MANATEE DEATH RATE STAYS HIGH\Florida scientists fear for species' existence.

Byline: Craig Quintana Orlando Sentinel 

For the second year in a row, manatees have died in near-record numbers, worrying scientists about the future of Florida's most endangered marine mammal.

The Florida Department of Environmental Protection announced Wednesday an official count of 201 manatee deaths in 1995 - five below 1990, the worst year on record. About 2,000 animals are believed to live in the wild.

Scientists said the death toll in 1995 was alarming because it followed the 193 animals that died the year before. They have been unable to pinpoint an obvious cause.

Scott Wright, the DEP scientist who directs the study of dead manatees, said the growing number of deaths makes the animals particularly susceptible to an environmental catastrophe such as the cold snap in 1990 that killed nearly 50 animals.

"It would really clobber the population," he said.

Wright and other DEP scientists say it is uncertain how long the species can withstand such a high level of deaths.

"You're looking at almost 400 animals, which is roughly 20 percent of the population," Wright said of the past two years. "We may be at a critical juncture."

Researchers still don't know exactly how many manatees there are and how often they reproduce. The 2,000-animal estimate is based primarily on semiannual aerial surveys in which no more than 1,856 animals have ever been observed.

The DEP hopes to conduct another population census this year, but the government shutdowns during the federal budget deadlock have hampered the plan.

A controversial 1994 report by University of Florida researchers concluded that about as many manatees die each year as are being born. The report said the population, while apparently stable, was far from robust.

However, DEP officials noted Wednesday that the UF report was partially based on pre-1994 mortality figures, during a period when deaths had experienced a three-year decline.

One bright spot in the 1995 figures is a small decrease in deaths caused by boats and man-made objects such as locks and floodgates.

"I'm sorry to see the high numbers, and glad we didn't have a bad emergency to make it worse," said Robert Kirn, a director of the Florida Marine Industries Association.

The 15-animal decline in human-caused deaths in 1995 was more than offset by increases in deaths of newborn manatees and instances where no cause could be determined.

Biologists remain perplexed by the calf deaths. Neither can they explain the jump in deaths listed as "undetermined." That category usually describes animals who have decomposed too badly to determine what killed them.

Biologists say more cooperation from the public could help them recover carcasses more quickly and better identify causes of death.

The high death tolls come during a revitalized effort to save the species, said Patti Thompson, biologist for the Maitland, Fla.-based Save the Manatee Club.

"It's distressing," she said. "It's clear that we're not addressing the problem as adequately as we would like."