The Epidemic

Lionfish from the Indo-Pacific have recently invaded the northwest Atlantic Ocean, Gulf of Mexico, and Caribbean Sea. As voracious predators, they pose a major threat to economically and ecologically important fish species, and, therefore, the overall health of marine ecosystems. Rapid growth of the lionfish population could have disastrous consequences for the marine environment and related industries across their entire invaded range. With that in mind, the only solution that might prevent any such negative ecological impact is a well-developed lionfishery.

Since the discovery of lionfish in Florida in 1985, their population has expanded rapidly to stretch from Venezuela to Rhode Island, with recent sightings as far south as Brazil. All of this arose through the aquarium trade and the release of pet lionfish into the ocean by irresponsible owners.

In their native range, prey species recognize lionfish as a potential threat and naturally avoid them. As a result, lionfish became opportunistic predators with broad diets. Throughout their invaded range, prey species are naïve of them, not recognizing their inherent danger, and become an easy meal. To make matters worse, lionfish have no natural predators. Although large predators may eat them occasionally, the reality is that such events do not occur frequently enough to control the lionfish population.

Lionfish eat everything, including ecologically important species of fish and crustaceans, whether they are juveniles or small-bodied adults. With this broad diet and the potential for each female to spawn twice a week, producing two million eggs each year, their population has successfully established itself and is growing rapidly. Compared to the Indo-Pacific, lionfish in the Atlantic Ocean are far more abundant (5 times more so), far larger (just about 6 inches bigger), and eat much more. In fact, lionfish in Bermuda have been found with more than 30 juvenile fish in their stomachs.

The lionfish story suggests they could have a tremendous impact on invaded ecosystems and evidence of this is building. Research in the Bahamas, for example, has shown a single lionfish can reduce the population of juvenile reef fish by nearly 80% in as little as five weeks. Based upon our understanding of the biology and ecology of lionfish, it appears that an uncontrolled population of them could wreak havoc upon the marine environment throughout the western Atlantic Ocean. The only way to stop them is to catch them ourselves and eat them. The problem is we must catch huge numbers to minimize their damaging impact. One estimate suggests we must catch 35-65% of the entire population each year. For the sake of argument, if a hypothetical ecosystem has 10,000 lionfish, roughly 5,000 would need to be removed in the first year. That’s a lot of fish and a lot of effort that would need to be maintained annually. At this point, it’s very difficult to reach that target because lionfish rarely take a hook, leaving us with just two options to catch them: spearfishing and fish pots or lobster/crab traps. Unfortunately, pots or traps catch a lot of other species, many of which are not marketable as they are unpalatable or too small, and some that may even be protected by law. So although they are reasonably effective, they might not be a feasible solution until a lionfish specific trap is designed that excludes all other species. That leaves us with spearfishing, which is less wasteful because divers can specifically target lionfish without harming other species, but limited in the numbers that may be caught. In some places where lionfish are incredibly abundant in shallow water, spearfishing can be quite useful and markets have been established, but when lionfish are found at great numbers in deep water, this option becomes more complicated, expensive, and potentially quite dangerous. One last option would be to use Remotely Operated Vehicles (ROVs) to collect lionfish. Until recently, this conversation has not gone very far because of the financial expense of such an endeavor. That is, until Atlantic Lionshare was formed.

Corey Eddy PhD - Marine Ecologist