San José, Costa Rica, since 1956

Lionfish Plague Caribbean Reefs

About a year ago, a graceful, striped and spiny fish, the lionfish, was first spotted in Costa Rica’s southern Caribbean waters. That was the beginning of what is shaping up to be one of the worst exotic pest infestations to ever threaten the country.


The lionfish, native to Indo-Pacific waters, is a venomous beauty, equipped with dorsal, pelvic and anal spines that are lethal to other fish and can inflict serious pain on humans unlucky enough to contact them. But the lionfish’s sting is hardly the most pressing concern arising from its increased presence in Caribbean waters.


In the last decade, the lionfish, which is presumed to have entered Atlantic and Caribbean waters via Florida, has been spotted as far north as Rhode Island and as far south as Colombia and Bonaire, an island just north of Venezuela.


Removed from its natural habitat in the Pacific, the lionfish lacks predators in the Atlantic Ocean. As a result, it is feeding on just about whatever it wants, which could result in the dramatic alteration of marine ecosystems, fish populations and coral reefs along the east coast of the Americas. And it’s showing no sign of slowing down.


A 2009 study by the National Oceanic and Atmospheric Administration (NOAA), “Biology, Ecology, Control and Management of the Invasive Indo-Pacific Lionfish: An Updated Integrated Assessment,” contained this troubling forecast:


“The future expansion of lionfish into the coastal waters of the southern Caribbean, Gulf of Mexico and eastern South America is probable. The addition of a non-indigenous, predatory reef fish along with the existing coral reef stressors could cause irreversible changes in these systems. Probable impacts include a reduction of forage fish biomass, possible increase in algal growth owing to herbivore removal by lionfish and competition with native reef fish.”


“The first time I saw one was in April of 2009,” said Guillermo Valdez, owner of the PuntaUvaDiveCenter on Costa Rica’s southern Caribbean coast. “Now, I see them every time I dive and have to warn divers and snorkelers of the dangers. My concern is that they will damage the reef and keep divers from coming. Currently, no one is doing anything to stop them.”



How They Got Here



Legend has it that during Hurricane Andrew in 1992, a Miami, Florida aquarium ruptured, releasing six lionfish into Biscayne Bay, and starting the infestation. While the exact truth will never be known, it’s probable that the introduction of the lionfish in Atlantic and Caribbean waters was through aquariums in the United States.


“There’s probably not one single event that caused it, but we think it’s likely that the aquarium trade brought the lionfish here,” said Paula Whitfield, a research ecologist for NOAA. “From everything that we have found out about where they were introduced, it looks like they came from Florida, went up the east coast of the U.S. in the Gulf Stream (also) crossed the Gulf Stream to the Bahamas, and from there have continued to spread southward.”



How Can They Be Stopped?



How to slow or stop the spread of lionfish is what Whitfield referred to as “the million dollar question.” Because lionfish are acclimated to cooler Pacific waters, the warmth of the Caribbean increases their activity across the board, from eating to breeding. According to NOAA, as of 2008, lionfish densities in the Caribbean averaged 150 lionfish per hectare, with some sites reporting up to 350 per hectare.


“It is just exploding beyond control,” said Shawn Larkin, Tico Times columnist and a dive instructor for Aquamor Talamanca Adventures in Manzanillo. “I’ve been diving since the mid-80s and I’d never seen one before last year. Now, every reef in Manzanillo has many of them. It seems like this is going to spread through this entire area extremely quickly.”


Larkin said he saw one lionfish on one Manzanillo reef in August of 2009 and, by December, spotted many on reefs throughout the area. As the population of lionfish has swelled, Caribbean dive shops and fishermen have turned to the Environment, Energy and Telecommunications Ministry (MINAET) for assistance in controlling the outbreak. And although MINAET claims to be conducting extensive research on limiting the growth of the lionfish population, no government action in this respect has been implemented.


The story is similar in many Caribbean nations whose reefs are over-populated with lionfish. While the governments of the Bahamas and Belize offer $50 for the kill or capture of each lionfish, other Caribbean nations have been reluctant to endorse such measures.


Nevertheless, the threat to economic interests has people taking matters into their own hands.


“We usually make note of where we see lionfish while we are out on dives with visiting divers,” said Rick Ramos, a dive instructor at Subway Water Sports on RoatánIsland in Honduras. “They usually stay in the same area and we go back after the dives to kill them with a sling or small spear fin. It’s about the only method there is right now to control them.”


Other ideas to slow population growth have hinted at promoting the fish as a pet, which is illegal in Costa Rica, or to serve the fish, which has an average weight of about two pounds, as a menu item, a current practice in the Bahamas. Jorge Gonzalez of MINAET considers promoting lionfish consumption a plausible option for Costa Rica. Gonzalez said this would boost the fishing industry, provide a new dish for restaurants and justify killing the fish.


Though such tactics have made a small dent in the infestation, the pace of reproduction of lionfish in the Caribbean is currently too great to slow without dramatic action. According to NOAA, in some parts of the Atlantic and Caribbean, lionfish reproduce at an average of every four days and can produce over two million eggs each year.



Could They Swim Into the Pacific?



With the lionfish making its way along the coasts of Costa Rica, Panama and Colombia, there has been some concern that the lionfish will pass through the Panama Canal and threaten waters and reefs along the Pacific coasts of Central and South America.


Whitfield, however, was skeptical: “Our lab tests have shown that lionfish die when exposed to fresh water. There are several locks of fresh and brackish water in the canal and (therefore) their survival across the canal is very unlikely.”


While the passage of the lionfish to the Pacific may be unlikely, MINAET’s Gonzalez  and others consider it to be a potential threatthat requires attention.


“The fish population hasn’t been controlled in the Caribbean,” Gonzalez said. “If they arrive in the Pacific, they will spread up and down the coasts there just as they did here.”


Though some countries are trying to unite to control the lionfish population, for now the struggle continues to be a country to-country affair, with each nation searching for its own method to slow the outbreak. However, despite exhaustive marine and biological research by organizations in several countries, ten years into the fight the problem isn’t being solved. It’s actually worsening.


“Lionfish have now become the most dangerous form of marine life,” Larkin said. “Not only can they sting you if step on them or touch them, but they are devouring all indigenous types of reef life. The pace at which they are growing is unbelievable and…there aren’t a lot of ways known to top them.”


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