Increase in hawksbill sea turtle Eretmochelys imbricata nesting in Barbados, West Indies

Abstract

Nesting by hawksbill sea turtles Eretmochelys imbricata in Barbados, West Indies, has been monitored since 1992. Data from the index beach indicate that the number of nests may have increased as much as 8-fold over this period. The estimated abundance of nesting females on Barba- dos is 1250, suggesting that this eastern Caribbean island now hosts one of the largest rookeries in the wider Caribbean, with over 230 females nesting on the index beach alone. Given its extreme east- erly position and the prevailing north-westerly current flow into the Caribbean Sea, Barbados is likely to be a significant contributor to foraging grounds throughout the region. Primary females, which are untagged and without tag scars, made up the majority of females encountered on nesting beaches in most years, suggesting that reductions in juvenile and sub-adult mortality, both nationally and regionally, are significant to the increase in number of nesting females. Females nest every 2.47 yr on average, although remigration intervals of individual females vary (range: 1 to 6 yr), sug- gesting environmental influences on nesting periodicity. The average clutch frequency estimated from the index beach was 4.1 nests per female, but that calculated from less intensively surveyed beaches was lower. Primary and Remigrant females differed in length, mass and clutch frequency; the results must be viewed with caution, however, as preliminary laparoscopic examinations re- vealed that some Primary females were not in fact nesting for their first season, and because differ- ences in nest site fidelity between the 2 groups of females could potentially cause the differences in clutch frequencies estimated.