Effects of Low Oxygen Concentration on Development and Survivorship of Caiman latirostris : Preliminary Results

IUNGMAN, J.; PIÑA, C.I.

Montélimar, France

Congreso; 18th Working Meeting of the IUCN-SSC Crocodile Specialist Group; 2006

Grupo de Especialistas en Cocodrilos (CSG/UICN/SSC)

Ambient conditions during incubation affect development and survivorship of reptilian embryos. In crocodilians, incubation temperature has a profound effect on incubation period, development rate and hutching success. It has been suggested that sex determination is more related to embryonic development rate than incubation temperature per se. Yet little is known about the effect of the gaseous enviromnent on these parameters. Here we evaluated the effect of hypoxia on Caiman latirostris embryos. We incubated 53 C. Iatirostris eggs at either of two temperature treatments (31°C and 33°C producing 100% females and 100% males, respectively) and two O2 concentrations (10% and 21%), in a factorial design. To evaluate differences in development among treatments we opened eggs on days 28 and 42 of incubation (beginning and the end of the thermosensitive period). Incubation under hypoxia tended to reduce embryonic grow rates and survivorship and increase the incubation period. No hatchlings were produced at 33ºC with low O2 treatment, and hatching success at 31°C with low O2 concentration was reduced relative to that at normal O2 levels.