High carbon dioxide levels cause baby fish to lose their way

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High carbon dioxide levels cause baby fish to lose their way

April 14, 2018 - 23:11
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A new study has found that baby fish in elevated carbon dioxide environments may avoid ocean noises that they would normally be attracted to, and lose their way.

In the study, the larvae of barramundi (an adult is pictured in the foreground) were found to lose their way when exposed to elevated levels of carbon dioxide

The larvae of some fish species and invertebrate depend on ocean sounds to direct them to places they are supposed to go, for instance, a sheltered location in shallow waters where they spend their juvenile or adult lives.

However, in environments of elevated carbon dioxide (CO2) levels, they may find themselves led astray.

In a study by researchers of the University of Adelaide, barramundi larvae exposed to high CO2 levels predicted for the turn of the century were found to avoid ocean noises they would normally be attracted to.

"In our study we found that while larvae of barramundi are attracted to the sounds of tropical estuaries, larvae raised under future ocean conditions with elevated CO2 were deterred by these natural sounds," said project leader Professor Ivan Nagelkerken, from the University's Environment Institute.

"Moreover, under elevated CO2, larval barramundi were attracted to the wrong sounds," he added, referring to noises found on cold water reefs (not the species' natural habitat) and artificial sounds or "white noise." As a result, they would end up in places where they would not be able to survive.

This would subsequently have a detrimental impact on the population and, in the case of commercial or recreational fish stock, on fisheries.

Professor Sean Connell, from the University's Southern Seas Ecology Laboratories, added, "The research also raises questions about future fish populations in areas with unnatural sounds. Will some species be more attracted, for example, to areas where there are a lot of human structures and sounds in and under the water, such as harbours and oil platforms, in the future?"

The findings of the study have been published in the latest issue of Scientific Reports.

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