Acid oceans make fish "fatally attracted" to their predators

From ANI

London, November 22: In a new research, scientists have found that ocean acidification can cause fish to become "fatally attracted" to their predators.

Danielle Dixson, from James Cook University in Queensland, who led the study, claims fish are unable to "smell danger" because of the dissolved CO2.

She and her colleagues tested orange clown fish larvae that were raised in water with the same slightly alkaline pH as their ocean reef habitat, and those raised in more acidic water.

A "flow chamber" with two water sources flowing in parallel was built for the project.

One source was taken from tanks containing the clown fishes' natural predators and one was drawn from tanks in which non-predatory fish were swimming.

"The flow rates are identical, so the water won't mix. This allows the fish in the chamber to choose which water cue they prefer or dislike," The BBC News quoted Dixson as saying.

The researchers made sure that the fish reared in normal water was kept away from the stream of water that their predators were placed in.

It was noted that they detected the odour of a predator and swam away from it.

However, fish raised in more acidic water were strongly attracted to both the predatory and the non-predatory flumes.

The scientists asserted that the fish larvae "might exhibit a fatal attraction to predators at CO2 and pH levels that could occur in our oceans by 2100 on a business-as-usual scenario of greenhouse gas emissions".

Dixson concluded: "Ocean acidification has the potential to become a widespread problem and it's unknown how many organisms and ecosystems will cope with the decrease [in] pH.

"This study shows that ocean acidification could lead to an increase in the mortality of larvae."

The study was published in the journal Ecology Letters.


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