[Lionfish] Vulnerability of the Caribbean region to lionfish invasion

Amongst the species of lionfish that occur in the Indo-Pacific, two have been introduced in the Caribbean : Pterois miles and Pterois volitans, both displaying an highly invasive pattern. Both share many biological and behavioural characteristics and the impacts they cause are very closely similar. They will be referred to as “lionfish” in this document without further distinction between the two species.

It is considered that the lionfish was introduced into Florida waters and later spread across the Atlantic, affecting reefs in the southeastern United States and the Caribbean. One theory of its introduction to the marine environment shows in 1985 were deliberately released several specimens of lionfish (aquarium trade) off the coast of the United States and subsequently have been presented other accidental or intentional releases.

Several factors can explain the high invasive potential of the liofish in the Wider Caribbean : success in the colonization process, rapid reproduction and lack of predators in the area.

The first lionfish was reported in South Florida waters in 1985 with many additional sightings occurring until they were documented as established in the early 2000s and further distribution has reached most if not all of the Caribbean in the following decade (see figure 2).

Figure 2 : Current distribution of invasive Lionfish in the Caribbean (Updated February 2013).

Today, the lionfish has invaded all the Greater Antilles, the major part of the Lesser Antilles, and the continental countries bordering the Gulf of Mexico down to Central America and Latin America. Lionfish have become established outside of the Atlantic coast of the United States from Florida to Cape Hatteras, North Carolina, where apparently the cold waters (less than 16 ° C) are a barrier for them. The Gulf Stream carries the lionfish eggs, causing further dispersion along the Atlantic coast.
In their newly invaded range, Lionfish have been found to be generalist carnivores that consume more than 60 species of fish and many invertebrate species (crustaceans, molluscs), with prey up to half the lionfish’s body size, and many of the lionfish prey are commercially, recreationally, or ecologically important. The “naive” behaviour of Caribbean reef species compared with the one of the lionfish preys in its original range leads to high levels of predation. Furthermore and as mentioned before, native potential predators, with a few exceptions that are not all confirmed yet, exhibit avoidance for lionfish. The lionfish has very few parasites compared to native species.

On heavily invaded sites, lionfish have reduced their fish prey by up to 90% and continue to consume native fishes at unsustainable rates. Lionfish can reach densities over 200 adults per acre (500 per hectare), consuming more than 460,000 prey fish/acre/year.