It was a landmark year, good and bad, for Florida manatees.
The endangered mammals suffered the deadliest year on record in 2009 as state wildlife biologists documented 429 fatalities, a mark boosted by a trio of all-time highs for boat strikes (97), newborns (114) and cold stress (56).
The totals, announced Wednesday by the Florida Fish and Wildlife Conservation Commission, ended a year that started brightly with an annual aerial survey tallying 3,807 manatees, which topped the previous all-time high by 500 animals.
Manatee advocates pointed to the death spike as evidence that the future of the slow-moving sea cows remains precarious, with death rates outpacing population growth in some areas.
“It’s very significant,” said Pat Rose, executive director of the Save The Manatee Club. “Between the watercraft and the ability for manatees to stay warm in the winter, those are the two greatest risks manatees face.”
FWC Chairman Rodney Barreto believes the rising numbers indicate that seasonal slow-speed zones imposed in areas heavily used by manatees are working.
“I think the herd is as big as it’s ever been, and unfortunately, you’re going to have more accidents,” he said.
Southwest Florida led the state in boat deaths with 49. There were 39 along the Atlantic Coast, including two in Miami-Dade, three in Broward and three in Monroe.
State biologists cautioned that the annual carcass and aerial counts provide limited snapshots that don’t capture the full picture of how the state’s manatee population is fairing. Many dead manatees aren’t found or are too decomposed to determine the cause of death, for instance, and weather can cause wide swings in aerial survey numbers.
Population models suggest manatee numbers have stabilized or increased over the last decade everywhere but Southwest Florida, where boat deaths have continued to rise but scientists don’t have a solid handle on the population.
Still, Martine DeWitt, a research scientist at the FWC’s Fish & Wildlife Research Institute in St. Petersburg, said the leap in cold-stress deaths was notable — doubling the average over the past five years.
That underlined the importance of natural springs and power plants that provide warm water refuges during the winter, she said. “A lot of young animals, calves and sub-adults, get affected by that. That can definitely be a threat to the population.”
To curb boat-strike deaths, Rose said that instead of expanding slow-speed zones, which are unpopular with many boaters, the Manatee Club has begun floating an alternative: Installing cameras along critical waterways to record and ticket violators, similar to cameras now common at many roadway intersections and toll booths.
“What I think we really desperately need is greater participation from the boating community to gain compliance with the existing zone,” Rose said.
Barreto echoed the desire for more enforcement, but said the state’s continuing budget troubles make adding officers difficult. Barreto said he would need more details before assessing proposals to videotape speeding boaters, but his initial reaction was dubious.
“I think you would have to hire people to protect the cameras,” he said.