Age determination of loggerhead sea turtles, Caretta caretta, by incremental growth marks in the skeleton

Impact of exceptional growth rates on estimations of life-stage duration in Hawaiian green sea turtles

“…For each method, the mean difference between observed and expected time to grow was significantly different for turtles with and without growth spurts p < 0.005) require an understanding of the relationship between humerus diameters and carapace length across the population's ontogeny, which necessitates an adequate sample size of paired humeri and carapace lengths from hatchling to adult. Another key drawback of skeletochronology is the loss of early growth marks due to bone resorption (Zug et al 1986). Statistical models have been developed to estimate the number of growth marks lost in resorption cores in order to assign age to individual turtles (Parham & Zug 1998, Zug et al 2002.…”

“…Procedures detailed in Zug et al (1986) and Snover & Hohn (2004) were used in processing the 99 humeri ( Table 1). The humeri were frozen, thawed, flensed, boiled, and dried.…”

Foraging dichotomy in loggerhead sea turtles Caretta caretta off northwestern Africa

“…Skeletochronology has been successfully used in several species of sea turtles, where LAGs on bones can be visualized as concentric layers of deposited calcium carbonate in transverse sections (Zug et al 1986, Bjorndal et al 1998, Snover & Hohn 2004, Avens & Goshe 2007, Piovano et al 2011. A section of bone approximately 3 to 5 mm thick was cut from the narrowest part of the diaphysis of the humerus, where the greatest number of periostal growth layers is expected to be retained (Zug et al 1986). The bone sections were stored in 70% alcohol for 36 h and then decalcified in 5% nitric acid for a minimum of 96 h (the maximum duration was variable depending on the diameter of the section and the structure of the bone).…”

Age and growth of loggerhead sea turtles in southern Brazil

“…soaked in water for 2 to 3 wk until the soft tissue was removed, and the bones were then air-dried for ~2 wk . After cleaning the bone, 7 morphometric measurements were recorded by using digital calipers (± 0.1mm): (1) maximal length, (2) longitudinal length, (3) proximal width, (4) delto-pectoral process width, (5) medial width, (6) distal width, (7) thickness, and (8) weight (Zug et al 1986). The histological method used to prepare humerus sections used for skeletochronological analysis was based on Avens & Goshe (2007).…”

“…In contrast, skeletochronological studies have been validated and applied to Caretta caretta (Zug et al 1986, Klinger & Musick 1992, Parham & Zug 1997, Snover & Hohn 2004, Casale et al 2011a, allowing estimation of age from growth increments formed in the humerus bone (Parham & Zug 1997). This approach allows for understanding some age-based parameters, similar to mark−recapture; however, the skeletochronological method has the potential to yield results more rapidly.…”