Lionfish

Lionfish are venomous marine fish native to the Indo-Pacific. They are characterized by conspicuous warning coloration with red or black bands and ostentatious dorsal fins tipped with venomous spines. Pterois radiata, Pterois volitans, and Pterois miles are the most commonly studied species in the genus. Pterois species are popular aquarium fish. P. volitans and P. miles are recent and significant invasive species in the west Atlantic, Caribbean Sea, and Mediterranean Sea.

Taxonomy

Pterois was described as a genus in 1817 by German naturalist, botanist, biologist, and ornithologist Lorenz Oken. In 1856, French naturalist Eugène Anselme Sébastien Léon Desmarest designated Scorpaena volitans, which had been named by Bloch in 1787 and which was the same as Linnaeus's 1758 Gasterosteus volitans, as the type species of the genus. This genus is classified within the tribe Pteroini of the subfamily Scorpaeninae within the family Scorpaenidae. The genus name Pterois is based on Georges Cuvier's 1816 French name, "Les Pterois", meaning "fins", which is an allusion to the high dorsal and long pectoral fins.

Description

According to the National Oceanic and Atmospheric Administration, "lionfish have distinctive brown or maroon, and white stripes or bands covering the head and body. They have fleshy tentacles above their eyes and below the mouth; fan-like pectoral fins; long, separated dorsal spines; 13 dorsal spines; 10–11 dorsal soft rays; three anal spines; and six or seven anal soft rays. An adult lionfish can grow as large as 18 inches."
Juvenile lionfish have a unique tentacle located above their eye sockets that varies in phenotype between species. The evolution of this tentacle is suggested to serve to continually attract new prey; studies also suggest it plays a role in sexual selection.

Species

Currently, 12 recognized species are in this genus:

Image	Scientific name	Common name	Distribution
	P. andover	Andover lionfish	Indonesia and Papua New Guinea and ranges as far as Sabah, Malaysia, and the Philippines
	P. antennata	Spot-fin lionfish	Tropical Indian and Western Pacific Oceans
	P. brevipectoralis		Western Indian Ocean
	P. cincta	Red Sea lionfish	Jeddah, Saudi Arabia, Red Sea
	P. lunulata	Luna lionfish	Western Pacific Ocean
	P. miles	Common Lionfish, Devil firefish	Indian Ocean, from the Red Sea, to South Africa, and to Indonesia
	P. mombasae	African lionfish, frill-fin turkeyfish	tropical Indian Ocean and the Western Pacific
	P. paucispinula		India to northern Australia ; north to southern Japan; eastward to Wallis and Futuna Islands
	P. radiata	Clear-fin lionfish	Red Sea to Sodwana Bay, South Africa and to the Society Islands, north to the Ryukyu Islands, south to New Caledonia
	P. russelii	Plaintail turkeyfish, soldier lionfish, Russell's lionfish	Persian Gulf and East Africa to New Guinea, south to Western Australia
	P. sphex	Hawaiian turkeyfish	Hawaii
	P. volitans	Red lionfish	Indo-Pacific region, Western Atlantic Ocean, Caribbean Sea

Molecular studies and morphological data have indicated that P. lunulata is a junior synonym of P. russelii, and that P. volitans may be a hybrid between P. miles and P. russelii ''sensu lato''.

Ecology and behavior

Pterois species can live from 5 to 15 years and have complex courtship and mating behaviors. Females frequently release two mucus-filled egg clusters, which can contain as many as 15,000 eggs. In total, they can lay up about 2 million eggs per year.
All species are aposematic; they have conspicuous coloration with boldly contrasting stripes and wide fans of projecting spines, advertising their ability to defend themselves.

Prey

Pterois species prey mostly on small fish, invertebrates, and mollusks, with up to six different species of prey found in the gastrointestinal tracts of some specimens. Lionfish feed most actively in the morning; they are skilled hunters, using specialized swim bladder muscles to provide precise control of their location in the water column, allowing them to alter their center of gravity the better to attack prey. They blow jets of water while approaching prey, which serves to confuse them and alter the orientation of the prey so that the smaller fish is facing the lionfish. This results in a higher degree of predatory efficiency, as head-first capture is easier for the lionfish. The lionfish then spreads its large pectoral fins and swallows its prey in a single motion.

Predators and parasites

s, bluespotted cornetfish, barracuda, and large groupers have been observed preying on lionfish. Sharks are also believed to be capable of preying on lionfish with no ill effects from their spines.
Park officials of the Roatan Marine Park in Honduras have attempted to train sharks to feed on lionfish to control the invasive populations in the Caribbean. The bobbit worm, an ambush predator, has been filmed preying upon lionfish in Indonesia. Predators of larvae and juvenile lionfish remain unknown, but may prove to be the primary limiting factor of lionfish populations in their native range. In Texas and Florida, where lionfish are regarded as an invasive species, scuba divers and breath-hold divers are encouraged to capture lionfish for sport and food.
Parasites of lionfish have rarely been observed, and are assumed to be infrequent. They include isopods and leeches.

Interaction with humans

Lionfish are known for their venomous fin rays, which make them hazardous to other marine animals, as well as humans. Pterois venom produced negative inotropic and chronotropic effects when tested in both frog and clam hearts and has a depressive effect on rabbit blood pressure. These results are thought to be due to nitric oxide release. In humans, Pterois venom can cause systemic effects such as pain, nausea, vomiting, fever, headache, numbness, paresthesia, diarrhea, sweating, temporary paralysis of the limbs, respiratory insufficiency, heart failure, and convulsions, and can be fatal. Fatalities are more common in very young children, the elderly, or those who are allergic to the venom. The venom is rarely fatal to healthy adults, but some species have enough venom to produce extreme discomfort for a period of several days. Moreover, Pterois venom poses a danger to allergic victims as they may experience anaphylaxis, a serious and often life-threatening condition that requires immediate emergency medical treatment. Severe allergic reactions to Pterois venom include chest pain, severe breathing difficulties, a drop in blood pressure, swelling of the tongue, sweating, or slurred speech. Such reactions can be fatal if not treated.
Lionfish [|are edible] if prepared correctly.

Native range and habitat

Lionfish are native to the Indian Ocean and western Pacific Ocean. They can be found around the seaward edge of shallow coral reefs, lagoons, rocky substrates, and on mesophotic reefs, and can live in areas of varying salinity, temperature, and depth. They are also frequently found in turbid inshore areas and harbors, and have a generally hostile attitude and are territorial toward other reef fish. They are commonly found from shallow waters down to past depth, and have in several locations been recorded to depth. Many universities in the Indo-Pacific have documented reports of Pterois aggression toward divers and researchers. P. volitans and P. miles are native to subtropical and tropical regions from southern Japan and southern Korea to the east coast of Australia, Indonesia, Micronesia, French Polynesia, and the South Pacific Ocean. P. miles is also found in the Indian Ocean, from Sumatra to Sri Lanka and the Red Sea.

Invasive introduction and range

Western tropical Atlantic

Two of the 12 species of Pterois, the red lionfish and the common lionfish, have established themselves as significant invasive species off the East Coast of the United States and in the Caribbean. About 93% of the invasive population in the Western Atlantic is P. volitans.
The red lionfish is found off the East Coast and Gulf Coast of the United States and in the Caribbean Sea, and was likely first introduced off the Florida coast by the early to mid-1980s. This introduction may have occurred in 1992 when Hurricane Andrew destroyed an aquarium in southern Florida, releasing six lionfish into Biscayne Bay. However, a lionfish was discovered off the coast of Dania Beach, south Florida, as early as 1985, before Hurricane Andrew.
These captured lionfish resemble those of the Philippines, implicating the aquarium trade, and suggesting that the fish may be descendants of individuals discarded by dissatisfied aquarium enthusiasts. Lionfish require experience to maintain in an aquarium, but are often sold to novices who find their care too difficult.
In 2001, the National Oceanic and Atmospheric Administration documented several sightings of lionfish off the coast of Florida, Georgia, South Carolina, North Carolina, Bermuda, and Delaware. In August 2014, when the Gulf Stream was discharging into the mouth of the Delaware Bay, two lionfish were caught by a surf fisherman off the ocean side shore of Cape Henlopen State Park: a red lionfish that weighed and a common lionfish that weighed. Three days later, a red lionfish was caught off the shore of Broadkill Beach which is in the Delaware Bay approximately north of Cape Henlopen State Park.
The timeline of observations points to the east coast of Florida as the initial source of the western Atlantic invasion, though it has been suggested that the Bahamas may also have been an independent source. Lionfish were first detected in the Bahamas in 2004.
In July 2011, lionfish were reported for the first time in the Flower Garden Banks National Marine Sanctuary off the coast of Louisiana.
In June 2013 lionfish were discovered as far east as Barbados, and as far south as the Los Roques Archipelago and many Venezuelan continental beaches. Lionfish were first sighted in Brazilian waters in late 2014.
Genetic testing on a single captured individual revealed that it was related to the populations found in the Caribbean, suggesting that the spread of the species occurred by larval dispersal rather than by intentional release. Pelagic larval dispersion is assumed to occur through oceanic currents, including the Gulf Stream and the Caribbean Current. Ballast water discharged from ships can also contribute to the dispersal.
Adult lionfish are now found along the United States East Coast from Cape Hatteras, North Carolina, to Florida, and along the Gulf Coast to Texas. They are also found off Bermuda, the Bahamas, and throughout the Caribbean, including the Turks and Caicos, Haiti, Cuba, the Dominican Republic, the Cayman Islands, Aruba, Curacao, Trinidad and Tobago, Bonaire, Puerto Rico, St. Croix, Belize, Honduras, Colombia and Mexico. Population densities continue to increase in the invaded areas, resulting in a population boom of up to 700% in some areas between 2004 and 2008.