Invasive lionfish increase activity and foraging movements at greater local densities

Abstract

Density-dependent changes in predator foraging behavior due to intraspecific competition for food can have important implications for population dynamics of both the predator and its prey. The Indo-Pacific red lionfish Pterois volitans is an invasive predatory reef fish that has reached high population densities and can cause large reductions in small native fishes. To determine whether lionfish behavior or movement varies with local lionfish and/or prey densities, I conducted observations of lionfish on 16 coral patch reefs in The Bahamas. Lionfish foraging activity and movement varied significantly with lionfish density. At higher densities, lionfish exhibited greater activity levels, time away from shelter, and more short-term foraging movements between coral patch reefs and surrounding seagrass habitats. However, these changes were not uniform throughout the day, with differences in activity occurring only at dusk and differences in movement occurring at both dawn and dusk, but not midday. Although some lionfish foraging behaviors varied with prey density, overall lionfish density was more strongly related to differences in lionfish activity patterns. These temporal and spatial changes in lionfish foraging behaviors are consistent with the predicted effects of intraspecific competition and may have important consequences for lionfish removal efforts and native prey populations. Specifically, in areas with higher lionfish densities, prey fishes that are more active at dusk and/or inhabit seagrass beds near coral patch reefs may be more vulnerable to lionfish predation. By culling lionfish, managers may reduce the local foraging movements of lionfish and thus help maintain native fish communities in multiple habitats.

Testing the efficacy of lionfish traps in the northern Gulf of Mexico

“…Counterintuitively, our results indicated that lionfish density on the adjacent artificial reef was not a significant predictor of lionfish recruitment nor catch. We had expected lionfish movement from reefs to traps would be driven by overcrowding given high lionfish densities have been related to local prey depletion [12,14,58], cannibalism [59,60], and lower body condition [53], and greater movement on coral reefs [61,62].…”

“…This is higher than many fisheries where removal efficiency is <10% [63–65], but considerably lower than the >85% removal efficiency for spearfishing lionfish on nGOM artificial reefs [46]. Given spearfishing can reduce lionfish densities in areas frequented by divers [66–68] and spearfishing fisheries have caused severe depletion of other reef fishes [69–71], we expect spearfishing to remain the most efficient and cost-effective method for removing lionfish biomass at depths <40 m. Removal efficiencies and uncaptured lionfish will need to be considered when evaluating the potential community benefits offered by lionfish trapping as lionfish removals do not necessarily translate into ecological benefits [14,72,73] given lionfish predation [62,74], growth [53,75], and colonization [14,73,76] rates are controlled via density-dependent feedbacks. Ecosystem models may be appropriate for examining the potential community effects of a deepwater lionfish fishery [15,77].…”

“…Lionfish densities on nGOM artificial reefs are about two orders higher than on nGOM natural reefs [3,46,53], suggesting trap structure may readily attract lionfish from natural reefs. However, if lionfish movement is largely driven by density-dependence or food availability [14,61,62], then the substantially lower densities on natural reefs may limit the effectiveness of lionfish traps near these reefs and the economic viability of a deepwater lionfish fishery.…”

Spatiotemporal population genomics of marine species : invasion, expansion, and connectivity

“…Glutamate receptors have been shown to be under selection in other teleost fish species, including the European eel and small yellow croaker (Pujolar et al 2014b;Liu et al 2016). There is some evidence that behavioral movement patterns are changing as the lionfish invasion progresses (Benkwitt 2016), which could be related to changes in the pathways …”

Behavioural traits and feeding ecology of Mediterranean lionfish and native species naiveté to lionfish predation

“…sunrise, noon and sunset) to test the hypothesis of a crepuscular pattern in hunting activity (i.e. sunrise and sunset) as this has been shown in the Atlantic invasion (Cure et al 2012, Benkwitt 2016) and invoked as one of the behavioural traits facilitating their invasive success (i.e. increased hunting success and broader array of preys available) (Hobson 1973, Potts 1990, Green et al 2011).…”