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Effects of temperature on the reproductive physiology of female elasmobranchs: the case of the narrownose smooth-hound shark (Mustelus schmitti)

Citation

Elisio, M and Awruch, CA and Massa, AM and Macchi, GJ and Somoza, GM, Effects of temperature on the reproductive physiology of female elasmobranchs: the case of the narrownose smooth-hound shark (Mustelus schmitti), General and Comparative Endocrinology, 284 Article 113242. ISSN 0016-6480 (2019) [Refereed Article]

Copyright Statement

2019 Published by Elsevier Inc.

DOI: doi:10.1016/j.ygcen.2019.113242

Abstract

The knowledge of how temperature influences elasmobranchs reproductive physiology allows a better understanding of their reproductive patterns. This study describes the relationship between temperature fluctuations and the plasmatic changes of the sex steroids related to reproduction: testosterone (T), estradiol (E2) and progesterone (P4), throughout the female reproductive cycle of the shark Mustelus schmitti. A total of 123 adult females were bi-monthly sampled in Buenos Aires, Argentina, coastal waters. Bottom temperatures were recorded at each sampling point and blood samples were taken from each female for plasma sex steroids measurement. Sex steroid plasma levels were analyzed in relation with maximum follicular diameter (MFD), uterosomatic index (USI, as indicator of pregnancy) and temperature using Generalized Additive Models. Plasmatic E2 and T increased during follicular growth until MFD reached 1.34 and 1.46 cm, respectively. Peak of T occurred at the follicular stage associated with parturition (MFD, 1.41.6 cm), just prior to final maturation and ovulation (MFD, 1.62.0 cm). Progesterone significantly increased at this last ovarian phase, while T and E2 decreased. The increase of USI with pregnancy was associated to a decrease in T and mainly E2 levels, while P4 remained unaffected. Prior to ovulation, T plasma levels decreased with temperature below to 13 C and then increased progressively with a pronounced elevation above 17 C, while E2 presented an opposite pattern. Progesterone plasma levels changed with temperature showing a similar pattern to that observed for T. Using M. schmitti shark as model species, this study shows a clear picture of how seawater temperature variations can affect the reproductive physiology in elasmobranch females. A hypothetical mechanism (based on T elevation driven by temperature increase and its connection by feedback with a P4 rise and parturition/ovulation induction) is proposed as evidence to support that the increase in temperature can trigger reproductive events in elasmobranchs. In addition to its ecological scope, this work contributes to reinforce the relatively scarce general knowledge of elasmobranchs reproductive physiology.

Item Details

Item Type:Refereed Article
Keywords:pregnancy, sex steroids, elasmobranchs, environmental cues, ovulation, vitellogenesis
Research Division:Biological Sciences
Research Group:Zoology
Research Field:Animal physiology - systems
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the biological sciences
UTAS Author:Awruch, CA (Dr Cynthia Awruch)
ID Code:137557
Year Published:2019
Web of Science® Times Cited:6
Deposited By:Zoology
Deposited On:2020-02-20
Last Modified:2020-06-24
Downloads:0

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