Conservation of Hawksbill Sea Turtles: Perceptions and Realities

sea turtle species survive in only a limited area of its natural range. Sea turtles must occur throughout their natural ranges to ensure that they fulfill their ecological roles. For example, hawksbills are primary predators in coral reef ecosystems and thus assist in maintaining the biodiversity and ecological processes of these complex ecosystems. Unfortunately, as is made all too clear in the status justification (Meylan and Donnelly, 1999), the status of the hawksbill worldwide as Critically Endangered does not need to rely on the status of hawksbill populations in only one or two significant regions. The survival outlook for hawksbills is bleak in almost all regions, including the Caribbean. But why have we been so slow to perceive the dire survival status of Caribbean hawksbills? I believe four concepts are primarily responsible. First, and most critical, we do not have the proper perspective, or a reliable baseline, against which to assess declines in hawksbill populations. For centuries, hawksbills have been extensively exploited for the keratinized scutes covering their shells, which are the source of tortoiseshell or bekko (Parsons, 1972; Groombridge and Luxmoore, 1989; Meylan, 1999). Thus, populations were already greatly reduced or extirpated before they were recorded and/or quantified. This lack of proper perspective is not restricted to hawksbill populations (Dayton et al., 1998) and has been termed the “shifting baseline syndrome” (Pauly, 1995; Sheppard, 1995) or the use of inappropriate baselines to assess population change or stability. Referring to fisheries management, Pauly (1995) first described the syndrome as the tendency of scientists to use population levels at the beginning of their careers as the baseline against which to measure population change. He stressed the importance of incorporating historical anecdotes of fish abundance into population models of commercial fish species. Jackson (1997) discussed the misinterpretations of the present status of Caribbean coral reef ecosystems, in general, and the sea urchin, Diadema antillarum, and the green turtle, Chelonia mydas, in particular, as a result of the shifting baseline syndrome. Based on old landing records and calculations of carrying capacity, Jackson (1997) estimated that green turtle populations in the Caribbean have declined by at least 99% since the arrival of Columbus. Bjorndal et al. (1999) evaluate the trend in green Archie Carr Center for Sea Turtle Research and Department of Zoology, University of Florida, P.O. Box 118525, Gainesville, Florida 32611 USA [Fax: 352-392-9166; E-mail: [email protected]]