Defenders Magazine

Heeding the Sirens' Song

Researchers and conservationists take steps to help the imperiled Florida manatee.

By Bill Updike

© Douglas Faulkner/Peter Arnold, Inc.

Capturing a manatee is like lassoing a bucking bronco, only underwater. But on this sunny January day near Everglades National Park, the folks rounding up these “sea cows” aren’t cowboys, they are marine biologists trying to learn more about the endangered creatures so they can better protect them.

The team of eight scientists drives their open-transom boat slowly through the shallow waters at Port of the Islands, in southwestern Florida, searching for the snouts of manatees, which must surface periodically to breathe fresh air. Hundreds of the bulbous mammals come to these waters each winter to find freshwater for drinking and warm water in which to rest.

After hours of waiting and watching, someone finally spots a lone manatee nearby and releases a net as the captain quickly drives in a loop to encircle the animal. The net works like a purse that slowly encloses the manatee as its lines are drawn. Two men lay on their bellies in the back of the boat, pulling in part of the net, while others stand on the boat’s sides pulling in the buoyed edges.

Realizing its predicament, the manatee tugs on the net and pokes its head above the water searching for an escape. The hardy biologists adjust their efforts, and ultimately pull the thrashing animal on board. They check the animal’s vital signs, prepare to take blood and skin samples for later analysis, and attach a radio transmitter to the manatee to track its movements.

It’s tricky business capturing animals that can grow longer than 12 feet, and weigh more than 3,000 pounds, and the last thing the researchers want to do is harm the manatees. “Because they’re a protected species, we are doing everything we can to protect their health, and monitor them in the process,” says Jim Reid, a biologist with the U.S. Geological Survey’s Sirenia Project and one of the team’s leaders.

Reid’s team is carefully capturing and tagging manatees to track their movements and responses to environmental changes. Among other things, the team hopes to learn how manatees will respond to federal and state plans to restore the Everglades ecosystem closer to its historic “river of grass” condition.

The changes in the Everglades are just one of many issues facing manatees and those trying to protect them. Fewer than 3,500 of the endangered mammals are found in the United States, mostly in the waters around Florida. While the population has likely increased in the past couple of decades, many researchers point out that the animals are still in jeopardy. The number of calves born here each year is nearly matched by the number of manatees that die from motorboat collisions, red tide, cold stress and other causes.

One of the biggest threats facing manatees is that from power boats. Although they can hold their breath for as long as 20 minutes, the slow-moving mammals must rise to the surface to breathe air periodically, and are thus vulnerable to being struck by the hulls and propellers of powerboats. Because they range widely, and are naturally curious and playful (manatees will often approach swimmers looking for a scratch on their back or for a nuzzling), they often end up near boats.

According to Bob Bonde, another researcher with the Sirenia Project, almost the entire population of adult manatees shows evidence of boat trauma. He says that by age 2 or 3, even the young have scars. Almost all of the manatees captured in the Port of the Islands project show signs of mutilations from collisions with boats. Their thick, elephant-like hide offers a small measure of protection from boats—but not immunity. “One female manatee was hit at least 49 times by powerboats,” says James “Buddy” Powell, a leading manatee expert. “We know this, because the fiftieth boat strike killed her. Sadly, this is the fate of many manatees.”

Boat-strike scars, because they are used for identification, have a tragically ironic usefulness to scientists attempting to track and help the creatures. Another sad irony of manatee-boat interactions is that manatees belong to the order Sirenia, a name derived from the fables of beautiful mermaids that lured sailors onto deadly shoals. The modern-day mariners of Florida have turned the tables on the “mermaids” though. Since 1974, there have been 1,237 manatee deaths directly caused by boating accidents.

But efforts to curtail motor boating can be controversial. According to Jim Kraus, manager of the U.S. Fish and Wildlife Service’s Crystal River National Wildlife Refuge, a winter mecca for both manatees and manatee-loving people, efforts to limit boating collisions become a “real flash point for the community.”

“Some people suspect that we ultimately want to close down the area to humans and boats,” which is untrue, he adds. Kraus notes that most residents favor safeguarding manatees, evidenced by the fact that the local county initiated the protections. The biggest problems, according to Kraus and his staff, are people who do not obey the speed zones, the rules governing manatee-human interaction and the manatee sanctuaries that they’ve set up to protect the creatures.

But motor boats are only one threat to manatees. Of the 380 manatee mortalities in 2003 (the second-highest total of yearly deaths since records have been kept), 83 were human-related, including 73 from boating accidents. But 96 were believed to be caused by red tide, a toxic bloom of algae in the water. Another 45 were from cold stress syndrome, a condition similar to frostbite in humans, caused by the manatee’s inability to survive in cold water (see Defenders, fall 2003). An additional 72 were from complications at birth, 6 from other natural causes and 78 were undetermined.

Over time, annual manatee deaths have been increasing, and according to some researchers, the percentages are worrisome. Says Brad Stith, with the Sirenia Project, “a 10 percent mortality rate is not a sustainable number.” Stith notes that the federal government’s manatee recovery plan calls for a mortality rate of only 5 percent. A recent study by the USGS suggests that, unless actions are taken to control boating collisions in the Southeast, the species will not recover within 100 years.

But there is some dispute about the manatees’ numbers and prospects. Kipp Frolich, a biologist with the Florida Fish and Wildlife Conservation Commission (FWC) contends “there are more manatees in Florida now than probably any time in the 20th century. The manatee is not going extinct in the next 100 years or probably far beyond that.”

The FWC last year proposed to down-list manatees on the state endangered species list. But conservationists, including members of Defenders of Wildlife, protested that the state listing criteria were flawed, and the FWC temporarily halted its plans. “Clearly the Fish and Wildlife Commission understood that there were serious problems in the listing criteria,” says Pat Rose of Save the Manatee Club, a conservation group. Rose agrees that, because of endangered species protections, there are more manatees now than in the first half of the 20th century, when the animals were poached for food. However, he argues that it’s more important to talk about the modern population’s health and what can best be done to protect today’s animals. “The FWC’s own conclusions were that there was a significant risk that the population could be reduced by 50 percent in the next 45 years,” Rose says. “Some other population models also show that manatees could go extinct within a 100 years.”

Reid concurs that it’s more important to talk about modern, long-term population trends. “Censusing the entire population is extremely difficult. It’s hard to take numbers from just a couple of years,” he says. “The more appropriate way to do it is over a longer period of time where you can more fairly measure the changes.”

Despite the myriad challenges that they face, all is not gloom and doom for the charismatic creatures. Speed zones and manatee sanctuaries have done much to protect the species. And, in recent years, a network of government agencies and private groups have been successful in rescuing and rehabilitating manatees suffering from boat-collision injuries, cold stress and traumas, one manatee at a time.

“These animals are absolutely amazing us,” says Nicole Adimey, a biologist with the U.S. Fish and Wildlife Service in Florida, when speaking of the successful rescues. “I don’t know of any other marine mammal that can [recover] so well.”

Another positive sign is the amount of scientific attention manatees are receiving. Reid’s team and other researchers have heard the sirens’ song, and are dedicated to studying and protecting this species. “The animals have done much to adapt to the challenges that we present them and that is why we still have them today,” says Reid. “They are quite unique and figure into the Florida ecosystem and as such should remain protected.”

Writer/editor Bill Updike spent several days with government researchers in Florida last winter reporting this story.