A new trap has been developed in the fight against invasive lionfish.
The lionfish originates from the Indo-West Pacific Ocean and was first reported off Florida’s Atlantic coast in the 1980s. By 2000 it had started to spread and is now found along the western Atlantic coast of the US and throughout the Caribbean. It has a voracious appetite — and no natural predators.
Frank Cooney Jr. — whose family owns a resort and marina in the Bahamas — has designed the trap so it catches up to 37 lionfish without harming native fish.
At the moment, lionfish are killed using divers who spear individual fish. In fact Cooney has helped organise 'diving derbies' where teams compete to catch as many lionfish as possible, for cash prizes.
But he told the Miami Herald: "Lionfish are multiplying faster than the divers are going in the water."
His prototype trap is octagonal in shape and very lightweight, being made of net mesh and PVC pipes. It's around 120cm/4' tall and 90cm/36" wide, weighted with lead at the bottom so it sits upright in the sand.
A clear pipe in the trap's centre holds small fish — rather cleverly their size is enhanced with the use of a magnifying strip — and these attract the lionfish into the trap via a passage that's wide at the mouth, but becomes narrower further in.
Lionfish are known to stun their prey by "huffing and puffing", sucking in water and then expelling it as a water jet, thought to overwhelm the lateral line system of the fish. It may also make it easier for the lionfish to capture and swallow its prey head first as fish typically face the currents to reduce drag. Cooney explains that lionfish spread their pectoral fins for the kill — and when they do this inside his trap they will become caught in the netting and unable to escape. However, the prey fish will be safe inside the pipe.
Cooney's trap is expected to get its first scientific trial soon, as fisheries biologists at Biscayne National Park have expressed an interest, to see if it's more cost-effective than using divers. It's hoped that authorities will allow the research to go ahead — the use of fish traps is generally illegal in Florida waters.
Why not take out a subscription to Practical Fishkeeping magazine? See our latest subscription offer.
Don't forget that PFK is now available to download on the iPad.