Losing Nemo 2 - clownfish swim towards predators as CO2 levels rise

If you think the stars of Pixar’s Finding Nemo had it rough, spare a thought for the plight of real clownfish. These popular fish may struggle to survive in oceans that are becoming enriched with carbon dioxide. High levels of CO2 dissolved in the water can muddle a clownfish’s sense of smell, preventing it from detecting both shelter and threats. Philip Munday from James Cook University has shown that at levels of carbon dioxide within what’s predicted for the end of the century, a clownfish’s ability to sense predators is completely shot. Some larvae become literally attracted to the smell of danger and start showing risky behaviour. It’s not surprise that they die 5-9 times more frequently at the mouths of predators. The conditions that Munday simulated in his experiment aren’t too far away. Thanks to the carbon dioxide that human activities produce, carbon dioxide levels in the atmosphere are ...