Scientific spat stalls sea-turtle conservation

Nature News: Scientific spat stalls sea-turtle conservation
A disagreement within the US National Oceanic and Atmospheric Administration's (NOAA's) Fisheries Service has meant that the service is delaying making a decision over whether to elevate the status of a threatened population of loggerhead sea turtles (Caretta caretta) to endangered. The six-month delay means that the loggerheads will have to spend another summer migrating through Atlantic fisheries under rules that the regulators call "inadequate to ensure the long-term viability of the population".

"This is the first time within our agency that there's been a disagreement after we've proposed to list a species," says Marta Nammack, who coordinates listings at the fisheries service in Washington DC. Although counts of nesting loggerheads on US beaches declined by 40% from 1998 to 2008, some agency scientists pointed to a big bump in 2009 and 2010 as indicators that the population should not be considered endangered. "The six-month extension gives us an opportunity to get more data," says Nammack.

Lack of data has been an issue in the debate over turtle conservation for more than 15 years. Starting in 1995, expert working groups convened by the fisheries service have argued that nesting turtles represent a small, biased sample of the larger population, and have repeatedly recommended that the knowledge base be extended through data-sharing and monitoring programmes. Yet a report last year by the National Research Council called the service's modelling of sea-turtle populations "nearly incomprehensible" owing to data gaps. It also criticized the service for a lengthy and opaque process for granting research permits to turtle scientists.

Science or policy?
Conservationists argue that the fisheries service needs to take action on the nesting declines and that regulations need to be revised immediately to protect the loggerhead. "NOAA is trying to portray this as a scientific dispute," says Eric Bilsky, a lawyer with the conservation group Oceana in Washington DC. "In reality, it's political." He says that the fishing industry in the northeastern United States is opposed to the listing because it could lead to additional regulations, such as the use of turtle-excluder devices on fishing nets — a practice that has been successful in the Gulf of Mexico.

Loggerheads were first listed under the Endangered Species Act as threatened throughout their worldwide range in 1978, and their populations are managed by the fisheries service in conjunction with the Fish and Wildlife Service (FWS). At the time of the original listing, tens of thousands of turtles were drowning in shrimp trawler nets each year. By the 1990s, populations of many species, such as the Kemp's Ridley (Lepidochelys kempii), were recovering under the new policies, but loggerheads began to decline again. "We haven't cracked the problem," says Larry Crowder, director of the Duke Center for Marine Conservation in Beaufort, North Carolina.

In 2007, conservation groups, including Oceana and the Center for Biological Diversity in Tucson, Arizona, petitioned the agencies to elevate the listing for the Northwest Atlantic population as well as the North Pacific population, which does not nest in the United States. Although the fisheries service and FWS agreed with conservationists that the petition had merit in March 2008 and created a biological review team, they failed to make a decision within the 12-month timeline required by law. The conservationists sued, and the agencies agreed to complete their review by 19 February 2010. That deadline slipped again, but on 16 March 2010, the agencies proposed elevating the status both populations, writing that they were "in danger of extinction".

At that point, Nammack says, "one or two" individuals in the agency who were not part of the assessment objected to the change because the most recent nesting data had shown a rise in the population. The agency convened several internal workshops to resolve the disagreement, and it expects to make its decision by September.

The clash underscores the challenge that agencies face in applying consistent, objective criteria for the listing of endangered species. "The Endangered Species Act says that we want to keep things from going extinct by protecting them and the ecosystems on which they depend," says Lynn Maguire, who studies environmental decision analysis at Duke University in Durham, North Carolina. "It doesn't articulate what probability of extinction how soon in the future should trigger a listing."

Differing criteria
In an unpublished survey of 21 agency biologists, Maguire and her collaborators have found that most biologists would list a species as endangered if it was expected to go extinct in the next 100-200 years. However, some would consider a species as endangered even if it was only destined for extinction in the next 1,000 years.

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Although turtle experts are disappointed with the fisheries service's approach to assessing loggerhead populations, they are divided about the need for raising the status of the Atlantic population because its numbers, although down from previous levels, are still about a hundred thousand reproductive animals, plus millions of juveniles and hatchlings. "It's frustrating knowing that there are tools that fisheries managers can use in data-poor situations that are not being applied, such as changes in the size distribution of turtles being caught," says Selina Heppell, a population biologist at Oregon State University in Corvallis. Using size distribution to model the reproductive potential of the population, she says that those data indicate that many large turtles will soon be reaching maturity.

"My guess is they will go to all this effort to uplist and 5-6 years from now there will be this massive increase in numbers of nesters and they will have to go though this whole process of downlisting," Heppell says.