Biology and Conservation of Aquatic Turtles
in the Cinaruco-Capanaparo National Park, Venezuela
JOHN B. THORBJARNARSON,1 NAYIBE PÉREZ,2 and TIBISAY ESCALONA 3
1 Wildlife Conservation Society, 185th St. and Southern Blvd., Bronx, NY 10460, USA / e-mail: email@example.com
2 INPARQUES, San Fernando de Apure, Apure, Venezuela
3 Pro Vita Animalium, Apdo. 47552, Caracas 1041-A, Venezuela
ABSTRACT: As in many parts of South America, turtles in the llanos region of Venezuela are widely hunted for subsistence and commercial purposes. The Capanaparo River, much of which is situated within the recently declared Capanaparo-Cinaruco National Park, has populations of Podocnemis expansa, P. unifilis, P. vogli, and Chelus fimbriatus. During the annual dry season, eggs of all three of the Podocnemis are widely consumed. Yaruro Indians also hunt adults and subadults of these species, principally using drop lines baited with plantain. Some turtles are consumed by the Indians, but the majority are sold or bartered for other food or for alcohol. Anecdotal information suggests that populations have declined significantly during the lifetimes of the Yaruros who presently hunt them.
Local populations of P. expansa are apparently quite small. Isolated females nest on the riverbanks in March, coincidental with the lowest annual water levels, and the eggs hatch in May as the river rises. P. vogli is principally a savanna pond species, but occasionally individuals are found in the river. The most abundant turtle is P. unifilis, locally called terecay. P. unifilis nests in the early dry season (late Januaryearly February) as the river level is falling, and the eggs hatch in April. In 19911992 mean clutch size was 23.3 and average egg mass was 26.5 g. Incubation time averaged 62.8 days in simulated nests. Nest predation rates were quite high, with the principal predators being the Yaruro people, Tupinambis lizards, and crested caracaras (Polyborus plancus).
From a sample of 188 P. unifilis captured by the Yaruro, mean female maximum plastron length was 30.9 cm and mean male maximum plastron length was 22.9 cm. A conservation program is currently being designed in collaboration with the Venezuelan national parks department (INPARQUES) to restrict the commercialization of turtles. The program may also involve a trial headstarting project.