Abstract

Lionfish (Pterois volitans and P. miles) from the Indo-Pacific invaded the northwest Atlantic Ocean nearly 30 years ago and have since spread into the Gulf of Mexico and Caribbean Sea. As generalist predators with a broad diet, they pose a major threat to economically and ecologically important fish species and, therefore, the overall health of coral reef ecosystems. At this time, the invasion appears to be developing slowly in Bermuda, relative to other locations throughout the Atlantic, providing an opportunity to study their ecological impact at an early stage. Using stable isotope analysis, this study investigated the feeding ecology of lionfish and, to provide a more complete assessment, lionfish prey and competitors were included in the analysis to investigate community structure and trophic interactions. Results suggest that lionfish in Bermuda primarily derive resources from the planktonic food web with only a small contribution from that of macroalgae. Further, it appears that lionfish resource use overlaps substantially with other similarly-sized mesopredators found in the same habitats, in particular the coney grouper (Cephalopholis fulva). Finally, this study is the first to experimentally derive stable isotope discrimination factors for lionfish and the first to visualize Bermuda’s demersal ecosystem in two-dimensional isotope space. This information will help track the ecological impact of lionfish over time, predict potential changes in community structure, and inform a developing control strategy.

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