In most cases, warming ocean waters that get brought about by climate change have a negative impact on marine wildlife. But some reef fish appear to exhibit natural self-defense mechanisms that could protect their offspring from the harmful effects.

Researchers from the ARC Centre of Excellence for Coral Reef Studies and the King Abdullah University of Science & Technology reported their surprising findings in the journal Nature Climate Change this week.

Image Credit: ARC CoE for Coral Reef Studies/Jennifer Donelson

"When parents are exposed to an increase in water temperature, we found that their offspring improved their performance in these otherwise stressful conditions by selectively modifying their epigenome," explained Prof Philip Munday, a senior author of the study.

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As it would seem, the excess exposure to heat stress signals particular genes in the reef fish’ DNA to either activate or deactivate, and these changes get passed on to their offspring. As a result, said offspring display improved tolerance and enhanced performance in warmer ocean waters than the previous generation(s).

"We reared spiny chromis damselfish, a common Indo-Pacific reef fish, for two generations under three different water temperatures, up to 3 degrees Celsius warmer than current-day ocean temperatures," added study co-author Prof Timothy Ravasi.

"The next generation appeared to be advantaged by parental exposure to elevated temperatures. The offspring's altered gene expression, also referred to as 'acclimation,' allowed them to maximize oxygen consumption and energy use."

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The findings are substantial because they portray how life adapts to cope with a volatile environment, but the researchers also warn how it may not be enough to save the species from climate change indefinitely; instead, it may delay the inevitable.

While the fish themselves become less susceptible to warming ocean waters, climate change continues to deal calamitous blows to coral reefs. Reef fish rely on coral reefs for survival – evading predators and having a place to call home. On the other hand, their disappearance invokes a domino effect and consequently impacts the reef fish too.

It should be interesting to see if any other types of fish exhibit similar traits. Perhaps future research could shed light.

Source: EurekAlert