Oceana experts fear that optimistic preliminary estimates of the 2008 sea turtle nesting season - which formally ends Friday, October 31 - fail to express the dire status of the species. Oceana continues to call upon the U.S. government for increased protections of sea turtle populations that are threatened with, or in danger of, extinction.
Nesting data from the Archie Carr National Wildlife Refuge in Florida, the most important nesting habitat for loggerhead sea turtles in the United States, shows that although we are seeing a slight rise in nesting from dismal 2007 levels, the long-term trend illustrates an enormous decline. Some believe this year's heightened nesting numbers could be due to increased conservation efforts, but Oceana says it is more likely the result of the natural fluctuation that occurs because female loggerhead sea turtles only nest every two to four years.
"I'm pleased to see an increase in sea turtle nesting this year, but it doesn't affect the overall downward trend," said Elizabeth Griffin, marine wildlife scientist at Oceana. "Despite increased nesting, the survival of sea turtle hatchlings might have actually decreased this year due to a devastating hurricane season."
Hurricanes can affect sea turtle nests by washing them away from the beach, flooding them with sea water or changing the depth of sand that lays over them. Hurricanes Fay, Ike, Hanna and Gustav caused massive flooding and beach erosion, which damaged thousands of nests and washed sea turtle hatchlings back to shore. The threats posed to sea turtle populations by hurricanes may increase in the future as climate change is expected to enhance the severity of storms.
Data from a decades-long monitoring study, conducted by the Florida Fish and Wildlife Research Institute, shows that while leatherback and green sea turtle nesting has slightly increased in recent years, loggerhead nesting has decreased by more than one-third since 1998.
In November 2007, Oceana and the Center for Biological Diversity petitioned the U.S. government to designate western North Atlantic loggerheads as a distinct population segment and to change their status from "threatened" to "endangered" under the Endangered Species Act (ESA). The federal government responded in March 2008 by announcing it would conduct a detailed review that would determine if loggerheads should be declared "endangered" under the ESA and if further habitat protections are warranted, both in the water and on land. A final decision is expected later this year.
"Sea turtles face grave threats when they leave the beaches," said Dave Allison, senior campaign director at Oceana. "Until the U.S. government increases restrictions on the capture and killing of sea turtles by commercial fishing, populations will continue to dwindle away."
Threats Facing Sea Turtle Populations:
Without human interference, it is estimated that less than one percent of all hatchlings survive to adulthood. This is in part due to female sea turtles reaching maturity late in life. When humans injure, displace and kill thousands of additional sea turtles, we push them to the brink of extinction.
Human activities threaten the survival of sea turtles, from nesting beaches to ocean fisheries. Sea turtles are harmed and killed most frequently by commercial fishing gear, including longlines, gillnets, bottom trawls and scallop dredges. Additional threats to their survival include beachfront development, pollution, motor vehicles crushing nests, collisions with boats and the hunting of turtles and their eggs.
Another threat to the survival of sea turtles is climate change. Oceana's report, Climate Change & Commercial Fishing: A One-Two Punch for Sea Turtles, focuses on the effects of climate change to sea turtle populations. The report explains that climate change can cause more severe storms, erosion and sea level rise, all of which can affect sea turtle nesting on beaches. Rising temperatures caused by climate change can alter the timing and/or location of nesting or may increase the number of female turtles, because the sex of the hatchlings is temperature dependent. Climate change also may affect sea turtles by altering ocean currents and migration routes. Finally, ocean acidification caused by rising carbon dioxide levels breaks down the shells of preferred sea turtle prey, such as mollusks and crustaceans, and could alter sea turtles' food supply.