Are Florida's iconic and endangered marine mammals truly on the rebound?
by Nick Jans
On a gusty autumn day in Montana's Glacier National Park, I hiked toward the Great Divide through a world shimmering with yellow leaves, burgundy-colored berries and silvertipped bears. First came a female and yearling cub in a forest of subalpine fir, then a loner nosing its way into a serviceberry thicket. A pair of young adults rested high on a limestone ledge. Farther along, a straw-colored female appeared by a turquoise lake. Her focus was huckleberries; for the little cubs at her heels, it was nonstop wrestling. By afternoon, I'd tallied more than a dozen grizzlies. Three days later, I covered the same route and never saw one.
On an April morning on the Crystal River National Wildlife Refuge on Florida's north-central Gulf coast, a crowd mills—more than 150 wetsuit-clad snorklers finning in limpid water. Occasionally, a swirl breaks the surface, and an excited knot converges around a gliding, gray shape: one of several hundred manatees that have wintered in this 72-degree, spring-fed protected area.
The creatures, a few weighing over a ton, flow serenely past their admirers like celebrities on Rodeo Drive; some seem to enjoy the attention, and detour to court gentle touches and scratches along their scarred, leathery flanks. They're used to the commotion. Tens of thousands of visitors flock to Crystal River and other Florida refuges each year, hoping for a little schmooze time with these endangered, iconic mammals.
A few minutes ago I was part of the throng and met a manatee, whiskered nose to mask. Now I sit aboard the dive boat, shaking my head—awed by my point-blank encounter, and bemused by the almost surreal nature of the setting. Like most areas key to manatee survival, Crystal River lies enmeshed in a web of burgeoning coastal development: upscale homes and marinas, resorts and malls, all spreading with no apparent end in sight. Local waterways are crisscrossed by thousands of watercraft; lined by docks; tainted by runoff, subject to increasing human draw-down of vital freshwater springs. Millions of people live within a two-hour drive of all of Florida's critical manatee habitat.
And yet, somehow, almost miraculously, we have these enormous wild creatures surviving in our midst—a population estimated to exceed 3,800. But our ongoing expansion into their habitat begs the question: Are manatees, an endangered species whose numbers seem to be rising, truly on the rebound?
To put it mildly, manatees have been around a skosh longer than we have. The fossil record traces back their forebears in Florida at least 45 million years. To better take advantage of rich sea-grass beds and other vegetation, large, now-extinct wading mammals evolved into fully aquatic creatures with stout, nailed front flippers and paddle-shaped tails. Though manatees and their cousins, dugongs, most resemble walrus, they are in fact most closely related to elephants.
The West Indian manatee is divided into two subspecies: the Florida and the Antillean. They can live for 60 or more years in the wild, and grow throughout their entire lives. While adults average 10 feet long and around a half ton, the current record (a captive female) tips the scales at a whopping 3,300 pounds. Manatees could teach us a thing or two about energy conservation; they typically mosey along at a sedate 3 to 5 mph, and spend the majority of their time eating and resting—preferably in warm water less than 12 feet deep. Though slow-paced and odd-looking by our standards, studies indicate manatees may be as intelligent as seals and dolphins, and possess acute hearing and vision. "They're very much individuals, with recognizable personalities," says U.S. Fish and Wildlife Service biologist Joyce Kleen.
Biologically speaking, manatees are generalists, able to live in both fresh and salt water, and to graze on a variety of plants. They eat up to 10 percent of their body weight a day. Some animals are homebodies, while others make regular annual migrations over hundreds of miles. Though most common in Florida, in warmer months manatees wander to neighboring states, and occasionally much farther. One individual swam up the Mississippi; others have traveled as far up the eastern seaboard as Massachusetts. But their range is limited by their inability to survive for extended periods in water colder than 68 degrees Fahrenheit. The most recent north-wandering manatee, off Cape Cod in 2008, succumbed to cold-water stress despite a rescue attempt.
Even cautious advocates agree that Florida's manatees as a whole are faring better than they were a generation ago. Says aquatic biologist Patrick Rose, executive director of the Save The Manatee Club, based in Maitland, Florida, "Statewide, numbers are up in three of four populations. In that sense, we've made progress."
Florida's manatees are divided into four distinct stocks. Three of these—the Northwest (including Crystal River), the upper St. John's and the Atlantic—are growing or stable. The Southwest, comprising around 40 percent of Florida's entire stock, seems to be declining. Rose says that protective statutes and regulations have also improved; a 2001 settlement of two lawsuits, brought by a coalition of conservation groups (including Defenders of Wildlife) against federal and state management agencies, has established slow-speed boating zones and sanctuaries in critical habitat, and imposed restrictions on coastal development in sensitive areas.
While manatee advocates applaud these protections, they say enforcement remains inconsistent and violations are commonplace. Last year, a video widely viewed on YouTube showed a boatload of people harassing mothers with calves and even walking on animals.
Still, public concern and support seems on the rise. A 2007 University of Florida study of boaters—a group historically resistant to manatee-related regulations—indicates that roughly 75 percent agree that the mammals should be protected (though the study also found that fewer than half of those same individuals actually slowed enough in posted waterways). Manatee awareness programs—including instructional videos, boaters' guides, more speed zone signs and educational outreach—seem to be working. The manatee reigns as the state marine mammal, and November is officially designated as Manatee Awareness Month.
At Homosassa Springs Wildlife State Park in north-central Florida, as many as 400 elementary school students a day come for manatee education starring captive animals in a natural setting. Says wildlife care supervisor Susan Lowe as a group of excited fourth-graders watch manatees feed and interact with a keeper, "Here's where we can make a real, lasting difference."
In fact, Florida's manatees have been doing so well, according to the pro-boating and recreational fishing Coastal Conservation Association (CCA), that in 2001 they petitioned Florida agencies to downlist the manatee from "endangered" to "threatened" under controversial new state guidelines. After strong opposition from Defenders and other conservation organizations and prominent scientists, the state reclassification was postponed in 2007, pending a review of the listing criteria. Meanwhile, a federal move to down-list the manatee under the Endangered Species Act, also urged by pro-development forces and boating advocates, is currently simmering on the back burner.
Despite welcome progress, the future of the species is far from assured. A 2007 study by the U.S. Geological Survey for the Florida Fish and Wildlife Conservation Commission stresses that the manatee's long-term prospects hinge not on present conditions, but on those in the future. Despite improved regulation and awareness, human activity—especially boat strikes—still poses the greatest single risk to manatee survival.
A majority of adult manatees bear the scars of repeated, often gruesome maimings from hulls and propellers; some dead animals show evidence of having survived more than 50 collisions. "Manatees have especially dense, un-resilient bones, and they shatter like porcelain," says Lowe, whose facility is one of a handful statewide that helps rehabilitate injured manatees. "But these animals are capable of absorbing incredible impacts. Some manage to live with ribs or even parts of organs protruding through their skin."
Over the past decade, the recorded death toll from boat collisions alone has averaged almost 80 individuals a year. Add to that the number of manatees unable to reproduce or care for young due to injury, and the seriousness of just this single factor looms huge. Says Elizabeth Fleming, Florida representative for Defenders of Wildlife, "While the results of the recent count seem encouraging, the manatee's future is far from secure given the looming threat of loss of warm-weather habitat." She points out that the viability of the species hinges on the number of reproducing females—almost certainly, fewer than half that total. Also, the low genetic diversity of Florida's manatees suggests potential problems, including vulnerability to disease.
Humans have long impacted manatee survival rates; Native Americans hunted them, and settlers sought them for their meat and skins. Killing manatees was declared illegal in 1893, and subsequent federal and state laws established further safeguards. Still, 2006 set a record for confirmed manatee deaths from all causes: 417, more than 10 percent of the estimated population. 2005 ranked second, and while 2008's count decreased to 337, it included 90 confirmed deaths from watercraft strikes—second only to 2005. Though protections have greatly increased in recent years, so has the death toll.
The greatest long-term threat to manatees is loss of warm-water refuges for over-wintering animals. As freshwater springs are tapped for increasing human use, vital winter habitat for manatees constricts. And, as coastal power plants and other industrial warm-water discharge sources (used by hundreds of manatees) become obsolete and are decommissioned, habitat will shrink further. The loss of more essential habitat seems sure; the question is how much, and how soon.
Economic downturn or no, Florida is experiencing explosive growth, much of it from people attracted to manatee habitat. According to a 2007 state report, the state's human population increased by 65 percent between 1985 and 2007; in roughly that same period, boat registrations in Florida increased 59 percent. Currently, there are nearly a million registered watercraft in the state—roughly one for every 20 Floridians, and, more important, 300 for every manatee. That's not counting an estimated 350,000 non-Florida registered watercraft plying the state's waterways. In short, motor-driven boats—the manatee's most immediate threat—are multiplying far faster than the animals themselves.
If you're willing to wade through raw science and graphs, the results of the 2007 U.S. Geological Survey analysis are sobering. According to the study, the chances of manatee populations declining over the next century to 500 individuals on either the Gulf or Atlantic coast is potentially 50 percent if major threats (boat strikes and loss of warm-water habitat primarily) stay the same. However, if the number of watercraft deaths doubles over that time—as it well might—the odds of such a decline skyrocket to 95 percent. Under the same scenario, the chance of a plummet to a population of 250 or fewer individuals on either coast in the next 100 years is calculated at 55 percent; to a population of 150 or fewer animals, 25 percent.
The report's analysis of the projected impact of warm-water refuge loss is no more comforting. The worst-case scenario—a doubling of boat strikes plus a more-rapid-than-predicted loss of warm-water habitat—is left to conjecture. Yet, that negative double whammy is entirely possible. Adding to the potentially bleak prospect are the inevitable loss of feeding habitat; the potential of the powerful pro-development lobby to decrease manatee protections; and various other threats, notably red tides, which seem to be increasing in some areas—perhaps due to climate change and/or pollution.
In short, if we're to ensure the survival of this unique species, maintaining the status quo is not an option. Says Patrick Rose, "We need to push for consistent, continued enforcement and protection to avoid playing catch-up 20 years from now." Adds Laurie Macdonald, Florida program director for Defenders, "We have it within our grasp to promote healthy populations of manatees now and in the future. We just need to make sure we're doing all we can to address their essential needs."
One fact is certain: the fate of this gentle, iconic creature, totally willing and able to abide in our midst, lies squarely in our hands.
Defenders contributor Nick Jans lives in Juneau, Alaska. Each winter he spends several weeks in north-central Florida, near manatee habitat.