Sea Turtles & Manatees

COVERING THE TAMPA BAY AND ITS WATERSHED

Our subscribe page has moved!

Please visit baysoundings.com/subscribe to submit your subscription request.

SEA TURTLES & MANATEES:
Concerns Mount

The number of loggerhead sea turtle nests at monitored Florida beaches dropped to a 14-year low in 2002, while mortality peaked over the last three years - with 2003 the highest year on record.

The dramatic upswing in the number of dead or injured sea turtles washing ashore in 2003 has sparked concern. Through November 22, the state documented 1655 strandings, mostly loggerheads and green sea turtles. By year's end, that number is expected to exceed 1800, nearly double the state's 10-year average and roughly 500 animals above the previous high.

"And that may be as little as 10% of the actual number," says Allen Foley, a biologist with the Florida Fish and Wildlife Conservation Commission (FWC).

Causes vary by region. Mounting deaths in southwest Florida are likely driven by red tide, a noxious algal bloom that has been known to kill fish and manatees, while an increased incidence of disease is suspected on the Atlantic coast. Shrimp trawlers, outfitted with turtle excluder devices whose openings may not be tall enough to prevent entrapment, also are thought to have played a part in the Panhandle.

While four of Florida's sea turtles, the loggerhead (Caretta caretta), Kemp's ridley (Lepidochelys kempii), green (Chelonia mydas) and hawksbill (Eretmochelys imbricate), are found in Tampa Bay, loggerheads predominate and are the only sea turtle species to regularly nest on area beaches. Florida is home to one of only two globally significant loggerhead nesting populations.

Manatee populations are faring better, based on the latest aerial count of 3276 animals in 2001, although a population viability analysis conducted by the FWC suggests that manatees could decline by 50% over the next 45 years and up to 80% in Southwest Florida.

The model determines the probability of future population decline and extinction given a variety of scenarios that incorporate expected declines in carrying capacity through loss of warm-water refuges and increases in mortality from natural and human impacts.

Presenters at BASIS 4 also discussed results of a three-part study by the region's Manatee Awareness Coalition comparing the effectiveness of education versus regulation in influencing boating behavior. The study concluded that regulation was more effective than education alone.

For more information, contact Elsa Haubold at elsa.haubold@fwc.state.fl.us.

Photos: Victoria Parsons

ESTUARY ACADEMY: "In-seine" fishing was just one of the activities offered to the participants in Estuary Academy, a day-long workshop created by the Tampa Bay Estuary Program as part of BASIS 4 especially for non-scientists eager to learn more about Tampa Bay. Above, volunteers drag seines through Riviera Bay as part of the Florida Marine Research Institute's fisheries monitoring session. Random sites are identified in key waters around the state to track fish populations and predict future landings. Left, Brent Winner (center), marine biologist for the FMRI, and volunteer researchers from Estuary Academy, count fish captured in a seine off Weedon Island.