Population genetic structure, movement patterns, and environmental preferences of the pelagic wahoo, Acanthocybium solandri

The wahoo, Acanthocybium solandri, is a pelagic marine fish which inhabits tropical, subtropical, and warm temperate waters worldwide. Despite being highly mobile and economically important over most of their range, there is little scientific data concerning population structure, movement patterns, or environmental preferences of wahoo. In this study I investigate wahoo genetic population structure and phylogeography on a global scale, and deploy pop-up satellite archival tags (PSAT's) in the western Atlantic Ocean to determine movement patterns and environmental preferences of wahoo.; Wahoo population genetic structure was examined across their entire global range with intron six of lactate dehydrogenase-A (ldhA6, 10 locations, N = 213) and mtDNA cytochrome b (Cytb, 13 locations, N = 322). Results show extensive sharing of haplotypes and no significant structure between all locations (mtDNA &phis;ST < 0.0001, P = 0.634; nuclear FST = 0.0125, P = 0.106). Overall nuclear heterozygosity (H = 0.714) and mtDNA haplotype diversity (h = 0.918) are both high, while overall mtDNA nucleotide diversity (pi = 0.006) and nuclear nucleotide diversity (pi = 0.004) are uniformly low. Coalescence indicates an effective female population size (NeF) at ∼816,000, and a population bottleneck ∼690,000 years ago.; Movement patterns and environmental preferences were investigated by deploying PSAT's onto four individual wahoo in the western Atlantic Ocean. Tagging success rate (75%) validates the deployment protocol developed for this project. Results indicate that wahoo in the western Atlantic ocean spend the greatest portion of their time between 0 and 20 meters of depth, and between temperatures of 20°C and 26°C. More time was spent near the deeper extremes of their range during the nocturnal period, and daily visits to the surface were observed. Wahoo were observed traveling north in Fall and Winter, contrary to previous notions concerning the migratory movements of this species.; The genetic results indicate a worldwide stock for wahoo, which reinforces the mandate for international cooperation on fisheries issues. The PSAT results demonstrate the value of the acquired data to the investigation of important life history parameters in pelagic species. The information generated from this project will benefit fisheries managers, marine biologists, evolutionary biologists, and both commercial and recreational fishing interests.