Baby fish may become easy meat for predators as the world's oceans become more acidic due to CO2 fallout from human activity, an international team of researchers has discovered.

In a series of experiments reported in a recent issue of the Proceedings of the National Academy of Science (PNAS), the team found that as carbon levels rise and ocean water acidifies, the behaviour of baby fish changes dramatically -- in ways that decrease their chances of survival by 50 to 80 per cent.

"As CO2 increases in the atmosphere and dissolves into the oceans, the water becomes slightly more acidic. Eventually this reaches a point where it significantly changes the sense of smell and behaviour of larval fish," says team leader Professor Philip Munday of the Australian Research Council's Centre of Excellence for Coral Reef Studies (CoECRS) at James Cook University.

"Instead of avoiding predators, they become attracted to them. They appear to lose their natural caution and start taking big risks, such as swimming out in the open -- with lethal consequences."

Dr Mark Meekan from the Australian Institute of Marine Science, a co-author on the paper, says the change in fish behaviour could have serious implications for the sustainability of fish populations because fewer baby fish will survive to replenish adult populations.

(ScienceDaily)

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