Shy fish said to have better survival odds

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MONTREAL, Oct. 22 (UPI) -- Being shy or bold can be a matter of life or death for a trout, Canadian researchers say, with shyness being a better survival strategy.

Fish respond to, and learn from threats, they said, and experiments show bold trout forget predator odor, and hence a potential predator threat, quicker than shy trout.

As predators can be present in different locations and at different times, learning and retaining information about a predator threat, and being able to recall it at a later stage, is key to responding to relevant threats in the future, scientists at Concordia University said.

Writing in the journal Behavioral Ecology and Sociobiology, the researchers said how long juvenile rainbow trout retained information they had previously learned about a predator was influenced by the fish's personality, whether they were "shy" or "bold."

The trout were classified depending on how quickly they escaped from test tanks once a movable Plexiglas barrier was removed. Those who moved quickly displayed risk-taking behavior and were considered bold, while those who moved more cautiously were avoiding risk and thus shy.

The researchers conditioned trout to recognize the odor of a freshwater trout predator fish called a pumpkinseed, and then tested whether they still recognized the odor later.

The fish's personality shaped how long the information was retained, they found; shy trout continued to demonstrate a response to pumpkinseed odor eight days later, while bold trout did not.