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ESR prepress abstract   -  DOI: https://doi.org/10.3354/esr01198

Effect of body size on the long-term reproductive output of East Atlantic loggerhead turtles Caretta caretta

Samir Martins*, Luis Cardona, Elena Abella, Elton Silva, Nuno de Santos Loureiro, Michael Roast, Adolfo Marco

*Corresponding author:

ABSTRACT: We assessed the relationship between body size and several important life history parameters to understand the demographic significance of inter-population variability in the body size of loggerhead turtles Caretta caretta nesting in Boa Vista Island (Cabo Verde). The adult growth rate (0.34 ± 0.60 cm yr–1), annual mortality rate (0.13, 95% CI: 0.12–0.15), and remigration interval (3.1 ± 1.2 years) were independent of curved carapace length (CCLmin). Conversely, the body condition index decreased significantly with female CCLmin. The clutch size, mean egg mass, mean hatchling straight carapace length and mean hatchling mass increased significantly with female CCLmin. However, there was no relationship between female size and hatching success. Randomization and bootstrapping were used to incorporate variability when calculating the average individual fecundity over 20 years, a period that accumulated, on average, 94% of the adult mortality. The overall fecundity during this period increased with carapace length at first maturity (71 cm CCLmin: 815 eggs, 95% CI: 653-863; 80 cm CCLmin: 906 eggs, 95% CI: 822-959; 90 cm CCLmin: 1089 eggs, 95% CI: 926-1415). However, only 8% of the adult females nesting in Boa Vista Island are larger than 90 cm CCLmin and they produce less than 12% of the total annual egg production. The scarcity of large females might result from a shortage of high-quality foraging grounds where females may reach first sexual maturity at a large carapace length and from the combined effect of a small carapace length at first sexual maturity, low adult somatic growth and high adult mortality.