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Increased CO2 Levels Make Fish Unafraid Of Predators


SYDNEY, April 15 (RTRS) - Fish on a remote coral reef in the South Pacific have altered their behaviour, as acidification of the ocean changes their natural habits, making them attracted to the smell of their predators and unafraid of approaching them.

The research, carried out at an isolated "natural laboratory" off the coast of Papua New Guinea, where coral reef waters are made acidic by the natural carbon dioxide seeping from the ocean bed, found small fish were attracted to their predators, instead of avoiding them.

"They are more active and display riskier behaviours, venturing further away from shelter, which makes them even more vulnerable to predators," Professor Philip Munday, from the ARC Centre of Excellence (CoE) for Coral Reef Studies at James Cook University, told Reuters on Monday.

The report found the location ideal for studying how fish and other coral reef species may respond to the extent of ocean acidification forecast for the next 50-80 years.

"We've found fish living in those conditions similar to what we predict in the second half of the century. Their behaviour is fundamentally altered and impaired such that we see they've become attracted to odours they'd normally avoid," Munday said.

Close to the seeping carbon dioxide, there is no coral growth, but further away lies a unique coral reef zone with carbon dioxide levels similar to risig levels predicted to be ocean-wide by the end of the century.