Endocrine control of embryonic diapause in the Australian sharpnose shark Rhizoprionodon taylori

Waltrick, Daniela, Jones, Susan M., Simpfendorfer, Colin A., and Awruch, Cynthia A. (2014) Endocrine control of embryonic diapause in the Australian sharpnose shark Rhizoprionodon taylori. PLoS One, 9 (7). e101234. pp. 1-10.

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Abstract

The reproductive cycle of the Australian sharpnose shark, Rhizoprionodon taylori, includes a temporary suspension of development at the commencement of embryogenesis termed embryonic diapause. This study investigated levels of 17 beta-estradiol (E-2), testosterone (T) and progesterone (P-4) in plasma samples of mature wild female R. taylori captured throughout the reproductive cycle and correlated them with internal morphological changes. Levels of T were elevated through most of the embryonic diapause period, suggesting a role of this hormone in the maintenance of this condition. Increasing plasma T concentrations from late diapause to early active development were associated with a possible role of androgens in the termination of embryonic diapause. As in other elasmobranchs, a concomitant increase of E-2 with ovarian follicle size indicated a direct role of this hormone in regulating vitellogenesis, while a peak in P-4 suggested this hormone is associated with preovulation and ovulation. Additionally, significant correlations between photoperiod or water temperature and maximum follicular diameter and hepatosomatic index suggest that these abiotic factors may also play a role triggering and regulating the synchrony and timing of reproductive events.

Item ID: 36140
Item Type: Article (Research - C1)
ISSN: 1932-6203
Additional Information:

© 2014 Waltrick et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Funders: Winifred Violet Scott Foundation (WVSF), Australian National Network of Marine Science, James Cook University
Projects and Grants: WVSF Sco-2.181/51
Date Deposited: 12 Nov 2014 11:59
FoR Codes: 06 BIOLOGICAL SCIENCES > 0602 Ecology > 060205 Marine and Estuarine Ecology (incl Marine Ichthyology) @ 60%
06 BIOLOGICAL SCIENCES > 0606 Physiology > 060603 Animal Physiology Systems @ 40%
SEO Codes: 83 ANIMAL PRODUCTION AND ANIMAL PRIMARY PRODUCTS > 8302 Fisheries - Wild Caught > 830204 Wild Caught Fin Fish (excl. Tuna) @ 100%
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