Patterns of predation of native reef fish by invasive Indo-Pacific lionfish in the western Atlantic: Evidence of selectivity by a generalist predator

Abstract

Among invasive species, introduced predators have some of the most dramatic impacts on native biodiversity, causing declines and extinctions. Selective predation by invasive predators may contribute to their effects on native taxa and taxa that are preyed upon out of proportion to their abundance may be at greatest risk of decline. In this study we aimed to document patterns of selective predation by a spreading invasive species, the Indo-Pacific lionfish (Pterois volitans/miles), with the goal of the identification of native taxa that may be subject to future decline. We took advantage of published data on invasive lionfish stomach contents and native reef fish abundances from a single region (hardbottom reef habitats of North Carolina) and applied a null simulation model to identify native fish taxa that were occurred as lionfish prey more or less frequently than would be expected based on their abundances. Using this method, we found that six of 28 native fish families were significantly under-represented in lionfish stomachs, suggesting that these taxa are avoided by lionfish or occur in different microhabitats. Twelve taxa appeared as prey items only as frequently as would be expected, given their abundance. We identified ten fish families that occurred as lionfish prey drastically and significantly more frequently than would be expected based on their abundance alone. These families include ecologically important species that play important functional roles and help maintain reefs (some parrotfish; Scaridae) and popular food and sport fish and some of the few native species to have been observed eating lionfish in the wild (some groupers; Serranidae). Preferred families were consumed at rates up to 90 times greater than would be expected based on natural abundance, suggesting the potential for local population declines as a result of lionfish predation.