Abstract

The substantial costs involved in the eradication of the invasive lionfish (Pterois volitans and P. miles) leave physical control measures (culling) as the only viable option to limit their populations and associated impacts. To maximize culling effectiveness, identification of habitat types or characteristics most correlated with lionfish presence would be beneficial. Reef complexity in particular is a characteristic that is expected to affect lionfish numbers. This study investigated varia-tions in lionfish densities across habitat types of different complexity and attempted to determine at which scale (site vs. structure) complexity best correlates with lionfish presence and abundance. The seven study sites in the Parque Nacional Marino de Punta Francés, Isla de la Juventud (Cuba) included different habitat types such as patchy reefs and reef slopes. Lionfish density for each site was calculated as the average number of individuals found inside three 30 x 30 m sample areas. The same areas were sampled for rugosity, a proxy for habitat complexity, by taking a measurement every 5 m along six 30 m transects. Rugosity was also measured for every spot where lionfish were found inside the site. Preliminary analysis indicates that site-scale habitat complexity does not significantly affect lionfish presence or density. At a structure scale, however, lionfish appear to preferentially occupy highly complex reef elements such as overhangs where they often congregate. These preliminary results suggest that focusing culling on sites where these structures are present, rather than across more generic habitats, would maximise culling effectiveness.

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