World Status, Exploitation and Trade - WIDECAST

INTRODUCTIONrecruitment could have ceased many years ago, and the population is ineffect already doomed to disappear. Many turtle biologists believe thatpresent and past exploitation of sub-adult and adult turtles, egg harvest,incidental catch and habitat disturbance, have put many populations in justsuch a precarious position. This interpretation, together with the observeddecline in many populations, and the disappearance of a few, clearly callfor urgent conservation measures, even though large numbers of turtles arestill evident in many parts of the world, and the quantitative dataavailable may not in themselves justify application of the "Endangered"category.The prevailing view is that the Hawksbill Eretmochelys imbricata is mostaccurately categorised as "Endangered" and, while a reasonable case can beargued that the species is faced globally with imminent extinction, as isstipulated by the current definition of the lUCN "Endangered" category, thatcase is based as much, or more, on inference than on hard evidence. Therelative lack, of information on populations of Hawksbill, and strict literalinterpretation of the lUCN status category definitions, could alternativelysuggest that "Indeterminate" would be an appropriate category. It is notthe case, contrary to a common misconception, that this category necessarilyimplies some lesser degree of threat to the species than the "Endangered"category; included are species that may be "Endangered" although data areinsufficient to establish with certainty that this category is mostapposite, rather than "Vulnerable" (or even "Rare"). Such data areavailable for some nesting populations, notably in the Caribbean region, butnot globally.Implementation of the firmest and most extensive protection and managementmeasures is required for both C. mydas and E. imbricata , as befits"Endangered" species, whether or not the use of that category, sensu lUCN,is strictly justified. There is currently a need to demonstrate the risk ofimmediate extinction to merit use of the lUCN category "Endangered", andthis can only clearly be demonstrated for certain populations of eachspecies. However, it can be argued that wherever data on numbers and trendsdo not strictly meet the criteria for use of the "Endangered" category, todemand such rigorous data in the case of sea turtles may be dangerous.Several factors suggest a more cautious approach would be prudent, notably,the observed lack, of individual movement between turtle populations suchthat depleted populations appear not to be replenished by those moreflourishing, and the long-delayed attainment of maturity with consequentlong-delayed population response to adverse or beneficial influences. Ifspecies conservation is the goal, it must be preferable, in cases of doubt,to err on the side of caution rather than wait until every possible item ofevidence is assembled.These considerations suggest that, in order to treat sea turtles (and otherspecies with similar biological features) in a rational, fair and effectivemanner, either the system of categorisation or the unit being categorised,should be modified. Either new lUCN status categories or new definitionsare necessary, or means should be found adequately to represent therelatively discrete nature of sea turtle nesting populations, presumably bydefining and categorising each separately. The data are now available, atleast for the C. mydas complex, to allow a useful attempt at separatecategorisation of individual or regional population groups.51