Thousands of Sea Turtle Eggs To Be Moved Out of Oil's Way (Via HerpDigest)

Thousands of Sea Turtle Eggs To Be Moved Out of Oil's Way
by Lauren Schenkman on June 29, 2010

For the tens of thousands of sea turtle eggs incubating in the sands of the northern Gulf of Mexico-and dangerously near the oil-it's come to this: Officials are planning to dig up the approximately 700 nests on Alabama and the Florida panhandle beaches, pack the eggs in Styrofoam boxes, and fly them to a facility in eastern Florida where they can mature. Once the eggs have hatched, the young turtles will be released in darkness on Florida's Atlantic beaches into oil-free water. Translocation of nests on this scale has never been attempted before.

"This is really a worst-case scenario," says Michael Ziccardi, a University of California, Davis, veterinarian and oil-spill veteran who is leading the government's response efforts for marine mammals and sea turtles. "We hoped we wouldn't get to this point."

Sea turtles that hatch in the Northern Gulf of Mexico typically spend a few months near the coast, and many eventually enter the Loop Current to make their way into the Atlantic. This year, that path would put them right in the oil spill. Federal officials in charge of response "believe that most, if not all, of the 2010 Northern Gulf hatchling cohort would be at high risk of encountering oil during this period," according to the written translocation plan, developed by the U.S. Fish and Wildlife Service, the National Oceanic and Atmospheric Administration's National Marine Fisheries Service, and the Florida Fish and Wildlife Conservation Commission. They estimate that 50,000 hatchlings could be lost to the oil.

Nests are already being marked so that cleanup crews can skirt them, and officials hope to begin moving them within weeks, says Ziccardi. The operations will continue well past laying season, which ends in August, because eggs incubate for about 60 days. The logistics of finding contractors to train and lead collection teams, a facility where the eggs can come to term, and an air-freight company that can transport them three times a week for the next 3 months are daunting.

Officials plan to dig up the eggs at about day 50 of their incubation-well after the hatchling's sex, which is determined by the nest's temperature, is set. Workers moving the eggs have to be careful not to turn them over or roll them so as not to disturb membranes that connect the embryo to the shell and cushion it, says Philip Allman, a marine biologist at Florida Gulf Coast University in Fort Myers. "If the orientation of the egg is turned significantly from the position in the nest, the rotation can break the membranes and cause the embryos to die," he says. "Even in flight, turbulence and a bumpy landing could be enough" to break the membranes.

Moving the eggs could also affect where the turtles go to nest once they're adults, Allman says, because "a lot of evidence indicates that sea turtles return to the same region where they hatch from to nest." Some researchers believe embryos somehow learn the location of their home beach while still in the egg; others think that "imprinting" process happens as hatchlings make their way to the water. The plan could mean the hatchlings imprint on the east coast of Florida, which "may impact which breeding population they join once maturing," Allman says. Although this could change the genetic makeup of east coast populations, which aren't identical to those in the northern Gulf of Mexico populations, he thinks the risks of negative effects are minimal. "I think it is a chance worth taking," he says.

Individual nests are sometimes moved above high tide or brought into captivity to protect eggs from predators or poaching. Although an operation of this scale is unprecedented, it's the best option right now, says Thane Wibbels, a herpetologist at the University of Alabama, Birmingham. "You're either reactive or proactive, and if you're reactive, it's too late."

Smaller-scale translocations have been successful, Wibbels points out; Each year from 1978 until 1988, about 2000 Kemp's ridley sea turtle eggs were moved from the species' sole nesting beach in Rancho Nuevo, Mexico, to Padre Island National Seashore near Corpus Christi, Texas, in a bid to start a second nesting beach. Today, he says, about 200 turtles nest there.

After the Ixtoc I well blew out in the Gulf of Mexico in 1979, 9000 Kemp's ridley hatchlings were kept on their nesting beach and then transported to cleaner waters, says Allman. "Multiple authors reported a few years later that the oil spill did not have a significant impact to the Kemp's ridley sea turtles," he says.

"In a normal year you'd think, 'That's crazy,' " Wibbels says. "We want these turtles to do what's natural, ... but if you have to prevent a large amount of mortality, you have to make tough decisions."