Abstract

A pressing concern in the Caribbean is the invasion of the Indo-Pacific lionfish, Pterois sp. This invasive species poses a threat to native coral reef communities by competing with other predators and feeding on fish and invertebrates, some of which are commercially or ecologically important. The aim of this study was to assess the efficiency of removal efforts on Roatan, Honduras, in controlling lionfish populations and its impact on fish and benthic communities using a combination of stakeholder interviews and reef surveys. Removals were opportunistic and voluntarily performed by dive instructors and tourists, thus frequency of removals varied across dive sites. Frequent removals significantly reduced lionfish abundance to 20 fish/ha compared to 100 fish/ha at control sites and shifted size frequency distribution towards smaller individuals. On sites with no extractions, lionfish abundance was higher than snapper and grouper abundance, indicating intense competi-tion. The abundance of prey-sized fishes, particularly from the families of pomacentride, grammatide and tetraodontidae, was positively and significantly affected by extractions. Invertivores and cleaners as functional groups showed significantly higher abundances on sites with frequent extractions. Herbivore density was similar among sites, however species richness in scaridae was also higher, and turfalgae cover was slightly lower on sites with extractions. Functional diversity indices also indicate higher functional richness related to trophic traits. Therefore, this study shows that local management efforts can control the impact of lionfish and thereby may contribute to protect ecosystem functioning. Consequently, removal ef-forts should be focused on sites of high ecological value.

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