title: Evidence for transoceanic migrations by loggerhead sea turtles in the southern Pacific Ocean.
abstract: Post-hatchling loggerhead turtles (Caretta caretta) in the northern Pacific and northern Atlantic Oceans undertake transoceanic developmental migrations. Similar migratory behaviour is hypothesized in the South Pacific Ocean as post-hatchling loggerhead turtles are observed in Peruvian fisheries, yet no loggerhead rookeries occur along the coast of South America. This hypothesis was supported by analyses of the size-class distribution of 123 post-hatchling turtles in the South Pacific and genetic analysis of mtDNA haplotypes of 103 nesting females in the southwest Pacific, 19 post-hatchlings stranded on the southeastern Australian beaches and 22 post-hatchlings caught by Peruvian longline fisheries. Only two haplotypes (CCP1 93% and CCP5 7%) were observed across all samples, and there were no significant differences in haplotype frequencies between the southwest Pacific rookeries and the post-hatchlings. By contrast, the predominant CCP1 haplotype is rarely observed in North Pacific rookeries and haplotype frequencies were strongly differentiated between the two regions (F(st)=0.82; p=<0.00001). These results suggest that post-hatchling loggerhead turtles emerging from the southwest Pacific rookeries are undertaking transoceanic migrations to the southeastern Pacific Ocean, thus emphasizing the need for a broader focus on juvenile mortality throughout the South Pacific to develop effective conservation strategies.
authors.affiliation: School of Marine and Tropical Ecology, James Cook University, Angus Smith Drive, Townsville, Queensland 4811, Australia. michelle.boyle@jcu.edu.au
authors.forename: M C
authors.initials: MC
authors.lastname: Boyle
authors.forename: N N
authors.initials: NN
authors.lastname: Fitzsimmons
authors.forename: C J
authors.initials: CJ
authors.lastname: Limpus
authors.forename: S
authors.initials: S
authors.lastname: Kelez
authors.forename: X
authors.initials: X
authors.lastname: Velez-Zuazo
authors.forename: M
authors.initials: M
authors.lastname: Waycott