Is The Lionfish Invasive Species A Threat or Just A Change?

In today’s article, we delve into the mystery of the lionfish invasive species!

Lionfish hail from the warm coral reefs of the South Pacific, the Indian Ocean, and the Red Sea, yet they have established populations in other regions where they pose a threat to native ecosystems. How is this possible? They’re fish, not Martians from ‘War of the Worlds’.

The issue lies in their lack of natural predators and their rapid reproduction rate, allowing these voracious carnivores to assert their presence. It’s evident; anyone who has dived in the Caribbean has seen them, but… How does the Lionfish Invasive species affect ecosystems? How did these invasive lionfish reach the Atlantic? Are they truly a threat? Can the lionfish invasion be reversed and how are efforts being made to do so?

The mystery of the invasive species of lionfish has made a permanent home along our shores! Let’s uncover it.

1. Detailed Description of The Lionfish Invasive Species

Although there are several species of lionfish in the world’s oceans, two species stand out as the invaders of the Caribbean Sea. All sightings correspond predominantly to the species Pterois volitans and, to a lesser extent, Pterois miles. Pterois volitans is recognized for its pattern of brown and white stripes, while the stripes of Pterois miles are darker and denser. Surprisingly, there’s a remarkable genetic similarity between these two invasive species in the Caribbean.

Which one arrived first in these waters? That remains a mystery yet to be solved by scientists.

Their distinctive pattern of red, brown, and white stripes around their bodies makes them visually appealing, almost like a candy cane to a child’s eyes. Moreover, lionfish can reach a length of up to a foot, around 30 cm. They reach sexual maturity very quickly, in less than a year, and are still not fully grown, although their growth slows down from that point on.

The peculiar reproduction method of lionfish invasive is another noteworthy detail. Females can release up to 2.4 million eggs per year and spawn every two or three days, laying between 2,000 and 15,000 eggs per spawning, which float adrift awaiting fertilization.

These predators are armed with 18 venomous spines used for defense against predators. To a human, a sting can cause swelling for a few days.

The spines are strategically located on the front part of the dorsal fin, two shorter ones on the pelvic fins, and three additional ones on the front edge of the anal fin.

Well-protected against predators, they are highly adaptable. Once they find a suitable environment, they tend to stay, sometimes reaching densities of over 200 adults per acre.

Lionfish meat is delicious and highly prized by restaurants.

2. How Lionfish Became an Invasive Species

The reign of the lionfish began far from the shores of the Caribbean and the South Atlantic, in the warm waters of the Indian and South Pacific oceans, more than 10,000 miles away from Florida or the Bahamas. However, since 1985, this intruder began to make its presence known in the United States. Its appearance in the Caribbean was recorded later, around 2009.

The theories about how this invasive species arrived in the Caribbean vary, but one of the most popular involves the escape of an aquarium during Hurricane Andrew, a weather phenomenon that wreaked havoc in The Bahamas and Florida. However, genetic studies suggest something different: they entered through multiple points. It wasn’t just a single pair of fish with a particular genetic code that escaped and colonized these waters.

Another intriguing possibility is being considered: it turns out that Americans import thousands of lionfish each year for use in aquariums. It seems that their owners realized how challenging it is to maintain these fish, given that they do not feed on processed food but instead hunt moving prey to devour them, and may have intentionally released them into the sea.

3. The Spread of Lionfish in the South Atlantic’s Waters

As we just mentioned, in 1985, the first sightings of lionfish invasion occurred in Florida, near Dania Beach. During the 2000s, sightings of these invasive species began to be documented along the Atlantic coasts of North Carolina, South Carolina, and Georgia, while reports from Bermuda and Florida continued to surface. Populations of invasive lionfish were also growing there. By 2010, they started appearing even in areas where they had not been previously spotted, such as in the northern Gulf of Mexico, off Pensacola and Apalachicola.

The lionfish’s expansion has been rapid. It’s presumed their movement followed currents along the Atlantic coast, headed towards the Bahamas, and eventually reached the Gulf of Mexico and the Caribbean. This proliferation has raised concerns due to their presence in areas where they hadn’t inhabited before. But why?

4. Why Do Invasive Lionfish Species Pose a Risk to The Local Ecosystem?

Relentless Hunger

Lionfish are stalking predators that ruthlessly corner their prey, displaying a voracity that defies their size.

Their hunting prowess relies on camouflage and lightning-fast reflexes. During the day, they hide within crevices, under rocks, or amidst coral formations, while at night, they hunt with their heads directed toward the safety of their hiding spot or near a passage or crevice. Adult lionfish then spread their fins (remember the venom contained in their spines), herding their prey and trapping them in the chosen location. Moreover, their ability to stretch their mouths and swallow prey larger than their heads enables them to target larger prey than other predators of their size.

Their diet, it is estimated, encompasses around 250 different species of fish and crustaceans, including grunts, snappers, parrotfish, and damselfish.

They fiercely compete for food with native predatory fish such as groupers and snappers.

What’s the threat?

The threat lies in the depletion of populations, for instance, native fish populations like herbivores that control algae, which would exert additional pressure on coral reefs and increase their stress.

Furthermore, by preying on commercially important fish like snappers and groupers, their presence negatively impacts commercial fishing.

Additionally, lacking natural predators means their population remains unchecked.

5. Control And Management Strategies of The Lionfish’s Caribbean Invasion

There are several strategies to control the expansion of the lionfish in the Caribbean and the South Atlantic, among them:

Maintaining lionfish invasive species populations below a critical threshold

Efforts do not aim to completely eradicate the lionfish, as institutions like the National Oceanic and Atmospheric Administration (NOAA) point out the impossibility of such an endeavor. Instead, the goal is to keep their populations below a critical threshold. This approach aims to ensure the survival of native species, safeguarding their habitat against the invasion of the lionfish.

Strategic Lionfish Hunting

Divers and fishermen deploy hunting programs focused on capturing and reducing lionfish populations in predetermined areas.

“Early detection and rapid response” programs have been developed in the US. When a lionfish sighting is reported in a new area, trained officials respond to capture them to prevent their invasion into new areas.

Empowering natural allies: groupers

A key shift lies in empowering natural predators of the lionfish, such as the formidable groupers. These powerful marine inhabitants could become strategic allies in controlling not only lionfish populations but also other invasive species threatening ecological balance.

Lionfish as a food source

Other initiatives involve promoting their consumption as human food. Establishing a market for invasive lionfish as a food source is not only viable but practical, advocating for its promotion.

There is a need to develop traceability strategies for lionfish, in addition to profitable collection and distribution channels. The aim is to turn small-scale fishermen into the best tool for invasion control.

6. Forecast of the Presence of Lionfish in The Atlantic

The invasion of the lionfish has transcended borders, spreading across the western Atlantic and the waters of the Mediterranean Sea. However, it seems that the scenario is changing under the effects of climate change, as an expansion towards higher latitudes is looming due to the lionfish’s adaptive capacity to extreme thermal and saline conditions.

Predictive models foresee its arrival on the coasts of France, the United Kingdom, Uruguay, South Africa, and New Zealand, among other regions, as global warming progresses. Nevertheless, this temperature rise could make tropical latitudes less habitable.

The lionfish invasive species is undoubtedly a global challenge that demands the cooperation and concerted action of the international community.