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Fooling Nemo

Clownfish

Ocean acidification results in behaviour that decreases the odds of survival for reef fish

By Kate Osborne

Clownfish use their sense of smell to warn them of the presence of predators, but the pH conditions expected as a result of climate change fool them into swimming towards impending danger.

Kate Osborne is an ecologist and science writer.

The full text of this article can be purchased from Informit.

Have you ever had the feeling that something is wrong? “The hair on my neck prickled” and “I smelt a rat” are two examples of expressions to describe that feeling. What we perceive as intuition is our sensory system sending messages to our brain.

For the orange clownfish (Amphiprion percula), “I smell danger” is literally true. Larval fish have an innate ability to avoid seawater that has come from a predator tank. However, scientists have found that when the pH of the water is lowered to conditions that are expected as a result of climate change, the clownfish were attracted to the water where the predators were living.

Clownfish spend most of their life within a few metres of their host anemone. However, like many reef fish, the earliest life stage as larval fishes is spent away from the reef surface, living and feeding in the water column.

Initial research on the clownfish olfactory system, or sense of smell, sought to discover how the larval fish were able to locate an anemone amongst the myriad of life on the reef. Scientists found that the larval fish were able to smell chemicals released by the anemone and were attracted towards them.

Now there is a growing body of research suggesting that clownfish can detect a surprising variety of scents. They can, for example, smell traces of leaf litter from rainforest plants that indicate they...

The full text of this article can be purchased from Informit.