Tartarugas verdes na ilha atlântica de Fernando de Noronha, Brasil. Trinta e cinco anos de proteção (1988-2022): ecologia reprodutiva, tendências populacionais e conservação

Abstract

Knowledge of ecological parameters and population trends are key for species of conservation concern. For marine turtles, annual nest counts are commonly used for estimating population size. However, complementary information on reproductive parameters (e.g. clutch parameters, internesting intervals, clucth frequency, remigration interval) is also needed for reliable population estimates. In Brazil, green turtles (Chelonia mydas) nest mainly on oceanic islands. This study uses long-term beach monitoring data (35 years) to describe the reproductive biology and population trends for green turtles at the Fernando de Noronha Archipelago, Brazil. An increasing trend in the annual number of nests was found over the studied period. The average annual number of nests in the first five years of monitoring (1988-1992) was 38.6 nests, while in the last five years (2018-2022) it was 285.6 nests. Internesting intervals ranged from 9 to 17 days (mean +- SD = 11.7 ± 1.3 days; median = 12, n = 1236). Remigration intervals of 3 years were the most frequent (range 2 to 16 years). The longest reproductive life span observed was 25 years. Average hatching success was 75.6% (SD = 24.8, range = 0-100, n = 2612 nests). The growth in the annual number of green turtle nests observed in Fernando de Noronha suggests conservation efforts initiated in the 1980s likely contributed to the recovery of this population. However, the small population size and restricted nesting distribution, coupled with the existence of threats from fishing and climate change, makes this population still of conservation concern.