Florida’s 7,444 recorded manatees deaths in the last dozen years nearly matches the number thought to be surviving today.
In 2010, state officials tallied 766 mortalities, topping 500 in a year for the first time since records began nearly 50 years ago. Since then, most years have seen counts above 500, including last year’s record 1,101.
So far this year, the Florida Fish and Wildlife Commission has reported 661 deaths, which already marks the fourth deadliest year on record.
Patrick Rose, Save the Manatee Club executive director, said the acceleration of mortality statistics is disturbing in light of the manatee’s deadly foes that remain far from solved: cold vulnerability, lethal red tides, boat strikes and starvation.
While governments are stepping up to restore environments that manatees depend on, Florida’s growth promises to undo gains, Rose said.
“We are going to see more and more adverse consequences to our aquatic ecosystems,” he said. “They are all coming together.”
Having not done a hard count for many years, the Florida Fish and Wildlife Conservation Commission currently estimates the state’s manatee population is a minimum of 7,520 animals.
The most watched indicator now for the species’ well-being is the extent of seagrass growth, which is most vigorous from May through this month.
The St. Johns River Water Management District, a regional state agency that regulates and monitors water resources of Central and North Florida, recently finished its summer mapping of seagrass in the Indian River Lagoon along the state’s east coast.
Encompassing a complex of water bodies from Volusia to Martin counties, the Central Florida portion has experienced a prolonged biological collapse from pollution, resulting in an extermination of once-lush seagrass that manatees depend on as a primary food source.
That depletion of vegetation triggered mass deaths in Brevard County and an emergency response by the state’s wildlife agency, feeding 100 tons of lettuce to manatees.
Data from the mapping, which examines established locations year after year, is not yet finalized, said Chuck Jacoby, a lead scientist at the water district.
Preliminary results suggest some glimmers of hope for recovery of seagrass beds, Jacoby said, especially in shallow waters where more sunlight can penetrate to nourish growth.
Jacoby said that just as it took years of degradation to bring about the lagoon’s current condition, reviving the coastal system will require sustained effort.
He said the recent, modest signs of seagrass rebound may be linked in part to the lagoon’s relatively clear waters this summer. The water district measures the footprint of where seagrass is present and the density or cover within the footprint.
“I think with multiple years of good water clarity, we would potentially see a step up in the footprint and the cover,” Jacoby said. “One year is not going to get you there. Two years is helpful. Three to five would maybe give us some confidence to say this is a substantial change.”
While waiting years for significant improvement in manatee habitat, the status quo for the species is grimmer than “the bare numbers” reveal, said Elise Pautler Bennett, Florida director and senior attorney for the Center For Biological Diversity, an environmental group.
“The true impact on the manatee population is likely even greater than the shocking death toll we’re seeing,” Bennett said. “For every recorded death, there are an unknown number of manatees who are sick or have died and simply not been found. This includes breeding-aged females who have died or had reduced reproductive capacity, and also orphaned manatees.”
Rose said the state is ramping up environmental restoration and abilities to respond to stricken manatees, but the overall effort is a fraction of what’s needed.
“They are all helping to make some difference to help make us feel better,” Rose said. “The real true hope is we have to improve the water quality.”
To pull that off, he said, will require a commitment on par with what the nation has undertaken to review the Everglades and Chesapeake Bay.
“Otherwise, we are going to have to keep hoping and praying,” Rose said.
This article by Kevin Spear was first published by Phys.org on 22 August 2022. Lead Image: Credit: Pixabay/CC0 Public Domain.
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