Trait‐based vulnerability reveals hotspots of potential impact for a global marine invader

Abstract

Predation from the invasive Indo‐Pacific lionfish is likely to amplify declines in marine fishes observed in multiple ocean basins. As the invasion intensifies and expands, there is an urgent need to identify species that are most at risk for extirpation—and possible extinction—from this added threat. To address this gap and inform conservation plans, we develop and apply a quantitative framework for classifying the relative vulnerability of fishes based on morphological and behavioural traits known to influence susceptibility to lionfish predation (e.g. body shape, water column position and aggregation behaviour), habitat overlap with lionfish, and degree of geographic range restriction. Applying the framework to fishes across the invaded Caribbean Sea and ahead of the invasion front in the southwestern Atlantic revealed the identity of at least 77 fishes with relatively small ranges that are likely to be most affected by lionfish predation. Trait‐based vulnerability scores significantly predict the probability of fishes appearing within the diets of lionfish across the invaded region. Spatial richness analyses reveal hotspots of vulnerable species in the Bahamas, Belize and Curaçao. Crucially, our framework identifies 29 vulnerable fishes endemic to Brazil, which has not yet been colonized by lionfish. Of these, we suggest reefs around offshore island groups occupied by a dozen highly vulnerable and range‐restricted species as priorities for intervention should lionfish spread to the region. Observations of the rate of lionfish spread across the invaded range suggest that an average of 5 years (with a median of nearly 2 years) elapses from first sighting to maximum observed densities. This lag may allow managers to mobilize plans to suppress lionfish ahead of an invasion front in priority locations. Our framework also provides a method for assessing the relative vulnerability of cryptobenthic and/or deep‐reef fishes, for which population‐monitoring data are limited.

Lionfish on the loose: Pterois invade shallow habitats in the tropical southwestern Atlantic

“…Marginal tropical reef assemblages from northeastern Brazil are characterized by low coral species richness and high endemism (Castro and Pires, 2001;Floeter et al, 2008;Pinheiro et al, 2018). The equatorial coast of Brazil has a higher number of cryptic and endemic fish species (Araujo et al, 2020) compared to the Caribbean region (Linardich et al, 2021), and further impacts need to be studied. A recent trait-based vulnerability approach detected 29 fish species endemic (e.g., Entomacrodus vomerinus and Haemulon squamipinna) to Brazil and are vulnerable to lionfish impacts (Linardich et al, 2021).…”

“…The equatorial coast of Brazil has a higher number of cryptic and endemic fish species (Araujo et al, 2020) compared to the Caribbean region (Linardich et al, 2021), and further impacts need to be studied. A recent trait-based vulnerability approach detected 29 fish species endemic (e.g., Entomacrodus vomerinus and Haemulon squamipinna) to Brazil and are vulnerable to lionfish impacts (Linardich et al, 2021). If the lionfish populate these natural and artificial reefs at the same densities that they have reached in the Caribbean, local population reductions are a possibility among some endemics (e.g., H. squamipinna, Scarus trispinosus, and Sparisoma frondosum) (Araujo et al, 2020;Luiz et al, 2021).…”

Trait-based approaches to global change ecology: moving from description to prediction

“…While continuous trait variables are more tractable for modeling, classifying taxa into discrete (i.e. categorical) trait groups may offer convenience, especially for conservation prioritization [42,43]. The list of traits synthesized in this review could provide a starting place for researchers who seek to identify suites of organism attributes related to ecological processes within their research (electronic supplementary material, tables S2 and S3).…”

Lessons From the Western Atlantic Lionfish Invasion to Inform Management in the Mediterranean

“…The situation is complicated by the fact that nations like Israel and Egypt border two seas-the Mediterranean where lionfish are invasive and the Red Sea where lionfish and other Pterois species are native protected species that cannot be fished or traded. Lessons from Western Atlantic indicate lionfish abundances increase rapidly following detection and can reach peak levels two years (Linardich et al, 2021), highlighting the need for rapid action.…”

“…Given limited resources, it is important to identify and/or prioritize removal efforts spatially and temporally. These may include highly visited tourist areas, marine protected areas, and nursery and spawning aggregation sites for commercially and ecologically important fishes that are impacted by lionfish (Akins, 2012;Linardich et al, 2021).…”