An individual based larval dispersion model for the Hawaiian hawskbill sea turtle in the Hawaiian archipelago

The Hawaiian hawksbill sea turtle (Eretmochelys imbricata) is a critically endangered species, with an observed adult female population of approximately 6-20, nesting each year at known nesting sites on the big island of Hawaii. To create efficient management strategies for the survival of the species, a better understanding of habitat selection in the early stages of the hawksbill's life is needed. We investigate an individual-based, advection-diffusion, larval transport model, as it applies to the Hawaiian hawksbill population in the greater Hawaiian Archipelago. The model considers the release time and location, size, foraging behavior, and geographic location of the hawksbill hatchlings first three years of life, over a six year period of study, and how their habitat selection may be affected by the geostrophic currents, sea surface temperatures, and chlorophyll-a concentrations that they encounter. Results indicate that the inclusion of simple behavior rules significantly (p 0.01) increases retention, exposure to higher sea surface temperatures, and exposure to higher chlorophyll-a concentrations. Statistical analysis suggests a need to consider all three environmental parameters of the ocean surface currents, sea surface temperature, and chlorophyll-a concentration to better predict the resulting distribution of the individuals.