The larvae of coral reef fish are able to smell their way back to their home reefs after currents take them away, according to a report published in the PLOS ONE Journal. The report, “Reef Odor: A Wake Up Call for Navigation in Reef Fish Larvae” by Claire Paris of the University of Miami details how damselfish and cardinalfish larvae changed their swimming speeds and the direction in which they were swimming when they smelled reef water from several kilometers away, but didn’t exhibit the same behavior when exposed to water from the open ocean. The study also pointed out that water temperatures and the direction of currents didn’t appear to influence the orientation of the larvae.
“Unlike most animals that migrate as adults on a seasonal basis, coral reef fish undertake their longest voyage early in their life history. Here we find that coral reef fish larvae smell the reef kilometers away and then switch to a proximal cue which allows them to navigate with a landscape frame of reference,” Paris said.
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The authors studied 83 larvae from the fish families Pomacentridae and Apogonidae around One Tree Island in the southern Great Barrier Reef.
While other fish such as sharks and salmon are known for using their olfactory senses to navigate, this is the first study that details how reef fish larvae use their noses to find their way.
The researchers conclude that the role of olfactory signals in marine species can be affected by ocean pollution and ocean acidification, effectively altering chemical cues that fishes rely on to navigate.
The complete paper was authored Claire B. Paris, Jelle Atema, Jean-Olivier Irisson, Michael Kingsford, Gabriele Gerlach, and Cedric M. Guigand.