No abstract

mark associated with maturation were 90.5 for females (range 75.0-101.3) and 95.8 for males (range 80.6-103.8). Ages at maturation estimated from (1) the rapprochement skeletal growth mark; (2) back-calculated SCL-at-age data; and (3) bootstrapping and fitting Fabens modified von Bertalanffy growth curve to back-calculated growth data were very similar between approaches, but demonstrated a wide possible range. Mean age predictions associated with minimum and mean maturation SCLs were 22.5-25 and 36-38 years for females and 26-28 and 37-42 years for males. Post-maturation longevity (i.e., adult-stage duration) was similar for males and females, ranging from 4 to 46 years (mean 19 years).

Characterization of a population of green turtles inhabiting the northeastern Gulf of Mexico was made possible by the mortality of a subset of > 4500 sea turtles that stranded during a mass cold stunning event in Florida, USA, during January 2010. In total, 434 dead, stranded green turtles Chelonia mydas were evaluated through necropsy and skeletochronological analysis to characterize morphology, sex, body condition, disease status, age structure, and growth patterns. Standard straightline carapace lengths ranged from 18.1 to 78.5 cm (mean ± SD = 36.3 ± 10.4 cm) and did not significantly differ from those of stranded green turtles that survived this event. Prevalence of fibropapilloma (FP) was low, at 6%, and sex ratio was significantly biased toward females (2.45F:1M). Age estimates ranged from 2 to 22 yr (mean ± SD = 9 ± 4 yr) and female age distribution was significantly greater than that of males. Mean stage durations, as calculated through sum mation of size class-specific growth rates and fitting smoothing spline models to length-at-age data, were similar and ranged from 17 to 20 yr. Generalized additive models and generalized additive mixed models were used to assess the potential influence of discrete and continuous covariates on growth rates. Somatic growth was significantly influenced by size, age, and calendar year; however, no effect of sex, FP status, or body condition was found. Increased understanding of population parameters will improve population models for the species and can also serve as a reference for assessing potential effects of the 2010 Deepwater Horizon oil spill in the Gulf of Mexico. 458: 213-229, 2012 mation was recently emphasized in the aftermath of the April 20, 2010, Deepwater Horizon (DWH) MC-252 oil spill in the Gulf of Mexico during initiation of efforts to assess the effects to sea turtles of this catastrophic event (Bjorndal et al. 2011, Crowder & Heppell 2011. However, collection of these data is made difficult by deficiencies in the ability to assess sea turtle populations in an unbiased manner (Heppell et al. 2003). Population characterizations based on nesting beach studies, while prevalent due to the relative accessibility of the females on the beach, are necessarily focused in their scope (NRC 2010). In-water studies are often restricted to limited geographic areas (Bjorndal & Bolten 2000) and the proportion of individuals available to be sampled can be influenced by stage-and population-specific partitioning of habitat use (Musick & Limpus 1997, Plotkin 2003 and sex-specific behavior (Wibbels 2003). In addition, the time frames over which data collection must occur to adequately assess population parameters for these generally slow-to-mature, long-lived species are daunting (Heppell et al. 2003). OPEN PEN ACCESS CCESSMar Ecol Prog SerLife history data obtained from dead, stranded sea turtles can be informative, but often need to be interpreted with caution given the general lack of information regarding cause of death (natural vs. anthropogenic) (NRC 2...