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Genetic tracking survey shows tarpon can be excellent long-distance swimmers

About 300 tarpon zoom along in 180 feet about 70 miles off Sarasota. A state program studies the species’ migratory habits.

Nolan Sadorf | Special to the Times

About 300 tarpon zoom along in 180 feet about 70 miles off Sarasota. A state program studies the species’ migratory habits.

Nolan Sadorf didn't know what to think of the large school of fish skimming along the surface about 70 miles off Sarasota last month.

"They were swimming fast, real fast," said Sadorf, a 21-year-old free diver. "They weren't stopping for nothing."

Sadorf grew up on the Gulf of Mexico and has seen his share of unusual sights in the open ocean: sea turtles, sharks, even the occasional whale. But he wasn't prepared for what he found when he jumped overboard in 180 feet to swim with the school.

"We went ahead of them in the boat and then dropped over the side," Sadorf said. "Then they were on us. Hundreds of them, tarpon."

In June, most people look for tarpon along local beaches and in the sheltered waters of Tampa Bay. The prized game fish — sometimes called silver king — is usually thought of as an inshore species. Nobody would think to fish for them in 180 feet of water.

"They were headed due north," said Sadorf, who estimated there were more than 300 fish. "They stopped to look at us for a moment and then kept on swimming. There was no way we could keep up with them. They must have been moving 8 knots."

Sadorf, son of legendary local tarpon angler Scott Sadorf, documented the behavior with photographs that prove tarpon not only are thick-bodied brutes with tackle-busting prowess but excellent long-distance swimmers.

"They do like to travel," said Kathy Guindon of the Florida Fish and Wildlife Conservation Commission. "We have documented fish swimming hundreds of miles."

Tarpon can grow to 8 feet and weigh 280 pounds. They are found throughout the estuaries and coastal waters of the Gulf of Mexico and Caribbean Sea and in the eastern Atlantic as far north as Nova Scotia.

The migratory habits of this species, sought by sportsmen on Florida's west coast since the 1880s, have been the subject of much discussion. For decades, anglers knew tarpon gathered during the summer in places such as Boca Grande Pass to feed. Where they went afterward was anybody's guess.

In 2005, the Florida Fish and Wildlife Conservation Commission and Sarasota's Mote Marine Laboratory launched the Tarpon Genetic Recapture Study, which enlisted anglers to gather DNA samples from tarpon they caught and released.

To date, more than 100 genetically tagged tarpon have been recaptured.

In the summer of 2010, anglers tagged two tarpon in Charlotte Harbor that were caught again the following spring in the Florida Keys, about 150 miles away. A tarpon caught near Islamorada in July 2011 was recaptured about a month later near Sarasota, about 125 miles away.

The research also shows fish hooked on the southwest coast will travel as far as the Panhandle. A tarpon caught near Apalachicola in July 2007 was caught again near Captiva Island, about 285 miles away, in May 2009.

So far, anglers have taken DNA samples from about 13,000 tarpon, including about 4,000 last year.

"Using DNA samples is a less costly way to track tarpon," Guindon said. "It is also less invasive for a fish."

An added plus: tags last forever.

"As long as that fish is alive and swimming, that unique DNA fingerprint will not change," Guindon said. "We hope everybody who fishes for tarpon participates. Getting a sample should be second nature."

About 165 bait and tackle shops carry the DNA kits. Anglers also can get one mailed by calling toll-free 1-800-367-4461 or sending an email to tarpongentics@myfwc.com. Each kit contains a plastic bag and enough material to sample three tarpon.

The process is simple. Anglers scrape the tarpon's jaws to remove skin cells, dab the cells on a sponge and store the sponge in a vial. The researchers do not care how big or small the tarpon is. Information gathered from baby tarpon is just as valuable as full-grown tarpon.

As for Sadorf's school, they had no time for sightseeing.

"We tried getting them to eat," he said. "We threw crabs, bait at them.

"But they wanted no part of it. They had someplace to go."

Terry Tomalin can be reached at tomalin@tampabay.com.

Tarpon Genetic Recapture Study

To study migratory habits of tarpon, anglers take DNA samples of those caught and released. For example, one caught near Apalachicola in July 2007 turned up near Captiva Island, about 285 miles away, in May 2009.

Genetic tracking survey shows tarpon can be excellent long-distance swimmers 06/07/12 [Last modified: Thursday, June 7, 2012 8:58pm]

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