Experts plead for help in reducing manatee deaths

Published: Thursday, March 28, 2013 at 6:32 p.m.
Last Modified: Thursday, March 28, 2013 at 6:32 p.m.

More than 400 manatees in Florida have already died this year — and some of those are due to human activity such as collisions with boats, according to a report by the U.S. Fish and Wildlife Service released Thursday.

“It’s a wake-up call,” said Jacki Lopez, a staff attorney for the Center for Biological Diversity in St. Petersburg. “We’ve been on this path of indiscriminate activity .... not much has changed in the last few years.”

In the past few months, boat collisions caused 14 of the 409 manatee deaths. Six of those were in Lee County, and the rest spread throughout the state. Lopez suspects these are from boats going over the speed limit.

“Manatees need a certain amount of time to get out of the way. If you aren’t going slow enough, they can’t do that,” Lopez said. “For many of the manatees, the ultimate death blow is from a collision with boats. It will die of internal injuries.”

To amend these “largely unintentional deaths,” Lopez said boater education and enforcement of laws regulating speed need to improve.

“Enforcement of laws is very low,” Lopez said. “In Florida, you buy a boat, you register it. There is no analog to having a driver’s license for a car.”

Furthermore, many of the state’s estimated 1 million registered boaters are from out of state and seasonal users of Florida’s waters, so an extra effort needs to be made to educate them, Lopez continued.

“We have this animal that we’ve collectively decided is important to our cultural heritage,” Lopez said. “We should require a course ... beef up enforcement — make sure that the speed signs adequately reflect conditions of the local environment and are visible to boaters.”

On average, human activity — namely boating collisions — cause about 94 manatee deaths per year, which is more than six times the average of 14 needed to maintain the optimal sustainable population level, according to the U.S. Fish and Wildlife Service.

Manatees have been classified as an endangered species since the enactment of the Endangered Species Act in 1973.

According to Dr. Robert Bonde, a biologist with the U.S. Geological Survey in Gainesville and an expert on manatees, enforcing laws around manatee sanctuaries throughout the entire state — especially southwest Florida — would help control unnecessary manatee deaths.

“If we are going to cohabitate with manatees, unfortunately they suffer the consequences of having to deal with our boats,” Bonde said. “We need to be stringent and concerned enough ... we often interfere with their existence.”

Bonde added that red tide, also known as algal bloom, is causing a record-high number of manatee deaths. Although the Fish and Wildlife Service didn’t designate a separate category for red tide deaths, they fall under its “natural” causes of death category, which number 192 of the 409 deaths so far this year — the highest number for any cause of death.

Red tide is mostly a problem on the western and southwestern shores of the state, and it releases a neurotoxin that’s lethal to manatees.

“If you’re a dog sniffing it, you wake up with a hangover the next day. If you ingest it and you’re a manatee in the water, you end up drowning,” Bonde said.

He added that even as early detection and prognosis of red tide exposure in manatees improves, red tide will likely persist because it is suspected to be a byproduct of climate change and global warming.

“On the brighter side, there appear to be a lot of manatees around,” Bonde said, adding that the statewide guesstimate is at least 5,000.

Bonde added that the species does not have a lot of genetic diversity, however. So in the event of some sort of disease outbreak, its population would have a limited ability to survive.

Contact Kristine Crane at 338-3119, or

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