Sea turtle status and trends: integrating demography and abundance

Abstract

Long lifespans and wide-ranging migrations make the seven species of sea turtles difficult to monitor. They are susceptible to many sources of mortality, including direct and incidental “takes” (basically any potential impact on a turtle or its behavior [50 CFR 17.3]) from coastal and oceanic human activities worldwide. All six of the species that occur in U.S. waters1 (loggerhead [Caretta caretta], green [Chelonia mydas], hawksbill [Eretmochelys imbricata], Kemp’s ridley [Lepidochelys kempii], olive ridley [Lepidochelys olivacea], and leatherback [Dermochelys coriacea]) are listed as endangered or threatened under the Endangered Species Act, thereby prohibiting their direct harvest, although incidental take is permitted under some circumstances. (The seventh sea-turtle species is the flatback (Natator depressus), which is only found in the waters around Australia, Papua New Guinea, and Indonesia.) Accurate assessments are necessary to evaluate the status and trends of populations and the impacts of incidental takes and to assess the value of implemented protections on specific populations.