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Indian River Lagoon mystery ailment killing dolphins, manatees, pelicans
Tampa Bay Times

The Indian River Lagoon on Florida’s east coast has long been known as
the most diverse ecosystem in North America.

Its 156 miles of water boast more than 600 species of fish and more than 300
kinds of birds.

The lagoon is not just an ecological treasure. To the towns along its edge —
Titusville, Cocoa, Melbourne, Vero Beach and Stuart, among others — it accounts
for hundreds of millions in revenue from angling, boating, bird-watching,
tourism and other waterfront activities.

Scientists puzzled by manatee deaths on Florida’s east coast

3 Months Ago – Florida’s vanishing springs

7 Months Ago – Red Tide fades; manatee population down about 10 percent

2 Months Ago – Red Tide study shows toxins, potential benefits

More than a Year ago – U.S. Sugar deal crucial for Everglades, group says

More than a Year ago. But these days the Indian River Lagoon has become known as a
killing zone.

Algae blooms wiped out more than 47,000 acres of its sea grass beds, which one
scientist compared to losing an entire rainforest in one fell swoop.

Then, beginning last summer, manatees began dying. As of last week, 111 manatees
from Indian River Lagoon had died under mysterious circumstances. Soon pelicans
and dolphins began showing up dead too — more than 300 pelicans and 46 dolphins
so far.

How bad is it? In the past week, a dolphin a day has turned up dead in the
lagoon, said Megan Stolen, a research scientist at Hubbs-SeaWorld Research
Institute.

“When you lose the manatees, pelicans and dolphins, you know something is going
on,” said Marty Baum of Indian Riverkeeper, a nonprofit environmental group that
tries to act as a steward for the lagoon and the Indian River that flows into
it.

Yet so far nobody can name the killer. Biologists have some suspicions but are
baffled about any connection among the species’ problems. The diets are
different: Manatees are vegetarians, while pelicans and dolphins eat fish. The
symptoms are different: The manatees’ stomachs are stuffed, while the pelicans
and dolphins are emaciated.

Baum’s family has lived around the lagoon since the 1860s, but he can’t remember
anything like this ever happening.

The lagoon has had algae blooms before. None of them were like the one that hit
it in 2011. Experts called the explosion of the greenish Resultor species a
“superbloom” because it covered nearly 131,000 acres and lasted from early
spring to late fall.

Then came the “brown tide” algae bloom last summer, tinting the water a
chocolate brown. The algae, Aureoumbra lagunensis, have been a recurring problem
in Texas. Why it suddenly showed up in Florida is another mystery.

The algae blooms shade out sunlight needed by sea grass. By the time the algae
was done, the lagoon had lost more than half its sea grass, essential to
nurturing fish and other marine species.

Then came what Pat Rose of the Save the Manatee Club called “a cascade of
events.”

The mysterious manatee die-off began in the northern part of the lagoon last
July, hit its peak around March and now produces another dead manatee about
every two weeks, said Martine DeWit of the Florida Fish and Wildlife
Conservation Commission.

Biologists at a state laboratory in St. Petersburg examine every dead manatee
that’s found in Florida for a cause of death. But the Indian River Lagoon
manatees have them stumped. The manatees appeared to have abruptly sickened and
drowned.

Normally manatees eat sea grass. With much of the sea grass gone, the manatees
turned to eating a red sea weed called gracilaria. But so far there is no sign
that played any role in their deaths, DeWit said. The lab is continuing to test
for viruses, pollutants or something else.

Similar tests are being run on the dead pelicans and dolphins. Stolen of
Hubbs-SeaWorld said the dolphin die-off first became evident in January and has
not let up since.

And the lagoon’s 700 dolphins are already somewhat beleaguered. They tend to
suffer from high levels of mercury. In fact, research by the Harbor Branch
Oceanographic Institution at Florida Atlantic University has found that there’s
so much mercury in the lagoon’s fish that people who eat them have higher
mercury concentrations in their tissues than those who eat imported fish.

Scientists caught a break Friday when a kayaker discovered an ailing, sunburned,
underweight dolphin stranded in the shallows, Stolen said. Rescuers were able to
capture it for rehabilitation, and they hope it offers clues to what killed the
others.

When it comes to naming the cause, the list of suspects rivals a game of Clue.
Stormwater runoff filled with fertilizer and other nutrient pollution has been
blamed for fueling the algae blooms. Other theories point to the U.S. Army Corps
of Engineers dumping polluted water from Lake Okeechobee, changes in water
temperature or salt levels, overflow from contaminated mosquito-control ditches,
even climate change, which is boosting the acidity of the world’s oceans.
The Harbor Branch Oceanographic Institute had hoped for $2 million in state
money this year for a study of the lagoon’s water chemistry, but Gov. Rick Scott
vetoed the appropriation.

There are a few hopeful signs. The pelican die-off appears to have ended. As for
the sea grass, “we’re starting to see some regrowth in certain areas, but not as
much as we’d hoped,” said Tony Rice of the Indian River Lagoon Estuary Program,
a government-sponsored partnership among local and state agencies.

Meanwhile, a new brown tide bloom was spotted last month. If the lagoon hasn’t
hit a point where it’s sliding toward oblivion, said Rose, of the Save the
Manatee Club, a return to normal is a long way off. “I’m thinking it’s seven,
eight, nine years,” he said. “We could be looking at a decade before it
recovers.”

Craig Pittman can be reached at craig@tampabay.com.

Source: http://www.tampabay.com/news/environment/die-off-in-indian-river-lagoon-killing-dolphins-manatees/2127017