US: 54 bottlenose dolphins, 112 manatees, roughly 300 pelicans died mysteriously in Florida’s Indian River Lagoon – 250713 0830z

At least 54 bottlenose dolphins have died mysteriously in Florida’s Indian River Lagoon since January.

Today, the federal government is stepping in to help find out what’s killing them. In a normal year, that number would be closer to 22.

On July 24, NOAA declared the mass die-off an “Unusual Mortality Event” – a declaration that will send federal resources and scientists to help teams already on the ground in Florida. It’s the lagoon’s worst dolphin die-off on record, and the cause is mysterious.

“This has become a national investigation, instead of a local investigation,” said Megan Stolen, a marine biologist with Hubbs-SeaWorld Research Institute, the nonprofit organization that has been investigating and keeping track of the dolphin deaths so far. “This will definitely help us.”

It’s the second time this year that NOAA has declared an Unusual Mortality Event for marine mammals in the lagoon, a 156-mile-long estuary that runs along Florida’s Atlantic coast. In April, a mass manatee die-off received the same designation. This is the third time a UME has been declared for dolphins in the lagoon. What caused the others, in 2001 and 2008, is still a mystery.

The lagoon is a treasured but troubled ecosystem, and has been besieged by a combination of nutrient run-off, pollution, and algal blooms – ingredients that have created a lethal situation for 112 manatees, roughly 300 pelicans, and 54 dolphins since last July. Scientists don’t yet know if the die-offs are linked, or if there are multiple killers on the loose in the estuary. Multiple investigations are ongoing, with teams trying to find out whether algal toxins, or pollution, or something else is to blame.

Stolen became concerned about the dolphin deaths in January. But it wasn’t until late spring that the carcasses really began to pile up; at one point, scientists were retrieving a dolphin a day from the northern and central lagoon. The die-off is affecting dolphins of all age classes and sexes. Some of the bodies are intact, others have been scavenged by sharks.

Unlike the dead manatees, which appear normal except for being dead, the dolphins are emaciated – thin and bony. But whether they’re starving because of disease, or a toxin, or a lack of food is still unknown. Clues are scarce, and only one sick dolphin has been found alive. Now, Stolen says, the die-off has slowed a bit. In July, five dolphins have been pulled from the lagoon’s brackish water.

“The last few dolphins have been calves,” she said. “Newborn babies.” It’s not clear yet whether the calves, three of them, are casualties of the mysterious scourge. But, Stolen says, “We would expect that if moms are getting hit by the UME cause, that we would start seeing dead calves as well.”

She and her colleagues will continue to monitor and respond to situation as NOAA’s team determines which direction to take the investigation in. “We are starting to look in [the dolphins’] stomachs now,” she said. “Normally when we do a necropsy, we kind of scoop everything out of their stomachs and put it in a bag. What we’ll do now is we’ll separate the liquid from the solid.” The liquids are good for toxin analyses, and the solids will tell researchers what, exactly, the dolphins have been eating – and if there are any clues to be found in their last meals.

Thursday, 25 July, 2013 at 03:31 (03:31 AM) UTC RSOE

Other Reports

Seagrass-planting project designed to restore bare spots in lagoon

Florida Today

(Photo: floridatoday.com) Seagrass transplants added to Indian River Lagoon: Seagrass is being transplanted from healthier areas of the Indian River Lagoon to areas where the grass has died out in hopes that it will come back. By Rik Jesse and Tim Walters Posted July 24, 2013

“SEBASTIAN INLET Scientists transplanted tufts of seagrass along an otherwise bald Indian River Lagoon bottom Wednesday in hopes of growing back the once-lush fish habitat that algae blooms doomed.

No one knows whether the $110,000 experiment will work or whether the cloudy waters that smothered seagrass during the past few years will return to do so again.

But researchers hope the grass transplants teach them the best ways to grow back a vital nursery habitat for fish and crabs, as well as the manatees favorite meal.

This used to be as far as you could see grass, Adam Gelber, a senior scientist with Atkins North America, said as he and two other scientists transplanted shoal grass along Sebastian Inlets interior.

At the inlet, their environmental consulting firm is planting seagrass harvested in Vero Beach. That effort ispart of a larger project that could transplant grass at up to 30 sites in the lagoon but likely fewer occupying about 1 acre of lagoon bottom. The project ranges from Merritt Island National Wildlife Refuge to Titusville, to Vero Beach.

Seagrass provides prime habitat for fish, crabs and other marine life and is considered a key barometer of the estuarys overall health. Each acre of seagrass supports about 10,000 fish and $5,000 to $10,000 in economic activity in the lagoon region, according to St. Johns River Water Management District and other studies.

Transplants are just one way biologists hope to restore some 74 square miles of seagrass lost since 2009, much of it clouded out by algae.

The scientists harvest the seagrass with hand tools only no machinery and manually install the grass at the recipient study sites.

They use shoal grass, because its among the fastest growers.

They place metal manatee cages over many of the transplants to keep ravenous seacows from chomping the experiment bare. But at least one manatee was quick to find this weeks plantings among the inlets seagrass-starved shoals. After Atkins consultants planted the first tufts of grass, they returned later that day and found evidence a seacow had made a snack of their work.” - Written by Jim Waymer / floridatoday

Indian River Lagoon

Extract from wikipedia the free encyclopedia

The Indian River Lagoon is a grouping of three lagoons: Mosquito Lagoon, Banana River, and the Indian River, on the Atlantic Coast of Florida. It was originally named Rio de Ais after the Ais Indian tribe, who lived along the east coast of Florida.

Contents

Course

Its full length is 156 miles (251km), extending from Ponce de Len Inlet in Volusia County, Florida, to Jupiter Inlet in Palm Beach County, Florida,[1][2] and includes Cape Canaveral. Lake Okeechobee is connected to the lagoon by the Okeechobee Waterway and the St. Lucie River meeting in Sewall’s Point.

Aerial view of Indian River Lagoon

Portions of the Lagoon, from north to south:

Natural history

The Indian River Lagoon is North Americas most diverse estuary with more than 4,300 species of plants (2,100) and animals (2,200), including 35 that are listed as threatened or endangered more than any other estuary in North America.[3][4] The Lagoon varies in width from .5 to 5 miles (0.80 to 8.0 km) and averages 4 feet (1.2m) in depth.[3] It serves as a spawning and nursery ground for many different species of oceanic and lagoon fish and shellfish. The lagoon also has one of the most diverse bird populations anywhere in America. Nearly 1/3 of the nations manatee population lives here or migrates through the Lagoon seasonally. In addition, its ocean beaches provide one of the densest sea turtle nesting areas found in the Western Hemisphere.

Red Drum, Spotted seatrout, Common snook, and the Tarpon are the main gamefish sought by anglers in the Titusville area of the lagoon system.[5]

Dolphins

Between 200 and 800 Bottlenose dolphins (Tursiops truncatus) normally live in the Indian River Lagoon. The dolphins resident in the lagoon system may belong to three or more different communities. There is little exchange of individuals between the lagoon and coastal populations. However, individuals from coastal populations are occasionally seen in the lagoon. One individual from the lagoon communities, Dolphin 56, was tagged in the lagoon in 1979 and was sighted in the lagoon more than 40 times through 1996. In 1997 Dolphin 56 left the Indian River Lagoon and was spotted many times along the east coast of the United States from Florida to New York into 2011.[6][7]

Female Bottlenose dolphins in the Indian River Lagoon tend to live longer than males. The maximum age attained by both sexes is one to almost two decades less than that reached by dolphins resident in Sarasota Bay, the most thoroughly studied wild population of Bottlenose dolphins.[8]

History

In 2011, a superbloom of phytoplankton resulted in the loss of 32,000 acres (12,900ha) of lagoon seagrass. In 2012, a brown tide bloom fouled the northern lagoon. The county has approval for funds to investigate these unusual blooms to see if they can be prevented.[9]

In 2007, concerns were raised about the future of the lagoon system, especially in the southern half where frequent freshwater discharges seriously threaten water quality (decreasing the salinity needed by many fish species) and contribute to large algae blooms (water heavily saturated with plant fertilizers promote the algae blooms). The lagoon has also been the subject of research on light penetration for photosynthesis in submerged aquatic vegetation.[10] The seagrass covers over 100,000 acres (40,000ha) and is a critical component to the overall health of the lagoon.[10][11]

In 2010 3,300,000 pounds (1,500,000kg) of nitrogen and 475,000 pounds (215,000kg) of phosphorus entered the lagoon.[12]

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