TAMPA, Fla. – For four straight years, more manatees were found dead in Florida because they were hit by boats than ever before. That trend will break in 2020, but not on account of any good news for the state’s signature threatened species.
To the contrary, researchers were tracking more manatee deaths than usual this year. As of Dec. 11, at least 562 manatees had died in Florida, according to the Fish and Wildlife Conservation Commission. That was nearly two dozen more than the five-year average for the same time period.
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“We did not have mass mortality, but manatees face the threat that they always do,” said Martine de Wit, a veterinarian in the state’s marine mammal lab. “That is watercraft issues.”
At least 88 manatees had died because of injuries from boats, though that is an undercount. Researchers saw their work interrupted because of the coronavirus pandemic, and for weeks in the spring they did not examine carcasses to determine causes of death.
“I’m convinced it’s well over 100,” said Patrick Rose, executive director of the Save the Manatee Club, about the boating-related death toll. Last year, the state reported 136 manatees killed because of watercraft collisions, out of 606 total.
Rose noted that the state’s five-year death average is inflated by an unusually high count of deaths in 2018, more than 800, when a large Red Tide bloom killed the beloved animals in droves. Florida did not suffer such a devastating bloom this year.
The uptick in boat deaths has come alongside higher numbers of registered boats, more than 961,000 last year, according to state data. While the pandemic forced closures that limited social outings this , boating was a notable exception.
“One of the few things people could still do was go out on the water,” de Wit said. “Obviously that exposes manatees to a higher risk of boat collisions.”
Rose, a boater himself, said he is not trying to vilify everyone on the water. Smart boaters, he said, are careful in no-wake and protected zones and call rescue hotlines when they spot a manatee in distress. But the animals congregate in plenty of places where the state does not strictly regulate speed.
Even when necropsies were put off this year, de Wit said, officials kept going out to rescue manatees. As of Dec. 11, the Fish and Wildlife Conservation Commission had tracked 101 rescues, up from 96 total the previous year. Of those, at least 27 animals had been hit by boats.
Manatees face many threats, both human-caused and natural. As of early December, rescuers had helped four caught in crab traps and five tangled in fishing line. Though de Wit said about two-thirds of manatees examined this summer and fall with known causes of death were hurt by boaters, cold temperatures earlier in the year killed others.
Forty-five manatees died because of cold stress by early December. Rose said that figure might rise because of a quick temperature drop before the holidays, before all manatees moved to warmer water.
Brevard County far and away led the state with 143 manatee deaths by early December. Algal blooms and poor water quality have further depleted sea grasses that manatees need for food, Rose said. They are forced to swim to unfamiliar areas.
“As they’re moving, it actually makes them more vulnerable to boat traffic,” Rose said.
Of the counties around greater Tampa Bay, Manatee saw the most deaths by Dec. 11 at 25, fifth in the state. Pinellas and Hillsborough were slightly behind, with 20 each. Hillsborough logged nine deaths because of boats, Manatee had eight and Pinellas had six.
The state numbers are not comprehensive because some manatees die in remote areas and are never found, de Wit said. Researchers do not know exactly how many manatees live in Florida either. The latest estimate from the Fish and Wildlife Conservation Commission suggested at least 7,250.
A few years ago, the federal government decided to reclassify manatees from endangered to threatened.
The yearly death reports show the many perils the species still faces, Rose said, factors he expects to worsen as more people move to the state and more boaters hit the water. Many manatees have become dependent on wintering in warm water discharged from power plants, he said, a resource that could go away as people transition to an economy built on sources like solar and wind power. That will put additional pressure on the state’s springs, which draw their own concerns as businesses pull water from the Floridan aquifer, Rose said.
Altogether, he said, the threats mean future manatee populations could struggle to recover as quickly after mass die-off events like a big Red Tide.
“I don’t see that we’re in a position to be able to relax in terms of what the future holds for manatees,” Rose said.
If you see an ailing manatee, the state asks that you call and report it to 1-888-404-FWCC (1-888-404-3922). Boaters are urged to abide by speed regulations, avoid motoring over shallow seagrass beds and to keep their powerboats at least 50 feet from any manatees they see.