More sea turtles were killed or injured in the Gulf of Mexico in the months following the BP oil spill than in any similar period during the past two decades, a report released Wednesday found.
While the report suggested many of the 600 turtles were hurt by the spill, it's still not clear exactly how many died from ingesting the crude or how many drowned in fishing nets in the scramble to catch shrimp and fish before the oil ruined them. The sea turtles could have also been killed by cold weather or other factors unrelated to the spill.
The report said the rate of dead, disabled and diseased sea turtles discovered in the months following the massive April 20 spill was four to six times above average. The analysis -- by the National Wildlife Federation, the Sea Turtle Conservancy and the Florida Wildlife Federation -- was conservative and only took into account turtles found on shore, not those rescued or recovered at sea.
Researchers with the federal government said it would take years to determine the full impact of the spill on sea turtles. Necropsies have been done on more than half of 600 turtle carcasses, and while some may have died from oil, most of the turtles drowned in fishing gear, said Monica Allen, a National Oceanic and Atmospheric Association spokeswoman.
Unseasonably cold temperatures last winter were also detrimental to sea turtles, most of which are considered endangered, said Gary Appelson, policy coordinator for the Sea Turtle Conservancy.
"Sea turtles have had a tough year," Appelson said.
Doug Inkley, senior scientist at the National Wildlife Federation and a co-author of the report, said while some of the turtles' deaths could not be linked to the spill, the much higher-than-usual number indicated the disaster was at least partially responsible.
He said turtles suffered more than other species because their populations are already low and face long odds of reaching adulthood. It takes turtles 10 to 30 years to reach maturity, meaning it could take decades to restore the damage to their population, Inkley said.
"Of all the species affected by the oil spill, those for which I have the greatest concern are the sea turtles," he said.
Wildlife officials undertook Herculean efforts to try to save turtles during the oil spill. All told, hundreds of loggerhead nests containing nearly 15,000 hatchlings were successfully transported and later released along the Atlantic.
Besides urging lawmakers to uphold funding for beach conservation, the report's authors urged the elimination of subsidies for construction projects along coastlines and the protection of less developed areas of the shore.
More than 90 percent of North American sea turtle nesting happens on Florida's beaches. Five of the planet's seven species of sea turtles are found in the state. Four of those -- green, hawksbill, leatherback and Kemp's ridley -- are considered endangered, or at risk of becoming extinct.
The fourth, loggerheads, is listed as threatened, or likely to become endangered.
Matt Sedensky of The Associated Press wrote this report.