Invasive Lionfish Research Articles

Growth parameters of the invasive lionfish (Pterois volitans) in the Colombian Caribbean

The success of the lionfish invasion in the western Atlantic can be explained by its rapid dispersion rate, as well as a rapid population growth due to its high fecundity. The adequate invasion control measures may vary between (sub) populations of the wider Caribbean region with differences in ecological and environmental conditions. Lionfish growth studies have been conducted in several places in the invaded region, but are missing from the southern Caribbean. We estimated the growth parameters and empirical natural mortality rates of P. volitans in the Colombian Caribbean and compare them with other native mesopredatory fish. To do so, we used Tropfish R and fishboot, a recently developed statistical stock assessment package that incorporates resampling techniques and allows for estimating the confidence interval around the estimates. Size records of 1184 speared fish caught between 2014 and 2017 in continental and insular reef areas were analyzed. Our results confirm the rapid growth of lionfish (K=0.44; C=0.62) and reveal high similarities in growth rate among Colombian Caribbean areas but differences among the invaded area regions, primarily explained by water temperature, habitat heterogeneity and structural complexity, food availability, potential bathymetric ontogenetic movement, and the time elapsed since colonization. The invader’s efficiency over its competitors is best explained by the lionfish’s fast growth and early age at maturity.

Relative Effects of Multiple Stressors on Reef Food Webs in the Northern Gulf of Mexico Revealed via Ecosystem Modeling

Since 2010, the northern Gulf of Mexico (NGoM) has experienced two unique environmental stressors. First, the 2010 Deepwater Horizon oil spill (DWH) impacted a broad range of taxa and habitats and resulted in declines of small demersal reef fish over the study area (88.5°-85.5° W, 29°-30.5° N). Then, from 2011-2014 the invasive Indo-Pacific lionfish (Pterois volitans) underwent exponential population growth, leading to some of the highest densities in their invaded range. The primary objective of this study was to evaluate the effect of these stressors on reef ecosystems, and specifically how invasive lionfish and fishing may have impacted recovery following DWH. Site-specific datasets on fish density and diet composition were synthesized into an Ecopath with Ecosim food web model of a NGoM reef ecosystem. The model consisted of 63 biomass groups and was calibrated to time series of abundance from 2009-2016. The model accounted for mortality from the DWH using forcing functions derived from logistic dose-response curves and oil concentrations. Eight stressor scenarios were simulated, representing all combinations of DWH, lionfish, and fishing. Simulated biomass differed across model groups due to singular and cumulative impacts of stressors and direct and indirect effects arising through food web interactions. Species with high exploitation rates were influenced by fishing more than lionfish following DWH. Several small demersal fish groups were predicted to be strongly influenced by either the cumulative effects of lionfish and DWH or by lionfish alone. A second group of small demersal fish benefited in the stressor scenarios due to reduced top-down predation and competition in the combined stressor scenarios. We conclude that lionfish had a major impact on this ecosystem, leading to slower recoveries following DWH and lower fish biomass and diversity. Additionally, the lack of recovery for some groups in the absence of lionfish suggests system reorganization may be preventing return to a pre-DWH state. We intended for this work to improve our understanding of how temperate reef ecosystems, like those in the NGoM, respond to broad scale stressors and advance the state of applied ecosystem modeling for resource damage assessment and restoration planning.

Stable Isotope Ecology of Invasive Lionfish (Pterois volitans and P. miles) in Bermuda

Over the past three decades, lionfish (Pterois volitans and P. miles) from the Indo-Pacific have invaded the northwest Atlantic Ocean, Caribbean Sea and the Gulf of Mexico. As generalist predators with a broad diet, they could pose a major threat to economically and ecologically important species and, therefore, the overall health of coral reef ecosystems and the communities that rely on them. In Bermuda, the lionfish invasion appears to be progressing at a slower rate than elsewhere in the invaded range, providing an opportunity to study their ecological impact at an early stage. This study used stable isotope analysis of lionfish, their major prey, and their competitors to investigate the feeding ecology of lionfish in Bermuda and provide a more complete evaluation of their potential impacts on community structure and trophic interactions. Results suggest that lionfish in Bermuda primarily derive resources from the plankton-based food web, with only a small contribution from food chains supported by macroalgae. Further, it appears that lionfish resource use overlaps substantially with other similarly-sized sympatric mesopredators, in particular the coney grouper (Cephalopholis fulva), a species commonly targeted by local commercial fisheries. This visualization of Bermuda’s demersal ecosystem in two-dimensional isotope space, the first of its kind, will help track the ecological impact of lionfish over time, predict potential changes in community structure, and better inform developing control strategies for this invasive species.

Low salinity negatively affects metabolic rate, food consumption, digestion and growth in invasive lionfish Pterois spp.

The establishment of the piscivorous lionfishPteroisspp. in the Western Atlantic and wider Caribbean is a well-documented example of a successful marine invasion. Recently, lionfish have been shown to colonise a wide range of ecosystems and tolerate a wider range of salinities than previously thought. In the present study, lionfish were maintained in aquaria under differing salinity treatments (10, 20 and 37 psu) similar to those they might experience in an estuarine ecosystem. The effects of long-term hyposaline exposure on growth, metabolic rate, maximum food consumption and digestion were examined. Consistent with previous studies, lionfish were able to survive in hyposaline conditions for extended periods of time. However, lionfish in the most hyposaline treatment (10 psu) exhibited reduced growth under low food conditions, lower maximum metabolic rate, lower aerobic scope, lower maximum food consumption, took longer to digest a standardized meal size and occupied a greater percentage of their aerobic scope during digestion. Results suggest that (1) given the ability of lionfish to tolerate low salinity, updated range expansion models should incorporate salinity data to improve accuracy of predicted range expansion and (2) the invasion of lionfish into low salinity ecosystems, although a serious concern, will not likely lead to the same level of population increase observed for coral reef habitats due to the physiological costs associated with living in low salinities.

The effect of salinity on behavioural interactions between native Schoolmaster snapper (Lutjanus apodus) and invasive lionfish (Pterois spp)

Species invasions are a widely-recognized threat to regional and global biodiversity. Lionfish (Pterois spp.), are an invasive marine fish that have been shown to reduce the recruitment and biomass of native reef fish throughout the Caribbean. Recently, it has become clear that lionfish are able to colonise a wide range of ecosystems (mesophotic reefs to brackish estuaries to mangroves) and tolerate a wider range of salinities than previously thought. Estuarine ecosystems often experience hyposaline conditions and act as critical foraging habitats for many ecologically and economically important species. Using a habitat competition experiment at two salinity treatments (10 practical salinity units (psu) and 37 psu control) we investigated the potential effects of lionfish on native Schoolmaster snapper (Lutjanus apodus; a tropical fish species found in high abundance in estuarine ecosystems). Schoolmaster snapper showed a 62% and 47% reduction in cover use when in the presence of lionfish in the 10 psu and 37 psu treatments, respectively. Further, five of the seven behaviours investigated during the interaction period, where both lionfish and snapper had access to the shelter, showed a significant reduction at low salinity, suggesting physiological or behavioural impairment of lionfish at low salinity. Because estuarine habitats are disproportionately important habitats for juvenile fishes, even physiologically or behaviourally compromised lionfish are likely to have some impact.

Genetic connectivity of lionfish (Pterois volitans) in marine protected areas of the Gulf of Mexico and Caribbean Sea.

Lionfish (Pterois volitans) have rapidly invaded the tropical Atlantic and spread across the wider Caribbean in a relatively short period of time. Because of its high invasion capacity, we used it as a model to identify the connectivity among nine marine protected areas (MPAs) situated in four countries in the Gulf of Mexico and the Caribbean Sea. This study provides evidence of local genetic differentiation of P. volitans in the Gulf of Mexico and the Caribbean Sea. A total of 475 lionfish samples were characterized with 12 microsatellites, with 6–20 alleles per locus. Departures from Hardy–Weinberg equilibrium (HWE) were found in 10 of the 12 loci, all caused by heterozygous excess. Moderate genetic differentiation was observed between Chiriviche, Venezuela and Xcalak, México localities (F ST = 0.012), and between the Los Roques and the Veracruz (F ST = 0.074) sites. STRUCTURE analysis found that four genetic entities best fit our data. A unique genetic group in the Gulf of Mexico may imply that the lionfish invasion unfolded both in a counterclockwise manner in the Gulf of Mexico. In spite of the notable dispersion of P. volitans, our results show some genetic structure, as do other noninvasive Caribbean fish species, suggesting that the connectivity in some MPAs analyzed in the Caribbean is limited and caused by only a few source individuals with subsequent genetic drift leading to local genetic differentiation. This indicates that P. volitans dispersion could be caused by mesoscale phenomena, which produce stochastic connectivity pulses. Due to the isolation of some MPAs from others, these findings may hold a promise for local short‐term control of by means of intensive fishing, even in MPAs, and may have regional long‐term effects.

Changes in Reef Fish Community Structure Following the Deepwater Horizon Oil Spill

Large-scale anthropogenic disturbances can have direct and indirect effects on marine communities, with direct effects often taking the form of widespread injury or mortality and indirect effects manifesting as changes in food web structure. Here, we report a time series that captures both direct and indirect effects of the Deepwater Horizon Oil Spill (DWH) on northern Gulf of Mexico (nGoM) reef fish communities. We observed significant changes in community structure immediately following the DWH, with a 38% decline in species richness and 26% decline in Shannon-Weiner diversity. Initial shifts were driven by widespread declines across a range of trophic guilds, with subsequent recovery unevenly distributed among guilds and taxa. For example, densities of small demersal invertivores, small demersal browsers, generalist carnivores, and piscivores remained persistently low with little indication of recovery seven years after the DWH. Initial declines among these guilds occurred prior to the arrival of the now-widespread, invasive lionfish (Pterois spp.), but their lack of recovery suggests lionfish predation may be affecting recovery. Factors affecting persistently low densities of generalist carnivores and piscivores are not well understood but warrant further study given the myriad ecosystem services provided by nGoM reef fishes.

Size, weight, and diet of the invasive lionfish Pterois volitans (Linnaeus, 1758) on the southern coast of Veracruz, Gulf of Mexico

The invasion of the Indo-Pacific lionfish Pterois volitans has produced detrimental impacts on the regional biodiversity and fisheries of invaded ranges. To understand the effect this lionfish may have on the native fish communities, it is necessary to understand its feeding habits. The objectives of this study were to report new distribution records of P. volitans along the southern coast of Veracruz (México), to document the feeding habits of the collected specimens, and to determine if there was a relationship between the diet, size, and weight of those specimens. The density of P. volitans in our study area was low. Diet composition for this species consisted of bony fishes (95.40%), crustaceans (4.20%), and mollusks (0.36%). Lionfish size and weight were positively correlated. We did not find statistical differences between the diet and the size/weight groupings; however, the smaller specimens seemingly had a more varied diet than the larger specimens.

Habitat suitability, niche unfilling and the potential spread of Pterois miles in the Mediterranean Sea

The common lionfish Pterois miles has rapidly spread across the eastern Mediterranean Sea. We compiled occurrence data from both native and invaded range under the framework of Species Distribution Modelling (SDM). Through a construction of an environmental suitability model and estimation of spread rates we investigated the lionfish climate niche in both its native and invaded domains, this latter represented by the Mediterranean region. Model projections allowed to identify suitable areas for lionfish establishment in the Mediterranean. Spread analysis suggested that a further geographical expansion in this basin could be completed within the next years. Our results did not provide evidence for niche expansion but highlighted a high degree of niche unfilling thus prospecting a likely spread of Mediterranean lionfish invasion beyond the predictions of current SDMs. These findings provide novel inputs to forecast the future geographical evolution of the lionfish in the Mediterranean Sea and asses the related risk of invasion.

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

The detrimental effects of invasion by Indo-Pacific lionfish Pterois volitans/miles on western Atlantic fishes have spurred concerns for Mediterranean fish biodiversity, where Lessepsian lionfish P. miles have recently established populations in the eastern basin. In order to assess the potential impact on biodiversity, we examined key behavioural and ecological traits of lionfish and the resident fish community in the Mediterranean that may contribute to lionfish invasion success. We focussed on Cyprus, where lionfish were first sighted in 2012 and have now formed abundant and stable populations. Using field observations, we examined lionfish predatory behaviour and feeding ecology, and naiveté of resident fish species to hunting lionfish. Our findings suggest that lionfish in the Mediterranean are crepuscular generalist predators, with targeted prey dominated by small-bodied benthic or bentho-pelagic associated species. Such prey are more likely to be native than introduced (Lessepsian) fishes, with native prey fishes showing greater naiveté towards lionfish than Lessepsian prey species. Notably, one of the Mediterranean’s key ecological fish species (the native damselfish Chromis chromis) showed the highest level of naiveté and was the most heavily targeted prey. Overall, lionfish in the Mediterranean show similar predatory behaviour and ecology to their western Atlantic counterparts. Although the establishment of Mediterranean lionfish populations is still recent, it may result in a similar disruption to reef fish biomass to that recorded in the Atlantic, with impacts on the structure and biodiversity of reef fish communities and the services they provide.

Physiological limits to inshore invasion of Indo-Pacific lionfish (Pterois spp.): insights from the functional characteristics of their visual system and hypoxia tolerance

Indo-Pacific lionfish (Pterois spp.) have become established throughout the Caribbean and the coastal regions of the Gulf of Mexico and western Atlantic Ocean from North Carolina to central Brazil. Lionfish may also invade estuaries, as they tolerate salinities down to 4‰. We hypothesize that the functional characteristics of their visual system (which evolved in the clear tropical waters of the Indo-Pacific) or their inability to tolerate hypoxia will limit the capacity of lionfish to occupy these areas. We assessed the former with corneal electroretinography and the latter with intermittent-flow respirometry. The luminous sensitivity, temporal resolution (quantified as flicker fusion frequency), and spectral sensitivity of the lionfish visual system are like those of native piscivores, indicating that their visual system will be functional under estuarine photic conditions and allow lionfish to be effective piscivores. In contrast, acute exposure to reduced oxygen levels (equivalent to those commonly occurring in mid-Atlantic and Gulf of Mexico estuaries) exceeded the physiological tolerances of lionfish. We therefore conclude that hypoxia will control or limit estuarine invasion.

Stable isotope analysis of eye lenses from invasive lionfish yields record of resource use

Patterns of stable isotopes recorded in metabolically stable, serially synthesized, structures such as eye lenses can yield robust descriptions of resource use across the life histories of individual fish. We performed stable isotope analysis of eye lenses sampled from invasive lionfishes Pterois spp. and a potentially competitive native mesopredator, the graysby Cephalopholis cruentata, to compare lifelong patterns of trophic resource use on a coral reef ledge in Biscayne National Park, Florida, USA. In both lionfishes and graysby, stable isotope values increased logarithmically with eye-lens radius, likely reflecting increases in trophic position with growth. Tissue samples toward the interior of the lens were the most isotopically similar between lionfish and graysby, suggesting interspecific resource use overlap may be strongest in smaller fish. We observed substantial variation in isotopic chronologies around the underlying logarithmic trend within individual fish, potentially driven by patterns of movement across measured environmental isotopic gradients, intraspecific variation in resource use specificity, or other ecological variables of interest. These results are the first to describe patterns of size-structured resource use across the life of individual lionfish, an important objective for researchers studying the interactions of this highly invasive species with the surrounding ecological communities. Additionally, through this example, we illustrate analytical approaches and considerations for the application of eye-lens stable isotope analysis to the study of vertebrate ecology.

Missing the mark(er): pseudogenes identified through whole mitochondrial genome sequencing provide new insight into invasive lionfish genetics

As documented marine invasions rise, determining the underlying molecular mechanisms of successful invasions is an immediate concern to management, but the relevance of such genetic studies hinges upon choosing the right markers. Most invasive lionfish phylogeography studies have used only the mitochondrial D-loop marker. For this study, three markers were targeted in invasive lionfish (n = 148): D-loop (mitochondrial), cytochrome oxidase I (mitochondrial), and S7 ribosomal intron-1 (nuclear). Using both mitochondrial and nuclear markers showed evidence of hybridization. At the D-loop marker, all sequences grouped with the Pacific Ocean lineage represented by Pterois volitans. At the S7 intron-1, all sequences grouped with the Indian Ocean S7 intron-1 haplotype associated with the Indian Ocean lineage represented by Pterois miles, showing discordance between the mitochondrial and nuclear markers. Further, at the COI marker, three out of 163 individuals sequenced matched P. miles. High throughput sequencing of the entire mitochondrial genome (n = 7) revealed that incongruence between mtDNA markers may be due to the insertion of mitochondrial DNA from P. volitans into the nuclear genome of fish genetically identified as P. miles. These data suggest hybridization and demonstrate that careful marker choice is important in future studies of lionfish genetics and invasive species in general.

Lionfish (Pterois volitans) as biomonitoring species for oil pollution effects in coral reef ecosystems

With oil spills, and other sources of aromatic hydrocarbons, being a continuous threat to coral reef systems, and most reef fish species being protected or difficult to collect, the use of the invasive lionfish (Pterois volitans) might be a good model species to monitor biomarkers in potentially exposed fish in the Caribbean and western Atlantic. The rapid expansion of lionfish in the Caribbean and western Atlantic, and the unregulated fishing for this species, would make the lionfish a suitable candidate as biomonitoring species for oil pollution effects. However, to date little has been published about the responses of lionfish to environmental pollutants. For this study lionfish were collected in the Florida Keys a few weeks after Hurricane Irma, which sank numerous boats resulting in leaks of oil and fuel, and during the winter and early spring after that. Several biomarkers indicative of exposure to PAHs (bile fluorescence, cytochrome P450-1A induction, glutathione S-transferase activity) were measured. To establish if these biomarkers are inducible in PAH exposed lionfish, dosing experiments with different concentrations of High Energy Water Accommodated Fraction of crude oil were performed. The results revealed no significant effects in the biomarkers in the field collected fish, while the exposure experiments demonstrated that lionfish did show strong effects in the measured biomarkers, even at the lowest concentration tested (0.3% HEWAF, or 25 μg/l ƩPAH50). Based on its widespread distribution, relative ease of collection, and significant biomarker responses in the controlled dosing experiment, it is concluded that lionfish has good potential to be used as a standardized biomonitoring species for oil pollution in its neotropical realm.

Precipitous Declines in Northern Gulf of Mexico Invasive Lionfish Populations Following the Emergence of an Ulcerative Skin Disease

Invasive Indo-Pacific lionfish Pterois volitans/miles have become well-established in many western Atlantic marine habitats and regions. However, high densities and low genetic diversity could make their populations susceptible to disease. We examined changes in northern Gulf of Mexico (nGOM) lionfish populations following the emergence of an ulcerative skin disease in August 2017, when estimated disease prevalence was as high as 40%. Ulcerated female lionfish had 9% lower relative condition compared to non-ulcerated females. Changes in lionfish size composition indicated a potential recruitment failure in early summer 2018, when the proportion of new recruits declined by >80%. Remotely operated vehicle surveys during 2016–2018 indicated lionfish population density declined in 2018 by 75% on natural reefs. The strongest declines (77–79%) in lionfish density were on high-density (>25 lionfish per 100 m2) artificial reefs, which declined to similar levels as low-density (<15 lionfish per 100 m2) artificial reefs that had prior lionfish removals. Fisheries-dependent sampling indicated lionfish commercial spearfishing landings, commercial catch per unit effort (CPUE), and lionfish tournament CPUE also declined approximately 50% in 2018. Collectively, these results provide correlative evidence for density-dependent epizootic population control, have implications for managing lionfish and impacted native species, and improve our understanding of biological invasions.

Risk screen of lionfishes, Pterois, Dendrochirus, and Parapterois, for southeastern United States coastal waters of the Gulf of Mexico and Atlantic Ocean

The trade in marine ornamental fishes includes over 1800 species and is regarded as an introduction source for non-native fishes. Given this large pool of potential invaders, a targeted approach that evaluates risk for groups of fishes with demonstrated invasion history is both practical and feasible. In this way, proactive risk management frameworks can be used to identify risky species prior to introduction. Though the establishment of introduced marine ornamental species is uncommon, the invasion of Pterois volitans and P. miles in the western Atlantic Ocean has demonstrated the risks associated with the marine ornamental industry. These species, along with several other lionfishes, are regularly imported into the United States. We used the Aquatic Species Invasiveness Screening Kit to evaluate the risk of invasion for 14 species of traded lionfishes in the genera Pterois, Dendrochirus, and Parapterois for southeastern United States coastal waters of the Gulf of Mexico and Atlantic Ocean. The lionfish invasion is widely considered to be one of the worst marine invasions to date. Despite this, risk associated with the trade of lionfishes was estimated to be low, with notable exceptions. We identify Pterois russelii, Pterois lunulata, and Dendrochirus brachypterus as species with potentially elevated invasion risk. State and federal management agencies within the western Atlantic, Gulf of Mexico, and Caribbean should consider a detailed evaluation of these species to inform management action. This study is the one of the largest risk screening application of marine fishes to date and demonstrates the utility of prioritizing risk assessment of taxa found in pathways with related or otherwise similar species with previous invasion history.

Los censos visuales en transecto de banda subestiman la abundancia del pez león &lt;i&gt;Pterois&lt;/i&gt; spp. en arrecifes coralinos del Caribe

The visual census of band transect (CVB) is one of the most used monitoring protocol on reefs, however this study confirms that its application fail in the detection and estimation of abundance of invasive lionfish. CVB vs Lionfish Search Census (CBP) was compared on Mexican Caribbean reefs. Differences in abundance of lionfish were found between CVB and CBP. Bias among both methods was significantly correlated to the cryptic behavior of inactivity and depth of the site. Finally, the use of different lionfish sampling methods and the application of CBP for monitoring reefs in the region are discussed.

Social media reveals the first records of the invasive lionfish Pterois miles (Bennett, 1828) and parrotfish Scarus ghobban Forsskål, 1775 from Egypt (Mediterranean Sea)

Social media reveals the first records of the invasive lionfish Pterois miles (Bennett, 1828) and parrotfish Scarus ghobban Forsskål, 1775 from Egypt (Mediterranean Sea)

EFFECT OF TIME DELAY IN A CANNIBALISTIC STAGE-STRUCTURED PREDATOR–PREY MODEL WITH HARVESTING OF AN ADULT PREDATOR: THE CASE OF LIONFISH

The progressive and increasing invasion of an opportunistic predator, the lionfish (Pterois volitans) has become a major threat for the delicate coral-reef ecosystem. The herbivore fish populations, in particular of Parrotfish, are taking the consequences of the lionfish invasion and then their control function on macro-algae growth is threatened. In this paper, we developed and analyzed a stage-structured mathematical model including P. volitans (lionfish), a cannibalistic predator, and a Parrotfish, its potential prey. As control upon the over predation, a rational harvest term has been considered. Further, to make the system more realistic, a delay in the growth rate of juvenile P. volitans population has been incorporated. We performed a global sensitivity analysis to identify important parameters of the system having significant correlations with the fishes. We observed that the system generates transcritical bifurcation, which takes the P. volitans-free equilibrium to the coexistence equilibrium on increasing the values of predation rate of adult P. volitans on Parrotfish. Further increase in the values of the predation rate of adult P. volitans on Parrotfish drives the system into Hopf bifurcation, which induces oscillation around the coexistence equilibrium. Moreover, the conversion efficiency due to cannibalism also has the property to alter the stability behavior of the system through Hopf bifurcation. The effect of time delay on the dynamics of the system is extensively studied and it is observed that the system develops chaotic dynamics through period-doubling oscillations for large values of time delay. However, if the system is already oscillatory, then the large values of time delay causes extinction of P. volitans from the system. To illustrate the occurrence of chaotic dynamics in the system, we drew the Poincaré map and also computed the Lyapunov exponents.

Invasive lionfish have turbocharged digestive systems

Wreathed with delicate-looking fronds, lionfish (Pterois spp.) are a delight to behold in their natural habitat. ‘They appear to just lazily swim very slowly around a reef’, says Erika Eliason, from the University of California, Santa Barbara, USA. However, in the wrong place, they're an ecological catastrophe. Thanks to their voracious appetites, they have aggressively colonised the eastern Mediterranean Sea and western Atlantic Ocean, obliterating the small fish and crustacean populations upon which they dine, shattering local ecosystems. So when Clay Steell joined Steven Cooke's lab at Carleton University, Canada, to study the physiology of fish in The Bahamas, the ferocious predators seemed the ideal species to investigate. And Cooke quickly invited ecophysiologist Eliason to join the team as it was apparent that the fish's appetites lay at the heart of their success.‘That led us to wonder if they have a specialized digestive physiology that might enable them to eat large meals’, says Eliason, who joined Steell at the Cape Eleuthera Institute, The Bahamas, to start investigating the fish. ‘Clay was an excellent lionfish captor’, she chuckles, recalling how they trapped the fish between two nets while SCUBA diving to avoid coming into contact with the animal's venomous spines. Back at the institute, Steell, Eliason and Travis Van Leeuwen waited until the lionfish were hungry before allowing the animals to stuff themselves on tasty silversides. Then they measured the lionfish's oxygen consumption as they digested the meals – ranging from 0.6% to 13.8% of their body mass – at 26°C and 32°C (winter and summer temperatures in The Bahamas), before converting the animals’ oxygen consumption into the amount of energy they consumed during digestion. Fortunately, as Eliason recalls, the lionfish were remarkably relaxed in the respirometry chamber compared with the trout and salmon that she has worked with in the past. Steell then calculated the fish's metabolic rates after chasing the animals around a tank, to compare with the amount of energy they consumed when digesting a meal.Amazingly, the lionfish put far more effort into digesting dinner than they exerted dashing around, consuming 1.7 times as much energy when digesting a large meal at 32°C as they did scurrying about. ‘Lionfish have a physiology that prioritises feeding over movement’, says Steell. And when the team compared the lionfish's diets at 26°C and 32°C, it was clear that the animals were able to consume almost 50% more during the summer months and digest it 45% faster.Eliason suspects that the lionfish's venomous spines, which protect them from predators, may give them a head start over more benign local species because they do not need to hold energy in reserve to take evasive action when threatened; with those spines, nothing is going to take them on. And she is concerned that lionfish may become even more of a menace as temperatures rise and their turbocharged appetites become more voracious, allowing them to decimate local populations even more effectively as they grow ever faster.