NAPLES NEWS
May 19, 2007

Manatee deaths up in SW Fla. ; red tide to blame, scientists say

By Julio Ochoa

http://www.naplesnews.com/news/2007/may/19/2007_shaping_bad_year_manatees_lee/?breaking_news

Red tide is still killing manatees in Southwest Florida , even though scientists haven't found the toxin in local waters for weeks. At least 29 manatees that died between March and early May were found with evidence of internal red tide poisoning.

The culprit: toxin-laced sea grass.

Scientists with the Fish and Wildlife Research Institute say grasses within the Caloosahatchee Estuary can contain a double dose of Karenia brevis, the toxin in red tide.

Not only does the sea grass absorb the toxin, but filter-feeding micro-organisms that live on the sea grass also absorb it. The deaths have helped make the first four months of 2007 among the deadliest in Lee County 's history.

Between January and April, 59 manatees died in Lee County , more deaths than in all of 2004. In Collier County, scientists found six dead manatees.

The statistics are not very promising for a species that came off the deadliest year ever in 2006, when 417 manatees died in Florida. “It's definitely not a good start,” said Pat Rose, executive director of Save the Manatee Club. But it's not the worst start ever for Lee. That came in 1996, when 107 manatees died in the first four months. That year, red tide killed 151 manatees on the Southwest Florida coast.

Because manatees graze on the sea grass, they can easily eat several pounds of it a day. In addition to the 29 deaths scientists attributed to red tide, they suspect the toxin is responsible for another 11 deaths, said Ken Arrison, a biologist with the Fish and Wildlife Research Institute.

The deaths spanned the entire county from the Imperial River in Bonita Springs to Matlacha Pass, but most occurred in the Caloosahatchee River.

The area has become more and more deadly for manatees. A steady decline in manatee populations in Southwest Florida over the past decade has caused biologists with the U.S. Fish and Wildlife Service to focus more research on the area.

Within the next 18 months, the research should begin to answer why the state's largest manatee population is in decline, said Chuck Underwood, public information officer for the U.S. Fish and Wildlife Service.

The service is compiling mortality surveys, red tide data and determining the effectiveness of speed zones, Underwood said. “Generally, we like to have 10 years of data before we feel like we have enough evidence to draw conclusions,” he said. “There will be an awful lot of things going on as the science ripens over the next 18 to 24 months, and we'll have a much better ability to say in Southwest Florida we know what is going on and can come up with additional protections.”

Over the past few years, the service put in new speed zones but has yet to determine if those are stopping boaters from killing manatees.

So far this year, boaters struck and killed eight manatees in Lee and three manatees in Collier.

The Florida Fish and Wildlife Conservation Commission continues to increase its patrols in Southwest Florida, said Capt. Denis Grealish, supervisor of the commission's Fort Myers law enforcement office.

The commission has run undercover stings with unmarked boats to catch speed zone violators, Grealish said. But with 235 square miles of inside coastal waters and miles and miles of manatee zones to patrol, officers can't be everywhere at once.

“Lately, there appears to be a lot of noncompliance issues in certain areas,” Grealish said. “These are local people who well understand and know posted zones but choose to take a chance and violate them.” Obeying the law is one way residents can help, Grealish said. Rose, with the Save the Manatee Club, said residents can do even more.

Residents should look out for signs and symptoms of manatees dying from red tide. If the manatees are rescued in time, they can be saved.

A manatee with red tide symptoms may struggle to breathe or appear to arch its back by raising its head high out of the water. “That is not normal behavior,” Rose said. Sick manatees may also linger in unusual areas such as along sea walls or in shallow water, Rose said.

“We're enlisting anyone who might be on the water to know what to look for,” he said. “If a manatee can be rescued, they can be brought back to life.”

Manatee deaths from Jan. 1 to April 30

Lee County : 59 in 2007, 28 in 2006, 34 in 2005, 19 in 2004, 47 in 2003

Collier County : 6 in 2007, 7 in 2006 (incomplete data), 20 in 2005, 11 in 2004 (incomplete data), 19 in 2003.