A new paper out last month presents the possibility that typical sea turtle population assessment methods via foot patrols may be overestimating nesting populations by as much as a factor of 2. You can view it here.
The paper uses satellite tracking of nesting green turtles (Chelonia mydas) at their study site to show that they lay an average of 6 nests per nesting season. This is about double what has been found by foot patrols in some previous work, meaning that our fecundity estimates may be low. Further, the practice of counting tracks and nests and then estimating the population status (without identifying individuals during nesting via flipper tags) from these counts may lead to a significant overestimate of population size.
This is potentially problematic, and highlights both the value of satellite tracking data and the need for more detailed information. However, we suggest that much more follow up work is needed before generalizations should be made for other populations. For example, we are very confident in the fecundity and nesting frequency data that we collect for our hawksbill (Eretmochelys imbricata) study population with the Jumby Bay Hawksbill Project in Antigua. Headlines like this one: “Sea Turtles Are in Much Worse Shape Than Previously Thought” may be somewhat excessive at this point in time.
Image courtesy of theatlantic.com