Coral larvae actively avoid the smell of degraded marine ecosystems — potentially impeding efforts to rebuild damaged reefs.

Credit: João Paulo Krajewski

Mark Hay at the Georgia Institute of Technology in Atlanta and his team studied coral reefs near Fiji (pictured). They focused on the behaviour of coral larvae in water from healthy, protected reefs and from reefs overgrown with seaweed.

Given the choice between the two streams of water, Acropora coral larvae spent more than 85% of their time in water from the protected areas. The organisms also showed a similar preference for clean water containing chemical cues from a variety of corals, whereas seaweed cues decreased this preference.

Conservationists will probably need to boost coral-attracting chemicals when rebuilding seaweed-choked reefs, the authors suggest.

Science 345, 892–897 (2014)