[Mike]

Manatees Dying in Droves on Both Coasts of Florida
Posted by HeartmindAnimals, Pets, WildlifeFriday, March 22nd, 2013

Large numbers of manatees are dying on both coasts of Florida.

(NOTE – Red tide, or the metallic electromagnetic environment? – MC)

In the southwest, a persistent red tide in the Gulf of Mexico has killed nearly
200 manatees this year. These tides are algal blooms, and occur when
microorganisms called dinoflagellates proliferate, staining oceans and releasing
toxins into the water and air. Harmful to organisms including fish, manatees and
humans, the toxins attack the nervous system, causing short-term memory loss,
paralysis, seizures and ultimately death.

In the east, near Cape Canaveral on the Atlantic Ocean, manatees are also dying.
But there the cause is unknown.

“There are indications of the animals being otherwise completely healthy — but
having died of shock and drowning,” said marine mammal biologist Ann Spellman,
with the Florida Fish and Wildlife Conservation Commission, the state agency
tasked with the investigation.

In July 2012, manatees started turning up dead in the Indian River Lagoon; now,
there are 80 dead animals, 50 of them since the beginning of February.

“They’re all dying from a cause that we suspect is a common one — common to
those manatees — but right now, is still unknown,” said Kevin Baxter, spokesman
for the Florida Fish and Wildlife Conservation Commission.

Alligators aren’t a threat to manatees, but microorganisms and boat propellers
are.

The gentle, blimp-shaped animals, with their bristled snouts and large, fanlike
tails, have been on the federal endangered species list since 1967. Scientists
estimate that roughly half the world’s West Indian manatees (Trichechus manatus)
live in the shallow waters in and around Florida, where aside from
microorganisms and mystery killers, the thousand-pound animals are threatened by
watercraft, fishing gear and the loss of their warm-water habitats.

Now, the simultaneous mass-mortality events are threatening the state’s manatee
population.

“This is very unusual and is unprecedented in magnitude,” said Patrick Rose, a
former government biologist and current director of Save the Manatee Club. Rose
has studied and worked with manatees since the late 1960s. “This is fast
approaching the all-time record catastrophic mortality from cold shock and cold
stress experienced in 2010,” he said. During that winter, more than 250 manatees
died. “The difference here is that by this time, the cold stress issues were
abating with the arrival of spring — and we don’t know when either of these
unusual mortality events will extinguish.”

Red Menace

Red tides have thrived for as long as people have kept records of Florida’s seas, with centuries-old descriptions of fish kills and human illness. Now, Florida’s west coast sees a bloom almost every year, Baxter said, though the duration and location are hard to predict in advance. The last time red tide-related mortality was this high was in 1996, when 151 manatees were killed by algal blooms.

In September, a red tide began blooming off Florida’s southwest coast. In October, Sarasota newspapers called it the “worst red tide” in years, reporting tons of dead fish along Florida’s Gulf Coast beaches. Biologists and oceanographers tracked the bloom, watching its progress and sampling the stained waters. “This tide has pretty consistently been over 100, 150 miles long,” said Jason Lenes, a biological oceanographer with the University of South Florida. “The average bloom is generally between two and four months, and this one is lasting for almost six months at this point,” he said.

Occasionally, water tests have come back packed with more than 10 million cells per liter. The threshold for a “high” concentration is one-tenth of that. Though not anomalously high, Lenes said the bloom’s concentrations of cells have been sustained for a long period of time.

‘They’re not finding them alive. They’re finding carcasses.’The bloom microorganisms are called Karenia brevis, dinoflagellates that thrive in warm water and are photosynthetic. But K. brevis excrete toxins into the water, compounds that attack nervous systems and cause paralysis, seizures and drowning. Brevetoxins are absorbed by shellfish, can lead to massive fish kills, and stick to seagrasses and other plants, contaminating food sources for herbivorous animals like manatees. At very high concentrations, such as those present periodically during the southwest Florida bloom, brevetoxins can also be inhaled by marine mammals and humans.

As of March 21, 193 manatees have died from the tide since January. Recently, many of the manatees recovered have been found in the vicinity of the Orange River, site of a warm-water aggregation spot near a power plant, where the animals go when ocean temperatures are too cold to tolerate.

The Orange River spills into the Caloosahatchee River, which opens into the Gulf. “Right in that mouth area, where they go to get to the river, is one of the areas where the bloom has been persistent,” Lenes said. With the bloom parked near the river’s mouth, the manatees upstream are trapped behind a wall of toxic water — an unfortunate collusion of timing and location.

Now, Rose says, the waters are warming and the manatees are heading back out to the sea and brackish estuaries nearer the coast. There, the seagrasses are likely coated with toxins — toxins that will stick to the grasses even after the bloom dissipates.

Rescuers hoping to help manatees have to act fast. Toxins can harm an animal within a few hours, depending on its size and location. Telltale signs of brevetoxins include listing while floating, muscle twitches and difficulty breathing — all signs that, since the beginning of the bloom, officials have been patrolling the waters and keeping an eye out for, Baxter said.

So far, a dozen animals have been rescued early enough to be helped. The 12 manatees were taken to Lowry Park Zoo in Tampa, where they’ve all recovered. “If we can get them early enough, we can usually get them through it,” said Larry Killmar, the zoo’s vice president for animal science and conservation. “But what’s happening is, they’re not finding them alive. They’re finding the carcasses.”

After they’re admitted, the zoo’s red tide patients — who now have names like “Threepio” and “Cheer” — are given antibiotics and rigged with a buoy system to keep them afloat. Then, staff members sit with the animals until they’re well enough to float on their own. Instead of seagrass, which is difficult to harvest and potentially contaminated, the zoo’s patients are fed romaine lettuce.

A lot of it.

“Manatees eat 10 percent of their body weight in food a day,” Killmar said. “At our peak, with 22 manatees on site, that was 5,200 heads of romaine lettuce a week.”

The animals won’t be released into the wild until the bloom is gone. As of this week, it’s still offshore and in the area of Lee and Charlotte counties, though the concentration of cells is decreasing. But danger lingers even after the blooms have dissipated, since toxins stick to and encrust the seagrasses manatees rely on for food. Just last week, 13 dead animals were recovered near Lee County.

“The good part is, if you can rescue the manatees, there are good methods for eliminating toxins from their system and their recovery is pretty quick,” Rose said. “In contrast, I don’t know of any manatees that have been found alive from what’s happening on the east coast.”

Source: http://www.wired.com/wiredscience/2013/03/manatees-under-siege/