Reproductive biology of the loggerhead turtle (Caretta caretta L. 1758) on the island of Boavista (Cape Verde, West Africa)

Abstract

This paper presents the revised and up-dated data on the nesting population of

Loggerhead (Caretta caretta) on the island of Boavista, studied from 1998 to 2002. To

date, a total of 2,856 females have been tagged on different beaches of lhe island. The

number uf nests counled in the study area (on lhe beaches of Calheta, Ervatão and

Ponta Cosme), a total of 3.1 km uf beach, was 833 and 1,917 (only for lhe years 2001

(and 2002 respectivily). Nesting success for these two years is around 2G %, with

differences between one beach and another. The annual average curved carapace length

for females is between 81.3 and 82.4 cm, and clutch size is between 78.3 and 91.5 eggs.

The range of incubation times was 45-74 days, wilh differences between one year and

another and between one beach and another. Hatching success does not appear to

show inter-annual variations, but these results does vary from one beach to another. In

2000. a hatchery was built with nests from Ponta Cosme and Ervatão beaches, from

areas where the eggs were unlikely to develop. Hatching success for the artificially

incubated nests was higher than hatching success for Ponta Cosme beach and similar

to the success rate for Ervatão beach.