Thesis

Natal Origin of Juvenile Loggerhead Turtles from Foraging Ground in Nicaragua and Panama Estimated Using Mitochondria DNA

ABSTRACT NATAL ORIGIN OF JUVENILE LOGGERHEAD TURTLES FROM FORAGING GROUND IN NICARAGUA AND PANAMA ESTIMATED USING MITOCHONDRIA DNA by © Akiko Masuda 2010 Master of Science in Biology California State University, Chico Summer 2010 The loggerhead turtle, Caretta caretta, is a long-lived, slowly maturing marine species, and is currently classified as globally endangered species by the International Union for Conservation of Nature and Natural Resources (IUCN2010). As with all seven marine turtle species, loggerheads have a complex life history including migrations spanning entire ocean basins. Shallow (neritic) waters close to the Caribbean coast of Nicaragua are used as foraging habitat by juvenile and adult loggerhead sea turtles (Caretta caretta), but the natal origin of these foraging turtles have not been yet determined. Loggerheads in Nicaragua are affected by intense artisanal and commercial fisheries requiring urgent conservation efforts. Our study is an estimation of the rookery origins of turtles in the loggerhead foraging aggregation in coastal waters of Nicaragua, and migratory connection among other foraging grounds throughout the Atlantic and Mediterranean. I obtained mtDNA D-loop sequences from 72 of 78 juvenile loggerhead turtle samples collected. I detected 18 haplotypes from the full 835 base-pair sequence and six haplotypes from 380 base-pair region used previous studies. Genetic diversity indicated that the Nicaragua foraging is a diverse mixed stock (h=0.61 n=0.0021). I applied a Bayesian hierarchal method of many-to-many multiple mixed stock analysis to estimate the origins and destinations of individuals in all available published nesting and foraging areas including our new foraging data. I also discuss that the possible influence of turtle body size, ocean circulation system, and oceanographic distance between nesting and foraging grounds, on loggerhead migration and recruitment patterns.

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