Hawksbill × loggerhead sea turtle hybrids at Bahia, Brazil: where do their offspring go?

摘要

Hybridization between hawksbill (Eretmochelys imbricata) and loggerhead (Carettacaretta) breeding groups is unusually common in Bahia state, Brazil. Such hybridizationis possible because hawksbill and loggerhead nesting activities overlap temporallyand spatially along the coast of this state. Nevertheless, the destinations of theiroffspring are not yet known. This study is the first to identify immature hawksbill× loggerhead hybrids (n = 4) from this rookery by analyzing the mitochondrialDNA (mtDNA) of 157 immature turtles morphologically identified as hawksbills.We also compare for the first time modeled dispersal patterns of hawksbill, loggerhead,and hybrid offspring considering hatching season and oceanic phase durationof turtles. Particle movements varied according to season, with a higher proportionof particles dispersing southwards throughout loggerhead and hybrid hatching seasons,and northwards during hawksbill season. Hybrids from Bahia were not presentin important hawksbill feeding grounds of Brazil, being detected only at areas morecommon for loggerheads. The genetic and oceanographic findings of this work indicatethat these immature hybrids, which are morphologically similar to hawksbills,could be adopting behavioral traits typical of loggerheads, such as feeding in temperatewaters of the western South Atlantic. Understanding the distribution, ecology,and migrations of these hybrids is essential for the development of adequate conservationand management plans.