FORT LAUDERDALE, Fla. – Although no oil from the BP Deepwater Horizon disaster has yet been seen in Florida outside the panhandle, some fish markets, fishermen and even some scientists fear that oil contamination eventually could disrupt the delicate chain of life that leads from the ocean to the dinner table.

“We just don’t know the ecological effects,” said David Kerstetter, a marine biologist at Nova Southeastern University who spoke to a group of 250 anxious fishermen and charter boat captains at a Dania Beach seminar earlier this week.

“Fish go up and down the water column all the time, and we’re not sure how these contaminants work their way up through the ecosystem,” Kerstetter said. “So it’s a lot more complicated than just looking at the surface.”

Florida officials have demanded that BP put $2.5 billion in escrow to cover future losses after oil began to show up in Perdido Bay, near Pensacola. That oil could imperil the spawning grounds of several species, including red snapper, grouper and speckled trout.

Nonmigratory species, which include snapper and grouper as well as oysters, are of particular concern because they cannot easily run from contaminated waters, Kerstetter said.

Swordfish and tuna — and other nomadic species that live in the open ocean — can run.

“Fish aren’t dumb,” said Ally Mercier, a longliner who is captain of the 50-foot Kristin Lee out of Pompano Beach. “If they think there is something wrong with the food chain, they’re not going there.”

But Kerstetter pointed out that the young of those open-ocean species use as a nursery the floating islands of sargassum seaweed in which a host of tiny sea creatures thrive. Those islands also are likely places for oil to collect.

If the oil becomes widespread throughout Florida waters, said Kerstetter, “we don’t know the ecological effects.”

Gary Thomas, a fisheries researcher at the University of Miami who worked in Alaska after the Exxon Valdez oil spill in 1989, said the biggest impact on Florida and Gulf fisheries might come through the food chain, starting with forage species such as shrimp.

“If those species are all under a sheen of oil, and predators come to the surface to feed on them, then there is some serious, long-term damage,” said Thomas.

As a precautionary measure, the federal government has closed off 78,264 square miles, or about 32 percent of the federal waters in the Gulf of Mexico. The eastern edge of that closed area is about 120 miles west of the Dry Tortugas.

Right now, Florida’s seafood is safe, insists state Agriculture Commissioner Charles Bronson, who this week announced the creation of a toll-free hotline where consumers can get daily updates about the safety of fishing areas and food.

“We want consumers to know that Florida’s commercial fishermen continue to harvest wholesome seafood products from the waters that are unaffected by the oil spill,” said Bronson in a statement. “Florida seafood is safe and plentiful.”

Restaurants and fish markets want their customers to know that, too.

At Pop’s Fish Market in Deerfield Beach, owners John and Sandra Adeimy list a fish’s type, place of origin and whether it is fresh or frozen on its price tag, as most fish markets do. Still, folks have questions.

“People are very inquisitive,” said the Adeimys’ daughter Amanda Hyland. “One person asked if the salmon had oil on it.” Hyland gently informed her that salmon are caught in the Pacific Northwest, far from the oily gulf.

But retailers fear as the leak continues, more customers will shun their fish. “My parents are on pins and needles right now,” Hyland said.

Verne Oscarson, owner of Fish Peddler East in Fort Lauderdale, said his business is off about 15 percent to 20 percent, but he’s not sure if it’s from the poor economy in general.

Still, people are leery because of the spill. “We’re getting a psychological effect from it because of what people are hearing in the media about seafood being tainted,” he said.

Florida is the fifth leading producer of seafood in the United States, with an annual industry valued at $168 million.

Among those who make their living on the sea, and are worried about the future, is Mercier. “We won’t know for three or four years, but eventually this will hurt us,” said Mercier. “It’s going to get ugly, and that’s just a shame.”

At the J&J Seafood Bar & Grill in Delray Beach, Tina Hutchinson said most diners seem unconcerned about the oil spill.

“People are not asking as much as I thought they would be,” she said.

Chef Lenny Judice of the 15th Street Fisheries restaurant in Fort Lauderdale said his staff fields few inquiries from patrons nervous about fish drenched in oil rather than garlic butter. “I’m really surprised we haven’t had many questions about the spill,” he said. “It hasn’t really affected us.”

At Publix Super Markets, most seafood comes from areas outside the Gulf, and that which is caught in the Gulf is inspected and has not been affected by the spill, spokeswoman Kimberly Jaeger said.

The chain has not raised seafood prices, nor has it posted signs detailing seafood origins, opting instead to educate managers on how to answer customer questions, Jaeger said.

The Whole Foods Market chain has set out signs in front of its seafood counters assuring customers none of the fish came from closed areas. The company is also looking farther afield for its seafood. “We’re trying to source things from other areas, other parts of the world,” spokeswoman Libba Letton said from her Austin, Texas, office.

If oil does begin to show up in Florida seafood, the first signs may come through the smell test. Earlier this week William Mahan, an agricultural extension director with the University of Florida, was one of several people being trained at a federal lab in Mississippi to detect tainted seafood.

He spent hours bending over plates of shrimp, oysters and grouper that had been doused in oil drawn from motors, storage bunkers and the Deepwater Horizon spill to learn what’s edible and what’s not.

“So a seafood processor might call and say, ‘Bill, can you come in and have a look,’” said Mahan, now trained to detect a fish contaminated with just 10 parts oil per million. “I have the ability. But I’m praying it never gets to the point where I have to use it.”

Mahan’s advice to consumers: If a fish smells like oil, or what he called “a fence post soaked in creosote,” don’t eat it.