Habitat-specific density and diet of rapidly expanding invasive red lionfish, Pterois volitans, populations in the northern Gulf of Mexico.

Kristen A Dahl,William F Patterson,Craig A Layman

doi:10.1371/journal.pone.0105852

Abstract

Invasive Indo-Pacific red lionfish, Pterois volitans, were first reported in the northern Gulf of Mexico (nGOM) in summer 2010. To examine potential impacts on native reef fish communities, lionfish density and size distributions were estimated from fall 2010 to fall 2013 with a remotely operated vehicle at natural (n = 16) and artificial (n = 22) reef sites. Lionfish (n = 934) also were sampled via spearfishing to examine effects of habitat type, season, and fish size on their diet and trophic ecology. There was an exponential increase in lionfish density at both natural and artificial reefs over the study period. By fall 2013, mean lionfish density at artificial reefs (14.7 fish 100 m−2) was two orders of magnitude higher than at natural reefs (0.49 fish 100 m−2), and already was among the highest reported in the western Atlantic. Lionfish diet was significantly different among habitats, seasons, and size classes, with smaller (<250 mm total length) fish consuming more benthic invertebrates and the diet of lionfish sampled from artificial reefs being composed predominantly of non-reef associated prey. The ontogenetic shift in lionfish feeding ecology was consistent with δ15N values of white muscle tissue that were positively related to total length. Overall, diet results indicate lionfish are generalist mesopredators in the nGOM that become more piscivorous at larger size. However, lionfish diet was much more varied at artificial reef sites where they clearly were foraging on open substrates away from reef structure. These results have important implications for tracking the lionfish invasion in the nGOM, as well as estimating potential direct and indirect impacts on native reef fish communities in this region.

Highlights

Introduction of exotic species to marine ecosystems has been increasing in frequency and severity around the globe, which has lead to an increase in species invasions [1], [2]
Lionfish Density and Size Lionfish density increased rapidly from fall 2010, when no fish were observed at study reefs, through fall 2013, when mean density was 0.49 fishN100 m22 on natural reefs and 14.7 fishN100 m22 on artificial reefs (Fig. 2)
analysis of variance (ANOVA) is robust to violations of normality [45], the two-factor model testing the effect of habitat and year on lionfish density was computed with ln-transformed data

Summary

Introduction

Introduction of exotic species to marine ecosystems has been increasing in frequency and severity around the globe, which has lead to an increase in species invasions [1], [2]. Predator-prey interactions are known to shape community assemblages in both terrestrial and marine systems [11], [12], predator invasions are expected to have the most damaging impact on native ecosystems [13], [14], [15]. The GOM is the most recently invaded of these basins, where lionfish were not reported until 2009 off the northern Yucatan peninsula, Mexico [22]. Pterois volitans (hereafter lionfish), were first reported from northern GOM (nGOM) in summer 2010 and have since been observed in the western GOM as well [20], [23], [24]

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Results

Conclusion