Effective species conservation and management relies on a comprehensive understanding of a species’ population dynamics and the factors that influence demographic parameters. This is well illustrated by the endangered Kemp’s ridley sea turtle (Lepidochelys kempii), a species brought back from the brink of extinction that recently experienced a dramatic reduction in population growth rate that put the species’ recovery in question. Many factors are thought to have contributed to this reduction, but data gaps have stymied efforts to establish causal links. The primary goal of this project is to disentangle some of the factors that influence Kemp’s ridley sea turtle somatic growth rates and population dynamics.

To achieve these goals, we will employ complementary skeletal (skeletochronology) and biogeochemical analyses performed on the humerus bones of stranded sea turtles.  Such analyses will yield information on annual size, age, growth, diet, and habitat use throughout a turtles’ life lifetime, and over the past two decades. These data will be combined with population density estimates generated using hatchling production data and an existing population model to investigate relationships among diet composition, habitat use, population density, and somatic growth. Ultimately, these data will be incorporated into an updated population model to examine the influence of multiple factors on species population growth and recovery. The results of this study will help inform species conservation and management.


Project Members:

Matthew Ramirez, Department of Fisheries and Wildlife, Oregon State University

Selina S. Heppell, Department of Fisheries and Wildlife, Oregon State University

Larisa Avens, NOAA-NMFS

Lisa Goshe, NOAA-NMFS


Funding Source:

National Science Foundation Graduate Research Fellowship Program