First record sexual maturity in wild farm released Caiman latirostris.

LARRIERA, A; SIROSKI, P.A.; PIÑA, C.

Gainsville, Florida, USA

Congreso; XVI Working meeting of Crocodile Specialist Group (CSG/SSC/UICN); 2002

Crocodile Specialist Group

Sexual maturity is one variable in population dynamics, and a useful data for recovering population programs such as Proyecto Yacare, however there is few works about age at sexual maturity in crocodilians. Available information about age of first reproduction in Caiman latirostris is scare, only two papers were recently published, but they refereed to captive animals in São Paulo, Brazil. Since 1990, Proyecto Yacare (Caiman Project), have been working recovering wild population in Santa Fe province, Argentina using Ranching technique. Following hatching, Caimans are marked in the caudal scutes (referring to hatching year and nest of origin). Hatchlings are raised in concrete pools until November, so animals are keep, at most, nine months in captivity, and then reintroduced in the same place where the eggs were collected. During summer 2001-2002, we have captured seven age known females at their nests with a snare. All seven females are part of the released stock of Caiman latirostris from Proyecto Yacare. Four females have constructed the nest in savanna habitat, the remaining in forest habitat. Once cough, females were measure to the nearest cm in total length (TL) and weighed with 0.1 kg precision scale (BM). Once in the laboratory, we weighed clutch andcalculated average egg mass (clutch weight / clutch size; precision 0.05 kg). In this study we tested iffemales Body mass (BM), Total length (TL), Clutch mass (CM), Clutch size (CS), and Egg mass (EM)were different among habitats. We also tested CS of the seven females and a subset (31 nests) from the total nests harvested in the season (N = 196). Of the seven females five were nine years old, the remaining were ten. Females in this study have the same BM, TL, CM, CS, and EM among habitats. CS of the seven age known females was similar to a subset of data from the same season of unknown age females. Female age at sexual maturity was the same previously reported, nine years for C. latirostris, but those animals were keep in captivity. In order to start breeding C. latirostris should be at least four years old, and weight at least 12.4 kg. This is the first report of wild reproductive female age of broad snouted caiman.