Structure of the Loggerhead Turtle Assemblage in Okinawan Waters Estimated from Variation in Body Size and Blood Profile

Kawazu, Isao; Maeda, Konomi; Kino, Masakatsu; Oka, Shin-ichiro

doi:10.5358/hsj.32.190

Cited by 7 publications

(1 citation statement)

References 12 publications

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“…Therefore, body size may not be an effective indicator of sexual maturation in hawksbill turtles. In such cases, additional ultrasonography [Rostal et al, ], histology [Moncada et al, ; Pérez et al, ], and physiology [Kawazu et al, ] approaches will help with maturity determination in wild sea turtles.…”

Section: Discussionmentioning

confidence: 99%

Age and body size of captive hawksbill turtles at the onset of follicular development

et al. 2014

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The aim of this study was to record the age and body size of 23 captive female hawksbill turtles at the onset of follicular development. The age, straight carapace length (SCL), and body mass (BM) of the turtles were recorded between 2006 and 2014 at follicular development (determined via ultrasonography) these parameters were 17.7 ± 1.7 years (range: 13-20 years), 77.7 ± 3.3 cm (73.3-83.5 cm), and 61.1 ± 8.0 kg (48.2-76.1 kg), respectively. When the year of the onset of follicular development was designated year 0, the increase in SCL in years -7-0 and 0-3 averaged 2.2 cm and 1.0 cm, respectively. Correspondingly, the increase in BM in years -7-0 and 0-3 averaged 5.0 kg and 2.2 kg, respectively. This is the first study to report the age and body size of captive female hawksbill turtles at the onset of follicular development, which indicates the beginning of sexual maturation. The reduction in growth after follicular development suggests that at the onset of sexual maturation, female hawksbills may utilize energy for follicular development rather than growth.

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Section: Discussionmentioning

confidence: 99%

Age and body size of captive hawksbill turtles at the onset of follicular development

et al. 2014

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Signals of Vitellogenesis and Estrus in Female Hawksbill Turtles

et al. 2015

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This study reports a viable means of identifying the vitellogenic cycle and limited estrus period in hawksbill turtles for the purposes of developing captive breeding program, based on the combination of blood metabolite parameters (triglyceride, total protein, and calcium levels), feeding status, and ovary condition. Follicle size of two focal captive females showed clear seasonal changes, with major development occurring between March and May (19.0-24.4 mm), and exceeding 25 mm between June and September. Triglyceride, total protein, and calcium levels dropped with follicular development and maintenance (March to October), and then began to rise when follicular retraction occurred from October onwards. The two focal turtles reduced food intake during intensive follicular development (April to May). These findings suggest that blood metabolite parameters and feeding conditions are inferred by the vitellogenic cycle. An additional 10 females exhibiting follicular development were mated with a single male for 7-day period between May and June. Follicle size was measured immediately prior to pairing, and a statistically significant difference in follicle size of 10 females was recorded between the seven failed (20.9 mm) and three successful (23.6 mm) mating events. This indicates follicle development is essential to successful mate and monitoring of vitellogenic cycle may help improve the success rates of captive hawksbill breeding programs.

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Metabolic and Hormonal Changes Associated with Vitellogenesis in Salvator merianae Lizards

et al. 2021

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Structure of the Loggerhead Turtle Assemblage in Okinawan Waters Estimated from Variation in Body Size and Blood Profile

Cited by 7 publications

References 12 publications

Age and body size of captive hawksbill turtles at the onset of follicular development

Age and body size of captive hawksbill turtles at the onset of follicular development

Signals of Vitellogenesis and Estrus in Female Hawksbill Turtles

Metabolic and Hormonal Changes Associated with Vitellogenesis in Salvator merianae Lizards

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