Loggerhead sea turtle environmental sex determination: Implications of moisture and temperature for climate change based predictions for species survival

2015 ◽  
Vol 324 (3) ◽  
pp. 295-314 ◽  
Author(s):  
Jeanette Wyneken ◽  
Alexandra Lolavar
Keyword(s):  
Climate Change ◽  
Sex Determination ◽  
Sea Turtle ◽  
Environmental Sex Determination ◽  
Loggerhead Sea Turtle ◽  
Species Survival

scholarly journals Maternally derived sex steroid hormones impact sex ratios of loggerhead sea turtles

2020 ◽  
Author(s):  
Emma C. Lockley ◽  
Thomas Reischig ◽  
Christophe Eizaguirre
Keyword(s):  
Sex Determination ◽  
Steroid Hormones ◽  
Sex Ratios ◽  
Physiological Mechanism ◽  
Sea Turtle ◽  
Sex Steroid Hormones ◽  
Sex Steroid ◽  
Loggerhead Sea Turtles ◽  
Loggerhead Sea Turtle ◽  
Egg Yolks

AbstractGlobal warming could drive species with temperature-dependent sex determination to extinction by persistently skewing offspring sex ratios. Evolved mechanisms that buffer these biases are therefore paramount for their persistence. Here, we tested whether maternally-derived sex steroid hormones affect the sex-determination cascade and provide a physiological mechanism to buffer sex ratio bias in the endangered loggerhead sea turtle (Caretta caretta). We quantified estradiol and testosterone in nesting females and their egg yolks at oviposition, before incubating nests in situ at standardised temperatures. Upon hatchling emergence, we developed a new, non-lethal method to establish the sex of individuals. Despite standardised incubation temperatures, sex ratios varied widely among nests, correlating non-linearly with the estradiol:testosterone ratio in egg yolks. Males were produced at an equal ratio, with females produced either side of this optimum. This result provides evidence that maternal hormone transfer forms a physiological mechanism that impacts sex determination in this endangered species.

scholarly journals Climate change and pollution speed declines in zebrafish populations

2015 ◽  
Vol 112 (11) ◽  
pp. E1237-E1246 ◽  
Author(s):  
A. Ross Brown ◽  
Stewart F. Owen ◽  
James Peters ◽  
Yong Zhang ◽  
Marta Soffker ◽  
...  
Keyword(s):  
Climate Change ◽  
Sex Determination ◽  
Water Temperature ◽  
Endocrine Disrupting Chemicals ◽  
Population Viability Analysis ◽  
Population Viability ◽  
Interactive Effects ◽  
Environmental Sex Determination ◽  
Estrogen Synthesis ◽  
Inbred Populations

Endocrine disrupting chemicals (EDCs) are potent environmental contaminants, and their effects on wildlife populations could be exacerbated by climate change, especially in species with environmental sex determination. Endangered species may be particularly at risk because inbreeding depression and stochastic fluctuations in male and female numbers are often observed in the small populations that typify these taxa. Here, we assessed the interactive effects of water temperature and EDC exposure on sexual development and population viability of inbred and outbred zebrafish (Danio rerio). Water temperatures adopted were 28 °C (current ambient mean spawning temperature) and 33 °C (projected for the year 2100). The EDC selected was clotrimazole (at 2 μg/L and 10 μg/L), a widely used antifungal chemical that inhibits a key steroidogenic enzyme [cytochrome P450(CYP19) aromatase] required for estrogen synthesis in vertebrates. Elevated water temperature and clotrimazole exposure independently induced male-skewed sex ratios, and the effects of clotrimazole were greater at the higher temperature. Male sex ratio skews also occurred for the lower clotrimazole exposure concentration at the higher water temperature in inbred fish but not in outbred fish. Population viability analysis showed that population growth rates declined sharply in response to male skews and declines for inbred populations occurred at lower male skews than for outbred populations. These results indicate that elevated temperature associated with climate change can amplify the effects of EDCs and these effects are likely to be most acute in small, inbred populations exhibiting environmental sex determination and/or differentiation.

Aeromonas induced polyostotic osteomyelitis in a juvenile loggerhead sea turtle Caretta caretta

2018 ◽  
Vol 132 (1) ◽  
pp. 79-84 ◽  
Author(s):  
A Pace ◽  
L Meomartino ◽  
A Affuso ◽  
G Mennonna ◽  
S Hochscheid ◽  
...  
Keyword(s):  
Caretta Caretta ◽  
Sea Turtle ◽  
Loggerhead Sea Turtle

scholarly journals Exogenous estradiol alters gonadal growth and timing of temperature sex determination in gonads of sea turtle

2015 ◽  
Vol 408 (1) ◽  
pp. 79-89 ◽  
Author(s):  
Verónica Díaz-Hernández ◽  
Alejandro Marmolejo-Valencia ◽  
Horacio Merchant-Larios
Keyword(s):  
Sex Determination ◽  
Sea Turtle ◽  
Gonadal Growth
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