Survival and breeding interval of an endangered marine vertebrate, the leatherback turtle Dermochelys coriacea, in French Guiana

Abstract

In the context of global change, endangered species such as sea turtles undergo strong population dynamics changes. Understanding demographic processes inducing such changes is critical for developing appropriate measures for conservation and management. Nesting females of the French Guiana population of leatherback sea turtles Dermochelys coriacea represented 40% of the world’s total in 2001; today, they represent only 10%. Here, we analyze data from the long-term monitoring program of leatherbacks in French Guiana, based on 28 yr of capture-mark-recapture data from 46051 individuals in northwestern French Guiana. We used multievent models (multistate capture-recapture models with state uncertainty) to represent the main peculiarity of the life cycle, intermittent reproduction, and to take advantage of the use of several different types of marks to account for mark loss and incomplete detection. The average annual adult survival probability (mean ± SE) 0.789 ± 0.009 is low compared to published estimates for this species. By combining the estimates of departure and return probabilities, we provide an estimate of the interval among laying seasons equal to 2.777 ± 0.118 yr, which matches previous findings. Taking survival into account, this interval translates into an average of 1.704 ± 0.034 further reproductive seasons for an adult female having just bred, which is remarkably low compared to other long-lived vertebrates. The representation of the life cycle and mark loss in our models provides a sound structure for broader and richer analyses to extract biological information from marked individuals and offers an invaluable source of demographic information on leatherbacks, a species for which only a small segment of the population is accessible to intermittent sampling.

High fidelity of sea turtles to their foraging grounds revealed by satellite tracking and capture-mark-recapture: New insights for the establishment of key marine conservation areas

“…The literature remains scarce about foraging aggregations of immature green turtles in the Lesser Antilles, despite occurrences of such individuals around these islands (Chevalier, 2006;Meylan, 1983). In Martinique, Chambault et al (2018) evidenced the presence of immatures originating from different rookeries, among which some individuals departed in migration when approaching sexual maturity.…”

Maturity of a giant: age and size reaction norm for sexual maturity for Atlantic leatherback turtles

“…The demographic strategy of this species—and marine turtles in general—does not fit the r‐K continuum (Pianka, 1970). The longevity of adult female leatherbacks is potentially more than 10 years (Chevallier, Girondot, et al., 2020), which is typical of K‐selection. A female produces around 500 eggs during a nesting season (Briane et al., 2007; Caut et al., 2006), and it can nest during as many as 10 nesting seasons, thus producing around 5,000 eggs during its reproductive lifetime..…”

“…Our result is of primary importance for the conservation of leatherbacks. Several populations of which appear to be on the brink of extinction in different part of the world include the Pacific coast (Spotila et al., 2000) or in West French Guiana where 95% of population has disappeared in 20 years (Chevallier, Girondot, et al., 2020). Extinction risk is inversely associated with maximum per capita population growth rate ( r max ) (Mace et al., 2008).…”

Movements of green turtles from foraging areas of the United Arab Emirates: regional habitat connectivity and use of marine protected areas

“…Not all turtles breed every year (Hepell et al 2003), and the proportion of sea turtles at a nesting site is determined via the proportion of turtles undergoing vitellogenesis and spermatogenesis on the foraging areas in the months prior to nesting, which is governed by ambient conditions (Limpus and Nicholls 1988;Solow et al 2002;Saba et al 2007) and food availability (Chaloupka and Limpus 2001;Alerstam et al 2003) in the years preceding nesting. Predicting breeder abundance at a nesting site can help maximise monitoring efficiency and plan for efficient resource deployment (e.g., Saba et al 2007;Chevallier et al 2020). These predictions require long-term capture-mark-recapture records and extensive modelling of nesting beach data (and this is only possible for female turtles), or identification of breeding condition of sea turtles in foraging areas prior to the nesting season, such as that derived from laparoscopy.…”