Modeling transport and feeding of juvenile Kemp's ridley sea turtles on the West Florida shelf

Abstract

Survivorship during the juvenile oceanic phase likely acts as a bottleneck on the growth of sea turtle populations, and starvation mortality through this period is one potential factor influencing year class strength. We combined a simulation of juvenile Kemp's ridley (Lepidochelys kempii) sea turtle dispersal based on an ocean circulation model with an Atlantis ecosystem model to examine the spatial overlap of young sea turtles with their prey resources. We were particularly interested in whether ocean currents facilitated the movement of juveniles from western Gulf nesting beaches to areas in the eastern Gulf along the West Florida Shelf (WFS) with adequate food availability. We found that strong frontal gradients on the WFS may increase the potential for juveniles to remain offshore in areas of high per capita prey availability, allowing for more feeding opportunities during critical early life stages. Additionally, we found that multiple climatological indices are related to Gulf-wide patterns of juvenile dispersal, potentially via effects on the Loop Current. Findings from this study hold implications for continued population viability of protected sea turtle populations in the Gulf of Mexico, as well as other species with early life stages that disperse via ocean currents such as commercially important fishes.