $4 million annually in tourism—in a nation where the per capita income is little more than $4,000.

Gladden Spit stands at the crook of a massive reef at the edge of a coastal shelf that drops steeply to more than 6,600 feet within about six miles of the reef. Each year, after the full moons of late spring, the snappers and groupers converge for up to 10 days of frenetic spawning.

“At the height of the frenzy, the fish release their eggs in a volcano of reproduction,” Heyman says, his hands forming a cone that he pulls apart at angles to indicate an explosion. “It’s a magnificent sight.”

For generations, the annual spawning (which produces a telltale cloud of milky-white water) attracted local fishermen to reap an annual bonanza. But the fishermen overfished the coastal waters, and soon the snappers and groupers began to vanish.

To help regenerate the fish population, Heyman took part in national efforts to create marine reserves throughout Belize. These programs led to the declaration, management and recovery of many threatened areas in as few as five years.

By creating these new havens for the fish, however, the programs displaced the fishermen who depended on the spawning sites for their livelihoods. Thus, Heyman’s next step was to assist Belize in retraining the fishermen for careers in ecotourism. Today, former fishermen with weathered faces and scarred hands are
making their living by piloting chartered boats or by guiding divers to the prized ecotourism sites.

Environmentalists were concerned that diving tourists, as part of a boom in ecotourism in Belize, would upset the natural rhythms of the spawning grounds of cubera snappers and Nassau groupers.

But this solution created yet another concern for local environmentalists who wondered whether Belize’s new ecotourism economy could damage the underwater ecology as severely as overfishing had.

“The booming trade in ecotourism complicates the responsible management of resources and the kind of environment we worked so hard to establish,” Heyman says.

Funds from Conservation International allowed Heyman to investigate whether the presence of the divers disturbed spawning events. To test the hypothesis, his research group evaluated hundreds of hours of video footage—which he and others shot during the last 10 years—of interactions between the divers and the spawning fish.

The researchers selected more than 700 interactions for behavioral analysis. They found that divers appeared to disturb only 1.1 percent of the 200,000 snappers, 4,700 Nassau groupers, and 200 whale sharks that they observed.

“Even these disturbed fish returned to their original behavior,” Heyman says. “We saw no disturbance in the spawning rushes, and we observed only a short-term change in swimming direction to avoid the diver. The fish immediately went back to their business, with no apparent ill effects on spawning.”

Heyman believes that management measures imposed by the Southern Environmental Association—the nongovernmental organization that manages Gladden Spit and Silk Cayes Marine Reserve—have protected the site while sustaining the local economy.

Those measures include restricting the number of boats in the reserve and the number of divers allowed per boat and per guide. They also require a high level of training and special certification for guides to operate in the reserve.

These measures may serve as a template for managing similar spawning aggregations. “We wanted to make sure that dive tourism does more good than harm,” Heyman says. “After evaluating the data, I believe it does.”

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