Program: National Marine Fisheries Service – Sea Grant Joint Graduate Fellowship Program in Population Dynamics


Susan (Hilber) Piacenza was awarded three years of fellowship support with a National Marine Fisheries Service (NMFS) Sea Grant Joint Graduate Fellowship Program in Population Dynamics.

Fellows work with NMFS personnel on their dissertation projects and meet annually as a group to present research results. Susie's advisor is Selina Heppell, and she is working with mentors at Southeast Fisheries Science Center, Southeast Turtle Program in Miami (Paul Richards), and Pacific Island Fisheries, Marine Turtle Research Group in Honolulu (George Balazs).

For more information on the fellowship, visit the NOAA Sea Grant website.

Professional and Research Interests:

For her PhD research, Susie will study the dynamics of two population of the green sea turtle, Chelonia mydas. The green sea turtle is considered endangered in Florida and Mexico, and threatened elsewhere in US waters under the US Endangered Species Act (NOAA Fisheries). However, the species is showing signs of recovery in some parts of its range. Not only is this good news for green sea turtles, but it also represents an invaluable opportunity to study what happens to a large vertebrate population as it recovers after serious population decline.

This positive population growth of both the Hawaiian and Floridian populations of C. mydas is inferred from nesting beach surveys alone. Susie will examine long-term data sets to identify time-varying life-history traits that can improve the accuracy of population estimates and trends. Combining nesting data and in-water surveys may enhance the accuracy and reliability of population estimates. Examining how key life-history traits have changed as the population grows will provide useful information to biologists and managers seeking to understand how populations change over time and as a population recovers from severe depletion.

Finally, if these populations are indeed recovering, the public may push for changes in the conservation and management of this species. Therefore it will be of paramount importance to provide the best scientific information about how the population is likely to respond to a suite of potential management procedures using the simulation-based framework of the MSE.