Diet of invasive lionfish on hard bottom reefs of the Southeast USA: insights from stomach contents and stable isotopes

The Indo-Pacific lionfish (Pterois volitans and P. miles complex) has become widely established along the United States Southeast coast and continues to colonize the Caribbean, yet its biology and ecology is only beginning to be understood. We used stomach contents and stable isotope analyses to determine the diet of lionfish in the warm-temperate hard bottom reef community in the Southeast US Atlantic Ocean. During June to August 2004 and 2006, we collected lionfish with SCUBA from 18 different locations in Onslow Bay, North Carolina, at depths of 30 to 45 m. In 2006, we also conducted visual surveys of small benthic fishes to estimate the abundances of potential prey. Analyses of stomach contents (n = 183) and stable isotopes (n = 115) suggest a generalist carnivorous diet, and prey categories were predominately fish (similar to 99% of total volume) from 16 families. Major differences in the importance of prey occurred between years. Serranidae and Scaridae dominated the diet in 2004, while Haemulidae and Carangidae were important in 2006. Analyses of visual prey surveys did not reveal specialization on particular prey taxa but instead suggest that prey are consumed in relation to their local abundance. Given current theory pertaining to invasive species impacts, the expanding lionfish distribution, and observations that lionfish appear capable of settling to many different habitat types, the overall pattern of generalist piscivory emerging from these data indicates the potential for significant impacts to the invaded community.