Saturday, December 29, 2007

Red tide is the prime suspect in dolphins' deaths

Since Wednesday, nine dead dolphins have washed ashore between New Smyrna Beach and Melbourne Beach.Last week, a dead manatee was found in the Sebastian River in Brevard County.And so far this month, about 30 dead sea turtles have appeared on beaches, most in Brevard County.

Though they are still awaiting confirmation from test results, scientists suspect that red tide, the algae bloom that has invaded the state's Atlantic coast beaches, is likely to blame for the animals' deaths.A bloom that first appeared in the Jacksonville area about three months ago appears to be slowly meandering south, with medium concentrations in New Smyrna Beach and Cocoa Beach and high concentrations in Vero Beach, according to recent tests.

Though it has caused scattered fish kills, red tide's latest victims seem to be the mammals and reptiles of the sea.Red-tide experts can't say when this bloom will disappear. Recent cold weather is unlikely to have an effect, but winds associated with it could push the red tide out to sea -- or could push it closer to shore.Consisting of one-celled algae, red tide emits a toxin that can cause respiratory irritation when people inhale it and kill animals that ingest it.

Fish often eat the algae, and dolphins are typically exposed when they eat those fish. Once released into the water, the toxin tends to stick to sea grasses. When manatees and sea turtles eat those grasses, they, too, can be poisoned.The dolphins, most of which were found along Canaveral National Seashore and New Smyrna Beach, were badly decomposed, bitten up by sharks, and had been dead for several days, according to Megan Stolen, a research biologist at Orlando-based Hubbs-Sea World Research Institute, which removed the dolphins and will test them for red tide.

Martine deWit, an associate research scientist at the Florida Fish and Wildlife Research Institute, said there could be more manatee deaths and added that red tide-related manatee deaths often continue, even after a bloom has left an area. The toxin sticks around, she said.Since October, four manatees have died from red tide in Volusia and Brevard counties. Test results haven't come back yet for the one found last week.Red tide originates in the Gulf of Mexico, where it has been known to cause massive fish kills and kill dolphins, sea turtles and manatees, but researchers believe that a rare set of circumstances brought it to the East Coast this year.

Stolen said she hoped the changing weather would push the red tide away and keep more dolphins from washing ashore, but she said more dolphin deaths are possible."We're not out of the woods yet."To report a dead marine animal, call the Fish and Wildlife Conservation Commission at 1-888-404-3922.

Quick "Facts about Dolphins"