There’s a new fish in the sea that’s been making the rounds of the Caribbean and Western Atlantic. The newcomer is the lionfish (Pterois volitans) a member of the family Scorpaenidae that originally traces its roots to the Indo-Pacific where they spend their days camouflaged in the cracks and crevices of the coral reefs. They feed on small fishes by herding them with their large pectoral fins before catching them and eating them. They defend themselves from other predators by having 18 large venomous spines.
The problem comes when they were moved to their new home in the Western Atlantic. They were originally brought to this side of the world as part of the aquarium trade due to their beauty and value to home aquarists. Unfortunately as with many exotic pets at some point in the late 1980’s some of them were released into the waters of Florida. Here they found a new home where none of the other fishes had experience avoiding a predator which hunts in quite the same way or looks the same so they proved easy prey for the lionfish’s unprecedented hunting techniques. To make matters worse lionfish are extraordinarily efficient breeders, with females being able to spawn 25,000 eggs every four days. In their native Indo-Pacific it is believed there are environmental factors that control against rampant population growth, and these controls are simply not present in the Western Atlantic. Since their introduction in the 1980’s lionfish have made their way from the east coast of Florida all the way up the east coast of the United States to Massachusetts and throughout the Caribbean. Their numbers are currently highest in The Bahamas where they have reached densities more than 8 times that of their native range.
A dissected lionfish that had 21 juvenile fish in its stomach.[/caption]
So the problem the coral reefs of the Western Atlantic now face is that of a rapidly reproducing predator able to easily consume the relatively naïve fishes native to the region, and defended from predation by venomous spines making them unappetizing to the usual predatory fish such as sharks and groupers.
To top it all off there are also potential cascading effects both impacting the reefs and the people who rely on those reefs for their livelihood. Lionfish feed on similar food and live in similar parts of the reef as native grouper such as the Nassau Grouper. These are important fish for local fishermen with Nassau Grouper being one of the “Holy Trinity” of fisheries in The Bahamas, the others being spiny lobster and queen conch. By competing with the grouper lionfish are displacing them from their homes and exposing them to predation as well as reducing the available food for grouper consumption.
As far as their effect on the reefs one of their prey targets are a family of fishes known as parrotfish. One of the major ecosystem functions of parrotfish is feeding on algae that otherwise outcompetes corals and in some areas where parrotfish and other herbivores are largely absent have led to a phase shift to an algal dominated ecosystem which provides very little habitat for juvenile fishes to shelter from predators among other things. By reducing the number of parrotfish on the reefs there is the potential for the lionfish to have further ramifications on the reefs by releasing the algae to outcompete the coral for space on the reef.
The obvious question now remains what on earth can be done about this invasive species that is wreaking havoc on the hugely important reefs of the Western Atlantic. One of the major attempts is to create a fishery for lionfish. With the incredible efficiency with which humans can harvest fish from the sea comes an unexpected opportunity to use this to not only feed countless people but also to reduce the population of a harmful alien on the reefs of the Western Atlantic. There is even a cookbook out with various recipes for how to prepare your lionfish and some restaurants are catching on to it as a new source of protein. (Lionfish Meal) There is obviously the problem of the venomous spines which fortunately once removed leave the meat completely safe for consumption but can prove a harmful (though non-fatal) reminder to careless fishermen. Another possibility being explored and utilized by some governments is controlled removals by teams of divers. This has proven to be somewhat successful but it is currently unknown how long term the effects of these removals are or if they will prove to be more of a short term solution for a small area.
So what do you think? Do you think creating a fishery could help to solve or at least alleviate the problem of the lionfish invasion?
Or do you think there could be some as yet unknown complications? These could include people harvesting them in the Indo-Pacific, where they are relatively rare, or even possibly people introducing lionfish to maintain the population as they are caught.