New trap may fight invasive lionfish

Frank Cooney Jr. has plenty of firsthand experience with the lionfish infestation in the South Atlantic. His family’s Bimini Sands Resort & Marina in the Bahamas has hosted two successful diving derbies targeting the voracious exotic predators, but they still appear on wrecks and reefs in alarming numbers, devouring their weight in native species.

“Lionfish are multiplying faster than the divers are going in the water,” Cooney said.

He decided to try to develop a trap that would target the Indo-Pacific invaders specifically without harming native tropicals and other reef fish. With two engineer friends, Cooney came up with a prototype that has trapped as many as 37 lionfish in a deployment while sparing the natives. Now, his invention has drawn the attention of Vanessa McDonough, fisheries biologist at Biscayne National Park, who is looking for ways to knock down the population of the venomous, candy-striped exotics in park waters.

Cooney is expected to deliver one of his traps to McDonough and colleagues shortly for a possible scientific trial. Fish traps generally are illegal in Florida waters, but authorities may grant exemptions for research purposes.

McDonough said she would like to find out if Cooney’s trap is more successful and cost-efficient than using divers to spear lionfish. She also wants to make sure it doesn’t harm native species.

“We could determine how effective they are versus divers in the water, especially in light of sequestration,” McDonough said. “It costs money to put divers in the water every day.”

Cooney’s prototype is octagonal, roughly 4 feet tall and 3 feet wide and lined with lead weights on the bottom to ensure it sits upright in the sand. Made of net mesh and PVC pipes, it weighs no more than 20 pounds.

A clear plastic cylinder in the center of the trap holds small baitfish, which are made to look larger by a magnifying strip across the cylinder. This device is designed to lure lionfish into the trap through an entry passage made of wire material that is wide at the mouth, but narrows toward the inside.

Lionfish attack prey by first sucking in water and expelling it forcefully, creating a pressure wave aimed at stunning the smaller fish, which they then inhale. Cooney says once the lionfish fan out their pectoral fins for the kill, they get caught in the trap’s netting and can’t get out. Meanwhile, the decoy baitfish hover unharmed in the cylinder.

If scientific trials prove it effective, Cooney’s trap could help solve lionfish problems for the Florida Fish and Wildlife Conservation Commission and the Florida Keys National Marine Sanctuary.