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Cold Weather Puts Endangered Manatees in Hot Water

As biting cold weather stretches across the eastern United States into Florida, manatee conservationists will be concerned. Cold stress is one of the biggest killers of the endangered mammal.

Cold weather means high numbers of manatees may be concentrated in warm-water refuges near power plants, rivers and springs throughout the state, the Florida Fish and Wildlife Conservation Commission (FWC) said today. The agency cautions boaters to be on the lookout for manatees moving into Florida’s Intracoastal Waterway as they try to reach warm-water refuges. Boat strikes are another big cause of manatee mortality.

Correspondent Jordan Schaul looks at the status of manatees, including how zoos as far north as Ohio are helping manatee rehabilitation, education, and conservation.

By Jordan Schaul

Just before Thanksgiving, three manatees that had been rehabilitated at Tampa’s Lowry Park Zoo were released at nearby Apollo Beach Nature Park after recovering from cold stress which nearly killed them. Although cold stress is taking more of a toll on West Indian manatees (Trichechus manatus) they are increasingly observed north of Florida, with sightings off the coast of Massachusetts and Rhode Island in recent years.

Herds on exhibit at the Columbus and Cincinnati zoos  are not part of a wayward herd, but rather participants in the U.S. Fish and Wildlife Service’s Manatee Rescue, Rehabilitation, and Release Program. This Fall manatees have been on the move to and from Ohio– a ‘Midwestern Sea Cow Shuffle’ if you will. In two days nine manatees were moved among six institutions, including Tampa’s Lowry Park Zoo, and the Columbus and Cincinnati zoos.

manatee facts.jpg

The Service (USFWS), which rescues dozens of wild manatees each year, recruited the assistance of Cincinnati Zoo’s veterinarian Dr. Mark Cambell, the Zoo’s Director of Animal Health and Head Manatee Keeper Jamey Vogel.

The two staff members transported “CC Baby” and “Turner” by truck to Cincinnati’s Rickenbacker International Airport where both staff and manatees were flown by cargo plane to Orlando. The animal care staff met four new manatees and flew back to Cincinnati with them on a cargo plane. Following arrival, three of the manatees were transported to the Cincinnati Zoo — with another headed to the Columbus Zoo and Aquarium.

Three hundred-pound “Wooten,” 900-pound “Illusion,” and 1,800-pound “Betsy” are now on exhibit at the Cincinatti Zoo’s Otto M. Budig Family Foundation Manatee Springs exhibit — the first time the zoo has had three animals on display. Two of the three will be returned to the wild following rehabilitation and “Betsy” will remain at the zoo for a longer stay.

“Without a doubt, manatees are one of the most charismatic creatures and certainly one of the Zoo’s most popular animals,” said Thane Maynard, Director of the Cincinnati Zoo & Botanical Garden and a native of Floridia. “We are extremely proud to be part of this conservation program since 1999 and excited to welcome “Wooten”, “Illusion” and “Betsy” to the Cincinnati Zoo.”

The Cincinnati and Columbus Zoos are the only two facilities outside of Florida to hold and display manatees. Both began participating in the USFWS program just over a decade ago with the facilities opening their exhibits just a few weeks a part in the spring of 1999. Manatee Coast at the Columbus Zoo and its resident manatees welcomed “Bernice,” who is less than a year old and about 400 pounds.

SeaWorld Orlando, the Miami Seaquarium and Tampa’s Lowry Park Zoo also participated in the recent sea cow swap. The Columbus Zoo’s Manatee Coast exhibit features a 190,000 gallon pool and immerses patrons in a simulated mangrove habitat with live mangrove trees representative of the 10,000 Islands region of Florida.

Although manatees can live up to 60 years of age, human activities continue to influence early mortality, taking a toll on wild manatee populations. In fact, most surviving adults bear scars from watercraft propeller strikes. Boat traffic and subsequent watercraft-induced injuries has long been a culprit in manatee fatalities in Florida.

However, this past year has been the deadliest year on record for manatees and three of the last five years produced record mortality rates numbers. Already this year the state of Florida recorded 668 manatee deaths. That is 230 more than the second highest year on record–last year. And this year is not yet over and it’s only going to get colder.

[Update: On December 10, FWC reported that the cold weather earlier this year led to a record high number of manatee deaths in 2010. From the beginning of the year through December 5, biologists with FWC’s Fish and Wildlife Research Institute (FWRI) documented 699 manatee carcasses in state waters — nearly double the five-year average for that time period. Cold stress accounted for 244 documented manatee deaths, although it is likely the cold temperatures also contributed to many of the 203 deaths in the “undetermined” category and the 68 deaths in the “unrecovered” category.]

According to the Florida Fish & Wildlife Conservation Commission (FWC), many of the deaths are attributed to cold stress. To buffer this high mortality rate FWC may find consolation that the population appears to be slightly increasing or stable in most areas of the state.

The question is whether or not population growth and sustainability can withstand such stochastic events like cold spells. Boat related fatalities are actually lower than the 5-year average with 64 animals succumbing to lethal injuries.

Manatee illustration.jpgNGS stock illustration of manatees in Florida by Walter A. Weber

Although we can influence climate change we can not do much to influence weather like cold spells. We can educate people about recreational boating and the impact their activities have on manatees and we also can turn to rescue and rehab facilities like the Cincinnati and Columbus Zoos and facilities like SeaWorld, the Miami Seaquarium, and the Manatee and Aquatic Center and David A. Straz Jr. Manatee Hospital in the Mason M. and Charles P. Lykes Florida Wildlife Center at Tampa’s Lowry Park Zoo.

Tampa’s Lowry Park Zoo also works in partnership with the U.S. Fish and Wildlife Service, the Florida Fish and Wildlife Conservation Commission and its Florida Fish and Wildlife Research Institute (WRI) to rescue, rehabilitate and release Florida’s endangered manatees, as well as educate people about living harmoniously with manatees.

Florida Fish and Wildlife Conservation Commission manatee biologist Andy Garrett said that the “The Florida Fish and Wildlife Conservation Commission is the primary manatee rescue organization in the Florida. However, the success of the Florida manatee rescue, rehabilitation and release program depends on a multi-organizational partnership. We depend heavily on critical care facilities including Lowry Park Zoo and other zoos to provide top notch care for rescued manatees. By treating and rehabilitating sick, orphaned, or injured manatees, the dedicated and compassionate staff of these facilities work with us to achieve a common goal of releasing rescued manatees back into the wild.”

Aside from operating a facility to provide critical care for injured, sick and orphaned wild manatees, the Lowry Park Zoo objectives are:

  • To provide significant research facilities to allow scientists on staff and in the university community to study manatees; and
  • To educate more than 1.1 million visitors annually about the endangered status of manatees, the importance of aquatic and marine habitat preservation, and the steps necessary to conserve the population.
  • The Manatee and Aquatic Center and David A. Straz Jr. Manatee Hospital is comprised of an exhibit building with two underwater viewing pools, three medical treatment pools, and an emergency clinic with a public viewing boardwalk. Educational talks are presented at the manatee amphitheater which accommodates 100 guests.

The Manatee Hospital staff has treated more than 250 manatees with more than half of those re-introduced into Florida waters. Approximately 85 percent of those animals surviving the first 48 hours are candidates to be considered for release back into the wild.

The Zoo’s facility is the only non-profit hospital in the world specifically dedicated to manatee rehabilitation, and one of only three critical care facilities in the state of Florida prepared to handle these aquatic patients.

The Zoo’s operations commitment to manatee programs comprises up to 50 percent of its annual animal department operating expenses. Aquatic animals are expensive to care for and manatees are no exception. On average, it costs approximately $300 a day to treat a manatee patient. On average, it costs approximately $30,000 a year to feed an adult manatee.

Long-term research into the hearing capabilities of manatees has been conducted at the Zoo.

In March 2010, the Zoo reached a record-high manatee patient load of 18 manatees at one time, due in part to a period of prolonged record cold weather in Florida in early 2010 (exposing manatees to colder than normal water temperatures).

The Zoo also offers conservation outreach programs intended to educate the public about manatee biology and management in the wild. These include teacher workshops, and classes for children and adults focused on manatee conservation interests.

Manatees, (Order: Sirenia) are close relatives of elephants and hyrax, whereas cetaceans (whales and dolphins) are more closely related to the hippopotamus. The West Indian manatees are one of three species of “sea cows,” as they are also known and can be found as far north as Florida and Georgia. They are known to migrate into Florida rivers, including the Homosassa and Crystal rivers.

They commonly congregate near power plants, which warm the waters as a by-product of producing energy. The availability of the artificial water over the last 70 years has had an impact on winter distribution of manatees.

The loss of manatees this year to cold stress has been attributed to record cold temperatures that lasted an extended period of time.

The Florida Fish and Wildlife Conservation Commission stresses that these cold related mortalities underscore the importance of warm water habitat for manatees and a need to protect a sufficient warm water network for these aquatic animals.

Although the impacts of a large number of cold weather related deaths on the Florida manatee population are of concern along with the extensive geographic extent of these reported mortalities, scientists also recognize that this and other cold weather events are part of natural variation.

The FWC scientists and their partners intend to incorporate information about this past season’s mortality event into future mathematical modeling efforts so that we can better understand the roles of various threats and improve our ability to forecast population changes. FWC and FWRI report a preliminary count of 5,076 manatees statewide. This aerial survey is the highest population count since surveys began in 1991.


Jordan Schaul is a conservation biologist and a collection curator with the Alaska Wildlife Conservation Center. He received his PhD in conservation/veterinary preventive medicine from Ohio State University and a master’s degree in zoology. He is a council member (ex officio) of the International Association for Bear Research and Management (IBA), a member and coordinator for education and outreach for the Bear Specialist Group of the International Union for the Conservation of Nature, an advisor to the Bear Taxon Advisory Group of the Association of Zoos and Aquariums, correspondent editor and captive bear news correspondent for International Bear News, and member of the advisory council of the National Wildlife Humane Society, which promotes high standards for wild carnivore care and welfare among private sanctuaries in North America. He is the creator of the Zoo Peeps brand which hosts a blog for the global zoo and aquarium community and two wildlife conservation oriented radio programs. He enrolled in clinical degree programs in veterinary medicine and has been on leave to pursue interests in animal management/husbandry science and conservation education.

The views expressed in this article are those of Jordan Schaul and not necessarily those of the National Geographic Society. Read more blog posts by Jordan Schaul.

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