Lionfish are being hunted by native predators on Cayman’s reefs at much greater rates than previously imagined – an encouraging sign that nature may provide a solution to the problem of invasive species.
The finding comes from an ongoing study by the Central Caribbean Marine Institute in Little Cayman monitoring the movement, habits and mortality of tagged lionfish on reefs around the island.
The early findings of the study also reinforce the value of culling programs, using trained divers to target the invasive fish.
The data from 30 fish, tagged between June and July this year, also shows that lionfish have strong “site fidelity” and typically stay within a 200-meter zone along the reef wall.
Though researchers found evidence that lionfish often stray into deeper water, well beyond recreational diving limits, they concluded that the fish travel between the shallower depths and these deeper zones rather than staying at depth.
According to CCMI, the results are encouraging because they show that regular culling along the reef wall within recreational limits can still be effective in controlling lionfish populations which use deeper, inaccessible reefs.
The research team also found evidence of lionfish spawning along deep reef walls.
Summarizing the findings, CCMI researcher Alli Candelmo said, “Lionfish may utilize deep reef habitats, but can still be effectively removed by the local culling community when they move within recreational dive limits.
“These removal efforts, combined with a healthy native predator population and increased natural predation rates, are positive steps towards counteracting this invasive threat.”
She said the research team in the second phase of the project, which will involve another round of tagging, would seek to confirm early indications of predation from native predators.
“This is an exciting finding of the study as native predators may be capable of naturally reducing and maintaining lionfish populations,” according to a press release from CCMI.
“These results demonstrate how important conservation of native predators is to the management of invasive lionfish and the overall balance of reef ecosystems.”
CCMI plans to surgically implant acoustic tags into an additional 30 lionfish along the reef wall on Little Cayman between December and January.
A web page will be created for people to track the movement of each tagged lionfish, as well as their mortality and predation rates. Users will be able to click on each fish for details on their movement.
Schools have been invited to name a tagged lionfish so their students can track the fate of their fish and learn about the threat of invasive species.