Marine Science

Marine Science

Senior Theses 2003

Andrea K. Horntvedt (2003). Genetic differences between western Atlantic and eastern Pacific populations of the yellowtailed leatherjack, Oligoplites saurus
Faculty advisor: William Szelistowski


Oligoplites saurus, the yellow tailed leather jack, is one of few coastal marine bony fishes distributed both in the Western Atlantic and Eastern Pacific Oceans. The population genetic structure of this species is therefore particularly interesting. To determine the genetic differences between the Atlantic O. saurus saurus and Pacific 0. saurus inornatus, DNA sequencing and RFLP analysis of a portion of the 16s rRNA gene were used. Specimens were collected from three sites in the Western Atlantic (Caribbean, Gulf of Mexico and Atlantic), and one site from the Eastern Pacific. Results indicated no consistent base pair mutations among samples from the three Atlantic sites, and 10 bp mutations between Atlantic and Pacific samples, including 3 transversions and 7 transitions. Using a mitochondrial rRNA molecular clock rate of 0.14% transversion changes per million years, the age of separation is estimated at 7.44 MYA. This is compared to the geminate species pair Trachinotus kennedyi and T falcatus that only had 1 transversion and 6 transitions, and estimated to have diverged 2.58 MYA. The mutational differences and the predictions of the molecular clock support the hypothesis that Atlantic and Pacific populations of Oligoplites were separated at or before the rise of the Isthmus of Panama approximately 3.1-3.5 MYA. These results also suggest that the two populations should be considered separate species.

Student Research

Given the close proximity to the Gulf of Mexico and subtropical climate, the Tampa Bay region has a high concentration of marine research and academic institutions. Because of many local connections in the Tampa Bay area, a large number of opportunities are available to our students through government and private marine agencies and laboratories, public aquaria, marine conservation institutions, environmental consulting firms, and commercial aquaculture firms.

$1Mil Renovation Project

GMSL patio

The National Science Foundation awarded Eckerd College $870,720 to renovate research spaces within the Galbraith Marine Science Laboratory during the summer of 2011. Eckerd contributions to the project bring the total renovation budget to over $1 million. Learn more.