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Interactions among endocrinology, seasonal reproductive cycles and the nesting biology of the female green sea turtle

Hamann, M, Jessop, TS, Limpus, CJ and Whittier, JM (2002). Interactions among endocrinology, seasonal reproductive cycles and the nesting biology of the female green sea turtle. Marine Biology,140(4):823-830.

Document type: Journal Article
Citation counts: Scopus Citation Count Cited 13 times in Scopus Article | Citations

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Title Interactions among endocrinology, seasonal reproductive cycles and the nesting biology of the female green sea turtle
Author Hamann, M
Jessop, TS
Limpus, CJ
Whittier, JM
Journal Name Marine Biology
Publication Date 2002
Volume Number 140
Issue Number 4
ISSN 0025-3162   (check CDU catalogue open catalogue search in new window)
Scopus ID 2-s2.0-0036934684
Start Page 823
End Page 830
Total Pages 8
Place of Publication Berlin
Publisher Springer
HERDC Category C1 - Journal Article (DEST)
Abstract We collected data on plasma levels of testosterone+5a-dihydrotestosterone (T+DHT) and corticosterone (CORT) from adult female green sea turtles (Chelonia mydas) from southern Queensland during distinct stages of their reproductive cycle. Those females capable of breeding in a given year had elevated plasma steroid levels (T+DHT 0.91 +/- 0.08; CORT 1.05 +/- 0.29 ng/ml), associated with follicular development, until courtship began in October. At the beginning of the nesting season in November plasma levels of 2 CORT were related to when the female first nested (r(2) = 0.06; F = 10.45; P = 0.01). However, they were not correlated with the number of clutches a female laid in that season (F = 3.65; P = 0.08). We repeatedly sampled 23 turtles over the nesting season and profiled changes in steroids immediately following oviposition of each clutch. Levels of T+DHT (range 0.41-0.58 ng/ml) and CORT (range 2.13-2.81 ng/ml) were similar through the early stages of the nesting season and inter-nesting period, and declined to near basal levels (T+DHT 0.37 +/- 0.03 and CORT 1.85 +/- ng/ml) following the last clutch for the season. Steroid hormone levels were also low (T+DHT 0.38 +/- 0.16; CORT 0.46 +/- 0.21 ng/ml) in four independent post-breeding (atretic) females; samples for these females were taken at a time when body condition was presumably at the lowest for the season. Subtle changes in the nesting environment, such as variation in nesting habitat or the time of night that nesting occurred, were associated with a small and slow CORT increase. We suggest CORT is increased in nesting females to assist in lipid transfer to prepare the ovarian follicles and/or the reproductive organs for ovulation.
Keywords chelonia-mydas
stress-response
caretta-caretta
marine turtles
corticosterone
physiology
migration
behavior
patterns
ridley
DOI http://dx.doi.org/10.1007/s00227-001-0755-8   (check subscription with CDU E-Gateway service for CDU Staff and Students  check subscription with CDU E-Gateway in new window)
 
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