A new model developed by marine biologists at the University of Hawaiʻi at Mānoa and University of Alberta is providing insight into the impact of lionfish, a venomous predatory fish that has invaded more than 7.3 million square kilometers in the Atlantic Ocean and Caribbean Sea, wreaking havoc among native fish populations.

“As invasions take hold, scientists have few tools to help them predict what the effects will be, and as a result, we often don’t understand how invasive predators have changed environments until it is too late,” said Mark Hixon, UH Mānoa biology professor and senior author of the study.

Scientists have speculated that the invasive lionfish are so successful in the Atlantic because prey do not recognize them as a predator, but that may not be the case, according to University of Alberta marine biologist Stephanie Green, who led the study.

Hunting strategy success

The researchers suggest the lionfish’s success as a hunter is likely due to a combination of its particular stalking pattern, mouth suction and forward momentum as it strikes—characteristics that are unlike native fish predators.

The ranges of many predators are expected to grow due to climate change and future invasions. The new model—a systematic way of looking at behavioural traits—is designed to help scientists and conservationists better understand how predators select their prey.

In the case of lionfish, the scientists hope the model can help them identify areas where native species are most vulnerable to the novel stalking/hunting strategy of lionfish as the invasion spreads.

Hixon and Green hope their approach can be used by researchers in the Mediterranean who are keen to understand how fish in that sea will be most affected by the recent invasion of lionfish.

Green is also adapting the model to examine predator-prey interactions for albacore tuna with respect to climate change.

“We hope that using knowledge of species behaviours can help scientists and managers predict who will eat whom when predators and prey encounter one another in new settings,” she said.

The study, “Trait-Mediated Foraging Drives Patterns of Selective Predation by Native and Invasive Coral-Reef Fishes,” is published in Ecosphere.