CANBERRA, May 22 (Xinhua) -- An Australian-led study has found that ocean acidification is disrupting the social behavior of reef fish by making their habitat less complex, leading to smaller and less protective shoals.
Researchers led by Australia's Adelaide University found that reef fish, which typically rely on group living for survival, form smaller shoals when ocean acidification driven by climate change is causing a decline in reef complexity around the world, a university statement said on Friday.
The study, published in the Journal of Animal Ecology, showed that the size of a fish shoal affects their collective and individual behavior.
"Fish in bigger groups tend to be bolder, as they forage more efficiently, stay out in the open more, and spend less time hiding," while smaller groups offer less protection from predators and alter how fish feed and move, said study lead author Angus Mitchell from Adelaide University.
Importantly, researchers said these behavioral shifts were not driven directly by rising temperatures and lower pH levels. Instead, the changes stemmed from habitat degradation linked to acidification.
"Our results suggest that even when individual fish seem to be coping fine behaviorally under climate stress, the social structures supporting their behavioral expression can quietly fall apart," Mitchell said.
Using natural volcanic carbon dioxide seeps off Japan as future ocean analogues, the team observed fish communities under varying levels of acidity and warming. ■
