Ecological Drivers of Invasive Lionfish (Pterois volitans and Pterois miles) Distribution Across Mesophotic Reefs in Bermuda

Gretchen Goodbody-Gringley,Struan Robertson Smith,Joanna Maria Pitt,Alex D. Chequer,Corey Eddy

doi:10.3389/fmars.2019.00258

Gretchen Goodbody-Gringley, Struan Robertson Smith + Show 3 more

Open Access

https://doi.org/10.3389/fmars.2019.00258

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Abstract

Invasive lionfish (Pterois volitans and P. miles) are now ubiquitous throughout the Caribbean and Western Atlantic on shallow and deep reefs. Recent surveys in Bermuda have revealed dense aggregations of lionfish on mesophotic reefs (60 m depth), yet these densities are not pervasive across reefs at this depth. Using diver-led visual surveys of mesophotic reef sites, this study examines how variations in potential ecological drivers may affect lionfish distribution. Significant correlations of lionfish densities were found with prey fish density and prey fish biomass, where sites with higher abundances of prey fishes have greater densities of lionfish. Furthermore, higher densities of lionfish also correlated significantly with higher juvenile Paranthias furcifer biomass, a preferred prey type for lionfish. Prey fish diversity, on the other hand, was not related to lionfish density, nor did prey fish community composition differ in a way that reflected lionfish distributions. The influence of seawater temperature was found to have the strongest effect on lionfish distribution, where higher lionfish densities were found at sites with lower bottom temperature. However, temperature co-varied with prey fish density, prey fish biomass, and P. furcifer biomass, implying that physical parameters of the environment (i.e. temperature) likely influence ecological parameters (i.e. prey fish abundance), contributing to the structuring of lionfish distributions. We suggest, therefore, that cold-water upwelling currents may be fueling the food chain in certain locations, resulting in high abundances of prey fishes and thus lionfish. Understanding the factors that influence lionfish distributions will ultimately increase the efficacy of management strategies, which, as the data presented here suggest, must incorporate mesophotic lionfish populations.

Highlights

Pterois miles and P. volitans, collectively known as lionfish, are predatory fish belonging to the family Scorpaenidae, native to the Indian and Pacific oceans
Significant positive correlations were found between lionfish density and prey fish density (r = 0.7; p = 0.03) and between lionfish density and prey fish biomass (r = 0.7; p = 0.01), where higher lionfish density was correlated with higher prey fish density and higher prey fish biomass (Figure 3)
Lionfish density was significantly negatively correlated with bottom temperature (r = −0.7; p = 0.02), where higher lionfish density was found at sites with lower temperatures (Figure 3)

Summary

Introduction

Pterois miles and P. volitans, collectively known as lionfish, are predatory fish belonging to the family Scorpaenidae, native to the Indian and Pacific oceans. A high reproductive rate coupled with the lack of native predators has allowed lionfish populations in the western Atlantic to flourish, reaching densities exceeding those found in their native habitats by a factor of 13 to 15 (Darling et al, 2011; Kulbicki et al, 2012). These high densities of lionfish indicate that they have become invasive and could potentially affect the biodiversity and structure of reef fish communities, and cause significant ecosystem change (Lesser and Slattery, 2011; Albins, 2013)

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