TITLE: RED TIDE CULPRIT IN MANATEE DEATHS
BYLINE: Stephen G. Reed STAFF WRITER
EST. PAGES: 1
DATE: 12/11/97
DOCID: SSTA73450301
SOURCE: Sarasota Herald-Tribune; SSTA
EDITION: Venice; SECTION: LOCAL/STATE; PAGE: 1B
(Copyright 1997)
Red tide was responsible for the deaths of 16 manatees in
Southwest Florida last month, the state Department of Environmental
Protection announced Wednesday.
After analyzing tissue samples and studying the carcasses of
the stricken marine mammals, scientists concluded that the microscopic
alga was the culprit, said Wendy Quigley, a spokeswoman for the
DEP's Florida Marine Research Institute in St. Petersburg.
This is the second year in a row that red tide has been blamed
for a rash of manatee deaths. Last year, a severe outbreak killed
149 manatees and helped make 1996 a record year for manatee deaths
overall.
This year's fatalities were discovered Nov. 6 through 26, mostly
in Lee and Collier counties. One animal was found in Charlotte
County on Nov. 14 in a canal off Ainger Creek.
Tissue samples taken from the manatees were tested at the University
of Miami. There, scientists detected toxins associated with red
tide.
"They exhibited a range of conditions, generally in the
area of the liver, kidneys, lungs and in the brain," Quigley
said.
Red tide generates a neurotoxin that affects the nervous systems
of fish and other creatures. Scientists still aren't sure how
the manatees absorb enough to kill them, or exactly what it does
to them, Quigley said.
In the past, investigators have suspected that the animals
ate contaminated sea creatures - such as sea squirts - or inhaled
airborne toxins near the water surface.
Research "is still ongoing to try to understand those
mechanisms," Quigley said.
Red tide is a natural phenomenon that occurs when Gymnodinium
breve, a one-celled dinoflagellate, blooms in large numbers. The
blooms usually begin several miles offshore in the Gulf of Mexico,
and cause obvious problems only when they drift ashore.
That's when dead fish turn up on the beach and beachgoers report
irritation to their noses and throats - a symptom caused when
toxins are released into the air by crashing waves.
Before last year, scientists suspected that red tide might
kill manatees. In 1982, according to the DEP, 37 manatees in Lee
County were believed to have been killed by red tide.
But until last year, when massive numbers of the endangered
animals began dying and tests were done to detect red tide toxins,
scientists could only be suspicious.
"In terms of data to support it, it's a relatively new
thing," said Beverly Roberts, a DEP research administrator.
Modern testing methods were not available in earlier years, she
said.
Although most of this year's outbreak has cleared up, red tide continues to linger in areas south of Fort Myers. Quigley said it is present only in very low quantities.
OTHER TERMS: TAG: 9712110301