A Comparison of Reproductive and Energetic States in a Marine Apex Predator (the Tiger Shark, Galeocerdo cuvier)

Physiological and Biochemical Zoology : PBZ
N HammerschlagAustin J Gallagher

Abstract

To fuel the high energetic demands of reproduction, vertebrates employ different tactics of resource use. Large sharks exhibit long gestation periods and have relatively few well-developed young, which likely incurs high energetic costs. However, information on the relationship between the reproductive and energetic states for most shark species is lacking. In the present study, we used a noninvasive approach to assess relationships among reproductive stage, plasma triglyceride levels, body condition, and circulating reproductive hormones in free-ranging female tiger sharks (Galeocerdo cuvier). A total of 57 sharks were sampled (19 immature, 15 mature/nongravid, and 23 gravid). Circulating plasma triglycerides did not significantly differ among female tiger sharks of different reproductive stages, but body condition values were significantly higher for mature/nongravid sharks ([Formula: see text]) compared with gravid ([Formula: see text]) and immature ([Formula: see text]) sharks. For gravid and mature/nongravid sharks, no significant correlations existed among values of reproductive hormones, plasma triglycerides, and body condition. However, for immature sharks, estradiol values were negatively correlated with body condition...Continue Reading

Citations

May 13, 2020·Oecologia·Oliver N Shipley, Philip Matich
Jan 10, 2021·Scientific Reports·Oliver N ShipleyAustin J Gallagher
Apr 1, 2021·Brazilian Journal of Biology = Revista Brasleira De Biologia·J G Pérez-RojasS C Pardo-Carrasco
May 26, 2021·The Science of the Total Environment·Bianca de Sousa RangelNeil Hammerschlag

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