Environment News Service 15 Jul 10;
WASHINGTON, DC, July 15, 2010 (ENS) - Population sizes of the six species of sea turtles listed as either endangered or threatened in the United States cannot be accurately determined based on available information, says a report released today by the National Research Council.
Reviews of federal sea turtle population assessments and research plans are not sufficiently rigorous and transparent, and there are unnecessary obstacles to the collection and analysis of critical data, including the process for issuing research permits and inadequate training of scientists, finds the committee that wrote the report.
The committee of turtle experts from Oregon State University, the University of Hawaii, Duke University, Old Dominion University, the University of Massachusetts, Woods Hole Oceanographic Institution, the Florida Fish and Wildlife Conservation Commission and the University of Queensland, Australia does not evaluate the cause of sea turtle declines or conduct its own assessment of sea turtle populations.
But the expert panel finds that key data regarding birth and survival rates, breeding patterns, and other information will be required to predict and understand changes in populations and create successful management and conservation plans.
The National Marine Fisheries Service and U.S. Fish and Wildlife Service should develop a national plan to assess sea turtle populations, improve the coordination of collecting data and sharing it with other organizations, and establish an external review of the data and models used to estimate the current sea turtle population and predict future population levels, the committee advises.
"The biggest obstacle to assessing the status of sea turtle populations is that we know little about key characteristics of these creatures, such as what size they are at different ages, the average proportion of turtles that will survive through each year, and their growth rates," said Karen Bjorndal, chair of the committee that wrote the report and professor of biology and director of the Archie Carr Center for Sea Turtle Research at the University of Florida, Gainesville.
"Sea turtles can live for many decades, and can take more than 30 years to reach reproductive maturity," said Bjorndal. "When more is known about their ages, distribution, and genetic differences, models can provide better population estimates and help us understand changes in population abundance."
All species of sea turtles are listed as threatened or endangered. The leatherback, Kemp's Ridley, and hawksbill turtles are critically endangered. The Olive Ridley and green turtles are endangered, and the loggerhead is threatened.
The National Oceanic and Atmospheric Administration asked the research council to examine methods that could improve population assessments carried out by National Marine Fisheries Service, which is overseen by NOAA and responsible for the management of sea turtles in the water, and the Fish and Wildlife Service, which is responsible for sea turtles on land.
In its report, the committee emphasized that long lifespans and wide-ranging migrations over different habitats make sea turtles difficult to monitor.
Current sea turtle assessments in the United States are based heavily on estimates of adult females at nesting beaches, which are inadequate measures to make population assessments because adult females usually skip one or more breeding seasons, and nest counts provide no information on the number of immature turtles, adult males, and nonbreeding females.
Although information on the number of sea turtles at various life stages is essential, this alone is not sufficient to understand the causes of sea turtle population trends, develop management plans to protect sea turtle populations, or predict future trends, the report says.
The committee found that the most serious data gaps exist in estimates of the number of immature sea turtles, survival rates of immature turtles and nesting females, age at sexual maturity, the proportion of adult females that breed each year, and the number of nests each female creates in a breeding season.
In addition, adequate information is not available for population assessments because data either have not been collected or have not been analyzed and made accessible.
The report suggests that the NMFS and the FWS develop plans for the collection and analysis of data to address gaps, create a database that identifies datasets in the United States and territories, and review data being collected now under their agencies and evaluate the costs and benefits.
The agencies should support a program to safeguard and make accessible as many sea turtle databases as possible, they committee recommends. They should ensure that all research plans generated from within federal agencies are reviewed by panels of federal and nonfederal scientists, and convene a working group to evaluate the permitting process for research projects and find ways to expedite the process while safeguarding the species.
The report was sponsored by the National Oceanic and Atmospheric Administration. The National Academy of Sciences, National Academy of Engineering, Institute of Medicine, and National Research Council make up the National Academies. They are independent, nonprofit institutions that provide science, technology, and health policy advice under an 1863 congressional charter.
Committee members, who serve pro bono as volunteers, are chosen by the academies for each study based on their expertise and experience and must satisfy the academies' conflict-of-interest standards. The resulting consensus reports undergo external peer review before completion.
