Florida Researchers Test Deepwater Traps to Combat Invasive Lionfish
A team of Researchers from Florida has been working on a new method of capturing invasive lionfish in the Gulf of Mexico, designing deep water traps to catch a species which is causing a huge amount of damage to reefs along the eastern coast of the American continents.
Holden Harris, a Graduate Resource Fellow from the University of Florida, and Alex Fogg, the Marine Resource Co-ordinatior for Okaloosa County, have teamed up with Josh and Joe Livingston of Dreadknot Charters to install and test the deepwater traps, as reported by Laura Tiu, Okaloosa and Walton Counties Sea Grant Extension Agent.
Lionfish are favourites of divers throughout their native habitats of the Indo-Pacific region, however they have become a huge problem along the Atlantic coast of the Americas. With their striking red and white stripes and graceful, butterfly-like fins, they are popular aquarium fish, thought to be the source of the species' invasive prescence in the area, through the release of pet lionfish into the coastal waters of south east Florida in the mid-1980s.
By 2000, lionfish had spread throughout the US eastern seaboard and into the Caribbean, before reaching the northern Gulf of Mexico in 2010. Today, lionfish densities in the northern Gulf are higher than anywhere else in their invaded range.
Invasive lionfish negatively affect native reef communities. They consume and compete with native reef fish, including economically important snappers and groupers. Their presence has shown to drive declines in native species and diversity, and their venomous spines appear to deter native predators. The interaction of invasive lionfish with other reef stressors – including ocean acidification, overfishing, and pollution – is of great concern to scientists.
Lionfish harvesting by recreational and commercial divers is currently the best means of controlling their densities and minimizing their ecological impacts. Lionfish specific spearfishing tournaments have proven successful in removing large amounts in a relatively short amount of time. This year’s Lionfish Removal and Awareness Day removed almost 15,000 lionfish from the Northwest Florida waters in just two days. Furthermore, lionfish are considered to be an high-quality seafood, and hence they are now being targeted by a handful of commercial divers. Several Florida restaurants, seafood markets, and grocery stores chains are now regularly serving lionfish.
While diver removals can control localized lionfish population densities, lionfish inhabit reefs much deeper than those that can be accessed by scuba divers. Surveys of deepwater reefs show lionfish have higher densities and larger body sizes than lionfish on shallower reefs. In the Gulf of Mexico, the highest densities of lionfish surveyed were between 150-330ft / 45-90m. Recreational scuba diving is typically limited to less than 130ft/40m, lionfish have been observed in water deeper than 100ft/300m
For the past several years, researchers have been working to develop a trap that may be able to harvest lionfish from deep water. Dr. Steve Gittings, Chief Scientist for the Office of National Marine Sanctuaries at the National Oceanic and Atmospheric Administration (NOAA), has spearheaded the design for a 'non-containment' lionfish trap. The design works to 'bait' lionfish by offering a structure that attracts them. The trap remains open while deployed on the sea floor, allowing fish to move in and out of the trap footprint. When the trap is retrieved, netting is pulled up around the fish inside and they are brought to the surface.
The researchers are headed offshore to retrieve, redeploy, and collect data on the lionfish traps. Twelve non-containment traps are currently being tested offshore NW Florida. The research is supported by a grant from the Florida Fish and Wildlife Conservation Commission. The study will try to answer important questions for a new method of catching lionfish: where and how can the traps be most effective, for how long they be deployed, and is there any accidental bycatch of other species.
Recent trials have proved successful in attracting lionfish to the trap with minimal bycatch. Continued research will hone the trap design and assess how deployment and retrieval methods may increase their effectiveness. If successful in testing, lionfish traps may become permitted for use by commercial and recreational fisherman. The traps could become a key tool in our quest to control this invasive species and may even generate income while protecting the deepwater environment.