Abstract

Invasive lionfish have been present in Bermuda since 2000, but the population has expanded at a slower rate than elsewhere in the region. Culling officially began in 2008, with the first tournament held in 2011. Technical divers found high densities of lionfish at mesophotic sites in 2009, and surveys to assess lionfish and prey fish densities at various depths began in 2013. Cullers have reported increasing numbers of lionfish at shallow depths over time, while surveys found lionfish densities up to 1100 fish/ha at mesophotic depths. Analysis suggests cold- water upwelling may fuel the food chain at certain deep sites, increasing the abundance of prey, and thus lionfish. In 2017, three mesophotic “hot spots” were culled monthly for 6 months. Lionfish density declined at all sites over time, but there was a corresponding decline in prey fish abundances, so it is unclear whether regular culling or seasonal shifts in prey availability was the cause. Managing lionfish at mesophotic depths is challenging. We utilise technical diving, baited remote underwater video (BRUVs), and eDNA. We have worked with fishers to modify local lobster traps to target lionfish, and are now testing the trap developed by NOAA. We are also working with Robots in Service of the Environment and Atlantic Lionshare to develop remotely operated lionfish culling devices. Yet we still rely on volunteer cullers in the shallows and on grant funding to support deep-water removals. Some cullers are now licensed to sell lionfish caught during research and control efforts, building market demand in restaurants and stores and encouraging more local fishers to target lionfish. Having approached lionfish management from various angles, it is clear that ongoing control will require a range of management tools, along with monitoring to evaluate effectiveness.

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