Horizon Regime and Light Intensity Affect Sea-finding Orientation in Hatchling Kemp’s Ridley (Lepidochelys kempii) Sea Turtles


Meeting Abstract

65-2  Tuesday, Jan. 5 13:45  Horizon Regime and Light Intensity Affect Sea-finding Orientation in Hatchling Kemp’s Ridley (Lepidochelys kempii) Sea Turtles BONKA, AN*; HERNANDEZ, MH; ILLESCAS, FM; NAJERA, BM; MARTINEZ, LS; PENA, LJ; BURCHFIELD, PM; WIBBELS, TR; Univ. of Alabama at Birmingham; Gladys Porter Zoo, Brownsville TX; CDEN, Tamaulipas, Mexico; CONANP Ciudad Victoria, Mexico; CONANP Mexico City, Mexico; Gladys Porter Zoo, Brownsville TX; Gladys Porter Zoo, Brownsville TX; Univ. of Alabama at Birmingham abonka@uab.edu

Sea-finding orientation in hatchling sea turtles represents a critical early life history event. The behavioral and physiological basis of this event has significant implications for the ecology, evolution, and conservation of sea turtles. In the current study, sea-finding orientation of hatchling Kemp’s ridley (Lepidochelys kempii) sea turtles was investigated under two different naturally occurring horizon regimes (distinctive landward and open silhouettes) and under varying light intensity (5am, 6am, 7am). Hatchlings were monitored using time-lapse wildlife cameras and photos were reviewed immediately following trials. Results indicated sun position and horizon silhouettes represent major orientation cues affecting hatchling orientation. The results also provide insight for optimizing conservation strategies for programs that relocate nests. Nests relocated to areas with distinctly contrasting silhouettes between the landward and seaward direction reduces the amount of time hatchlings spend exposed to predators and/or desiccation on the beach during sea-finding. Finally, the results suggest that beach characteristics that enhance the efficiency of sea finding could represent a selective evolutionary pressure that contributes to the selection of optimal nesting beaches by sea turtles.

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