Abstract

Management focus on the lionfish (Pterois volitans) invasion has recently shifted from eradication to control. One popular method has been organized removals, such as derbies. Only recently have researchers addressed the efficacy of these strategies. However, no current studies have evaluated the recovery of native ichythofauna in response to these removals. This study assessed the effectiveness of a small scale, dedicated lionfish removal in Puerto Rico. We utilized volunteer, skilled spearfishermen and a standardized procedure to target one near-shore reef to reduce lionfish numbers and observe potential lionfish re-colonization and restoration of native cryptic fish species. A Before-After-Control-Impact design allowed for lionfish, native piscivores and native prey fish abundance and richness to be compared before and after the removal. Two control sites remained untouched but lionfish were tagged to monitor movements. The removal spanned 0.8 km along the forereef, to mimic a manageable marine protected area, and occurred on three nonconsecutive Saturdays in the month of June 2013. A total of 22 lionfish were removed; one year post removal only 10 lionfish were observed, none with tags. Lionfish size-frequency indicated that re-colonization was occurring from juveniles, most likely recruiting from back reef nursery habitats rather than through lateral movement from outside the removal zone. Abundance of native predators and prey increased after lionfish removal. This study demonstrates that a small effort can yield a large impact in reducing lionfish numbers, restoring the native ichythofauna, and thereby enhancing ecosystem balance.

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