Environment Sticking together keeps fish calmer

Sticking together keeps fish calmer

Coral reef fish get stressed and lose weight if they are separated from each other, new research about the Great Barrier Reef has found.

For the first time, researchers from the ARC Centre of Excellence for Coral Reef Studies at James Cook University have succeeded in measuring the metabolic rates of individual fish in shoals. Metabolic rate is an indicator of stress.

The researchers looked at shoals of blue-green damselfish near Lizard Island on the Great Barrier Reef.

“Fish were calmer and less stressed when they had their shoal-mates around, with a 26% decrease in metabolic rate compared to individuals tested alone,” said the study’s lead author, Lauren Nadler.

“If these fish were out in the ocean by themselves, in order to stay alive they would need more food to keep up their energy,” says Professor Mark McCormick, another author.

“Since they don’t have their buddies around to help look out for looming predators, foraging for food would be riskier.”.

The extra energy fish gain from shoaling is important because it allows them to survive, reproduce and pass on their genes to the next generation.

But natural disturbances like tropical cyclones can cause fish to become separated from each other.

“Our results show how important group living is for healthy fish populations,” Nadler said.

To read more about this Great Barrier Reef study, click here. [Story credit, James Cook University newsroom]

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