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Abstract:
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In marine flatfish of the genus Paralichthys , temperature plays a large role in sex
determination . Thus , global climate change could have significant effects on southern
flounder (Paralichthys lethostigma ) , a commercially and recreationally important flatfish
whose populations have steadily declined in Texas in the last 25 years . The most
susceptible areas to global climate change are shallow water environments , particularly
estuaries , which serve as essential nursery habitats for juvenile southern flounder . While
in the estuaries , juveniles develop , and sex is determined . Juvenile southern flounder
possess genotypic sex determination ; however , the sex of females is highly influenced by
temperature and can result in sex reversal . The temperature -sensitive enzyme complex
responsible for estrogen biosynthesis in vertebrates is aromatase cytochrome P450
(P450arom ) , a critical component in ovarian differentiation that can be used to measure
presumptive males and females exposed to a gradient of temperatures . This research
identifies that sex is influenced by temperature between 35 and 65 mm total length (TL )
and establishes that increases in temperature from 18 °C during this size range produce
increasingly male skewed sex ratios in southern flounder from Texas . The findings
presented here are critical for optimizing production of females in culture and for
developing stock enhancement programs of southern flounder in Texas . |