Some Fish Can Change Sex of Offspring in Warming Oceans

Written by on April 10, 2015 in Fish, Marine Life

New research from University of Technology, Sydney (UTS) shows that when certain reef fish develop from early life in warmer temperatures, they can adjust the gender of their offspring.

Spiny chromis damselfish. Photo credit: Nikita (Flickr: Tropical fish), CC BY 2.0 via Wikimedia Commons.

Spiny chromis damselfish. Photo credit: Nikita, CC BY 2.0 via Wikimedia Commons.

The ability to modify offspring sex ratios, called “transgenerational plasticity”, is switched on in spiny chromis damselfish (Acanthochromis polyacanthus) during early development of the parents and is not simply a result of adults being exposed to higher temperatures.

“Understanding the ability of species to respond and cope with rising environmental temperature is key to predicting the biological consequences of global warming,” lead author and UTS Chancellor’s Postdoctoral Research Fellow Dr. Jennifer Donelson explained in a news release.

While this trait could help mitigate some of the impacts of climate change, there are limits. If the temperature is too hot, transgenerational plasticity won’t help.

“The research findings are significant because global warming poses a threat to species with temperature-dependent sex determination (TSD), such as reptiles and fish, potentially skewing the sex-ratio of offspring and, consequently, breeding individuals in a population,” Dr. Donelson said.

For species with TSD, an unequal ratio of males to females can have serious consequences for population success.

“A reduction in the proportion of females in the population could be especially damaging because population growth rate is often constrained by female fertility,” Dr. Donelson continued.

The researchers found that just a 1.5 degree Celsius increase in average summer temperature can reduce the proportion of female offspring by over 30 percent. However, the ratio was restored when parental fish were raised at this temperature for their entire life. If temperatures continue to increase, though, it gets harder and harder to restore the ratio.

“Just precisely how our study species, the Spiny Chromis coral reef fish, engineer these amazing adjustments is unknown and is something we are now investigating,” said Dr. Donelson. “What we do know however is that oceans are warming and emerging research is showing the importance of transgenerational plasticity in reducing the negative impacts of climate change on species with TSD.”

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Copyright © 2015 by Marine Science Today, a publication of Marine Science Today LLC.

About the Author

About the Author: Emily Tripp is the Publisher and Editor of She holds marine science and biology degrees from the University of Miami's Rosenstiel School of Marine and Atmospheric Science and a Master of Advanced Studies degree in Marine Biodiversity and Conservation from Scripps Institution of Oceanography. When she's not writing about marine science, she's probably running around outside or playing with her dog. .


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