GENETIC COMPOSITION OF A GREEN TURTLE (CHELONIA-MYDAS) FEEDING GROUNDPOPULATION - EVIDENCE FOR MULTIPLE ORIGINS

Migratory marine turtles are extremely difficult to track between thei r feeding and nesting areas, and the link between juvenile and adult h abitats is generally unknown. To assess the composition of a feeding g round (FG) population of juvenile green turtles (Chelonia mydas Linnae us), mitochondrial DNA control region sequences were examined in 80 po st-pelagic individuals (straight carapace length = 31 to 67 cm) sample d in September 1992 from Great Inagua, Bahamas, and compared to those of 194 individuals from nine Atlantic and Mediterranean nesting coloni es. Evidence from genetic markers, haplotype frequencies, and maximum likelihood (ML) analyses are concordant in indicating that multiple co lonies contribute to the Bahamian FG population. ML analyses suggested that most Bahamian FG juveniles originated in the western (79.5%) and eastern (12.9%) Caribbean regions, and these proportions are roughly comparable to the size of candidate rookeries. These data support a li fe-cycle model in which individuals become pooled in post-hatchling (p elagic) and juvenile (benthic) habitats as a consequence of ocean curr ents and movement among FGs. A substantial harvest of immature turtles on their feeding pastures will influence the reproductive success of contributing nesting populations over a wide geographic scale..