A Master Invader: The Lionfish

Before the 1990s, lionfish were only found in the Pacific and Indian oceans. Their famous  spines and candy cane stripes have rendered them recognizable all over the world. Because of their eccentric appearance, they have been shipped internationally as part of the aquarium trade.

Invasive species, or those that are not native to an ecosystem and are detrimental, are everywhere. Commonly, they are introduced to new habitats due to international shipping routes. In some cases, pet owners are unable to provide necessary care for exotic animals and believe releasing them into the wild is the best possible option.

Based on genetic analysis, scientists estimate that the release of only three lionfish individuals into the Atlantic ocean began one of the most detrimental marine invasions yet.



So, just how bad can it be?

No one knows if these lionfish were released as pets, or if they escaped from capsized boats after Hurricane Andrew in 1992. The United States Geological Survey (USGS) has mapped their spread, showing how quickly they have traveled up the eastern coast of the US and into the Caribbean.

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The first sightings were near Miami in 1990. Courtesy of USGS.
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By 2000, lionfish had spread up the eastern coast of the United States and to Bermuda.
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In 2010, their range greatly expanded far into the Caribbean Sea.
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In 2018, lionfish congregated around shores of the United States and around Caribbean islands.

It’s bad.

Invasive species often outcompete native species for resources, are voracious predators, and destruct habitat. Lionfish have no natural predators in the Atlantic, can lay 2 million eggs in one year, and aren’t specific about what they eat. Additionally, their stomach can expand 30 times its original size after a meal.

On one reef in the Bahamas, lionfish exceeded 160 individuals per acre. Researchers found that during a two year period, biomass of small fishes declined by 65% due to lionfish predation. Not only were lionfish consuming these fish at extraordinary rates, but were also outcompeting other predators such as larger fish and sharks.

Why does this actually matter?

Not only do lionfish outcompete other native species for resources, but they can also cause some species to disappear completely. Communities that rely on these reefs or coastal ecosystems for fishery production are being threatened. Biodiversity has declined across surveyed sites.

Lionfish are incredible difficult to control because of their vast range, their effective predation habits, and because this issue crosses several nations with varying abilities and standards for dealing with invasive species. Additionally, as hurricanes continue to increase in severity to climate change, lionfish eggs will be carried to new locations and perpetuate the problem.

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Dawn Witherington, Loxahatchee River District

So how do we fix it?

The only way to potentially control this problem is by using a multi-pronged approach. Costs, wide spread, and lack of constant monitoring in marine environments mean controlling any oceanic invasive species is difficult. By the time they have established themselves as the lionfish has, eradication is impossible.

Researchers have found that in healthy marine reserves where grouper populations are at normal levels, grouper could potentially serve as a predator to these lionfish. Unfortunately, grouper are a popular food item and are largely overfished in the Caribbean. 7 common species of this fish group are marked as “avoid” by the Monterey Bay Seafood Watch due to harmful fishing methods or declining fish stocks.

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Two grouper going after an invasive lionfish – via Our World-Underwater Scholarship Society

Another study found that satellite data, remote sensing, and diver observations could narrow in on possible habitat that would be most desirable to lionfish, such as areas with rocky crevices. Remote sensing of benthic (bottom) characteristics and diver data helped to create a map of these areas, with both tools largely available to governmental organizations and the public. Using this data on reefs where lionfish are not already present is key, because monitoring of smaller areas can lead to more efficient and costly eradication practices.

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A view of the ocean floor. Using imaging like this can promote faster efforts of control.

Spearing lionfish can be part of eradication efforts, but can also aid in the cultural and culinary prospects of communities. If you can’t beat them, eat them. The Sarasota Lionfish Derby, which is curated by Mote Marine Laboratory, inspires spearfishes to capture lionfish for big cash prizes. The catch is then used in cooking competitions as part of the event.

The Flying Fish, GBI – via Michelle Maloney

The Flying Fish on Grand Bahama Island also uses lionfish in their restaurant. Tim Tibbitts, the head chef, has even volunteered some of his recipes to websites like Crave Local to inspire others to try the dish. Furthermore, major grocers such as Wegmans have included the fish in some of their stores, sparking what could be a new trend of invasive species fare.

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via USA Today

Invasive species, including the lionfish, are hard to avoid in today’s connected world. Without stricter trade laws and inspection of goods, species will continue to catch a free ride on ships, trucks, or even in our own cars. Citizen science programs, or those where non-scientists and hobbyists report invasive species, may be the key to controlling outbreaks in ecosystems. For the rest of us, buying local goods, reporting unknown species online, and even trying a new dish is the small part we hold in restricting their spread.




Top Image by: 8point.ky


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