Where Sea Turtles Spend Their ‘Lost Years’
ERIK STOKSTAD | Science NOW
Now, researchers have published the first satellite tracking data from young sea turtles, charting a leisurely voyage under the sun. The youngsters idly float north along the Gulf Stream, then head toward the Azores. Along the way, they spend most of their time riding the waves, and the sun helps raise their body temperature. “The data from this handful of turtles could lead to some really important developments” in understanding turtle populations, says Nathan Putman, a turtle biologist at Oregon State University, Corvallis.
The early life of loggerheads and other sea turtles used to be called “the lost years,” because no one knew exactly where they went. But over decades, researchers pieced together the animals’ natural history from ship observations, the pattern of ocean currents, and other data. More recently, other scientists have studied isotopes from turtle tissue to analyze their diet and past locations and created computer simulations of their journey. The basic picture is this: Hatchlings head out to sea to avoid fish, sharks, and other predators. Once off the continental shelf, they eventually end up in a current, called the North Atlantic subtropical g. A few years later, they come back to their birthplaces on the East Coast of the United States.
The transmitters survived between 27 and 220 days, during which some turtles roamed as far as 4300 kilometers, the team reports today in the Proceedings of the Royal Society B. As expected, the turtles all headed north with the Gulf Stream, then most turned eastward around Cape Hatteras in North Carolina. The paths were consistent with what Putman’s computer models had predicted. The turtles weren’t single-mindedly heading toward the Azores, but looping around in small eddies and trying to avoid the coldest water. They also spent almost all of their time on the surface, and Mansfield suspects that this is to help stay warm. “It’s kind of a common sense thing,” Mansfield says. (They may also be waiting to develop the lung capacity for diving.)
Green Sea Turtle scientific illustration… finally got around to finishing some artwork on my vacation
Birth of a Sea Turtle (by O.Blaise)
…except the turtle isn’t laying her eggs in a nest. She could be dumping them after a failed nesting attempt and the load being too much to bear. Those eggs wouldn’t survive. However, turtles can lay multiple nests during the season, so all is not necessarily lost!
The arribada is very much on the bucket list.
Green Sea Turtles (Chelonia mydas) erupting from their nest.
Conservation status: Endangered.
Turtle hatchlings use the safety-in-numbers-strategy. Hatchlings wait until the majority of the eggs have hatched, digging up to the surface together and erupting through the sand and heading for the brightest horizon.
With so many predators in their early life stages, the large number of hatchlings ensures that a few will survive to adulthood. Unfortunately with modern day threats, such as by-catch, net entanglement and poaching, affecting adult populations too, all species of sea turtle are listed under some level of threatened by extinction.
This was taken at a hatchery I worked at in Malaysia.
Study finds Loggerhead turtles depend on broader range of habitat than previously thought
A new US Geological Survey study suggests that the threatened loggerhead sea turtle may require broader habitat protection during the nesting season.
"This is the first study to locate and quantify in-water habitat use by female loggerheads in the Northern Gulf of Mexico subpopulation during their reproductive periods," said lead author Kristen Hart, a USGS research ecologist. "Our tracking results show they depend on a much broader range of habitat during this critical part of their lives than was previously thought to be required."
The study reveals detailed loggerhead movements during “inter-nesting” periods, showing patterns that vary for individual turtles. Generally, this period begins when a female returns from open seas around May and lasts roughly until September. Up until now, efforts to protect the species generally centered on beaches with high nesting activity under the assumption that once turtles had nested on those beaches, they either remained in their immediate vicinity or migrated back out to sea.
Satellite data and researchers observations confirm that the loggerheads nest at multiple beaches and sometimes these beaches are hundreds of miles apart.
"These data show it is not sufficient to just protect habitat around high density nesting beaches … because many turtles that nest on the Peninsula use the entire region from the eastern Florida Panhandle to Louisiana," said Lamont.
"We are working towards defining areas where sea turtles concentrate their activities at sea, effectively building a map of in-water turtle hotspots," said Hart. "The more we know about their habitat use, the more questions are raised about their behavior and ability to adapt."
Turtle conservationist Jairo Mora Sandoval found murdered on Playa Moín in Costa Rica
At around 6 a.m. on Friday, the body of 26-year-old Jairo Mora Sandoval, a young Costa Rican conservationist who monitored and protected turtle nests, was found on Moín Beach, on the northern Caribbean coast.
According to the Judicial Investigation Police (OIJ), Mora had been badly beaten and shot in the head, and his hands were tied behind his back. The OIJ released conflicting statements saying that Mora’s body was found both next to and inside the Jeep he used to monitor the beach.
Mora had worked as a beach monitor for the Wider Caribbean Sea Turtle Conservation Network (WIDECAST) at Moín, said WIDECAST’s Costa Rica Coordinator Didiher Chacón. The program has seen an increase in poachers, Chacón said, and a recent story in a national daily quoted Mora linking the poaching to drug traffickers.
WIDECAST has closed the program following the incident, and has said that they will no longer send staff or volunteers to monitor the beach.
“We can’t risk human lives for this project,” Chacón said. “But this is probably the exact result that the killers were hoping for.”
My thoughts go out to his family, friends and colleagues. I hope that they will continue to fight and his death will not be in vain.
Dr Kathy Townsend from Turtles in Trouble with the debris extracted from a coastal sub-adult flat back turtle in Moreton Bay, Australia. Much of this was plastic bag remnants.
Female Hawksbill turtles are monogamous.
Because "New insight into Hawksbill Turtles’ mating patterns" or "Hawksbill turtles’ monogamous sex life revealed" sounded creepy and overfamiliar.
Dr David S Richardson and Karl Phillips from the University of East Anglia looked at turtle nests on Cousine Island in the Seychelles, an eco-tourism holiday destination favoured by the rich and famous.
Working with the islands’ conservation staff they used a non-harmful procedure to collect DNA from the hard skin of the flipper, or around the shell.
The researchers looked at 43 mothers and 1600 young to reconstruct a genetic model of each nestling’s father, without having to catch the males out at sea. ‘It’s important to do this so that we can understand their mating system and see how much genetic variation there is within the population’ says Richardson.
This is the first comprehensive study into Hawksbill Turtle mating patterns and the findings may help conservationists refocus efforts to where they’re needed.
The scientists were surprised then to find all of the eggs from an individual female are normally fathered by the same male. This means the mothers mate only once and then store the sperm for the entire mating season, fertilising all their eggs with it.
Monogamy in the animal kingdom is the exception rather than the rule. Many females are forced to mate multiple times by aggressive males, or prefer to mate multiply to ensure they have the best quality sperm.
'If they mate with one male and then met another one that was in some way better, bigger or stronger, they might re-mate and have a mix of eggs fertilised by both,' Richardson explains. 'However, it seems female Hawksbills would rather mate just once, far away from their nesting site, then store the sperm, perhaps to avoid unwanted male attention.'
Now the scientists know that not only are there lots of males fathering the nestlings, but there are many male turtles scattered far across the Indian Ocean. Conservationists can use this information to widen their efforts, from the beaches where the females lay their nests to the entire Indian Ocean area, in order to protect males too.
Winning shot of the ‘Cuff-choice’ Cairns Underwater Film Festival 2012 by Jackie Campbell.
That’s pretty strong.
Who’s pumped for Shark Week!?!