Evidence for a hormonal tactic maximising green turtle reproduction in response to a pervasive ecological stressor

Jessop, Tim S., Hamann, Mark, Read, Mark A. and Limpus, Colin J. (2000) Evidence for a hormonal tactic maximising green turtle reproduction in response to a pervasive ecological stressor. General and Comparative Endocrinology, 118 3: 407-417. doi:10.1006/gcen.2000.7473


Author Jessop, Tim S.
Hamann, Mark
Read, Mark A.
Limpus, Colin J.
Title Evidence for a hormonal tactic maximising green turtle reproduction in response to a pervasive ecological stressor
Journal name General and Comparative Endocrinology   Check publisher's open access policy
ISSN 0016-6480
1095-6840
0435-2440
Publication date 2000-06
Sub-type Article (original research)
DOI 10.1006/gcen.2000.7473
Volume 118
Issue 3
Start page 407
End page 417
Total pages 11
Editor F. Moore
I. Henderson
Place of publication New York, NY, U.S.A.
Publisher Academic Press
Collection year 2000
Language eng
Subject C1
270603 Animal Physiology - Systems
780105 Biological sciences
Formatted abstract
Mortality of breeding sea turtles due to excessive heat exposure after nesting activities is an unusual feature of the Raine Island green turtle rookery. Breeding turtles that fail to return to the ocean after oviposition can experience increasing body temperatures that exceed lethal limits (>39°C) as ambient temperatures rise after sunrise. We investigated how acute increases in body temperature influenced plasma corticosterone (B) concentrations of individual turtles. Furthermore, interactions between progesterone (P) and testosterone (T) and increasing body temperature and the glucocorticoid corticosterone were examined for negative correlations. Breeding green turtles exhibited a 16-fold mean increase in plasma corticosterone concentration as body temperature (cloacal) rose from 28.2 to 40.7°C in less than 6 h. However, the absolute increase in plasma B was small and much less than expected, despite the lethal stressor. Comparatively, the maximal B response to lethal heat stress was similar to plasma B concentrations obtained from breeding female turtles exposed to 8 h of capture stress. However, the maximal B response of breeding turtles exposed to heat and capture stressors was significantly less than the B response of nonbreeding adult female turtles subjected to an 8-h capture stressor. No negative correlations were observed between plasma T and plasma B, between plasma T and body temperature, between plasma P and plasma B, or between plasma P and body temperature. Our findings provide further evidence that reduced adrenocortical function operates in breeding green turtles in the presence of even the most pervasive of environmental stressors.
© 2000 Academic Press
Q-Index Code C1

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Veterinary Science Publications
 
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Created: Tue, 10 Jun 2008, 12:39:29 EST