Saturday, September 29, 2012

Invasive Species 101: Lionfish in Local Waters

Lionfish, Pterois volitans and Ptrois miles found very far from their native home
There are waves and trends that flow through every field from fashion to education.  Those particular two divisions melded together for me about 10 years ago when I bought a t-shirt that simply read "Green is the New Black".  Think about health food trends: oat bran, wheat bran, no carbs, vegetarian friendly - as our worldwide culture constantly evolves, there is also regular shifting among conservation efforts too.
The new eco-based 3 R's: Reduce, Reuse, Recycle

Once upon a time, recycling was depicted as a homeless person in the big metropolis pushing a shopping cart around and digging through trash in search of valuable glass bottles or aluminum cans.  Now theme parks with large mouse ears on everything boast recycling bins throughout the park, conveniently located right next to standard trash bins.  Small children in school are learning a very different 3 R's than our grandparents did: Reduce, Reuse, Recycle.  From experience I know that kids are getting that phrase hammered into their brains at a very early age; but do they really understand what it means and how to implement these changes in their everyday lives?  Eh, maybe / maybe not.

A few years ago, the theme of plastic tailgated the recycling party. While this is still an extremely important issue across the globe, as Heidi states in every episode of Project Runway, "One day you're in, and the next day you're out."  I watched the next trend and was very much involved in sharing the message of "Water".  Water is a limited resource and far more valuable than any fossil fuel, but just wasn't getting the attention deserved.  Too many people living in "civilized" areas were, and still are, taking water for granted.  Living in a state which suffers serious droughts and water restrictions most years has taught me how little human beings understand water as a limited commodity.  Florida might be surrounded by water, but it is undrinkable and would kill most plants. That particular concept I took on as personal challenge to teach to as many children as possible.  Kids simply don't often ask questions like: Where does water come from? Where does it go when I am done with it? What would happen if the water ran out?

These questions are just as important as recycling and global warming, plus all of those issues are integrated on a very tightly knit little blue planet.  In fashion, by the time a style or article of clothing makes it to the shopping mall, it is time for the industry to move on; otherwise, it wouldn't be cutting edge, right?  So, now that the plight of water has made it onto to episodes of Super Why (popular toddler's educational cartoon about reading/spelling on PBS and Sprout networks) and even become the main topic for the Girl Scouts of America's Brownie level Journey: Wonders of Water (W.O.W.), I look ahead and feel comfortable predicting the next new eco-friendly trend. By the way, I did also predict the water trend - so it helps my confidence in calling out the next play.

So what is the latest environmental impact that YOU should know about to remain cutting edge on the eco-front?

Now, I would never throw a pitch without teaching you how to swing, so get you ready for the next wave of conservation efforts that are already in place despite not always making the media headlines.  Here is the 101 needed for understanding invasives.

First, a few foundation terms that it never hurts to properly define:
"Species" means a group of organisms all of which have a high degree of physical and genetic similarity, generally interbreed only among themselves, and show persistent differences from members of allied groups of organisms."
"Native species" means, with respect to a particular ecosystem, a species that, other than as a result of an introduction, historically occurred or currently occurs in that ecosystem."
"Invasive species" means an alien species whose introduction does or is likely to cause economic or environmental harm or harm to human health."

Let's start by looking at these terms.  Basically, a "native" means this organism has always been found in a region naturally.  There is a term often used interchangeably and inaccurately with "invasive" and that is "exotic".  An exotic species is not necessarily an invasive species.  One escaped pet lemur roaming around the neighborhood is simply an exotic animal on the loose.  It will not establish a breeding population all by itself, and will not cause any large scale or long term negative impacts to the ecosystem where it is wandering around.

An invasive species is much different.  It has adapted to the environment and is breeding.  By adding an entirely new population to an ecosystem, now there is the threat of serious, detrimental impact.

Look back in the archives to "Jellyfish 101" to see my first mention of an invasive species in local waters - the Tripedalia cystophora box jelly (July 2012).  Invasive plants and animals are an issue every time explorers set foot on new lands, so this is not a new problem.  The United States Department of Agriculture even has an Invasive Species Council that was established back in 1999 to take on the arguably impossible task of tracking and stopping invasives from establishing themselves.

Most of the invasive species to an area don't get attention because they are organisms like non-toxic plants or critters low on the food chain. An invasive plant that does not sting like Africanized bees or eat your small dog as a large boa constrictor might simply do not garner extensive media coverage. Take a very short walk anywhere in Florida and several lizard species will be darting out of the way - none of them are native save for the small green anole and the bluish black skink. But since they do not grow to the impressive 4' and up of an iguana, most people do not see them as a problem even though many tinier animals are now at risk of endangerment and extinction due to the uninvited reptiles' presence.

So how exactly does a species go from being simply an exotic to an invasive?
  • Often these invaders become very successful predators. This concept does not exclude plants.  Many vines and shrubs will move into an area and choke out the previous residents. (i.e. Brazilian pepper, Schinus terebinthifolius). The Australian Pine (Casuarina sp.) sheds needles with a high acidic content, and over time the soil below the tree itself becomes too acidic for much of the local fauna to grow.
  • Generally, the local wildlife does not see this new inhabitant as either threat or food.  So potential predators overlook the new food source, and instead the population booms.
  • Invasives breed successfully, and often.
  • Natural processes do not apply to an invasive species
To better explain, I will use a marine invader that is adapting so quickly and efficiently, researchers and conservationist are pulling out all the stops to get the public on board and involved in this local eco-war: Lionfish.
A very successful predator on local reefs is the schoolmaster snapper (pictured above).  The bait in this particular predator/prey relationship are small grunts.  This photos shows clearly how the prey recognizes its predator and swims around the snapper, staying out just out of striking distance.

Grunts in the same area on a similar reef behave in a completely different manner with the lionfish.  While many of the fish in the photo above could be eaten, they pay no attention to the predator in their midst.  This allows for the lionfish to essentially gorge themselves on a regular basis.  Study of stomach contents has shown lionfish will eat around 80% of the animals found on reefs, including crabs, shrimp, and fish species.  They can also consume an animal almost 1/2 their own size in one big gulp.

Where are lionfish native?  The Indo-Pacific region:

How did they get halfway across the planet? These bottom dwelling fish are not the type to migrate into open water, and certainly not across long distances.  So, like every other invasive, they are introduced to an area.  Lionfish are an extremely popular decorative aquarium fish.  I have personally spoken to dozens of people who kept them and soon realized that the other tank residents were disappearing, until only the lionfish and anything too big for it to eat remained.

An invasive species may arrive in the form of pets that are released often enough to find mates and breed, but sometimes an exotic species is intentionally released into an area.  It is now considered a last resort effort to control a destructive invader by introducing its natural predator.  The cliche goes "two wrongs don't make a right", but nobody was thinking that clearly when the mongoose was introduced to Hawaii.  Rats became rampant when the islands were originally discovered, as there are no native snakes or other rat predators in Hawaii.  To tackle this problem, the mongoose was introduced... but rats come out primarily at night, and the mongoose is a diurnal day hunter... anyone else see the problem?  So now essentially Hawaii has both a rat issue and a mongoose dilemma. Nice.

Back to the lionfish.  These fish are commonly thought to be poisonous, but the proper term is venomous.  Use this adage:
"Poison is ingested, Venom is injected"
The lionfish meat is not toxic, and very yummy (personal experience talking).  The venom of a lionfish is only found in the spines along the dorsal (back) and ventral (belly/anal) of the fish, meaning those beautiful flowery pectoral fins and tail plumage are harmless (also personal experience).  These barbs work on a pressure puncture system, meaning that touching the sides of these needles will not sting.  That does NOT mean I suggest trying this out on a live lionfish just for kicks - actually that is a really bad idea.  While there have been no reported deaths due to lionfish stings, the venom is still very painful and any lionfish victims should go to the hospital for treatment.  There is always a chance of allergic reaction, so take precautions if tagged.

Available online & with local vendors
Researchers with Florida International University, the Loxahatchee River District, REEF, and Martin County are just a few of the amazing organizations working in different regions of Florida alone - but they are all tied together and focused on the same goal: lionfish removal from the natural ecosystem.  These Lionfish Derbies are working hard to get the word out the lionfish are edible to humans!  Because let's face it, humans have proven themselves to be excellent predators particularly in the oceans.

This book also includes how to safely clean a lionfish, but there are also tutorial videos out there for free.  Instead of providing a long list of great organizations involved in the valiant effort of lionfish removal, instead I shall focus on some of the lionfish biology that is less known and very important to understanding why they have become such a successful example of an invasive species.

A strong invasive species population breeds early and often.  While lionfish are becoming rare in their own native habitats, the explosion of inhabitants locally has also provided a plethora of biological specimens for scientist to study.  We have learned that lionfish breed when reaching a length of only 4" for males and 7" for females; considering these relatives of the native scorpionfish can grow to a record length of 18" and have been found all too often in the 15-17" range, that is an opportunity for exponential population growth.

When the zebra mussel was introduced into the Great Lakes back in the 1980's, the population expanded all the way south to the Gulf of Mexico.  This freshwater mussel cannot survive in saltwater, and this natural process is the only factor that truly stopped this invasive filter feeder's progress.  A great dynamic map of this migration can be tracked here:

Natural barriers are often the deciding factor in the growth and success of an invasive species.  The jungle and heat loving iguanas found here will never reach into the states north of the Floridian border.  Cold snaps and even rarely freezing temperature put these endothermic animals into shock and they will quite literally fall out of trees from the cold.

So, lionfish live on saltwater reefs, and surely cannot breach the salinity gap - right?  Many estuaries, like the Loxahatchee River and Indian River Lagoon have brackish water that ebbs and flows with tidal influences.  This mixture of fresh and saltwater serves as a nursery for countless species in the area, and the further one paddles upstream the lower the salinity.  While the salt content in the water decreases, there are also changes to the species found.  Very few animals can withstand a full change from fresh to saltwater - snook is one popular local example.

A friend and associate with FIU, Zack Jud, has been working with the Loxahatchee River District (LRD) to track and study the lionfish population in the Loxahatchee River.  One scary development from an environmental standpoint is the discovery that every time the research crew goes further up river as part of the lionfish study and a long term Oyster Restoration Project (more about that study in a future post), lionfish are spotted.  The most recent sighting/sampling had researchers on the Loxahatchee shortly after a freshwater spike in the estuary due to rain and Tropical Storm Issac.  Lionfish have now been tracked 4 miles upriver into waters with a salinity of 8 ppt (parts per thousand).

Let me clarify this simple fact:  On average, ocean salinty ranges from about 32 - 37 ppt.  There can be extreme ranges like the Red Sea (42 ppt) and locations where freshwater and saltwater collide to lower the salinity, creating brackish ecosystems that eventually turn freshwater (0 ppt salinity).  As mentioned before, very few animals have the ability to adapt to this severe shift in salinity, so to find healthy lionfish so far upstream is disturbing.
Photo taken in the brackish waters of the Loxahatchee River, on one of the Oyster Restoration Project research sites.
Courtesy of Zack, here is the abstract from the original publication on the invasion of lionfish in the Loxahatchee River ecosystem:
Their initial discoveries immediately prompted more research, particularly to find out how fast these animals are migrating as a population, if at all.  This is the most recent published work in the Journal of Experimental Marine Biology and Ecology following up on the lionfish data regularly collected in the same area. Soon to be "Dr." Zack Jud and Dr. Craig Layman authored this particular paper as well.

Essentially, individual lionfish don't stray too far from home, showing a fairly strong inclination for "site fidelity".  Hey, if there is food here, why move?  Makes enough sense.  But, going back to the topic of successful breeding, larval lionfish will float in ocean (or in this case river) currents for around 30 days before settling in an area.  That fact will quickly compensate for any lack of migration from established individuals and keep the population growing and moving simultaneously - yikes!
Lionfish have since been documented 4 miles upriver.
So are invasive species a problem? Uh, yeah.  How are changes made to stop these earth-bound aliens from taking over?  Well, that is where everyone becomes an important part of the eco-puzzle.  Three major changes will have a huge positive impact:
  • Stronger regulations and enforcement on customs and international shipments will greatly reduce the introduction of new species.  One more reason to buy local!
  • Pet Trade
    • Do your research before getting any pet.  Instead of releasing that invasive animal because you feel bad about not being able to handle it anymore but don't want to kill it, research Pet Amnesty events in your area. Most zoos across the county have at least one pet amnesty day each year. The purpose is to find homes with prepared owners ready and willing to take responsibility for these exotic animals, so Fluffy the pet iguana will still have a good home.
  • Remove invasive species
    • Population culling/sterilization.  This means open fishing season on the lionfish in particular.
I want to address one last issue regarding the lionfish invasion here in south Florida - word of ciguatera fish poisoning in lionfish has come up.  First, a little note about ciguatera from the Center for Disease Control (CDC)
"Ciguatera fish poisoning (or ciguatera) is an illness caused by eating fish that contain toxins produced by a marine microalgae called Gambierdiscus toxicus. People who have ciguatera may experience nausea, vomiting, and neurologic symptoms such as tingling fingers or toes. They also may find that cold things feel hot and hot things feel cold. Ciguatera has no cure. Symptoms usually go away in days or weeks but can last for years. People who have ciguatera can be treated for their symptoms."
According to the Food and Drug Administration (FDA), this toxin is usually transmitted to human by consuming the following fish:
Marine finfish most commonly implicated in ciguatera fish poisoning include the groupers, barracudas, snappers, jacks, mackerel, and triggerfish. Many other species of warm-water fishes harbor ciguatera toxins. The occurrence of toxic fish is sporadic, and not all fish of a given species or from a given locality will be toxic.
These top predators essentially are so high up on their food chain, the toxin builds up in their tissues as they consume other animals that have been feeding on the algae blooms.   Several articles have inched their way out into the general population, and Zack has actually been awesome enough to research this and provide his professional opinions (see link below).  As of right now, the only lionfish found to have the ciguatera toxin in its tissues were in the Caribbean, not U.S. waters - and lionfish show high site fidelity, remember?  (Look at how much you have learned today!)  The FDA revealed the findings and made them public, as they should.  Unless you plan to not eat snapper or grouper anymore as well, there is no scientific reason to shy away from eating local lionfish.

 Special thanks to Zack for sharing his work and staying in touch!

Keep up with Zack's research directly on The Abaco Scientist Blog:
This site is updated regularly with the latest news by the ultimate experts on our local lionfish epidemic.  Photos and video clips are also included with many of the posts as well.  I can certainly recommend contacting these guys with any questions, comments, or sightings because unlike many brilliant scientists I have met, they are not only very knowledgeable but also friendly and approachable too.

To check out the lionfish cookbook or order online, visit:

For information on the how the government defines and addresses invasive species, follow this link:
Definitions of many terms were taken directly from this government website to ensure accuracy.

To find out more about Super Why episodes:
To learn about or get involved with the Girl Scouts of America's WOW program:

All photos were either taken by yours truly, or provided by Zack Jud and Dr. Craig Layman and their research team. Thanks again!
If you are interested in joining a lionfish derby, just post a comment on where you would like to participate and I will be happy to respond with the closest organization and event to your area.

I am extremely lucky to have worked with so many wonderful individuals on the cutting edge of research and conservation efforts.  It even inspired me to return to school myself for a Master's degree and to conduct some research of my own again too. Thanks, everybody!

-Callie Sharkey

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