Make us your home page

Today’s top headlines delivered to you daily.

(View our Privacy Policy)

Lack of genetic diversity threatens manatees, study says

The population of Florida's manatees, which have been on the endangered species list since 1967, has grown to somewhere between 4,000 and 5,000. As a result, U.S. Fish and Wildlife Service officials, facing a petition from a libertarian legal group, may take them off the endangered list.

But a new study, done by a research team from the University of Florida and the U.S. Geological Survey and announced Tuesday, suggests manatees' future is anything but assured.

The study, which began in 2007, looked at genetic samples from 362 manatees. Some samples came from dead manatees being examined at the state's lab in St. Petersburg, and some were snipped from the tails of calves in the wild, said lead author Kimberly Pause Tucker of Stevenson University near Baltimore.

What the scientists found is that the manatee population has a very low genetic diversity, Tucker said. If a disease were to hit the manatees, it could easily wipe them out. "Where there's some natural variations in the population, then you have some that are better able to resist," she explained.

The low diversity could also signal potential for inbreeding problems, such as in the Florida panther population.

Panthers had dwindled to about 20 animals, many suffering from birth defects such as holes in their hearts. The only thing that saved them from extinction was a bold experiment in 1995 that brought in eight Texas cougars to breed with the panthers. Now there are more than 100 panthers roaming South Florida.

So far, the manatees' lack of diversity has not produced any such effects. The population growth is "kind of a success story," Tucker said. Nevertheless, she said, while 5,000 manatees sounds like a lot, "that's not huge."

Because of the lack of diversity among their genes, she said, the study showed that it's as if there are only 1,500 manatees actually breeding.

For now, she said, the key will be in protecting their remaining habitat.

Last week the libertarian Pacific Legal Foundation petitioned the federal government to drop manatees down a peg from "endangered" to "threatened."

Federal officials had already been thinking about doing just that. The process of changing manatees' classification will likely begin in 2013, said Chuck Underwood of the U.S. Fish and Wildlife Service. Underwood said Tuesday that the genetic diversity research "is being factored in" to the agency's data collection.

To Pat Rose of the Save the Manatee Club, the study's findings show that manatees probably should stay on the endangered list. "Not only does the manatee's low genetic diversity signal that manatees were nearly wiped out by man but it also reminds us that the manatee's future is fraught with threats and risks from many sectors," he wrote in an e-mail.

Manatees have been on the endangered list since the first list was approved in 1967. Documents from that era show they were not classified as endangered based on their numbers, which were unknown, but because of the threats they faced from boats and losing their habitat to waterfront development.

Craig Pittman can be reached at

Lack of genetic diversity threatens manatees, study says 12/18/12 [Last modified: Tuesday, December 18, 2012 11:20pm]
Photo reprints | Article reprints

© 2017 Tampa Bay Times


Join the discussion: Click to view comments, add yours

  1. What you need to know for Thursday, Oct. 19


    Catching you up on overnight happenings, and what you need to know today

    White nationalist Richard Spencer is scheduled to speak at the University of Florida tonight and the school is on high alert for tensions. [Associated Press]
  2. Bowen: Park land deal raises Penny for Pasco questions


    The Penny for Pasco is unambiguous.

    At least it is supposed to be.

    There was no equivocating in 2004 when Penny for Pasco supporters detailed how the sales tax proceeds would be spent: schools, transportation, public safety and environmental lands. No money for parks. No money for recreation.

    Pasco County is considering a loan from its Environmental Lands Acquisition and Mangement Program to buy land for a park in the Villages of Pasadena Hills in east-central Pasco. Shown here is the Jumping Gully Preserve in Spring Hil, acquired by ELAMP in 2009 and 2011.
[Douglas R. Clifford, Times]
  3. Another Tampa Bay agency loses tax credits worth millions in dispute over application error


    LARGO — Another Tampa Bay housing agency has lost out on a multi-million dollar tax credit award because of problems with its application.

    A duplex in Rainbow Village, a public housing complex in Largo. The Pinellas County Housing Authority is planning to build new affordable-housing in the complex but was recently disqualified from a state tax credit award because of an issue with its application.
  4. Live blog: Many unknowns as Richard Spencer speaks in Gainesville today


    GAINESVILLE — A small army of law enforcement officers, many of them from cities and counties around the state, have converged on the University of Florida in preparation for today's speaking appearance by white nationalist Richard Spencer.

    Florida Highway Patrol cruisers jammed the parking lot Wednesday at the Hilton University of Florida Conference Center in Gainesville, part of a big show of force by law enforcement ahead of Thursday's appearance by white nationalist Richard Spencer. [KATHRYN VARN | Times]
  5. As Clearwater Marine Aquarium expands, it asks the city for help


    CLEARWATER — When Clearwater Marine Aquarium CEO David Yates saw an architect's initial design for the facility's massive expansion project, he told them to start all over.

    Clearwater Marine Aquarium Veterinarian Shelly Marquardt (left), Brian Eversole, Senior Sea Turtle and Aquatic Biologist (middle) and Devon Francke, Supervisor of Sea Turtle Rehab, are about to give a rescued juvenile green sea turtle, suffering from a lot of the Fibropapillomatosis tumors, fluids at the Clearwater Marine Aquarium Wednesday afternoon. Eventually when the turtle is healthy enough the tumors will be removed with a laser and after it is rehabilitated it will be released back into the wild.  -  The Clearwater Marine Aquarium is launching a $66 million renovation to expand its facilities to take in injured animals and space to host visitors. The aquarium is asking the city for a $5 million grant Thursday to help in the project. American attitudes toward captive animals are changing. Sea World is slipping after scrutiny on the ethics of captive marine life. But CEO David Yates says CMA is different, continuing its mission of rehab and release, it's goal is to promote education, not exploitation. JIM DAMASKE   |   Times