In their Science article, the authors describe the assessment of sea turtle populations as a microcosm of the larger issue. Sea turtle populations are monitored almost exclusively by counting nests on beaches, but when those populations increase or decrease, scientists often don't know why because nesting females are such a tiny fraction of the total population. In Florida, the number of loggerhead turtles, for example, increased from 1989-98, then plummeted.
Several factors could have contributed, but a lack of knowledge about age distribution, reproduction rates, mortality rates and other data have made it difficult to determine what triggered the changes and impossible to create management strategies to deal with them, noted Heppell, who has worked with the National Marine Fisheries Service on turtle conservation issues since 1995.
In contrast, Australian researchers have logged 30 years of demographic data on loggerhead turtles and when a steep decline in their population on the Great Barrier Reef took place in the 1980s and 1990s, they were able to attribute it to predation by foxes on nests and incidental capture in trawl fisheries.
"Both hazards have now been mitigated by government agencies," the authors wrote," resulting in an apparently recovering stock."
The authors list seven elements that should be considered in crafting new research priorities for protected marine species, including sea birds and mammals, as well as turtles:
|Contact: Selina Heppell|
Oregon State University