Vásquez-Bultrón, O. S., D. E. Moreno-Espinoza, L. T. Hernández-Salazar & J. E. Morales-Mávil

Rapid stress response in post-nesting Kemp’s ridley turtle (Lepidochelys kempii). pp. 146-150

Abstract. Vertebrate’s stress response plays a significant role in helping individuals adapt to changing environments. One of the most challenging stages in female turtles’ life cycle is during oviposition, especially when the turtles’ nest during the daytime and have to face massive nesting events (arribadas), limited space on the beach, and high temperatures. The Kemp’s ridley sea turtle (Lepidochelys kempii) is the smallest sea turtle, which has to withstand high temperatures during the nesting process due to its diurnal habits. Our objective was to determine corticosterone concentration as a response to induced stress and estimate its variations at the beginning, middle, and end of the nesting season. We measured the corticosterone concentration in serial blood samples (0, 20, 40, and 60 min.) in 22 Kemp’s ridley sea turtles during the beginning, the middle, and the end of the nesting season. Our results show that the turtles had a significant increase in corticosterone levels at 20 min. after the onset of stress, and we found that corticosterone decreased at the end of the nesting season. The results point to a rapid response of the hypothalamic–pituitary-adrenal axis. We suggest that glucocorticoid levels return to baseline at the end of the breeding season, and modulation may allow successful completion of nesting throughout the entire seasonal nesting period.

Key words. Testudines, Cheloniidae, Carettinae, Corticosterone, Gulf of Mexico, nesting, sea turtles, stress protocol.