1997 CRC Press. As detailed in the introductory chapter by Pritchard, sea turtles have a long and ancient history. Sea turtles arose in the early Mesozoic, and for the next 100 million years, during the rise and reign of the dinosaurs, they shared the oceans with a rich diversity of other air-breathing marine reptiles. By the end of the Cretaceous era, the sea-going ichthyosaurs and plesiosaurs were extinct, but sea turtles tenaciously survived and indeed flourished up until very recent times. But today their numbers are drastically reduced to the point that all seven remaining sea turtle species are considered either threatened or endangered on a worldwide basis. Undoubtedly, human interference is the cause of this collapse. The challenges that sea turtles now face from human activities impact every stage of their life cycle, from loss of nesting beach and foraging habitats to mortalities on the high seas through intense pelagic fishing practices. They are also harmed by the increasing loads of nonbiodegradable waste and pollutants that the oceans and coastal zones now receive.
