title: Female-Bias in a Long-Term Study of a Species with Temperature-Dependent Sex Determination: Monitoring Sex Ratios for Climate Change Research.
abstract: Alterations have occurred and continue to manifest in the Earth's biota as a result of climate change. Animals exhibiting temperature dependent sex determination (TSD), including sea turtles, are perhaps most vulnerable to a warming of the Earth as highly skewed sex ratios can result, potentially leading to population extinction resulting from decreased male recruitment. Recent studies have begun to quantify climate change impacts to sea turtle populations, especially in terms of predicting effects on hatchling sex ratios. However, given the inherent difficulty in studying sex ratios at this life stage, a more accurate assessment of changes in population sex ratios might be derived by evaluating the juvenile portion of foraging aggregations. We investigated the long-term trend in sex ratio of a juvenile loggerhead (Caretta caretta) sea turtle population inhabiting Pamlico and Core Sounds, North Carolina, USA. We used plasma testosterone reference ranges measured using radioimmunoassay (RIA) to assign sex for 959 turtles and confirmed sex assignment of a subset (N = 58) of the sampled turtles through laparoscopic examination of their gonads. Our results demonstrate that for this particular population of loggerheads, sex ratios (3Females:1Male) had not significantly changed over a 10 year period (1998-2007), nor showed any significant difference among 5-cm straight carapace length (SCL) size classes. Ultimately, these findings provide a basis for comparison with future sex ratios, and highlight the importance of establishing similar long-term studies monitoring secondary, rather than primary, sex ratios, so that needed mitigation measures to climate change impacts can be implemented.
authors: Southeast Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Beaufort, North Carolina, United States of America.
authors: Joanne
authors: J
authors: Braun McNeill
authors: Southeast Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Beaufort, North Carolina, United States of America.
authors: Larisa
authors: L
authors: Avens
authors: Southeast Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Beaufort, North Carolina, United States of America.
authors: April
authors: A
authors: Goodman Hall
authors: Southeast Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Beaufort, North Carolina, United States of America.
authors: Lisa R
authors: LR
authors: Goshe
authors: Center for Marine Sciences and Technology, College of Veterinary Medicine, North Carolina State University, Morehead City, North Carolina, United States of America.
authors: Craig A
authors: CA
authors: Harms
authors: University of Charleston, South Carolina at the College of Charleston, Charleston, South Carolina, United States of America.
authors: David W
authors: DW
authors: Owens
mesh_terms: D000818:Animals; D005260:Female; D057232:Global Warming; D008297:Male; D009657:North Carolina; D019849:Sex Determination Processes; D012744:Sex Ratio; D014426:Turtles