First, the lionfish must be understood as a species. It is estimated that at least 93% of the invading population is made up of Red Lionfish (Pterois volitans) while the other 7% is Common Lionfish (Pterois miles), both identical in the laboratory according to L. Scott Harrell, a leader in lionfish hunting organizations. Both species originate from the Indo-Pacific Ocean’s reefs, and are actually listed as threatened by IUCN. These large fish are very hard to mistake: they grow to 12 to 15 inches long, are white with red or black stripes and have magnificently long, very venomous spines. Due to this defensive adaptation, they naturally don’t have many predators in their native habitat besides exceptionally large fish such as groupers, sharks, and sometimes larger lionfish. Habitually, lionfish are “a solitary predator of small fishes, shrimps and crabs. Prey are stalked and cornered or made to feel so by the outstretched and expanded pectoral fins of the red lionfish in full ambush mode. Prey are ultimately obtained with a lightning-quick snap of the jaws and swallowed whole” (Robins). Naturally, lionfish make for quite a successful predator in their native waters; they seem to prove even more successful where they don’t belong.Confirmed lionfish occurrences first began in the 80’s, and it took only a couple of decades to infest the Atlantic waters. According to many sources, including the World Lionfish Hunters Association.
The first documented sighting of lionfish in the United States occurred in October of 1985 when a crab trap fisherman, Richard Nielsen, fishing off of Dania, Florida, brought up a red lionfish in a crab trap. While this is the first confirmed sighting, there are unconfirmed stories of very rare lionfish sightings along the east coast of the United States by fishermen and scuba divers from as early as the 70s. It’s safe to assume that non-native lionfish were a threat to the local environment the very day they were introduced.
There are quite a few theories as to how the lionfish came to invade the Atlantic, though they are difficult to prove as factual. One theory suggests that when Hurricane Andrew hit the Gulf of Mexico, a Floridian aquarium was destroyed and released lionfish into the ocean; this is unlikely since the hurricane occurred in 1992, a few years after the first sightings, but may have contributed to the population. Another theory claims that lionfish egg masses may have been carried over in the ballast tanks of international ships, a popular theory among marine invasive species scenarios. According to Harrell, the most popular theory is that Floridian residents may have released or disposed of lionfish from home aquariums into the ocean, and the fish have reproduced and flourished ever since. There is still plenty of scientific inquiry and debate on how they arrived; nevertheless, they invade. Ever since, the populations have “then distributed across the Western Atlantic Basin via ocean currents. Lionfish are now found as far north as Rhode Island and as far south as Brazil” based off of research by Harrell and the Lionfish Hunters Organization. They continue to flourish in massive numbers, above all reef organisms.
The lionfish’s interesting reproductive evolution is what mostly makes lionfish so successful. Lionfish are an r-selected species; in an excerpt from Encyclopedia Britannica written by John P. Rafferty, this means that they are “governed by their biotic potential,” or their maximum reproductive capacity, from which the “r” is derived from. R-strategists, as they are also called, have low life expectancy but mature reproduce quickly, producing large amounts of offspring at a time. Essentially, this type of species doesn’t live long, so it wants to produce as many precocial offspring as possible. This strategy is applied to organisms such as insects and weeds. Lionfish prove to be avid r-strategists, as “reproduction can occur about every 4 days throughout the year; a single female lionfish can spawn over 2 million eggs per year” according to studies in Bermuda. The egg masses also give off a scented solution that drives predators away.
Such a strategy makes them successful enough in their own native habitat, along with being very resistant to infection and disease as well as having venomous adaptations. This also makes them great invaders. Ever since lionfish have infested the Western Atlantic Basin, lionfish have had no predation pressure since they have no natural predators in the Atlantic (setting aside cannibalism). Given that the lionfish’s ecological role in the Indo-Pacific Ocean was to limit the populations of smaller fish by preying on them, the now invasive species is very ravenous in the Atlantic and will eat nearly anything smaller than itself. In the Bonaire area, its most preferred prey are species of damselfish and wrasse. However, one particular group of fish that it eats called the parrotfish are a very important symbiotic species with coral. Bonaire’s iconic spotlight parrotfish feed off the ocean floor and coral, picking off any macroalgae and seaweed that covers coral, keeping the flora at bay to allow coral to flourish. However, when lionfish decrease the parrotfish populations, seaweed and algae grow out of control, limiting the coral growth and thus limiting the reef fish that depend on the coral for food and shelter, according to research collected by the Lionfish Hunters. Therefore, overall biodiversity is greatly decreased due to the ravenous diet of the lionfish.
Why is this important to humans? It may be important enough to simply say that the infestation of lionfish on the beautiful reefs, including the world-famous reefs of Bonaire, and the potential loss of these underwater rainforests is such a cultural loss. This loss is most especially for the proud locals who call Bonaire or any Caribbean island home. They also lose interest from the public and the millions of tourists that visit these islands, and the revenue that comes with it. Bonaire is already an island that is heard of very scarcely, unless in context among divers and snorkelers; if it loses its magnificent biodiversity, then it may become bankrupt and forgotten. So measures must be taken by humans to protect the reefs from this invasion.
The first sightings of lionfish on Bonaire began in 2009, and courses of action were immediately initiated after the sightings to prevent the spread of them and their infestation. Their rapid growth on the island’s reefs was inevitable, however; soon enough, educational posters were posted in front of every dive shop and major building on Bonaire, telling residents and tourists alike to report any sightings so that the fish may be removed. The immediate response to lionfish sightings used methods of spearing the fish. Many volunteer divers have been grouped together to move out and spear the fish in the island’s water, and efforts have proved somewhat effective on some reefs, but many lionfish still linger below depths that scuba divers can dive, or dwell on reefs that are difficult to access, according to field researchers de León and colleagues who have executed these methods themselves. It is a tiresome and tedious method, but others all over the Basin are trying other strategies.
In Cuba, the Cuba Conservancy Program believes that they should attempt a method that can allow the ecosystem to defend itself, rather than have humans eradicate the lionfish on their own. The program has taken up “training” sharks to prey on and eat lionfish. This strategy is proving to be ethologically difficult, as sharks, instead of wanting to eat the lionfish, may shy away from them in captivity and be scared of them. Some sharks even begin to associate the trainers with food and try to eat them. This method would also be rather extensive, as cartilaginous fish, unlike mammals, do not teach their young how to hunt; thus, the concept of eating lionfish would not be passed down in generations. As far as Bonaire is concerned with adopting this potential method, Bonaire hardly has shark populations at all to train in the first place. Plus, introducing more sharks into the population than there are naturally, or even introducing non-native sharks that would be more prone to eat lionfish, would most likely prove detrimental to the ecosystem.
Another approach finds a way to take an economic standpoint. In fact, taking this standpoint may prove this particular invasive species to be very beneficial. Lionfish, given that they are reducing the tourist-baiting biodiversity of Caribbean islands such as Bonaire, have the potential to send ecotourism revenue into decline. Government and conservation groups are intending to counteract this loss of attraction by creating all-new attractions. In a paper written by Alfonso Aguilar-Perera, these groups are “now recommending physical removal methods as a measure of eradication, including derbies, safaris and fishing tournaments.” Hosting events such as these may generate an income while, at the same time, making the eradication of an invasive species more effective.
These fish can be eaten as well. Indeed, they are quite a delicacy among fish, much like lobster. Promoting the gastronomic use of lionfish with the public would have a very similar effect, as this also creates an economically advantageous drive to harvest the fish. The idea of this specific method has recently been established on Bonaire. In fact, ever since the management of the invasion has begun, there is an annual Bonaire Fall Festival that celebrates the eating of, metaphorically, all of the lionfish caught that year with culinary specials. They also host VIP lionfish hunting guides during this festival in celebration. This has proved the public to become very active with the invasion management community, as the lionfish has become such a savory dish at such little local dispense.
As direct eradication methods have been tested for effectiveness since 2013, according to de León, “results [of the current spearing method] show that the immediate start and subsequent continuation of local removal efforts using volunteers is successful at significantly reducing the local density and biomass of invasive lionfish on small Caribbean islands.” It seems that this is the best way to bring down the population numbers of lionfish for the time being, and long term research will need to be done in order to assess the effectiveness over time. Also, the greatest thing that can be done universally is to educate the public about this foreign fish in Bonaire waters, and promote recreational uses that are attractive to residents and tourists. Even if this method keeps the invasive lionfish at bay from Bonaire’s reefs, then efforts must be continued and expanded in order to restore what has been lost, or what may yet be lost in the future, to the invasion.