Lionfish

Across the Caribbean, targeted fishing is gaining momentum as a cost-effective method to control invasive alien lionfish (Pterois volitans and Pterois miles) by suppressing population numbers below site-specific threshold levels i.e. a population density that is predicted to cause declines in native fish biomass. Yet in marine reserve no take zones (NTZs) or reefs at depths of >18 m) where commercial fishing is either not permitted or impractical, alternative methods of lionfish control are required. This study evaluates the potential for conservation volunteers to act as citizen scientists monitoring invasive lionfish populations and to support removal efforts in Bacalar Chico Marine Reserve (BCMR), Belize. Two underwater visual census techniques were trialled with conservation volunteers, each with associated benefits and drawbacks. A log of opportunistic lionfish sightings on SCUBA dives has been used to record sightings per unit effort (SPUE) data 2011–2015. In 2014, more rigorous lionfish focused searches (lionfish-adapted belt transects) were introduced. Opportunistic lionfish sightings contributed to a five year SPUE dataset that suggests that lionfish population growth rate has slowed in BCMR, where a lionfish removal program was also carried out by conservation volunteers over the same timeframe. However, lionfish focused searches showed that the mean density in 2014 was high (mean = 27.05 ± 8.77 fish ha-1 , 1–30 m) relative to lionfish populations in their native ranges, particularly at sites at depths > 18m (mean = 43.39 ± 13.76 fish ha-1 , 18–30 m). Drawing on lessons from Belize, we discuss the potential for conservation volunteers to support invasive alien species (IAS) monitoring and control efforts in marine environments.

The silver-cheeked toadfish (Lagocephalus sceleratus, from the pufferfish family Tetraodontidae) and the Pacific red lionfish (Pterois miles, family Scorpaenidae)
have recently invaded the Mediterranean Sea. Lagocephalus sceleratus has spread throughout this entire sea with the highest concentrations in the eastern basin, while more recently, Pterois miles has spread from the Eastern to the Central Mediterranean
Sea. Their effects on local biodiversity and fisheries are cause for management concern. Here, a comprehensive review of predators of these two species from their native Indo-Pacific and invaded Mediterranean and Western Atlantic ranges is presented. Predators of Tetraodontidae in general were reviewed for their native Indo-Pacific and Western Atlantic ranges, as no records were found specifically for L. sceleratus in its native range. Tetraodontidae predators in their native ranges included mantis
shrimp (Stomatopoda), lizardfish (Synodus spp.), tiger shark (Galeocerdo cuvier), lemon shark (Negaprion brevirostris), sea snakes (Enhydrina spp.), catfish (Arius spp.), cobia (Rachycentron canadum), skipjack tuna (Katsuwonus pelamis), and common octopus (Octopus vulgaris). The only reported predator of adult L. celeratus in the Mediterranean was loggerhead turtle (Caretta caretta), whereas juvenile L. sceleratus were preyed by common dolphinfish (Coryphaena hippurus) and garfish (Belone belone). Conspecific cannibalism of L. sceleratus juveniles was also confirmed in the Mediterranean. Pufferfish predators in the Western Atlantic included common octopus,
frogfish (Antennaridae), and several marine birds. Predators of all lionfish species in their native Indo-Pacific range included humpback scorpionfish (Scorpaenopsis spp.), bobbit worms (Eunice aphroditois), moray eels (Muraenidae), and bluespotted cornetfish (Fistularia commersonii). Lionfish predators in the Mediterranean included dusky grouper
(Epinephelus marginatus), white grouper (Epinephelus aeneus), common octopus, and L. sceleratus, whereas in theWestern Atlantic included the spotted moray (Gymnothorax moringa), multiple grouper species (tiger Mycteroperca tigris, Nassau Epinephelus striatus, black Mycteroperca bonaci, red Epinephelus morio, and gag Mycteroperca microleps; Epinephelidae), northern red snapper (Lutjanus campechanus), greater amberjack (Seriola dumerilli), and nurse shark (Ginglymostoma cirratum). The sparse data found on natural predation for these species suggest that population control
via predation may be limited. Their population control may require proactive, targeted human removals, as is currently practiced with lionfish in the Western Atlantic.

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.

Located on the Caribbean coast of Central America and flanked by the second longest barrier reef in the world, Belize is a nation reliant upon marine resources. Each year, the country's predominantly small-scale fisheries generate an estimated US$22 million in revenue – 1.8%of GDP – and employ 3000 people. However, the nation's fishing communities are facing an unprecedented challenge. Existing threats posed by declining fish stocks have been exacerbated by the introduction of the invasive alien red lionfish Pterois volitans in 2008. This Indo-Pacific predator has the potential to cause significant losses to the recruitment of native fish, in turn disrupting coral reef community dynamics in the Belize Barrier Reef Reserve System, a UNESCO World Heritage Site. Howefver, targeted lionfish fishing may offer a cost effective means to control the invasion, while also creating an alternative livelihood solution and improving food security among Belize's coastal fishing communities. This study summarises the recent history of the lionfish invasion in Belize, describes the multi-sector approach being used to address the invasion, and presents preliminary research summarising the characteristics of invasive alien lionfish in Belize. Data from Belize's nascent 'lionfishery' are also presented, demonstrating that demand for lionfish is outweighing supply – largely as a result of awareness-raising initiatives – and highlighting the strong potential for replication of this approach elsewhere in the Caribbean. The study concludes by discussing the barriers and potential solutions to this market-based approach to invasive species management.

Invasive Indo-Pacific lionfish (Pterois volitans) have rapidly expanded in the Western Atlantic over the past decade and have had a significant negative impact on reef fish biodiversity, habitat, and community structure, with lionfish out-competing native predators for resources. In an effort to reduce this population explosion, lionfish have been promoted for human consumption in the greater Caribbean region. This study examined whether the geographical expansion of the lionfish into a known ciguatera-endemic region can pose a human health threat for ciguatera fish poisoning (CFP). More than 180 lionfish were collected from waters surrounding the US Virgin Islands throughout 2010 and 2011.  Ciguatoxin testing included an in vitro neuroblastoma cytotoxicity assay for composite toxicity assessment of sodium-channel toxins combined with confirmatory liquid chromatography tandem mass spectrometry. A 12% prevalence rate of ciguatoxic lionfish exceeding the FDA guidance level of 0.1 μg/kg C-CTX-1 equivalents was identified in fish from the U.S. Virgin Islands, highlighting a potential consumption risk in this region. This study presents the first evidence that the invasive lionfish, pose a direct human health risk for CFP and highlights the need for awareness and research on this food safety hazard in known endemic areas.

Following aquarium releases, invasive lionfshes have colonized large areas of the Caribbean and western Atlantic, resulting in an immense ecological damage. The early stages of that invasion are poorly known. Indeed, a lag of time between the introduction and detection often preclude genetic characterization of that crucial phase. With elevated awareness, the recent invasion of Pterois miles was quickly detected in the Mediterranean Sea. We hereby show that the very frst individuals establishing populations in the Mediterranean Sea display haplotypes that nest within the large genetic diversity of Red Sea individuals, thus indicating an invasion via the Suez Canal. We also show that only two haplotypes are detected in the Mediterranean Sea, suggesting that few individuals may have been involved in the invasion. Thus, we conclude that the Mediterranean invasion is the result of a movement of individuals from the Red Sea, rather than from other means, and that low genetic diversity does not seem to have a negative efect on the success and spread of lionfsh into the Mediterranean Sea.

The lionfish (Pterois volitans), has become an abundant alien species along the southeast coast of the United States of America and in Caribbean coastal waters. Although, they represent a major concern in conservation, no studies have yet assessed their population ecology and genetic structure simultaneously. We collected 227 lionfish from 24 sites around Puerto Rico to investigate, the length distribution, length-weight relationships, relative condition factor, and mitochondrial DNA (mtDNA) genetic diversity. The total length distribution ranged between 37 and 349 mm with a single peak between 130 and 149 mm. Our analysis indicated isometric growth for mature individuals and a positive allometric growth for immature lionfishes. These results suggest a different allocation of resources, most likely reproduction for mature individuals and somatic growth for the immature lionfish. The relative condition factor (KN) was similar for immature and mature individuals. Genetic analyses indicated that P. volitans is the only lionfish species present in Puerto Rico, and that its origin was likely
dispersal from the epicenter of introduction off the coast of Florida. Interestingly, only four of the nine mtDNA haplotypes identified in the Atlantic were observed in the Puerto Rican population. A fine-scale population genetic analysis suggested a significantly different population structure between the west and south coasts. Finally, our data suggests a second founder effect, but with a reduction of haplotype diversity.