Rapid Invasion of Indo-pacific Lionfishes (pterois Volitans and Pterois Miles) in the Florida Keys, Usa: Evidence from Multiple Pre- and Post-invasion Data Sets

Over the past decade, Indo-Pacific lionfishes, Pterois volitans (Linnaeus, 1758) and Pterois miles (Bennett, 1828), venomous members of the scorpionfish family (Scorpaenidae), have invaded and spread throughout much of the tropical and subtropical northwestern Atlantic Ocean and Caribbean Sea. These species are generalist predators of fishes and invertebrates with the potential to disrupt the ecology of the invaded range. Lionfishes have been present in low numbers along the east coast of Florida since the 1980s, but were not reported in the Florida Keys until 2009. We document the appearance and rapid spread of lionfishes in the Florida Keys using multiple long-term data sets that include both preand post-invasion sampling. Our results are the first to quantify the invasion of lionfishes in a new area using multiple independent, ongoing monitoring data sets, two of which have explicit estimates of sampling effort. Between 2009 and 2011, lionfish frequency of occurrence, abundance, and biomass increased rapidly, increasing threeto six-fold between 2010 and 2011 alone. In addition, individuals were detected on a variety of reef and non-reef habitats throughout the Florida Keys. Because lionfish occurrence, abundance, and impacts are expected to continue to increase throughout the region, monitoring programs like those used in this study will be essential to document ecosystem changes that may result from this invasion. Invasive species, non-native species whose introduction may cause economic or environmental harm, are one of the greatest conservation threats to global biodiversity, with economic costs estimated to exceed US$100 billion annually in the United States alone (Pimentel et al. 2005, Sutherland et al. 2010). Most invasions have occurred in terrestrial, freshwater, or estuarine environments, with fewer examples from fully marine systems (e.g., Sakai et al. 2001, Molnar et al. 2008). However, invasions in marine systems appear to be increasing in number and impact in recent years (Ruiz et al. 2000, Molnar et al. 2008). Over the past decade, Indo-Pacific lionfishes have invaded the tropical and subtropical northwestern Atlantic Ocean and Caribbean Sea, becoming the first nonnative marine fishes to establish self-sustaining populations and spread rapidly throughout this region (Whitfield et al. 2002, Freshwater et al. 2009, Morris and Akins 2009, Schofield 2009, 2010). Invasive lionfishes represent two morphologically similar species, Pterois volitans (Linnaeus, 1758) and Pterois miles (Bennett, 1828); hereafter “lionfishes” refers to both species. They are venomous members of the scorpionfish family (Scorpaenidae), native to the Indo-Pacific region. Lionfishes are generalist predators that feed on a wide variety of fishes and invertebrates (Morris and CORAL REEF PAPER