Sea turtles in general are promiscuous breeders, but previous leatherback paternity studies found only a very low
level of multiple paternity or none at all. Three highly polymorphic microsatellite markers (Dc99, Cc117, and Ei8)
were used to investigate the paternity of a recovering population of leatherback turtles nesting at Playa Gandoca
in Costa Rica, which is part of the Atlantic Costa Rican leatherback nesting population. The aim of this study was to
(i) detect multiple paternity, (ii) compare the results to previous studies in the same and different nesting populations,
(iii) consider the possibility of sperm storage, (iv) explore the possibility of successful inter-nesting mating
taking place, and (v) determine the effect of small population size on mating patterns. Tissue samples from
females and hatchlings were collected from one to three consecutive clutches (35 clutches total) of 18 nesting
females included in the assay with an average sampling effort of 21.91% of offspring per clutch. Evidence of
multiple paternity was found in four out of 18 females (22.22%), which had mated with two to three different
males. The results from this study indicate that multiple paternity is more common than previously observed
for the Atlantic Costa Rican leatherback nesting population. The analyses of successive clutches from the multiply
mated females showed that paternal contribution varies between successive clutches and “new” fathers in
consecutive clutches suggest the possibility of successful inter-nesting mating