Common names: Lionfish, more...
Synonyms: Brachirus zebra Quoy and Gaimard, 1825, more...
Species Description: The red lionfish, Pterois volitans, is an Indo-Pacific marine fish that has been recently introduced to the east coast of the United States including coastal Florida. P. volitans is banded with distinct red and white stripes that give the fish its alternate common name "zebrafish." The elaborate fan-like pectoral fins and long separated dorsal spines explain another alternate common name, "turkeyfish."
Fleshy tabs around the mouth and above the eyes are another characteristic feature of the species (Myers 1991, Whitfield et al. 2002, FishBase). The long dorsal and pectoral spines of P. volitans are venomous, with the venom being produced by glands located in grooves on the spines covered integument (Halstead et al. 1955, Ruiz-Carus et al. 2006). The spines are used by the lionfish both for predator deterrence and to facilitate prey capture. The fin-ray count is: dorsal XIII, 13; anal III, 7-8 (last 2 soft rays are united at the base); pectorals (left/right) 14/14; pelvics (left/ right) I, 5/I, 5 (Ruiz-Carus et al. 2006).
Potentially Misidentified Species: Pterois volitans is unmistakable for any other marine fish of the western Atlantic.
Regional Occurrence: Pterois volitans is native to the western Pacific (from southern Japan and southern Korea to the east coast of Australia, Indonesia, Micronesia and French Polynesia) and South Pacific (from western Australia to the Marquesas and Oeno in the Pitcairn Islands) (Schultz 1986 Myers 1991, Ruiz-Carus et al. 2006). The species has recently been observed and collected from the U.S. east coast from Florida north to Long Island, New York (Whitfield et al., 2002)
IRL Distribution: Pterois volitans has yet to be observed or collected from the IRL proper, but it has been collected from coastal waters at both the northern and southern ends of the IRL region. At the northern end of the IRL system, collections have been made in coastal waters off of Ponce Inlet, south off of Daytona and Cape Canaveral, and approximately 40 km SE of Port Canaveral. To the south, repeated observations and collections have been made in coastal waters off of Lake Worth, located approximately 40 km south of Jupiter Inlet in Palm Beach County. Red lionfish inhabit lagoons and turbid inshore areas and harbors as well as offshore reefs in their native range (Schultz 1986, Myers, 1991), so concern exists as to whether the species might eventually become established within the IRL proper and within other Florida estuaries as well. On the west coast of the state, P. volitans is considered a potential invasive of the greater Tampa Bay ecosystem (Baker et al. 2004).
Age, Size, Lifespan: The largest Pterois volitans specimen collected on the U.S. east coast, caught via hook and line off North Carolina in 2004, was over 43 cm long and weighed approximately 1.1 kg Baker et al. (2004) indicate that the species typically grows to 15-30 cm.
Abundance: Detailed abundance information for this recent invader to the U.S, Atlantic coast is lacking, but collection data and anecdotal observations suggest Pterois volitans is established and reproducing in Florida waters and that local populations are likely growing (Whitfield et al. 2002, Ruiz-Carus et al. 2006).
Reproduction: Pterois volitans reproduction is sexual and involves external fertilization of eggs and a suite of complex courtship and mating behaviors (Ruiz-Carus et al. 2006). The species is generally solitary outside of the reproductive season, but during courtship, males will aggregate with multiple females to form groups of 3-8 fish. Fishelson (1975) indicates that competing males use their spines and fins in agonistic visual displays. Females release a pair of mucus-encapsulated clusters of 2,000-15,000 eggs to the pelagic environment where they are fertilized by the male. Environmental microbiota break down the egg mass mucus to free the eggs and facilitate hatching. Ovarian and testicular histological examination by Ruiz-Carus et al. (2006) suggests P. volitans reproduction in Florida occurs early in the year.
Embryology: Embryonic development within the egg masses is evident around 12 hours post-fertilization, and larvae hatch out within around 36 hours of fertilization. The larvae become competent swimmers 2-3 days after hatching, capable of capturing and consuming ciliates and other small zooplankton (Fishelson 1975). The typical larval duration of various lionfish species likely falls in the range of 20-40 days (Whitfield et al. 2002). The congener P. miles is 10-12 mm at when metamorphosing from larva to adult (Fishelson 1975), and the situation is probably similar for P. volitans.
Temperature: Pterois volitans is a tropical species, but it nevertheless exhibits a fairly broad thermal tolerance across its native and introduced range. Although juvenile individuals have been collected as far north as Long island, New York, these individuals were almost certainly spawned in warmer waters of the U.S. southeastern coast (Meister et al. 2005). Thermal tolerance studies by Kimball et al. (2004) reveal an average lethal low temperature for P. volitans of 10.0°C and a low temperature at which feeding ceases of 16.0°C. These findings suggest red lionfish should survive typical winter temperatures on the U.S. east coast as far north as Cape Hatteras, NC, while it remains unknown if animals can overwinter north of this point (Whitfield et al. 2002).
Salinity: Pterois volitans is a marine species, although it is found in inshore lagoons in its native range. Juvenile individuals have been collected off the northeastern U.S. continental shelf where salinities are typically in the range of 30-33ppt, somewhat lower than salinities in southeastern coastal waters (34-36 ppt) (Whitfield et al. 2002).
Trophic Mode: Pterois volitans is a predator on small fish, shrimps, crabs, and similarly sized animals. The species actively hunts in open water at night (Myers, 1991). Allen and Eschmeyer (1973) note a hunting behavior in which P. volitans spreads its pectoral fins to corral prey items which it then ingests in a single rapid motion.
Associated Species: A parasitic leech, Myzobdella lugubris, was found attached to the tongue of a red lionfish collected off of Jacksonville, FL. While this leech has been found on some two dozen freshwater and estuarine fish species, and on the blue crab (Callinectes sapidus), and a grass shrimp (Paleomonetes pugio), this finding represents the first record from a marine fish (Ruiz-carus et al. 2006).
Invasion History: Pterois volitans is one of the most popular marine ornamental aquarium species, and this is the most likely avenue of introduction of this species to the U.S. Atlantic coast. The first documented release of red lionfish in the southeast was an accidental release of 6 individuals. This resulted from resulting from the Hurricane Andrew-related destruction of a large private aquarium located on a porch at the edge of Biscayne Bay in 1992 (Courtenay 1995). These fish were observed alive in the adjacent habitat several days later.
Between 1993 and 2002, sporadic and often unsubstantiated sightings of P. volitans from the Florida east coast were recorded. Then, in February and March 2002, three specimens were caught off northeast Florida, near St. Augustine, Jacksonville, and Amelia Island. Two of these specimens were sent to the Florida Fish and Wildlife Conservation Commission's Fish and Wildlife Research Institute (FWRI) where positive identification was made (Ruiz-Carus et al. 2006).
North of Florida, collections and observations of red lionfish began in 2001 with the capture of a single adult individual off Georgia and two juveniles off Long Island, New York. Since then, further collections and observations of live P. volitans occurring in natural habitats off Florida, Georgia, the Carolinas, New Jersey, and New York have been made (Whitfield et al. 2002, Hare and Whitfield 2003, Ruiz-Carus et al. 2006).
The observation of small aggregations of 2-4 P. volitans during manned submersible-based research dives off North Carolina and South Carolina in 2002 offer compelling evidence that a reproductive population may be established there. Although courtship behaviors and actual spawning were not observed, the typically solitary P. volitans usually forms small groups as a prelude to courtship and reproduction. Histological examination of an adult female specimen collected off of St. Augustine, FL, also suggests reproduction is occurring there, based on a regressed state of the mature ovaries indicative of a post-spawning condition (Ruiz-Carus et al. 2006).
If P. volitans has become established in Florida, it is believed to be the first marine (non-estuarine) non-native fish to successfully do so.
Potential to Compete with Natives: A broad array of suitable prey species for Pterois volitans occur on Florida reefs, as do a number of predatory fish with which this non-native species may come to compete over trophic resources (Fishelson 1975, Sano et al. 1984). Detailed information on Florida P. volitans population sizes and their food habits remains lacking, however.
Possible Economic Consequences of Invasion: The potential economic impacts of Pterois volitans in Florida and elsewhere in the southeastern U.S. have yet to be assessed. The species is venomous and as such may pose a threat to fishermen and scuba divers.
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