Steve Gorman, PlanetArk 19 May 10;
At least 150 sea turtles have washed up dead or dying along the U.S. Gulf Coast since the giant oil spill off Louisiana, a higher number than normal for this time of year, a leading wildlife expert said on Monday.
The toll among sea turtles has been steadily rising since the deep-sea well ruptured last month, and the stranding count began to reach an unusually high level in the past week, said Dr. Michael Ziccardi, a veterinarian overseeing some of the area's wildlife rescue teams.
Several days ago, when the number of dead turtles stood at just over 100, federal wildlife officials said that was still considered typical for the season.
Wildlife officials are especially concerned for the well-being of sea turtles in the Gulf following the spill because all five species native to the region are endangered, and they are just heading into their spring nesting season.
This is a time of year when dead or debilitated turtles would normally begin to show up with greater frequency, but the 156 found since April 30 along the coasts of Louisiana, Mississippi, Alabama and Florida "are in higher numbers than you would expect," Ziccardi said.
None of the animals had obvious signs of oil contamination. But, because of their proximity to the spill, they are being treated as possible victims of the crude oil that has been gushing from the ruptured wellhead since April 20, he said.
The 12 confirmed dead dolphin strandings along the same four Gulf Coast states, Ziccardi said, were "more or less in line" with what would normally be found for the same period of time without an oil spill.
No outward signs of oiling were detected on the dolphins either, and only one full necropsy has been performed to date.
Ziccardi, director of the Oiled Wildlife Care Network in California, a hub for the world's leading experts in capturing and caring for oil-soaked sea life, is the chief coordinator for teams across the Gulf tracking the status of turtles and marine mammals. He spoke to Reuters outside his office at a spill response command center near Houma, Louisiana.
No whales or manatees have been reported dead since the spill, though several sperm whales were spotted swimming in and around the oil slick, Ziccardi said.
Wildlife specialists said there has been relatively little impact on bird life so far.
Energy giant BP Plc said it has begun to have some success in containing the oil in the last two days.
A FORENSIC INVESTIGATION
Of 156 turtles collected as of Monday, eight were still alive when found, and six of those survived and are undergoing rehabilitation. "They're looking good," he said.
The rest range from relatively complete carcasses to specimens consisting of little more than a shell. Turtles known to have died before the spill, or thought to have been sick or injured beforehand, are not included in the tally.
Necropsies, the animal equivalent of an autopsy, have been performed on 40 turtles so far. And tissue samples taken from as many specimens as possible are being analyzed for abnormally high chemical levels associated with oil contamination.
Initial necropsy results are expected in a few days, but laboratory tests of the tissue samples will likely take weeks to complete. In many cases these results are needed to make a conclusive finding about the cause of an animal's death.
In some instances, it may be difficult to rule out other possible causes of death, such as illness or exposure to some toxin other than oil.
"It's a complex puzzle, and what we're doing is putting together all the pieces and trying to get the correct answer of whether or not the animals have been oiled," Ziccardi said.
One possible reason for the higher-than-normal count of dead turtles could be the intensive effort to monitor the region's wildlife with hundreds of individuals patrolling the shoreline for dead or distressed animals.
He acknowledged that some cases will remain inconclusive, and it will ultimately be up to damage assessment teams to determine what the likely death toll was due to oil pollution, based in part on mathematical "modeling."
The "chain of custody" for each sample collected is rigorously documented, the way evidence is for a criminal forensic investigation, Ziccardi said.
(Editing by Jackie Frank)
Gulf Oil Again Imperils Sea Turtle
Leslie Kaufman, The New York Times 18 May 10;
PADRE ISLAND NATIONAL SEASHORE, Tex. — It is nesting season here, and just offshore, Kemp’s ridley sea turtle No. 15 circles in the water before dragging herself onto the sand to lay another clutch of eggs.
The sea turtle, affectionately nicknamed Thelma by a National Park Service employee, has already beaten some terrible odds. Still in the egg, she was airlifted here from Mexico in after the 1979 blowout of the Ixtoc 1 rig, which spilled millions of gallons of oil into the Gulf of Mexico and covered the turtles’ primary nesting place.
Now Thelma and others of her species are being monitored closely by worried scientists as another major oil disaster threatens their habitat. Federal officials said Tuesday that since April 30, 10 days after the accident on the Deepwater Horizon, they have recorded 156 sea turtle deaths; most of the turtles were Kemp’s ridleys. And though they cannot say for sure that the oil was responsible, the number is far higher than usual for this time of year, the officials said.
The Deepwater Horizon spill menaces a wide variety of marine life, from dolphins to blue crabs. On Tuesday, the National Oceanic and Atmospheric Administration expanded a fishing ban in the gulf because of the spreading oil. But of the endangered marine species that frequent gulf waters, only the Kemp’s ridley relies on the region as its sole breeding ground.
Since the Ixtoc 1 spill, the turtles, whose numbers fell to several hundred in the 1980s, have made a fragile comeback, and there are now at least 8,000 adults, scientists say. But the oil gushing from the well could change that.
The turtles may be more vulnerable than any other large marine animals to the oil spreading through the gulf. An ancient creature driven by instinct, it forages for food along the coast from Louisiana to Florida, in the path of the slick.
“It lives its entire life cycle in the gulf, which is why we are so critically concerned,” said Dr. Pat Burchfield, a scientist at the Gladys Porter Zoo in Brownsville, Tex., who has studied the turtle for 38 years.
The nesting season for the sea turtles runs until mid-July, and for most of that time the mothers will remain off Padre Island and the beaches of Mexico, where there is currently no oil. But then things become more chancy, as new sea turtle babies go off to sea, floating on currents in the gulf or on seaweed patches that could be covered by crude. Hungry after egg-laying, adult females are known to go to the mouth of the Mississippi, a particularly rich feeding ground, to replenish themselves.
Juvenile turtles, who stay off the shore, have made up most of the turtle deaths in the gulf so far.
André M. Landry Jr. of the Sea Turtle and Fisheries Ecology Research Laboratory at Texas A&M University, Galveston, said satellite radios had been attached to several sea turtles, including Thelma, for research. He hopes these will offer clues about what is happening offshore.
“If she is beached, it is going to be constantly sending out a signal as opposed to the random signals they send out when they randomly come up to breathe,” Dr. Landry said.
Barbara Schroeder, national turtle coordinator for NOAA fisheries, the government agency charged with assessing damage to offshore life, said that the agency was investigating the sea turtle deaths intensively, but did not have many answers yet.
She said that so far full necropsies had been performed on 50 turtles and partial necropsies on another 17. Internal inspections of the animals, she said, did not reveal oil. But she added that scientists still had to test tissue samples taken from some of the turtles for evidence of oil.
She cautioned that it might be hard to determine conclusively how the turtles died or even how the spill was affecting the species more generally.
“People think this is like television, where the mystery is solved in one hour,” she said. “It is very complex. Most of the impacts occurring to turtles are out of sight. Most turtles never wash ashore.”
The Kemp’s ridley is millions of years old; its ancestors once swam with dinosaurs. Sandy olive in color, Kemp’s ridleys are the smallest of the sea turtles, only about two feet across. Although the turtles have been spotted along the Atlantic Seaboard, they return to the warm waters of the gulf to breed.
As recently as the 1940s, they were abundant in the Mexican gulf waters. Tens of thousands at a time would come ashore on the same day at Rancho Nuevo, a remote Mexican beach in Tamaulipas State, to lay their eggs in the synchronized pattern unique to their breed. But pollution, the collection of eggs for food and aphrodisiacs and the nets of shrimp trawlers depleted their numbers.
Then came the blowout on the Ixtoc 1. The deepwater well dumped three million barrels of crude into the gulf, covering the beach at Rancho Nuevo. Nine thousand hatchlings had to be airlifted to nearby beaches. Although the role of the oil in killing the turtles was never confirmed, by 1985, there were fewer than 1,000 Kemp’s ridleys left.
To prevent a single environmental catastrophe from sending the turtles into extinction, eggs from remaining turtles, including an egg that became sea turtle No. 15, were brought here to Padre Island to begin a new colony. She came in 1986.
At birth, the babies were set free in the surf down the road from the ranger station to allow them to imprint the beach on their memories, then captured again and protected until they were nine months old and less susceptible to becoming prey.
“We called it head start, after the school program,” said Donna J. Shaver, chief of sea turtle science and recovery for the National Park Service at Padre Island, who has worked with the sea turtles there since 1980.
No. 15 has returned to the island six times to lay clutches of eggs, burying her most recent round of 92 eggs in the sand by an enormous rusted, beached buoy only one and a half miles from where she was first put into the surf 24 years ago.
“Their precision is really amazing,” Dr. Shaver said. Scientists will be watching the radio blips from the tagged turtles closely, but the tracking devices are not infallible.
The transmitters might stop functioning because of dead batteries. And even if a turtle is known to have beached, the carcass might never be found or might be found only after serious decomposition, and the cause of death might never be known.
Still, Dr. Shaver prefers to think positively until more results come in. “When I got here, there were many who thought the species might not survive at all,” she said. “We’ve come so far.”
Read more!
Posts
visitors since Nov 07