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Please begin with an informative title:

[Last Monday night's broadcast of NBC News, Brian Williams was scheduled to run a story on the introduction of these fish to the U.S. This essay was originally published to Daily Kos on October 7, 2006. I still have this specimen in my collection, although it has grown substantially.]

So, what is this Southeast Asian lionfish doing in Southern New England? Over the past couple of years I've heard rumours that these fish were being spotted off the coasts of New York and New Jersey. One was a claim that someone caught one in a bay on Long Island, and the other was from a fisherman who says he saw one off the coast of New Jersey, drifting among weeds in the Gulf Stream Current.

Intro

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As we saw in a previous diary, it is not at all uncommon to find the young of fish native to the West Indies and the Caribbean in Rhode Island waters. They are known as "tropical strays" and many different species live here during the late summer and early fall because the eggs or young drifted northward during the spring. These fish die off as soon as the water cools down in late October. But a South Pacific lionfish? That was hard to believe.

First a little something about what a lionfish actually is. There are many different species, but the one we are dealing with is known as the Red Lionfish (Pterois volitans), first described by Linnaeus in 1758. It has many maroon stripes on its white body (or many white stripes on its maroon body. Like the zebra, it all depends on your perspective). They can grow to about fifteen inches in length.

Lionfish are highly venomous, although unlike their close relatives the scorpionfish, which are regarded as the most poisonous species of fish, this venom is not fatal to humans (although a sting is extremely painful). The poisonous spines are hidden among an elaborate mane of dozens of long, flowing fin rays which emanate from the dorsal and pectoral fins.

Before moving on to how these fish came to our shores, a little personal anecdote about their stinging ability. When I was a teen I had a friend who worked in a pet shop. Like many kids our age he was curious, but at times lacked a bit of common sense. Wanting to know how the sting of this fish felt (hell, it couldn't be worse than a bee sting, right?) he reached into a tank and brushed his hand against the top of its body. Blood-curdling scream quickly followed. He went to the hospital, his hand swelled up and he was in pain for hours.  I doubt he experimented with poisonous fish after that.

However, I was intrigued and needed to know how that sting could have been so powerful considering he had barely brushed the surface of the fish. I wrapped my hand in a dishrag, reached into the tank and brushed against the top of the fish. I felt a jolt go right through my arm, even though I wasn't actually stung. What I discovered was that it wasn't necessary to actually touch the spines yourself. The fish does that for you, and like the reflex reacton I described in the stingray diary, when anything brushes against the top of the lionfish the barbs reflexively strike upward. The speed and force was amazing for such a small animal and what I felt was a half dozen solid barbs quickly stabbing into the rag I was holding. Although I could feel the strike, the barbs weren't long enough to penetrate the cloth.

Ok, back to why these volitans are here all of a sudden. Doing a little research, I discovered that as early as 2001 a couple dozen young specimens of these fish were captured off the coast of North Carolina, and one was found on the island of Bermuda. Scientists at NOAA (National Oceanographic and Atmospheric Administration) were called in to find out where they came from. Lionfish are popular among experienced saltwater aquarium hobbiest, so the most logical answer was that someone released them on purpose. But most of those caught were young ones which indicates they were becoming established as a population and breeding.

As it turns out the pet industry had a saltwater fish facility in Biscayne Bay, Florida that was destroyed during Hurricane Andrew in 1992. Many of their specimens were accidentally released into the Atlantic Ocean, including six red lionfish. These fish survived and formed a colony on the Florida coast over the years as they reproduced.

Lionfish eggs, like the eggs of many tropical fish, are buoyant. Although most of the eggs stay close to the parent's habitat, some will get trapped in the northern-flowing Gulf Stream Current and travel up the Atlantic coast. As the Florida population increases the chances of some of their eggs flowing north also increases. So after a couple of years of rumour, this year Long Island and Southern New England became hosts to possibly thousands of these exotic animals. The one in these photos is one of only three found in Rhode Island, but as many as five hundred have already been collected on the south shore of Long Island. This specimen is about three inches long and I caught it while snorkeling in about three feet of water. It should be interesting to see what happens in the next few years; whether this year was a fluke or if these fish, like the ones I pictured in that previous diary, will become regular occurrences.


(Click the map to embiggen.)

Above is a map that shows where the red lionfish are native to (red dots) and where they have been recently found on the East Coast (white dots). I should note that, like most tropical strays, the lionfish that find themselves north of Florida are young ones and will not survive the winter. No lionfish colonies will become established in my area.

Back to more lionfish biology. The most intriguing features of this fish are the spines, the fin rays, and, to me at least, the eyes.

The venomous spines can't be seen by simply observing the live fish while it is swimming. Most of the long fin rays you see are harmless, but the spines are hidden among them, mainly on the dorsal surface. Each spine has a venom gland at its base which produces a neurotoxin called acetylcholine. When the spine strikes the gland basically shoots a few drops of venom up through the hollow spine and into your skin. Normally the pain is severe but only lasts a few hours. If it hits a blood vessel the pain can last for days and even induce seizures.

The spines are purely defensive, and although these fish are fierce predators, they reserve the toxin for protection only. However, this fish obviously knows its strengths. Unlike most fish, which will flee when approached by a larger animal (or an arm reaching into its aquarium), the lionfish instead turns and faces its attacker, dips its head downward and flairs out all its fin rays toward you. It's like it's daring you to attack.

This behavior is also used to capture its prey. The favorite food are shrimp and smaller fish. The volitans will slowly follow and stalk its prey until it has it cornered against a rock and then, amazingly, will surround the smaller animal with all of its long pectoral rays, leaving, in the victim's view, no escape. Then the huge mouth snaps open and sucks up the food like a vacuum. Lionfish are voracious and hobbyists are warned not to overfeed their pets as they will eat themselves to near bursting.

Notice the stripe running vertically through the eyeball. For all fish the most vulnerable part of its body are the eyes. Not only are they unprotected, but more importantly they give away the directional movement of the fish, helping the predator plan its attack. There are two ways to confuse an enemy regarding which way it is swimming. One is to reverse direction when in danger. Many eels do this. Instead of moving forward when it senses danger, an eel will reverse direction and actually swim backwards rather quickly.

Another way is to disguise the eye with its body pattern to make it less visible. This can be seen in the two photos to follow. Lionfish don't swim horizontally like most fish do. They swim lopsided at a forty-five degree angle, head slightly down and tail slightly raised (this helps when it is stalking prey of its own). In the photo below notice that the eye stripe neatly matches the stripe on its head, distorting the normally distinct eye on the head of most fish.

In the next photo we see a lionfish swimming more horizontally as it sizes up the photographer. Notice that the eye stripe is now skewed and doesn't match up exactly with the head stripe. When not swimming in its normally tilted position the eye becomes more distinguishable.

Finally, as exciting as all this is, the lionfish has the potential to cause problems ecologically. Animals that are introduced to areas where they are not normally native are known as invasive species. Although it is not yet known what, if any, negative impact volitans will have as it becomes more established, the history of invasive species is not a pleasant one. Whether they be mongoose introduced to Hawaii or poisonous toads brought to Australia (among way too many examples), these animals are responsible for the extinction or degradation of countless native species.

And, unfortunately, the responsibility for these introductions almost always lies with us. Intentionally or not, global commerce and human migration has introduced thousands of plants and animals to other locales, and the effects on the natives are often devastating. I'm hoping this is not the case for the red lionfish.

Fun Fact: This is the species of fish in Captain Picard's ready room on Star Trek: TNG. Its name is "Livingston".

All photos by Rebecca Bray.

Other diaries in this series can be found here.


Extended (Optional)

Originally posted to Mark H on Sun Jul 13, 2008 at 11:42 AM PDT.

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