Life History and Demographic Characteristics of the Magdalena River Turtle (Podocnemis lewyana): Implications for Management

Abstract

We conducted a four-year study of the life history parameters of the endangered freshwater turtle Podocnemis lewyana (Testudines: Podocnemididae) in four channels connecting wetlands to the Magdalena River in northern Colombia. Using capture–mark–recapture techniques, we documented body size growth rates, sex ratios, and size class distributions, and estimated survival rates for juveniles and adults. We also used body size/clutch size and body size/track width correlations to estimate the body sizes of females that nested in beaches in the Magdalena River near the study sites. The body size at first nesting (30 cm straight-line carapace length) was comparable to the estimate obtained by inspecting the reproductive tracts of 70 females using a sonograph. Growth rate analyses showed adult males to be smaller than adult females with an estimated size at sexual maturity of 20 cm straight-line carapace length. Females begin nesting at 5–6 years of age and may lay up to four clutches annually with a mean clutch...