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 census–the first underwater survey encompassing the entire Florida Keys ecosystem at once–is 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. 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,” he said.
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.
Snapshot of ecosystem
During the census, scientists from the University of Miami and the NOAA sampled 200 species of fish in a 3,100-square-mile patch of reef from Key Biscayne to Dry Tortugas National Park to form a snapshot of the entire ecosystem.
Using high-tech video equipment, a measuring stick, plastic paper and underwater pencils, they dived into the waters from a 100-foot boat and counted the fish one by one and checked lengths. Results of the 30-day census that ended in June will be used to evaluate the effectiveness of existing state and federal conservation policies and to help establish new guidelines–including the use of no-fishing zones, the most controversial tool in fishery management.
The Florida research also could be used as a model throughout the United States.
“It’s the first time we’ve done a whole system assessment in one fell swoop,” said University of Miami marine biologist Jerry Ault. “There is still a lot of discussion that things aren’t bad enough to invoke any management. The long-term goal is to develop high-precision monitoring of stock abundance at particular life stages to see what effects regulations like `no-take zones’ are having on coral reef fisheries resources throughout the Florida Keys.”
In a controversial experiment to determine if untouched fish populations could thrive again, the federal government last year declared 151 square miles of waters in and around the Dry Tortugas off-limits to all fishing. In 1997, the Florida Keys National Marine Sanctuary already had established 23 small “no-take zones” around popular, much smaller, coral reefs.
Other no-take zones are being considered, though recreational and commercial fishing groups have opposed them, claiming that most regulations are not enforced and that researchers have exaggerated the decline in fish and downplayed the effect of pollution and coastal development.
The no-take zone is particularly important to the future of Florida’s coral reef, which drapes the coast for 130 miles from Key Biscayne to the Dry Tortugas. Worldwide, the ancient, slow-growing reefs have been imperiled by everything from global warming, to boat anchors and snorkelers, to pollution.
Once classified as plants, coral reefs are animals that gather food instead of producing it themselves as most plants do. Along the Florida Keys, the Dry Tortugas plays an invaluable role in the marine ecosystem, harboring some 200 species of marine life that rely on it for food, shelter and protection. The reef also is a nesting ground for fish eggs and larvae that eventually populate the fish habitat throughout the coast.
`The crown jewel’
“The Dry Tortugas is really the crown jewel of the reef system,” said Steven Miller, director of the National Undersea Research Center at the University of North Carolina in Wilmington.
“This is one of the few spectacular places that remain today where you can see coral that has survived. But coral reefs also are probably the first ecosystems to exhibit catastrophic response to global warming. And if we don’t do something to protect them, they won’t always be around,” he said.
In the protected areas, researchers are seeing signs of progress. Larger fish are more prevalent in those zones.
The Goliath grouper that was nearing extinction a decade ago is making a comeback. The fish can grow to 800 pounds, but it takes decades for them to fully mature. The key to their survival is managing their environment, officials said.
“We haven’t had a problem telling people they can’t hunt for buffalo in Yellowstone National Park. But we’ve had a hard time telling them they can’t fish for grouper in the Dry Tortugas,” said John Hunt, research administrator for the Florida Marine Research Institute.
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Excessive fishing having drastic effect on ecosystem
A recent survey of fish in the Florida Keys suggests that overfishing is reducing the average size and age of 95 species. Excessive fishing is also threatening the 2,500-square-mile coral reef system found in the waters off the keys. With fewer fish around to eat algae, the reef is in danger of becoming inundated with underwater growth.
Florida Keys National Marine Sanctuary
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Census findings
BLACK GROUPER RED GROUPER MUTTON SNAPPER GRAY SNAPPER
Average weight
Historical 21.7 pounds 9.8 pounds 7.8 pounds 1.8 pounds
Current 9.0 pounds 5.3 pounds 4.1 pounds 0.9 pounds
Average age
Historical 8.3 years 9.0 years 7.0 years 4.8 years
Current 4.6 years 5.8 years 4.7 years 3.2 years
Average eggs*
Historical 5,000,000 1,400,000 1,000,000 1,000,000
Current 379,850 201,600 214,600 185,600
*Average number of eggs produced annually by a female fish.
Sources: Dr. Jerald Ault, University of Miami; The World Fish Center
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