Fish lose ability to smell danger in acidic oceans

LONDON - Fish lose their ability to smell danger as the oceans grow more acidic, says a new research.

Marine biologists, studying the impact of ocean acidification, which occurs when carbon dioxide dissolves in sea water, have found that it affects the ability of fish to smell, reports the Telegraph.

They have discovered that young fish reared in water with elevated levels of carbon dioxide are unable to distinguish the scent of predators and even seem attracted to their smell.

Philip Munday, who carried out the research at James Cook University in Queensland, Australia, said: “As atmospheric carbon dioxide increases, so does the amount dissolved in the sea.”

“We have found that levels of carbon dioxide that could be found in the ocean by the end of this century, affects the sense of smell and behaviour of fish larvae. They exhibit riskier behaviour which makes them more prone to predation,” he added.

The researchers also found that in the wild, these fish larvae take greater risks, swimming further from shelter that usually hide them from predators.

Most of the fish larvae die in the wild, sparking fears that as oceans become more acidic, fish populations could struggle to survive and replenish themselves.

Scientists predict that oceans will grow increasingly acidic as levels of carbon dioxide in the atmosphere rise and dissolve in the sea.

It has always been known that ocean acidification will be catastrophic for shellfish as the acidic water makes it harder for them to grow shells.

But this is the first evidence suggesting that ocean acidification could affect fish directly.

The researchers will present their findings at a conference in Belfast on fish and climate change later this month.