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Social lives of reef fish are crucial to saving coral reefs

Reef fish play a critical role in their environment by eating algae that may kill coral or overtake a reef if left unchecked. This means that the more algae a fish eats, the more a fragile ecosystem like a coral reef can flourish and thrive.

A study from the University of California, Davis analyzed the social feeding behavior of reef fish and found that overfishing not only devastates the populations of algae-eaters, but also may cause the fish left behind to consume less algae.

The research team, led by Mike Gil, a National Science Foundation postdoctoral research fellow at UC Davis, conducted the study off the island of Mo’orea in French Polynesia. They remotely monitored reef fish through mounted arrays of video cameras in large stands that were placed inside the coral reef. From the video footage, they measured how fish responded to one another in both the presence and absence of predators.

The team found that fish actually react to social situations similar to humans. Fish tend to copy the behaviors of others, such as swimming to a particular area of the reef to eat algae or quickly fleeing from a predator. These observations lead scientists to believe that the feeding behavior of the reef fish community may be more complex than once thought.

“Even though these fish don’t swim in schools, our study shows that they’re influencing one another,” says Gil. “They eat more algae when they’re surrounded by more fish. We don’t know why that is, but it likely has to do with safety in numbers. These fish may perceive that their chances of getting killed by a predator, like a shark, are reduced when more prey are around.”

The researchers believe these results show that past predictive models, which don’t take fish social behaviors into account, could be mischaracterizing how certain reefs respond to fishing. This is an important revelation, as overfishing continues to decimate fish populations around the world.

More information on this study can be found in the journal Proceedings of the National Academy of Science.

By Connor Ertz, Staff Writer

Source: University of California, Davis

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