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The great turtle-egg evacuation

July 2, 2010 By Melissa Gaskill This article courtesy of Nature News.

A generation of sea turtles in the Gulf of Mexico is to be lifted out of the oil spill's way.

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In about 10 days, eggs from nearly 800 sea-turtle nests in Alabama and the Florida 'panhandle' will be evacuated, in one of the largest of these delicate operations ever attempted.

The ambitious plan is intended to save a generation of already endangered sea turtles from the effects of immersion in oil from the Deepwater Horizon blowout. For the thousands of vulnerable hatchlings that would have emerged on these sands and swum into the Gulf of Mexico, those effects could range from infection to death.

To protect the turtles — primarily loggerheads and some green, leatherback and Kemp's ridleys — organizations including the US Fish and Wildlife Service (USFWS), National Marine Fisheries Service, and Florida Fish and Wildlife Conservation Commission developed the Sea Turtle Late-Term Nest Collection and Hatchling Release Plan.

In the operation, an estimated 70,000 eggs will be collected from their nests, packed into styrofoam boxes for transport by temperature-controlled Federal Express truck to a safe facility at the Kennedy Space Center near Orlando, Florida, and eventually released into unoiled waters of the Atlantic Ocean.

Mortality risk

"We looked at a variety of options," says Chuck Underwood, the spokesman for USFWS Southeast Region in Jacksonville, Florida. "In normal circumstances, we would never do this. We know we'll have mortality. But at least we can try."

For years, turtle eggs have been successfully collected around the world, during or immediately after laying, for safekeeping until emergence. But the Gulf plan has ensured a waiting period between laying and collection of about 50 days, to allow sex determination — which depends on temperature in the egg chamber — to occur.

The other reason to let the eggs stay in their nests this long is that sea turtles may imprint on location while in the egg.

Imprinting is important because it means the females will return to nest in the same general location where they hatched, helping to maintain regional genetic variation among populations of the same species. Females would not return to lay eggs for 15–20 years - hopefully long enough for the Gulf to become safe for sea turtles.

A potential downside of this wait, however, is that within 12–24 hours of the eggs being laid, embryos attach to an oxygen-supplying membrane. So any movement of the eggs could cause detachment and death, says Underwood.

Every precaution will be taken to minimize this risk, he adds. The plan includes detailed protocols for handling eggs, and collectors will be trained.

However, Chris Pincetich, a Florida-based marine biologist with the Sea Turtle Restoration Project (STRP) in Forest Knolls, California, expressed concern that the work is lagging. Not all approvals have come through because of short-staffed government agencies and the government-run Deepwater Horizon Unified Command's unwillingness to share information. "If and when they crack open the door, we have a list of qualified individuals ready to help."

Such people will be needed out on the beaches to monitor the location of nests, record where they are and when they were laid - critical for the 50-day window. The digging up and boxing of eggs also demands certain skills.

Todd Steiner, the executive director of the STRP, says, "There are two major problems. Lack of information — no one knows what is going on — and transparency. I have been vetting ideas with other scientists and am surprised by how few of them have been contacted by whoever is in charge."

Behavioural effect

Moving the eggs is not generally viewed as problematic. "We have adequate data showing that eggs moved with competence at that age have no difference in survivorship to those not moved," said Mike Salmon, a biologist at Florida Atlantic University in Boca Raton.

But the release could be another matter. "What we don't know is what impact it might have on other aspects of behaviour," says Salmon.

"The $64,000 question is, if you take hatchlings that would normally emerge in northwest Florida to the east coast," he said, "will they return there, or to the northwest, where they should go?" Because scientists don't know for sure whether imprinting occurs in the nest or after emergence, this remains a mystery.

"What we do know is that leaving these nests where they are means hatchlings headed into waters polluted with oil," says Salmon. It is not just contact with the oil that is potentially harmful; the oil's effect on productivity of the Gulf could also reduce the chances of the hatchlings' survival.

"We are between a rock and a hard place," Salmon adds. "If we leave the turtles where they are, they might not make it. If we move them, we may screw up their learning process."

"We have to do the best we can with what information we have at the moment, which is that a whole year's worth of turtles will be in bad shape if we leave them where they are. If we move them, they might be in better shape."

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