Evaluation of Reproductive Success of the Olive Ridley Turtle Lepidochelys olivacea (Testudinata: Cheloniidae) Using Different Incubation Treatments

Abstract: In nesting areas with extreme climatic conditions, such as high temperatures, it is advisable to use mitigation strategies that counteract these negative effects on the hatching success of sea turtle nests. We evaluated the effect of incubation treatment on hatching success and incubation period for olive ridley turtles Lepidochelys olivacea during the 2019 nesting season in Guerrero, Mexico. Three incubation treatments (T1 = shade & freshwater irrigation; T2 = shade, seawater pre-irrigation, sand covered & freshwater irrigated; T3 = shade, seawater pre-irrigation, covered with a plastic lid & freshwater irrigated) were trialed at two different times during the nesting season. One of our goals was to compare the reproductive success of hatchery nests versus in situ nests, however, in situ nests hatching success was zero. We found that treatments had no effect on hatching success or incubation period, but there were differences in proportions of dead and crushed hatchlings. Clutches incubated in the second relocation period had longer incubation times. However, nest relocation periods had no effect on hatching success, dead hatchlings, or the proportion of crushed hatchlings. Our results also showed that the amount of seawater applied to the holes and the rate of irrigation were not lethal for the incubating eggs, but prolonged the incubation period. These results could help to increase our understanding of sea turtle reproductive success and may serve as a baseline to adapt the spatio-temporal conditions of the hatcheries in other areas with similar environmental conditions.