Testing models of female reproductive migratory behaviour and population structure in the Caribbean hawksbill turtle, Eretmochelys imbricata, with mtDNA sequences

Abstract

Information on the reproductive behaviour and population structure of female hawksbill turtles, Eretmochelys imbricata, is necessary to define conservation priorities for this highly endangered species. Two hypotheses to explain female nest site choice, natal homing and social facilitation, were tested by analyzing mtDNA control region sequences of 103 individuals from seven nesting colonies in the Caribbean and western Atlantic. Under the social facilitation model, newly mature females follow older females to a nesting location, and subsequently use this site for future nesting. This model generates an expectation that female lineages will be homogenized among regional nesting colonies. Contrary to expectations of the social facilitation model, mtDNA lineages were highly structured among western Atlantic nesting colonies. These analyses identified at least 6 female breeding stocks in the Caribbean and western Atlantic and support a natal homing model for recruitment of breeding females. Reproductive populations are effectively isolated over ecological time scales, and recovery plans for this species should include protection at the level of individual nesting colonies.

Evidence of olive ridley mitochondrial genome introgression into loggerhead turtle rookeries of Sergipe, Brazil

“…Although hybridization events have previously been reported for marine turtles (Conceição et al 1990;Bowen et al 1992Bowen et al , 1994Karl et al 1995;Bass et al 1996;Bowen and Karl 1996;Lara-Ruiz et al 2006), this work is the first notification of hybridization between C. caretta and L. olivacea on the Brazilian coast.…”

Historical perspectives on population genetics and conservation of three marine turtle species

“…This combined dataset includes 417 individuals from 20 populations in Florida, Mexico, Brazil, and the Mediterranean. Hawksbill turtles (Eretmochelys imbricata) were evaluated using data from Bass et al (1996) including 93 individuals from 7 populations in the Caribbean and Brazil (excluding hawksbill/loggerhead hybrids). Green turtle (Chelonia mydas) populations were evaluated using data from Encalada et al (1996) including 147 individuals from 9 populations on the east and west coasts of the Atlantic Ocean and the Mediterranean.…”

“…The unique biology of marine turtles includes a complex life history characterized by multiple distinct phases, each with unique habitat and geographic range associations. Although marine turtle species share many lifehistory characteristics, patterns of genetic diversity vary among species based on life-history strategies and historical population processes (Bowen et al 1994;Bass et al 1996;Encalada et al 1996). Here we reexamine and compare published data on three species of marine turtles that use Western Atlantic and Mediterranean beaches as nesting grounds, the loggerhead (Caretta caretta), hawksbill (Eretmochelys imbricata), and green (Chelonia mydas) sea turtles.…”

“…Green turtles in Florida display a higher degree of NH/NSF, often within 10 km of their previous nest deposition (Carr et al 1978;Balaz 1980;Limpus et al 1992). High levels of NH/NSF in hawksbills have been demonstrated in the Caribbean (Bass et al 1996); however, movement between adjacent beaches or islands is reported in the Indian and Pacific Oceans (Diamond 1976;Limpus et al 1983). …”

“…Loggerheads nest primarily in warm temperate regions (Pritchard and Trebbau 1984), whereas green turtles and hawksbills nest primarily in the tropics Bass et al 1996). Efforts to conserve marine turtle species require consideration of these complex life-history traits, along with an understanding of how the population biology of these species has shaped genetic population structure through time, and will continue to do so in the future.…”