Productive Nesting for Kemp's Ridley Sea Turtles At Padre Island National Seashore, But Oil Awaits
Through a gift of nature that guides them through the seas, dozens of highly endangered Kemp's ridley sea turtles have made their way to the sandy beaches of Padre Island National Seashore to lay thousands of eggs. And many showed up on the same day.
With an average clutch size of 100 eggs, the roughly 70 nests laid through June 11 on the seashore's beaches translate into about 7,000 eggs. And with a hatching success of 80-85 percent, there soon could be almost 6,000 hatchlings heading out into the Gulf of Mexico to begin life. For many, though, that life will be short.
"We bring the eggs in for protected incubation, on the Texas coast, and we get an average of about 80 to 85 percent hatching success," said Dr. Donna Shaver, the sea turtle science and recovery chief at the national seashore. "Then the hatchlings are given a protected release. So all the hatchlings that survive after emergence get into the water, but after that point the turtles are on their own and we don’t know.
"We know that certainly only a fraction of them will make it to adulthood. There are a lot of perils out in the marine environment; predation when they’re hatchlings, birds, fish, and then as they grow sharks and, of course, all sorts of problems with cold stunning or incidental capture in the fisheries, boat propeller injuries, etc.”
The beaches of Padre Island National Seashore long have been favored nesting grounds for Kemp's ridley sea turtles. Indeed, noted Dr. Shaver, "the first published record of Kemp’s ridleys nesting anywhere in the world was here at Padre Island National Seashore in 1948, before it became a national seashore."
Almost two decades later, in the 1960s, an amateur video from 1947 came to light that captured an estimated 42,000 Kemp's ridleys coming ashore on one day at Rancho Nuevo in the Mexican state of Tamaulipas to nest. "When you see it it just brings chills to you because it’s so amazing, that so many of them would come up at one time at one place," Dr. Shaver said.
Padre Island has never come close to seeing that many turtles show up at once. Indeed, the national seashore's "record" for mass nestings is 14 in one day, a tally seen twice this spring, according to Dr. Shaver.
While Rancho Nuevo lays claims to about 95 percent of all Kemp's ridley nesting activity, according to the U.S. Fish and Wildlife Service, Texas beaches lure many of the female turtles to lay their eggs. This year the beaches of Padre Island seem to be the most popular with the turtles. While 69 nests had been counted on the national seashore through June 9, far behind in the count was South Padre Island, which stood second overall in nests with 24. No other nesting location in Texas reported more than seven nests.
As Traveler contributing writer Bob Janiskee noted in a Creature Feature on the turtle last month, Kemp's ridley turtles nest at intervals from late April to early July, laying about 110 eggs in each shallow nest. Females come ashore more than once, at intervals of about 10-28 days, typically laying two or four clutches of eggs in a season. Some females do not nest every year.
While the 69 nests counted so far at Padre Island is a vast improvement from 15 years ago, when only a small handful of Kemp's ridley turtles came to the seashore to dig their nests and lay their eggs, Dr. Shaver said the count this year so far is a bit down from 2008, when 94 nests were found, and 2009, when there were 117.
“We’re actually a little bit low compared to the last two years," the biologist said Friday. "Of course, we’ve been seeing big increases over the last decade. Fifteen years ago we were lucky to find four, five, or six nests. The numbers, we’re happy to have what we do, but it is a little bit low compared to the last couple of years. The nesting season is still continuing, it’s possible that we could make up some ground in the next month. That remains to be seen. We did have a late start to the nesting season, it was a very cold winter here.”
Like Florida, which saw a diving cold snap this past winter chill the air and waters enough to kill some sea turtles and manatees and stun many more, a similar cold snap swept across parts of the Gulf of Mexico.
"In Florida they had 4,000 turtles that were found floating or washed ashore due to freezing air temperatures, and we found over 400 in Texas," she said. "Now, these weren’t adult Kemp’s ridleys, but it shows that it was a very cold winter. The adult Kemp’s ridleys that were out in the Gulf of Mexico likely had to travel further off-shore to find warmer waters. And the further off-shore they get, it’s harder for them to find foraging resources. So it may have been that not as many of the turtles were ready to reproduce. They don’t reproduce every year.”
While the species has made great strides since 1985, when Dr. Shaver said only 702 nests were counted world-wide, she holds concerns that the Deepwater Horizon disaster could interrupt the success that today counts more than 12,000 nests annually, according to USFWS data. So far the oil gushing from the bed of the Gulf of Mexico is off to the east of Padre Island, but many Kemp's ridley turtles work their way from Texas over to the Florida coastlines, the biologist said.
“We haven’t seen any impacts here at the national seashore or down in Mexico yet. The beaches are not oiled, the trajectory for the oil spill is more in the eastern Gulf of Mexico, not the western Gulf. We haven’t seen problems with that, we haven’t seen any oil on any sea turtles here," said Dr. Shaver. "Our nesters likely came to the area before the spill occurred, because mating is thought to take place about 30 days before the first nest is laid, and off-shore from the nesting beach. We hope that our females were here already before the spill occurred. Again, we haven’t seen any traces of oil on any of them.
"But, we do have concerns because I’ve put out now 48 satellite transmitters on nesting females after they’ve laid their eggs, and a large percentage of those turtles travel northward after the nesting season is done and then the locations for them have been either in the waters off the upper Texas coast, Louisiana, Mississippi, Alabama or the west coast of Florida," she added. "So a large number of them have gone through those waters for migration or have set up residency in those waters for foraging. So, we are concerned about the females that are taking the year off from nesting, as well as our females after they’ve done nesting for the season."
Adding to the dire outlook is that when the hatchlings are set free, once they make it into the Gulf they float with the currents "and become associated with the seaweed and convergence lines of debris and the oil could accumulate there as well," said Dr. Shaver. "So, we haven’t seen impacts yet, but we are concerned what the impacts could be down the line. For Kemp’s ridley, more than any other of the sea turtles, their life cycle is so dependent upon the Gulf of Mexico. The other sea turtles are more far-ranging.”
Traveler postscript: According to Fish and Wildlife Service documents, sea turtles run into problems with oil when they come to the surface for air and by ingesting it when feeding. That could be especially fateful for Kemp's ridleys, which seldom go into waters deeper than 160 feet, according to the agency, and so could more likely find themselves in layers of oil near the water's surface.
"Additionally," says the agency, "sea turtles may experience oiling impacts on nesting beaches and eggs through chemical exposures resulting in decreased survival to hatching and developmental defects in hatchlings."
Federal agencies have been working to rescue sea turtles and other wildlife impacted by the Deepwater Horizon incident.
The Wildlife Branch of the Unified Command has organized trained wildlife care providers and investigators to assist sea birds, marine mammals and sea turtles that will be impacted by the Deepwater Horizon Oil Spill. The marine mammal and sea turtle response teams include authorized personnel from the Marine Mammal Health and Stranding Response Program and the Sea Turtle Stranding and Salvage Network who respond to stranded marine animals in the upper Gulf of Mexico and consist of experts from federal and state agencies, academia, wildlife and veterinary professionals and zoo/aquaria facilities. The overall response will build upon the local stranding programs but will call upon the national network to assist as needed. This is an outstanding example of collaborative conservation efforts that are being brought together to assist marine animal wildlife in this oil spill event.
NOAA’s National Marine Fisheries Service and the U.S. Fish and Wildlife Service have identified primary responders and rehabilitation facilities in the local areas for live cetaceans, manatees and sea turtles. Facilities have also been identified and are being readied for necropsies of dead marine mammals and sea turtles. Federal and state agencies are partnering with bird rehabilitation experts to provide facilities and care for sea birds.
Given the long time frame for this effort, experts from other areas of the country are also being identified and brought into the region. These are personnel who are highly trained in the special needs required for handling and treating marine mammal or sea turtles and will be used as the response progresses and as needed to assist the local rescue teams.
Additional rehabilitation and necropsy facilities outside of the upper Gulf region have already been identified and are on standby to assist or receive animals if circumstances demand.
Already, more than 300 sea turtles have been affected by the oil, according to the National Oceanic and Atmospheric Administration.
A total of 331 sea turtles have been verified from April 30 to June 9 within the designated spill area (The designated spill area for sea turtles and marine mammals is from the Texas/Louisiana border to Apalachicola, Florida). Between Tuesday, June 8, and Wednesday, June 9, nine turtle strandings were verified, including one dead oiled turtle from Louisiana, one live turtle from Louisiana that is being examined for evidence of oil, five dead turtles from Mississippi, and one live, unoiled turtle caught on a hook and line in Florida and released.
Thirty heavily oiled sea turtles have been captured in the on-water turtle search and rescue operation by NOAA, the Florida Fish and Wildlife Conservation Commission, and other partners working under the Wildlife Branch of the Unified Command. Twenty- five of those captured turtles are in rehabilitation at Audubon Aquarium outside New Orleans. Two turtles were collected dead and three captured alive subsequently died at the aquarium. A total of 38 stranded or captured turtles have had visible evidence of external oil. These include the 30 captured turtles from the on-water operation, four live stranded sea turtles (two caught in skimming operations) and four dead stranded sea turtles. All others have not had visible evidence of external oil.
Of the 331 turtles verified from April 30 to June 9, a total of 277 stranded turtles were found dead, and 24 stranded alive. Three of those subsequently died. Four live stranded turtles have been released, including two that were found in Mississippi and released after rehabilitation in Florida, and one caught on a hook and line in Florida where it was released. There are 42 turtles in rehabilitation. Turtle strandings during this time period have been higher in Louisiana, Mississippi and Alabama than in previous years for this same time period. This may be due in part to increased detection and reporting, but this does not fully account for the increase.