Lionfish - Invasive Introduction and Range

Invasive Introduction and Range

Two of the nine species of Pterois, the red lionfish (P. volitans) and the common lionfish (P. miles), 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 is P. volitans.

The red lionfish is found off the East Coast of the United States and the Caribbean Sea, and was likely first introduced off the Florida coast in the early to mid-1990s. It has been speculated that this introduction may have been caused when Hurricane Andrew destroyed an aquarium in southern Florida, It is also believed that six lionfish were accidentally released in Biscayne Bay, Florida after Hurricane Andrew in 1992. However, a more recent report states National Oceanic and Atmospheric Administration (NOAA) ecologist James Morris Jr. has discovered that a lionfish was discovered off the coast of south Florida prior to Hurricane Andrew in 1985. It is also believed that the lionfish were purposefully discarded by unsatisfied aquarium enthusiasts. The first documented capture of lionfish in the Atlantic occurred in Dania Beach, Florida. In 2001, NOAA documented multiple sightings of lionfish off the coast of Florida, Georgia, South Carolina, North Carolina, and Bermuda, and were first detected in the Bahamas in 2004. Recently (late November 2011) they have been discovered as far east as Barbados, and as far south as Los Roques Archipelago and many Venezuelan continental beaches.

Pterois volitans and Pterois miles are native to sub-tropical and tropical regions from southern Japan and southern Korea to the east coast of Australia, Indonesia, Micronesia, French Polynesia and in the South Pacific Ocean. Adult lionfish specimens are now found along the United States East Coast from Cape Hatteras, North Carolina, to Florida, and in Bermuda, the Bahamas, and throughout the Caribbean, including the Turks and Caicos, Haiti, Cuba, Dominican Republic, Cayman Islands, Aruba, Curacao, Bonaire, Puerto Rico, St. Croix, Belize, Honduras 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. Population densities have reached levels that are orders of magnitude greater than their native ranges.

Pterois are known for devouring many other aquarium fishes. Pterois are unusual in that they are among the few fish species to successfully establish populations in open marine systems.

Pelagic larval dispersion is assumed to occur through oceanic currents, including the Gulf Stream and the Caribbean Current. It is projected that currents could eventually result in new populations along the Gulf Coast. Ballast water can also be attributed to the dispersal.

Extreme temperatures present geographical constraints in the distribution of aquatic species, indicating that temperature tolerance plays a role in the lionfish’s survival, reproduction and range of distribution. Observational studies have shown that the abrupt differences in water temperatures north and south of Cape Hatteras directly correlate with the abundance and distribution of Pterois. Pterois expanded along the entire eastern coast of the United States and occupied thermal-appropriate zones within ten years. Although the timeline of observations points to the east coast of Florida as the initial source of the western Atlantic invasion, the relationship of the United States East Coast and Bahamian lionfish invasion is uncertain.