Warming Climates Threaten Leatherback Sea Turtles
Leatherback turtles could be the next victim of climate change, according to a new study in the journal Nature Climate Change by a research team from Drexel University, Princeton University, other institutions and government agencies.
The biggest cause of their death is the loss of turtle eggs and hatchlings in nests buried at hotter, drier beaches of the eastern Pacific.
Leatherbacks, the largest sea turtle species, are among the most critically endangered due to a combination of historical and ongoing threats including egg poaching at nesting beaches and juvenile and adult turtles being caught in fishing operations. And with the added difficulty that climate change poses to their breeding grounds, researchers say the turtle population may not be able to recover.
Like Us on Facebook
"In 1990, there were 1,500 turtles nesting on the Playa Grande beach," said Dr. James Spotila, the Betz Chair Professor of Environmental Science in the College of Arts and Sciences at Drexel. "Now, there are 30 to 40 nesting females per season."
If actual climate patterns follow projections in the study, the eastern Pacific population of leatherback turtles will decline by 75 percent by the year 2100.
The team used three models of the leatherback population to create a population model based on climate forces. They included the turtles' observed sensitivity to the nesting beach climate and ocean temperatures.
Leatherback turtle births naturally ebb and flow from year to year in response to climate variations, with more hatchlings, and rare pulses of male hatchlings, entering the eastern Pacific Ocean in cooler, rainier years, reports Environmental Protection Online.
Female turtles feast on jellyfish and they are more likely to return to their nesting beaches in Costa Rica when there is more food available during cooler seasons. The researchers also found that turtle eggs and hatchlings are also more likely to survive in the cooler, rainier seasons associated with the La Niña climate phase, as they reported in the journal PLoS ONE.
The heat inside the nest is also a factor in population size and makeup. The temperature inside the nest affects turtles' sex ratio, with most male hatchlings emerging during cooler, rainier seasons to join the predominantly-female turtle population.
"Warming climate is killing eggs and hatchlings," Spotila said in a statement from Drexel University. "Action is needed, both to mitigate this effect and, ultimately, to reverse it to avoid extinction. We need to change fishing practices that kill turtles at sea, intervene to cool the beach to save the developing eggs and find a way to stop global warming. Otherwise, the leatherback and many other species will be lost."
Spotila's research team is already looking into new methods to lessen the impacts of hot-dry beaches on hatching, such as watering and shading turtle nests.
© 2012 iScience Times All rights reserved. Do not reproduce without permission.