Grouper as a Natural Biocontrol of Invasive Lionfish

Peter J Mumby,Alastair R Harborne,Daniel R Brumbaugh,Brian Gratwicke

doi:10.1371/journal.pone.0021510

Abstract

Lionfish (Pterois volitans/miles) have invaded the majority of the Caribbean region within five years. As voracious predators of native fishes with a broad habitat distribution, lionfish are poised to cause an unprecedented disruption to coral reef diversity and function. Controls of lionfish densities within its native range are poorly understood, but they have been recorded in the stomachs of large-bodied Caribbean groupers. Whether grouper predation of lionfish is sufficient to act as a biocontrol of the invasive species is unknown, but pest biocontrol by predatory fishes has been reported in other ecosystems. Groupers were surveyed along a chain of Bahamian reefs, including one of the region's most successful marine reserves which supports the top one percentile of Caribbean grouper biomass. Lionfish biomass exhibited a 7-fold and non-linear reduction in relation to the biomass of grouper. While Caribbean grouper appear to be a biocontrol of invasive lionfish, the overexploitation of their populations by fishers, means that their median biomass on Caribbean reefs is an order of magnitude less than in our study. Thus, chronic overfishing will probably prevent natural biocontrol of lionfishes in the Caribbean.

Highlights

Over the last five years, one of the world’s most ornate fishes, the lionfish (Pterios volitans/miles), has invaded much of the Caribbean, spanning an area exceeding 5,000 km2 [1]
Fistularids are uncommon in the Caribbean [11] and the only confirmed indication of predation has been the observation of lionfishes in the stomachs of two large-bodied species of grouper, Epinephelus striatus and Myceteroperca tigris [12]
A 20 year ban on fishing in the Exuma Cays Land and Sea Park (ECLSP) has allowed predatory groupers to attain some of the highest biomasses reported anywhere in the Caribbean

Summary

Introduction

Over the last five years, one of the world’s most ornate fishes, the lionfish (Pterios volitans/miles), has invaded much of the Caribbean, spanning an area exceeding 5,000 km2 [1]. Fistularids are uncommon in the Caribbean [11] and the only confirmed indication of predation has been the observation of lionfishes in the stomachs of two large-bodied species of grouper, Epinephelus striatus and Myceteroperca tigris [12]. Some five years after the invasion began, we ask whether these increased densities of groupers are reducing lionfish densities and, if so, consider whether this biocontrol mechanism is likely to be feasible elsewhere in the Caribbean region.

Results

Conclusion