1The reason of decline of leatherback turtles (Dermochelys coriacea) in French Guiana: a hypothesis

Abstract. Beaches of French Guiana host the nests of more than half of the worldwide number of leatherback marine turtle females (Dermochelys coriacea). This species has shown a strong decline at other major nesting beaches, which makes the actual trend in French Guiana of major importance. We present the data of nest counts from the 1998 nesting season and show that the French Guiana/Suriname population is also declining. We suggest that the potential cause of this decline could be a two step process that began 25 years ago: since 1973, almost all females nesting in this region were concentrated on the beaches of the Maroni and Mana rivers estuary. These beaches appear to be very bad for nest incubation and therefore the juvenile recruitment in the population was very low. However, this effect could have been masked by the very high longevity of females. Development of industrial fishing performed illegally in the estuary for the past 6-7 years enhanced the adult mortality and could also provok the actual observed decline. We propose several ways to test this hypothesis. Key words. Dermochelys coriacea; French Guiana; decline; fishing; hatching success