Stress gives reef fish wonky ears Reef fish who are stressing
about environmental changes are creating irregular offspring,
says a new Australian study. The study, published in the latest
edition of Oecologia, shows a clear link between mothers
producing the stress hormone cortisol, and the development of
asymmetrical ears in the offspring of the common coral reef
fish, Pomacentrus amboinensis. Most animals, produce the hormone
cortisol as a response to stress. Reef fish typically produce it
in response to an encounter with a predator. "Cortisol is needed
for development," says study lead author Dr Monica Gagliano of
James Cook University in Townsville. But the researchers found
that if cortisol is produced in excess it can have harmful
effects on the development of the embryo. The researchers bathed
reef eggs in different concentrations of cortisol. According to
Gagliano, who is also a research fellow with the Australian
Institute of Marine Science, the levels chosen were based on the
amount of cortisol that