Variation in age and size at sexual maturity in Kemp’s ridley sea turtles

Abstract

ESR Endangered Species Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials ESR 25:57-67 (2014) - DOI: https://doi.org/10.3354/esr00608 Variation in age and size at sexual maturity in Kemp’s ridley sea turtles Karen A. Bjorndal1,*, Joe Parsons2, Walter Mustin2, Alan B. Bolten1 1Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, Box 118525, Gainesville, FL 32611, USA 2Cayman Turtle Farm, Grand Cayman KY1-1301, Cayman Islands *Corresponding author: bjorndal@ufl.edu ABSTRACT: Age at sexual maturity (AgeSM) is one of the most serious demographic data gaps for sea turtle populations. Better estimates of AgeSM and associated variance would improve evaluation of population dynamics and responses of populations to disturbances and conservation measures. A population of Kemp’s ridleys Lepidochelys kempii was raised in captivity under the same conditions from hatchlings to several years after maturity. Data collected from 14 female Kemp’s ridleys at Cayman Turtle Farm over a 16 yr period allowed us to determine mean and variance in age, length, mass, and body condition at maturity, average pre-maturity growth rates, and post-maturity growth rates, as well as interactions among these parameters. Age, length, and mass at maturity exhibited considerable variance, with ranges of 5 to 12 yr, 47.0 to 61.0 cm, and 20.0 to 36.8 kg, respectively. Pre-maturity length growth rate is the best single predictor of AgeSM, accounting for 87% of the variation in AgeSM. Pre-maturity mass growth rate is the best single predictor of size at maturity, accounting for 51 and 65% of variation in length at maturity and mass at maturity, respectively. Although estimates of age and size at maturity from captive Kemp’s ridleys cannot be applied to wild populations because of the effect of nutrition, the amount of variation around age and size at maturity in Kemp’s ridleys from Cayman Turtle Farm is a good first approximation of inherent (or genetic) variation in these parameters for wild Kemp’s ridleys. Population models for Kemp’s ridleys that now employ a knife-edge estimate of AgeSM would be improved by incorporating a maturity schedule that reflects the variation in AgeSM. KEY WORDS: Age at sexual maturity · Size at sexual maturity · Indeterminate growth · Lepidochelys kempii · Sea turtle Full text in pdf format PreviousNextCite this article as: Bjorndal KA, Parsons J, Mustin W, Bolten AB (2014) Variation in age and size at sexual maturity in Kemp’s ridley sea turtles. Endang Species Res 25:57-67. https://doi.org/10.3354/esr00608 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in ESR Vol. 25, No. 1. Online publication date: July 31, 2014 Print ISSN: 1863-5407; Online ISSN: 1613-4796 Copyright © 2014 Inter-Research.