Invasive Lionfish (Pterois volitans and P. miles): Distribution, Impact, and Management

Abstract

Non-native lionfish have invaded mesophotic coral ecosystems (MCEs) across the western Atlantic and are in the early stages of invading mesophotic depths in the Mediterranean Sea. Records of invasive lionfish at mesophotic depths from both non-native ranges are reviewed herein, including from 15 distinct countries/geographic areas in the western Atlantic region and 6 eastern Mediterranean countries. Lionfish (Pterois volitans and P. miles) generally occur at high densities on many western Atlantic upper MCEs (30–60 m), with the highest abundances associated with areas of greater structural complexity. Despite several studies reporting lionfish on lower MCEs (60–150 m) and the deep sea (>200 m), there has been little quantification of these deeper lionfish populations. There is currently conflicting evidence whether MCE lionfish populations represent extensions of shallow reef ontogenetic migrations. While many studies report larger lionfish on MCEs than adjacent shallow habitat, these are often confounded by the presence of shallow reef lionfish culling. Several studies have directly quantified invasive lionfish impacts on MCEs, which all record lionfish causing declines in fish abundance or diversity on western Atlantic upper MCEs. No studies have quantified lionfish impacts on reefs >91 m depth. While lionfish control measures for MCEs, such as culling and trapping, are increasingly being adopted, there is currently little evidence these mitigate lionfish impacts on MCEs.