Baddie in the Bahamas: The Invasive Lionfish

lionfish

Invasive lionfish are outcompeting native coral reef species in the western Atlantic Ocean and Caribbean Sea. (Photo credit: Photodisc/Getty Images)

The invasive lionfish, which is native to the Indo-Pacific, is now wreaking havoc in coral reef ecosystems in the western Atlantic Ocean and Caribbean Sea. So-named due to its mane of venomous fins, this voracious fish is outcompeting native species and growing quite profusely in population due to a lack of predators. Can anything be done to stop this invasive species before it’s too late?

The lionfish is a popular aquarium fish that was likely released into the Atlantic Ocean off the coast of Florida sometime during the mid-1980s. Research indicates that a disproportionate number of such non-native species spotted off the coast of the southeastern United States are common to the aquarium fish pet trade. There are 11 species in the genus Pterois, which, along with the name lionfish, are also known as zebrafish, firefish, turkeyfish, and butterfly cod. All of these are native to the western Pacific Ocean. There are confirmed sightings of two of these species, P. miles and P. volitans, along the U.S. Atlantic Coast and Caribbean Sea. According to researchers, within eight years of establishing a population in the Bahamas, lionfish colonized 7.3 million square kilometers of the western Atlantic, Caribbean Sea, and Gulf of Mexico region.

One of the fish’s secrets to its success is its fecundity. The lionfish is extremely good at reproducing. Female lionfish produce 10,000 to 40,000 eggs each time they spawn, and they are able to spawn almost continuously when conditions are right. For example, research indicates that female lionfish found in the Bahamas can spawn every four days during the summer season. This extreme fecundity means that females are producing upwards of 2,000,000 eggs per year. In addition, lionfish are quick to develop – evidence suggests that introduced lionfish in the Atlantic mature at a faster rate than do native western Pacific populations. The non-native fish also tend to grow larger in size than their western Pacific relatives.

Lionfish are ambush predators with a voracious appetite. Research conducted in the Bahamas indicates that between 2008 and 2010, an abundant lionfish population coincided with a rapid decline in populations of native fish species. During that two-year period, within a single study area, lionfish populations grew from 23 percent to 40 percent of the predator population. A large majority of the prey, 90% in fact, eaten by the lionfish were small reef fish. Data show that lionfish reduced the biomass of 42 other species in the Bahamas by an average of 65 percent.

Because of the their abundance and seemingly limitless potential for their population to grow, the fishing for lionfish is actively encouraged. However, care must be taken in safely handling the venomous catch. Within the United States, the Florida Fish and Wildlife Conservation Commission waives fishing license requirements and bag limits for divers that harvest the fish. In Texas state waters, an unlimited amount of lionfish is allowed to be harvested by spear, net, or hook and line. In Bermuda, the government is collaborating with fishers, scientists, and non-governmental organizations to develop a lionfish trap based on the design of lobster traps. Fishing tournaments in the Florida Keys and the Bahamas have been successful at reducing local populations of lionfish; in one such event, participants caught 1400 fish, which decreased the local populations of lionfish by 60 percent.

Intensive active management is key to preventing the takeover of coral reef ecosystems by lionfish. Research suggests that 27 percent of the lionfish population would have to be removed every month annually to reduce their growth rate to zero. If left to their own devices, lionfish have serious implications for energy flow in coral reef ecosystems and will wreak havoc on food chains and ecosystem functions.

More to Explore
As Lionfish Invade the Caribbean and Gulf of Mexico, Conservations Say Eat Up
Impacts of Invasive Lionfish
Predatory fish invaders: Insights from Indo-Pacific lionfish in the western Atlantic and Caribbean
Indo-Pacific lionfish are larger and more abundant on invaded reefs: a comparison of Kenyan and Bahamian lionfish populations
Why are Lionfish a Growing Problem in the Atlantic Ocean?
Why Divers in Bonaire Are So Eager to Kill the Beautiful Lionfish (audio)
National Geographic: Lionfish Facts

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