Lionfish

 The Invasion

Lionfish (Pterois volitans/miles) are a venomous fish native to the tropical reefs and rocky benthos of the southwestern Pacific Ocean, Indian Ocean, and Red Sea. Lionfish are a popular ornamental fish because of their unique coloring and feather-like fins; and they were historically one of the most valuable marine fish imported into the United States for the aquarium trade. Lionfish were first reported off Florida’s Atlantic coast near Dania Beach (Broward County) in 1985. Accidental release from an aquarium is the most probable vector of lionfish introduction to the western Atlantic Ocean.

During the late 1990’s and early 2000’s, lionfish were regularly reported off the southeast Atlantic coast of the U.S., and since then have successfully spread throughout the Caribbean and Gulf of Mexico. Thermal tolerances are believed to be the primary factor controlling the latitudinal boundaries of the species distribution. Lionfish have been found as far north as Rhode Island and are predicted to continue spreading southward along the coastline of South America.

Biology & Life History

Lionfish are a slow-moving, conspicuous species that rely on their unique coloring and large pectoral fins for predator deterrence. They are demersal species, meaning they live on the ocean floor, often under ledges and in crevices, and are more active during the evening.

Lionfish have 18 venomous spines; 13 are located on the dorsal fin, 1 on each pelvic fin, and 3 on the anal fin. The venom is a neurotoxin consisting of proteins that are denatured by the application of heat. Note: venom should not be confused with poison; lionfish are not a poisonous fish.

Lionfish are larger in their invaded range – reaching a maximum size of 18 inches, but growing to only 15 inches in their native range.

Female lionfish become sexually mature after one year of age (approximately 180mm) and release gelatinous egg masses (with up to 30,000 eggs) into the water column every two to four days. The eggs hatch and disperse via ocean currents for 26 days until settlement and growth. The average annual reproductive output of a single female lionfish is over two million eggs.

Ecological Impacts

Over 60 different species of fish and invertebrates have been identified in the stomach contents of lionfish.

Primary food sources include economically important species such as grouper, snapper, crustaceans (crab, shrimp), and bait fish as well as ecologically important species such as grazers and cleaner fish.

Lionfish have no natural predators within their invaded range, which allows for the absence of natural population control.

The introduction of lionfish into the Atlantic Ocean, Caribbean Sea, and Gulf of Mexico has reduced native fish biomass, increased algal growth as a result of herbivore removal by lionfish, created competition with native reef fish, and changed prey community structure.

 Interesting Facts

  • Two species of lionfish exist – Pterois volitans and Pterois miles. Approximately 93% of the invasive population are P. volitans.
  • The “fleshy” appendages above the eyes and below the mouth on juvenile lionfish are used to lure prey; however, as they gain hunting experience, they no longer have a need for this hunting tool.
  • Florida holds the world record on the largest lionfish by length: 477 mm (18.78 in). Caught by Captain Jimmy Nelson off Islamorada in 2015.
  • Lionfish stomachs can expand to 30 times its size, but if resources are scarce, they can live without food for up to 3 months.
  • Lionfish can inhabit depth ranges from 0m to >300m, salinity ranges from riverine and brackish water to full-strength seawater, and water temperatures as low as 50 degrees Fahrenheit.
  • Lionfish can consume prey that are more than half their body length.

 Harvest Equipment & Information

Scuba and free divers alike often use pole spears, Hawaiian slings, spearguns, hand nets, and other lionfish-specific devices to capture lionfish. Spears with a paralyzer or 3-prong trident tip with barbs are the most common. It is highly recommended that divers use a needle-proof container, such as a Zookeeper Lionfish Containment Unit or dry bag, to hold their catch while diving to prevent the spines from harming the diver. Lastly, wear puncture-resistant gloves to prevent getting stung while collecting lionfish.

Interested in harvesting lionfish? A recreational fishing license is not required to collect lionfish from Florida waters when using a pole spear, a Hawaiian sling, a handheld net, or any spearing device that is designed and/or marketed exclusively for lionfish.

Interested in selling lionfish that you collect? A saltwater products license is required to sell lionfish to wholesale dealers.

More information can be found on the FWC Lionfish website.