Babies of stressed fish mothers likely abnormal: study

Thu Apr 16, 2009 5:33am EDT
 
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SYDNEY (Reuters Life!) - Stressed reef fish mothers produce high-strung, sometimes abnormal, babies who have trouble surviving, according to an Australian study that sheds light on how human-induced stresses influence wild fish populations.

The study, by researchers from the ARC Center of Excellence, shows that the environment of a common reef species, Ambon damsel fish, is crucial for the future of their offspring.

Previous studies had shown that females of this species release the stress horme cortisol from their ovaries in response to environmental threats.

Fish in isolated reefs with few predators or competitors show low levels of the hormone while those in high stress environments bathe their eggs in high levels of the hormone.

The researchers exposed fertilised fish eggs gathered from the wild to different levels of cortisol in the laboratory.

"If the mother fish is more stressed and she passes on more cortisol, then the offspring will have a faster developmental rhythm and therefore errors will be more likely in their development," Dr Monica Gagliano said.

"One likely result of this is that the offspring are born asymmetrical," she added.

Asymmetrical fish have several developmental problems and a lower chance of survival.

This study, published today in the journal Oecologia, has implications for management of fish resources as well as increasing knowledge of the basic physiological processes governing the life cycles of fish.

(Editing by David Fox)