Age-specific growth and maturity estimates for the flatback sea turtle (Natator depressus) by skeletochronology.

Autor: Turner Tomaszewicz CN; NOAA Southwest Fisheries Science Center, La Jolla, CA, United States of America.; The Ocean Foundation, Washington, D.C., United States of America., Avens L; NOAA Southeast Fisheries Science Center, Beaufort, NC, United States of America., Seminoff JA; NOAA Southwest Fisheries Science Center, La Jolla, CA, United States of America., Limpus CJ; Department of Environment and Science, Brisbane, QLD, Australia., FitzSimmons NN; Department of Environment and Science, Brisbane, QLD, Australia., Guinea ML; Charles Darwin University, Casuarina, NT, Australia., Pendoley KL; Pendoley Environmental, Booragoon, WA, Australia., Whittock PA; Pendoley Environmental, Booragoon, WA, Australia., Vitenbergs A; Pendoley Environmental, Booragoon, WA, Australia., Whiting SD; Western Australia Department of Biodiversity, Conservation and Attractions, Perth, WA, Australia., Tucker AD; Western Australia Department of Biodiversity, Conservation and Attractions, Perth, WA, Australia.
Jazyk: angličtina
Zdroj: PloS one [PLoS One] 2022 Jul 20; Vol. 17 (7), pp. e0271048. Date of Electronic Publication: 2022 Jul 20 (Print Publication: 2022).
DOI: 10.1371/journal.pone.0271048
Abstrakt: To address a major knowledge gap for flatback sea turtles (Natator depressus), a species endemic to Australia and considered 'Data Deficient' for IUCN Red List assessment, we present the first-ever skeletochronology-derived age and growth rate estimates for this species. Using a rare collection of bone samples gathered from across northern Australia, we applied skeletochronology and characterized the length-at-age relationship, established baseline growth rates from the hatchling to adult life stages, and produced empirical estimates of age-at- and size-at-sexual-maturation (ASM, SSM). We analyzed humeri from 74 flatback sea turtles ranging in body size from 6.0-96.0 cm curved carapace length (CCL), and recovered from Western Australia (n = 48), Eastern Australia (n = 13), central Australia (n = 8; Northern Territory n = 3, the Gulf of Carpentaria n = 5), and unknown locations (n = 5). We identified the onset of sexual maturity for 29 turtles, based on rapprochement growth patterns in the bones. Estimates for ASM ranged from 12.0 to 23.0 years (mean: 16.3 ± 0.53 SE), SSM ranged from 76.1 to 94.0 cm CCL (mean: 84.9 ± 0.90 SE), and maximum observed reproductive longevity was 31 years for a 45-year old male flatback. Growth was modeled as a smoothing spline fit to the size-at-age relationship and at the mean SSM (84.9 cm CCL) corresponded with a spline-predicted maturity age of 18 years (95% CI: 16 to 24), while mean nesting sizes reported in the literature (86.4 to 94 cm CCL) corresponded to estimated ages of 24+ years. A bootstrapped von Bertalanffy growth model was also applied and showed consistencies with the spline curve, yielding an estimated upper size limit, Linf, at 89.2 ± 0.04 cm (95% CI: 85.5 to 95.9 cm) with the intrinsic growth rate parameter, k, at 0.185 ± 0.0004 (0.16 to 0.22); at the same mean SSM (84.9 cm CCL) the estimated ASM was 16.3 ± 0.05 years (95% CI: 12.8 to 27.7 years). Lastly, four of the samples analyzed were collected from deceased adult females that had previous sizes known from on-going mark/recapture studies at nesting sites in Western Australia. The paired CCL data (measured at nesting and back-calculated) did not significantly differ (p = 0.875). This first skeletochronology study for flatback sea turtles generates valuable empirical estimates for ongoing conservation and management efforts.
Competing Interests: The authors have declared that no competing interests exist.
Databáze: MEDLINE
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