1. Environment

New manatee population estimate hits 7,000 to 10,000 but more than 700 have died this year

DOUGLAS R. CLIFFORD A manatee swims near the entrance to Three Sisters Springs on on Kings Bay in Crystal River in Citrus County
DOUGLAS R. CLIFFORD A manatee swims near the entrance to Three Sisters Springs on on Kings Bay in Crystal River in Citrus County
Published Dec. 18, 2018

ST. PETERSBURG — More manatees than ever have been swimming around in Florida's waterways, scientists said Tuesday, although more than 700 have died this year, mostly from Red Tide and being hit by boats.

PREVIOUS COVERAGE: Red Tide taking a toll on manatees.

A new study by biologists with the Florida Fish and Wildlife Conservation Commission and the U.S. Geological Survey used data collected during aerial surveys in 2015 and 2016, combined with statistical estimation methods, to come up with a new estimate for the state's manatee population. It's between 7,520 and 10,280, the study found.

That's a considerable increase from the 5,680–8,110 manatees estimated by a previous study using data from 2011-2012. But in their study, the scientists warned against drawing any conclusions about manatees experiencing a population boom.

So much uncertainty is involved in making their estimates that "we're definitely not encouraging people to make any statements of a population increase," said lead author Jeff Hostetler, a research scientist at the Florida Fish and Wildlife Research Institute in St. Petersburg. Their findings are "not inconsistent with a population increase, but it's not certain," he explained.

But in a news release about the study's findings, state officials contended that the new estimate "contributes to the conclusion that conservation measures ... continue to create an environment that allows the manatee population to recover."

The study is the first new estimate of manatee abundance in five years. Hostetler said scientists may try to repeat the study in 2020 or 2021, but that's not guaranteed at this point.

Manatees were on the original endangered species list drawn up in 1967 because of the threats they faced from speeding boats, water pollution and loss of habitat. A lawsuit filed in 2000 by a coalition of environmental groups against state and federal wildlife agencies led to settlements requiring new boat speed zones and manatee sanctuaries. Biologists have credited those measures with spurring an increase in the population.

PREVIOUS COVERAGE: The Tea Party rails about manatee protection to the Daily Show.

The U.S. Fish and Wildlife Service knocked manatees down to "threatened" instead of "endangered" last year, although a record number of manatees were killed by boaters just the year before. For the first time ever, more than 100 manatees had died after being run over by boaters.

PREVIOUS COVERAGE: Manatees taken down a notch on endangered list.

So far this year, 117 manatees have been run over by speeding boaters — up from 102 in 2016 and 104 last year.

Meanwhile the lingering Red Tide algae bloom has been blamed for the deaths of 207 manatees this year. Of those 91 have been conclusively linked to the Red Tide toxins, and another 116 are still awaiting laboratory test results but show the symptoms of being poisoned by the algae.

Hostetler said scientists are now working on a method of estimating the impact to the population of such a large die-off of the species.

Contact Craig Pittman at or . Follow @craigtimes.


  1. Debbie and her husband Michael, of Parkersburg, West Virginia, fish from the Dunedin Causeway Thursday. Florida Fish and Wildlife Conservation Commission extended the period of catch and release for several species of fish along the west coast of Florida.
  2. A slurry of dead fish, the result of Red Tide, moved out of Clearwater Harbor on the north side of Sand Key Park during a 16-month-long algae bloom. So many fish were killed that the state is limiting anglers to catch-and-release when it comes to snook, redfish and sea trout.  [Times photo (2018) by Douglas R. Clifford]
  3. A pair of wood storks, left, and a large group of white ibis rest and feed in a wetland area off Loop Road in the Big Cypress National Preserve. Florida is home to more wetlands than any other state except Alaska. [DOUGLAS R. CLIFFORD | Times (2008)]
  4. Pasco County commissioners introduced an ordinance Tuesday governing upkeep of empty property after residents complained about the condition of the Links Golf Club in Hudson, which closed in June 2019.
  5. Rep. Blaise Ingoglia on the floor of the Florida House in 2017. [SCOTT KEELER   |   Times]
  6. In this radar image from the National Weather Service's Key West facility, a massive flock of migratory birds is seen moving north early Monday. The green/yellow objects are biological objects flying north over the Keys. The darker blue objects indicate rain.
  7. These marine mammals were named "right whales" because they were considered by whalers to be "the right ones to hunt."
  8. Island Estates, a neighborhood in Clearwater Bay. There are three City Council races on this year's ballot as the city prepares for the realities of climate change.
  9. Florida Department of Environmental Protection staff conduct regular seagrass monitoring to assess the health and diversity of seagrass meadows within the St. Martins Marsh and Big Bend Seagrasses Aquatic Preserves north of Tampa Bay. A state legislator wants to extend the aquatic preserve to all of Citrus, Hernando and Pasco counties.

Charlie Shoemaker for The Pew Charitable Trusts
  10. One of two dolphins found dead in Florida recently of gunshot or stab wounds.
  11. Florida stopped providing free juice at welcome centers last year. [Times (2015)]
  12. USF scientist Stephen Hesterberg holds two oyster shells from Crystal River -- one small and modern, the other large and prehistoric. Hesterberg was part of a team of scientists who have documented how Florida oysters have shrunk since prehistoric times. Climate change may be a factor. [Courtesy of the University of South Florida]