ST. PETERSBURG TIMES (Florida) 18 November 05 Tortoise deaths alarm state naturalists - The number of dead tortoises has climbed to 60 in the Withlacoochee State Forest, and similar die-offs seem to be more common statewide. (Dan DeWitt)
Inverness: Dan Taylor's crew made some unsettling discoveries last month as it walked the Withlacoochee State Forest marking trees for timber sales.
"They kept coming back to me and saying, "We found three shells today,' " said Taylor, a forester with the state Division of Forestry.
"Then it was four more the next day. ... When it got up to about 30, I decided to notify somebody."
Taylor's concern was justified: Naturalists from several state agencies have converged on the forest, alarmed that the number of dead tortoises has climbed to 60 and that similar die-offs seem to be more common statewide.
"Something strange is going on here," said Joan Berish, a researcher with the state Fish and Wildlife Conservation Commission.
Though the biologists have not firmly identified a cause of the recent deaths, it appears to be an upper respiratory ailment, possibly an infection of a bacteria called mycoplasma; the tortoises' sickness is not considered a threat to humans.
Berish, who has been studying this and similar diseases for more than a decade, said the die-offs seem to have increased sharply since the late 1990s, probably because more well-meaning residents are moving tortoises out of the way of development and onto public land.
Relocating tortoises, which is illegal, not only can introduce disease into a new population. It does nothing to protect tortoises because most natural areas in Florida already support as many tortoises as the habitat can bear.
"It's like dumping 300 new people into a residential neighborhood," Berish said.
Even the Citrus Tract of the state forest is at capacity, said Vince Morris, an ecology supervisor with the Division of Forestry.
He and Berish spoke at a news conference there on Friday, then led reporters into a forest with a high canopy of pine trees and an understory rich with a variety of tortoise forage.
"This is some of the best gopher tortoise habitat in Central Florida," Morris said.
Gopher tortoises are classified as a "species of special concern" because development is rapidly destroying their habitat and because many other species depend on their abandoned burrows for shelter.
The Citrus Tract, which covers nearly 50,000 acres of southern Citrus and northern Hernando counties, is seen as a long-term refuge for the species as surrounding natural land is consumed by development.
That is one reason the deaths are so worrisome. Also, workers have looked for tortoise remains only in the area designated for timber sales - less than 300 acres. As the search widens, more dead tortoises almost certainly will be found.
And, once the population declines, it might take many years to rebound, Berish said; tortoises, which can live as long as 60 years, do not breed until their teens and only lay a handful of eggs in each clutch.
"That's what makes this so sad and frustrating," Berish said.
She and Lori Wendland, a veterinarian and researcher at the University of Florida, will lead the investigation into the deaths. The study may last several years, they say, because so much remains unknown.
Berish said researchers are aware of more die-offs in recent years - including 350 in the Green Swamp about five years ago. But they have not compiled any statewide statistics. Nor have they documented how long the tortoises in the Citrus Tract have been dying.
Judging from the sun-bleached skeletons, some of the tortoises probably died more than a year ago. Other shells still retained skin and several of the brown exterior panels, called "scutes," meaning these tortoises died more recently, Berish said.
And, on Wednesday, a Division of Forestry biologist found the most significant clue yet - a tortoise that was not yet dead but very ill.
Removing the exhausted-looking tortoise from a ventilated plastic tub, Wendland pointed out symptoms remarkably similar to a common cold, including watery, swollen eyes and a runny nose.
But, unlike a cold, this disease will linger as long as the tortoise lives, she said, and may very well kill it.
Tortoise deaths alarm state naturalists