In the most ambitious study of marine life ever undertaken in the United States, scientists spent a month recently counting the fish in the Florida Keys, from the waters south of Miami to the coral forests beyond Key West.
The fish censusthe first underwater survey encompassing the entire Florida Keys ecosystem at onceis the most aggressive effort yet by scientists and wildlife officials in a campaign to save endangered fish stocks in South Florida and restore the shrinking Dry Tortugas, the largest living coral reef in North America.
As Florida's human population soared to more than 16 million in recent decades, the once abundant stock of snappers, groupers, and grunts has significantly declined because of recreational and commercial fishing.
Researchers say that 70 percent of all fish species have been overharvested, and the average size of the grouper, a huge fish, is 10 percent smaller.
"This is what happens when you have 900,000 fishing boats and people who feel that it is their God-given right to go out and catch fish," said James Bohnsack, a marine biologist with the National Oceanic and Atmospheric Administration.
"There are a lot more people today wanting to eat fish and who want jobs catching fish, so we are using up the resource faster than they can be replenished," he said. "Our goal is to find ways to maximize production while maintaining a high level of yield. Our biggest challenge is getting the public to understand that it's a win-win situation."
The problem is not unique to Florida. Historically considered an unlimited food source, fish populations have diminished around the globe, threatening not only natural marine habitats but also the economies of coastal areas that rely heavily on commercial fishing.
With few regulations in place before 1970, the fishing industry dipped into the far reaches of the ocean, gulping up everything from cod in the North Atlantic to anchovies in the Pacific off the South American coast.
Over the next decade, the demand for fish is expected to increase 40 percent, as world populations grow and more Americans are drawn to the health benefits of seafood. Yet, a study published last year in the British journal Nature found that the worldwide catch has declined by 360,000 tons since 1988.
According to the United Nations, 70 percent of marine fisheries worldwide are fully utilized, overfished or depleted, and 13 of the world's 15 major fishing areas are fished at or beyond capacity.