World Status, Exploitation and Trade - WIDECAST

INTRODOCTIOMone of the recorded causes of turtle mortality. Better documented is thephysical impact of floating debris on sea turtles. This includesentanglement in discarded fishing net as well as ingestion of plastic refuse(Balazs, 1985c, Carr 1987b). Frazier (1980b) and Carr (1986, 1987a, 1987b)both pointed out that, during the pelagic phase, turtles tend to aggregatealong the margins of currents and zones of mixing; features which cause theaccumulation of floating debris and other pollutants as well as food items.Other disturbancesSand extraction is a widespread activity which can disrupt nesting beaches.Even if the nests are not destroyed, the removal of sand may so alter thebeach as to make it unsuitable for nesting. Sand beaches are dynamicfeatures, and so the removal of sand elsewhere or even sub-marine dredgingmay affect the morphology of a beach at a distance.The feeding habitats of turtles are also susceptible to disturbance. In thecase of Hawksbills, the coral reef environment is suffering damage from suchdiverse factors as increased sedimentation (caused often by deforestation onland), coral extraction, dynamite- or poison-fishing, variations in oceantemperatures, and chemical pollutants (see Wells, 1988a). The feedinghabitat of adult C. mydas , mainly seagrass beds, may also be affected bysome of these factors, especially sedimentation and dredging.CONSERVATION STATUSIn 1620 the Bermuda Assembly prohibited the taking of young turtles up to 18inches broad within five leagues of the islands (the penalty being a fine of15 pounds of tobacco, to be shared between the informer and the community)(cited by Carr, 1952). This appears to be the first recorded recognition ofthe potential deleterious effects of heavy exploitation of sea turtles. Inthe present century, much concern has been expressed over the documented orsuspected decline of sea turtle populations in many parts of the world; seaturtles have come to be widely regarded as threatened species, and appear inthe protective legislation of many countries. The evidence for thisassessment has been reviewed on several occasions; on a world basis by King(1982, C. mydas and E. imbricata ). Ross (1979, and 1982, three otherspecies), and Groombridge (1982, all species). In this report we attempt toprovide a comprehensive survey of the status of populations of C. mydas andE. imbricata . The information given at greater length in the countryaccounts comprising the main body of the report is summarised in thissection and in Table 8 (below)Population status: summary tablesThe following Tables summarise select population data derived from thecountry accounts forming the main body of this report. It must berecognised that their compilation necessitated considerable simplificationof conditions that are complex and often poorly-known, and the making ofnumerous value judgements, few of which might be universally agreed upon.The intention is simply to provide a broad perspective on world populationsof the Chelonia mydas complex and Eretmochelys imbricata ; these must besubstantiated by reference to the country accounts.The term "geopolitical units" includes all areas separately itemised in thecountry accounts; thus, for example, the Pacific and Gulf /Car ibbean coasts44