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Statistics Paint Grim Picture For Sea Turtles

Associated Press file photo

Sea turtles face a variety of perils, from fishing to loss of nesting habitat to collisions with boats.

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KATE SPINNER

Sarasota Herald-Tribune

Published: February 12, 2009

SARASOTA - A young loggerhead sea turtle swims lopsided in a giant tub at Mote Marine's animal hospital in Sarasota, recovering from two severe boat propeller gashes that stranded him in Fort Pierce six months ago.

The turtle, called Billy by the hospital staff, is one of 683 loggerheads that washed up injured or dead on Florida beaches last year. As a survivor of his injuries he is a rare statistic, but part of a dismal and baffling decade-long trend prompting concern about the species' future.

About 80 percent of stranded sea turtles are found dead, victims of disease, boat injuries and entanglements in garbage and fishing line, said Allen Foley, a wildlife biologist and sea turtle expert with the Florida Fish and Wildlife Conservation Commission.

He said years of increased loggerhead strandings -- spiking in the bad red tide year of 2006, when more than 1,200 loggerheads washed ashore -- coincide with a 41 percent decline in loggerhead nests on state beaches.

The combination of increased strandings and decreased nests could jeopardize the animals' long-term survival.

Loggerhead nest counts of about 45,000 in 2007 were the lowest since counting began 20 years ago. Last year was not much better, continuing a 12- to 13-year decline.

"When we see numbers going down we're worried that something is going on that we're not aware of," Foley said. "It's probably not something that we don't know about. It's probably something that we just don't know the magnitude of."

Adult loggerheads spend most of their lives in the deep seas. When they die, they usually do not wash ashore, making it difficult for scientists to track the reasons they died.

But among the top causes suspected is the national fishing industry, which is allowed under the Endangered Species Act to kill about 4,700 loggerheads a year, according to estimates by the environmental group Oceana. Loggerheads are considered a threatened species.

Scrutiny of longline reef fishing in the Gulf of Mexico last year showed that upward of 500 loggerheads a year may be dying as a direct result of the longline fishing industry, eight times more than expected. The research, disputed by fishing industry associations, is likely to soon result in a ban on longline grouper fishing in the Gulf of Mexico.

Past fishing activity also has led to the decrease in nesting, said Marydele Donnelly, director of International Policy for the Caribbean Conservation Corporation. Shrimp trawling killed thousands of loggerheads each year in the 1980s before regulators required the trawls to have a turtle escape hatch.

Shrimp, scallop, swordfish, flounder and tuna fishing also take a toll on loggerheads and other sea turtles, Donnelly said.

But fishing is only one threat to Florida's most populous sea turtle. Oil rig spills make them sick. Plastic fishing line cuts their flippers. Boat propellers slice their bodies. They mistake garbage, especially plastic bags, for food. Heavy metals in their food sources and new diseases also cause illnesses in the aquatic reptiles.

Shoreline losses also affect the population. Sea turtles reach breeding age after about 30 years and return to nest on the beaches where they were born. Seawalls, jetties and developed coastlines hinder nesting. Projects to replenish eroding beaches with sand also disturb nesting.

The perils add up.

"It's hard to say that one person or that one fishery will mean that turtles won't survive, but when you add them all together, then it's a lot worse," Foley said.

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