Invasive lionfish reduce native fish abundance on a regional scale

Abstract

Invasive lionfish pose an unprecedented threat to biodiversity and fisheries throughout Atlantic waters off of the southeastern United States, the Caribbean, and the Gulf of Mexico. Here, we employ a spatially replicated Before-After-Control-Impact analysis with temporal pairing to quantify for the first time the impact of the lionfish invasion on native fish abundance across a broad regional scale and over the entire duration of the lionfish invasion (1990–2014). Our results suggest that 1) lionfish-impacted areas off of the southeastern United States are most prevalent off-shore near the continental shelf-break but are also common near-shore and 2) in impacted areas, lionfish have reduced tomtate (a native forage fish) abundance by 45% since the invasion began. Tomtate served as a model native fish species in our analysis, and as such, it is likely that the lionfish invasion has had similar impacts on other species, some of which may be of economic importance. Barring the development of a control strategy that reverses the lionfish invasion, the abundance of lionfish in the Atlantic, Caribbean, and Gulf of Mexico will likely remain at or above current levels. Consequently, the effect of lionfish on native fish abundance will likely continue for the foreseeable future.

The lionfish Pterois sp. invasion: Has the worst‐case scenario come to pass?

“…The losses observed so far have affected prey‐sized fishes (usually <10 cm L T ), as Albins & Hixon () had speculated, but even within longer studies, these losses have not translated into similar deficits in larger prey size classes (Green et al, ; Albins, ). The one possible exception is the regional decline of adult tomtate grunt Haemulon aurolineatum Cuvier 1830 off the south‐eastern U.S.A. (Table ), which has been attributed to lionfish predation on juveniles (Ballew et al, ). It might ultimately be difficult to ascribe part or all of downward trends in commercially important species to lionfish predation because of the coarseness of most fisheries data and the multiple stressors (including fishing) affecting these species.…”

“…Ballew et al . () found no changes in predatory fish numbers while lionfish density increased and H. aurolineatum abundance tumbled on the south‐east coast of the U.S.A. On one Bahamian mesophotic reef, however, there appears to have been a wholesale replacement of native mesopredators by the same density of lionfish (Lesser & Slattery, ), although the mechanism by which this substitution occurred is unclear. Other declines of mesopredators occurring concurrently with a build‐up of lionfish numbers cannot be clearly ascribed to predation or competition (Green et al, ; Tuttle, ).…”

“…In some places, rates of prey consumption by lionfish far exceed prey production rates and the majority of native fish biomass is being converted to lionfish biomass, as envisioned by Albins & Hixon (2013). A couple of trends, however, are emerging from the many observational and experimental (Elise et al, 2015;Ballew et al, 2016), predator declines ascribed to lionfish (Lesser & Slattery, 2011;Tuttle, 2017), predator declines not ascribed to lionfish (Ingeman, 2016); reductions in species richness on reefs with lionfish (Albins, 2013(Albins, , 2015Benkwitt, 2015;Ellis & Faletti, 2016); high rate of predation on a Belizean restricted-range endemic Indirect effects on benthos Decline in coral cover and increase in macroalgal cover…”

Lionfish misidentification circumvents an optimized escape response by prey

“…Released by accident or misadventure in the mid-1980s off the coast of Florida, they have spread throughout the Caribbean, where populations have grown exponentially, with substantial impact to the community composition (Betancur-R et al ., 2011; Albins and Hixon, 2013; Côté et al ., 2013; Benkwitt, 2014; Ballew et al ., 2016). Densities in some places of the Caribbean have been estimated at 400 ha −1 (Morris and Whitfield, 2009), with lionfish consuming 8–10% of their body weight per day (Green et al ., 2011).…”

Invasive species reduces parasite prevalence and neutralizes negative environmental effects on parasitism in a native mosquito

“…triseriatus larval abundance. Alterations to host density is one of the purported mechanisms of the dilution effect (Keesing et al, ), and one of the negative impacts invasive species has been shown to have on some native species (Ballew, Bacheler, Kellison, & Schueller, ). Previous laboratory studies have shown little asymmetrical competition between the two mosquito species in our study (Freed, Kesavaraju, & Leisnham, ; Hardstone & Andreadis, ), although we did predict that the removal of Ae .…”