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The Atlantic and Caribbean Lionfish Invasion

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lionfish are an invasive species in the atlantic

Lionfish are beautiful, but are wrecking havoc in the Caribbean!

© istockphoto.com, klaus-bobo
Have you ever seen a lionfish? If you have been diving in the Caribbean recently, you have probably seen one of these stunning, but troublesome fish. The fish species, Pterois volitans, commonly known as the Red Lionfish, is a brightly colored family member of the Scorpionfishes. As the name implies, members of this family have the capacity to leave divers with a painful scorpion-like sting if touched. More worrying to marine biologists and divers is the rate at which the Red Lionfish has taken over Caribbean reefs, endangering native marine life. Keep reading to learn more about these problematic fish.

How to Spot a Lionfish When Scuba Diving:

The lionfish is not a particularly big fish, averaging in size from 4 to 15 inches. Lionfish have long, flashy, fan-like fins and a few fleshy appendages hanging off their faces. It is hard to deny that it is not a handsome fish with its bright, red-orange coloring, white zebra stripes, and spots often dotting the membranes of all fins.

Where Can a Diver See a Lionfish?:

The lionfish is a native inhabitant of the tropical Indo-Pacific waters. It is found on coral reefs, rocky surfaces, and in lagoons between at depths ranging from 30 - 600 feet. As youngsters, lionfish tend to live in small groups, but become solitary as adults with a hostile attitude and strong territoriality towards other reef fish. Being rather unfriendly, lionfish typically hide in reef crevices during the day, coming out to feed at night in deeper waters.

If seeing a lionfish is on your diving bucket list, but a trip to the Indo-Pacific is not in the plans, worry not! This fish has now invaded Caribbean reefs!

Pack Your Bags, We Are Headed to the Caribbean!:

No one officially knows how the lionfish first appeared in the Caribbean. One theory is that in 1992, Hurricane Andrew destroyed an aquarium in Florida. Lionfish from the aquarium were set free in the Atlantic Ocean and eventually spread through the Caribbean and the Atlantic coast of the United States as far north as North Carolina.

The water temperature in these regions made a great secondary tropical home for the lionfish. Food was plentiful, and best yet, there were no natural predators in sight. Since it first appeared in 1992, the lionfish has taken over Caribbean reefs at an unprecedented rate. According to the US Geological Survey, lionfish have established populations on the Caribbean coasts of Central and South America, the Gulf of Mexico, the Greater Antilles, the Leeward Islands, and along the Atlantic US coast since November 2010.

To the dismay of many biologists, the ability of lionfish to withstand extreme differences in depth, water temperature, and salinity make it a difficult adversary to conquer. In the meantime, divers get a treat spotting this pesky but pretty fish!

Feasting on most anything that will fit in its mouth and reproducing with lightning speed, lionfish can now be seen in large numbers at nearly every dive site in the Caribbean. The lionfish is an example of an incredibly successful, but ecologically disastrous invasive species.

Conservation and Scuba Diving
• Dive Site Preservation
• Is Scuba Diving With Sharks Dangerous?
• Caribbean Reef Fish Identification
• Is Touching Aquatic Life Ever Okay?

What is an Invasive Species?:

Invasive species are plants or animals that make a new home in an area outside of their original habitat. These species have a fast growth rate, rapid reproduction, and the capacity to live off a range of food types. On top of this, predators that control their population are often not present within the invaded location. Thanks to these characteristics, invasive species may successfully outcompete native species. Unfortunately, in many cases this means that native inhabitants disappear as the new species takes over.

Since arriving in the Caribbean, lionfish have conquered reefs and nearby coastal areas. With no natural predators to keep the lionfish population at bay in this region, the health of the delicate Caribbean reef ecosystem is at risk.

Lionfish Reproduce Like Rabbits!:

One of the reasons that lionfish have successfully invaded the Caribbean is that they reproduce at an incredible rate. Mature females can release two egg clusters with up to 15,000 eggs every four days throughout the year. Fertilized eggs and larvae are dispersed by way of oceanic currents before reaching their final reef destination. With this many offspring, it is not surprising that this species has so successfully populated its new home.

Get in My Belly! Lionfish Have Incredible Appetites:

An expert and aggressive hunter, the lionfish spreads its large pectoral fins to trap small fish and crustaceans (such as crabs and shrimp) and then swallows prey in a single motion. With a voracious appetite, an individual lionfish can consume large quantities of prey. In particular, lionfish eat many juvenile fish that have not yet had the opportunity to reproduce, decimating fish populations. Imagine the damage an over-abundant lionfish population can cause!

Furthermore, many of the fish on a lionfish's menu play an important role in maintaining reef health. Parrotfish, for example, eat algae. If sufficient numbers of parrotfish are not present, algae can cover and smother coral. By depleting native fish populations, the lionfish offsets the balance of the food chain and health of the reef may be seriously affected.

Lionfish Have Few Natural Predators:

Few animals in the lionfish's native Indo-Pacific region find it a tasty morsel (besides other lionfish -- yes, they are cannibals). The situation in the Caribbean is even worse. It will take time for predators to learn to hunt lionfish in the Caribbean. Divers and researchers have seen Caribbean sharks, groupers and moray eels feasting on lionfish, but it is not known if this occurs regularly, or if it is even enough to reduce the population. Meanwhile, groupers are heavily over-fished in the Caribbean, which means their contribution to reducing the lionfish population is weakened.

Why Have Lionfish Not Taken Over the Indo-Pacific?:

Some scientists believe that lionfish have not affected the food chain of the Indo-Pacific due to the presence of natural lionfish predators. Many believe that predators of lionfish eggs, larvae, and juveniles have controlled the population. The fact that many offspring would be eaten during their trek through oceanic currents is probably why females evolved to produce so many eggs in the first place. The trick now is to find a similar predator throughout the Caribbean to snack on all of these baby lionfish!

Read on!
Lionfish are poisonous and can be dangerous if touched!
Scuba Divers Can Help Reduce the Number of Lionish on the Reef!
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