When the red lionfish (Pterois volitans) first began to appear along the shores of the Florida panhandle there was a great effort to make locals aware of the potential problem. Today it is rare to find people who do not know what a lionfish is. I was recently working with a group of elementary school students in the beach classroom at the school districts environmental center. There was a tank with a lionfish in it and as I approached, they all yelled out – “that’s a lionfish”. They were all aware of this invasive species.
Red Lionfish
Photo: Florida Sea Grant
The first record of lionfish in the northern Gulf of Mexico was logged in 2010 – though a presentation at our recent panhandle lionfish workshop suggested it may have been here as early as 2008. There was immediate concern from the fishing and diving community. We began to hold workshops and local non-profits formed to begin removal tournaments. The word on the aggressive spread, fast reproductive rate, and lack of predators sent an alarm across the region.
In 2013 we held our 1st panhandle regional lionfish workshop. Researchers indicated that the densities of lionfish off our shores were the highest in the south Atlantic region – a presentation at the recent workshop indicated, at that time, the density of lionfish here may have been the highest in the world. It was not uncommon to see videos of small artificial reefs with 100 or more lionfish hanging about. It was reported that they were opportunistic feeders and had identified no fewer than 70 species of small reef fishes in their guts. The reproductive rates were an average of 30,000 fertilized eggs every four days – basically year-round. Their eggs drifted in a gelatinous sac and the spread of the fish followed the ocean currents, spreading everywhere.
War was declared.
Lionfish tournaments began to pop everywhere. They began with a few hundred or a thousand lionfish turned into events where tens of thousands of lionfish were weighed during three-day events. Lionfish education and outreach expanded across the state. Some engaged in the commercial harvest of these fish. Turned out they were quite tasty. Knowing Pensacola was sort of ground zero for lionfish density – I was contacted by chefs from around the region seeking fillets.
At the 2019 workshop researchers reported that the densities had declined in waters less than 200 feet. Everyone pointed at the recreational and commercial harvest as a possible cause, but something was obviously working. Lionfish were beginning to develop skin lesions. Scientists were not sure of the cause, and not sure whether this played a role in the density declines, but it was happening. Harvesters reported problems on the commercial side. Dive time and location were becoming problems, densities were declining – less fish to harvest, and the price point between the harvesters and the seafood industry were not where either side wanted them. One thing that seemed to be working was ecotourism. Word about huge numbers of lionfish was drawing visiting divers from all over. Dive charters were finding they could make more money but taking visitors out to shoot lionfish, than selling them to the commercial markets. There was also a supply issue. One restaurant from Charleston South Carolina contacted me asking for a source of lionfish. He said he needed about 500 pounds a week. This order would be very difficult to fill. But things from the invasive side, at least in waters less than 200 feet, seemed to be improving.
We just held the 3rd regional workshop in 2024. Researchers indicated that the densities were still down. Anecdotal reports suggest an increase in lionfish. It was thought that the pandemic reduced tournaments and commercial harvest and populations of lionfish were on the rise again. This may very well may be, but science did not show this. More studies were needed. Skin lesions are still occurring, but researchers are still not sure what is causing it. There does seem to be a link between the decline in density and the frequency of these lesions – the researchers believe that these lesions are playing at least a part in controlling their population.
One researcher reported evidence of lionfish in our estuaries. Using eDNA methods she was able to identify lionfish DNA in the upper portions of Escambia, Blackwater, Perdido, and Mobile Bays. The monitoring was done during low tide to reduce the chance of tides moving the eDNA up into the bay. She also found evidence of lionfish DNA in the feces of shorebirds nesting on our barrier islands. They are still working out how this is happening, possibly the birds are feeding on newly hatched lionfish from the drifting egg mass – not sure. But it is very interesting.
The commercial harvest is doing okay in some parts of the panhandle, but not in others. Interviewing restaurants and seafood markets we found several barriers keeping some of these businesses from providing lionfish. First was the size of the fish and percent yield of fillet. Lionfish are small and labor intensive to prepare. A second concern was the venomous spines. There were also concerns about supply and price points. However, all the seafood markets and restaurants we spoke with were interested in selling lionfish if we could overcome these barriers and were very open to the idea of education/meetings on how to do so. Florida Sea Grant does plan to begin these meetings this year.
The tournaments continue to do well. Destin’s Emerald Coast Classic is now the largest lionfish tournament in the world. Interest and participation continue to be strong. Florida Fish and Wildlife Conservation Commission’s Lionfish Challenge is also doing well, though they reported a decline in the number of commercial harvesters participating.
So as of now
Lionfish remain in the Gulf of Mexico
Densities are still low
Lesions are still occurring
Commercial harvest has not gone as well as hoped
Tournaments are doing well
Lionfish appear to be moving into the estuaries
We will see what updates the 2029 workshop will add to the story.
Each year scientists, resource managers, science educators take some time in February to make the public aware of the invasive species issue. Over the last few decades, I believe this has happened. News articles, fact sheets, public events, even kids’ television programs have covered the topic. You wonder what else needs to be said. But I have found that there is still a lot of confusion about invasive species.
For one… what exactly IS an invasive species. The term is used for almost any creature we do not like or seems to be a problem for us. And on the flip side of that, some species which have been deemed invasive we don’t see a problem with. Many have told me – “What problem does the Chinese Tallow cause? I like this tree in my yard. It is one of the few that shows color in the fall and I want to keep it”.
The Chinese tallow is an invasive species the entire state is dealing with. Photo: Rick O’Connor
There are several characteristics used to identify a creature as invasive but causing an environmental or economic problem is a big one. Many species of vine come to mind. Kudzu, Japanese Climbing Fern, and Old World Climbing fern are good examples. These plants grow rapidly, covering all things in their way – other shrubs, trees, homes, garages, electric wires, and more. You can see them expand like a cancer across the landscape and realize that all other plant life will not be able to compete with them. Then you might realize that animals that depend on those native plants are in trouble as well. And then add into the labor and cost of removing them only to watch the invasion reoccur next year. I know here on Pensacola Bay they have spent thousands of dollars trying to remove kudzu from a shoreline bank near a popular restoration area. Only to find the entire area covered again in a couple of years.
Then there are the invasive animals that have caught our eye. The Burmese python and red lionfish come to mind. Burmese pythons can reach lengths between 15-20 feet and weigh almost 200 pounds. They can consume almost any small mammal in the environment and have even taken on large ones, as well as alligators. There are thousands of them now in heavily populated south Florida and their presence is unnerving to those residents – to say the least.
The Invasive Lionfish
The red lionfish is one of the most successful invasive species ever. After the initial release(s) in southeast Florida in the 1980s they have expanded to cover the entire south Atlantic region. They are opportunistic feeders consuming whatever they can get into their mouths and altering the ecology of our coral reef systems.
But then there are comments I have heard concerning the expanded growth of native muscadine or dewberry vines across one’s yard. “These things are invasive, aren’t they?” Actually… no they are not. They may be problematic, a nuisance, but not invasive. Living in the Florida panhandle I have had residents who have moved here from south Florida ask me whether mangroves would be considered invasive here. But the spread of mangroves north is occurring naturally – so, no it would not.
So… how DO we define an invasive species?
The University of Florida IFAS Extension defines an invasive species as (1) a species not native to the area, (2) a species that was introduced by humans – whether intentional or not, (3) a species that causes either an environmental or economic problem – possibly both.
Battling invasive species can be labor intensive and costly. As you can see on the graph below, the best method is preventing the species from ever reaching your area. Easier said than done. First you need to know which species to be on the lookout for. Second you need to know how it is dispersing across the environment before you can prevent it. If you miss the initial invasion, you will see Early Detection and Rapid Response (EDRR) is the next plan of attack.
The Invasive Species Curve
Making the public aware of these species, and the problem, is what NISAW is all about. Helping the public to better understand how to manage the invasive species and prevent new ones from arriving is also a part of this effort. We will post articles about invasive species found in the Florida panhandle throughout the rest of this week. Some are in the red part of the invasive curve. Some are just beginning to be found here. If you ever have questions about a species on your property, you can always reach out to your county extension office for help and advice.
Despite efforts by public and private land managers, feral hog populations continue to rise in many areas in Florida. Feral hogs damage crop fields, lawns, wetlands, and forests. They can negatively impact native species of plants and animals. Their rooting leads to erosion and decreased water quality. Feral swine can also harbor and infect domestic swine with diseases such as African Swine Fever, foot-and-mouth disease, pseudorabies, swine brucellosis, and others.
USDA APHIS conducts feral swine monitoring for diseases to help safeguard our pork production here in the US. More than 6,000 samples are taken annually to test for diseases of concern. This monitoring effort not only keeps our domestic swine safe but also keeps humans safe from diseases that can infect us. African Swine Fever (ASF) is the main disease of concern right now for the state of Florida, especially those counties bordering the Gulf of Mexico.
ASF is a deadly disease of both feral and domestic hogs. It is not transmitted to humans so it is not a health or food safety concern. It is, however, highly contagious and would likely have a catastrophic effect on our domestic pork industry. Although it has not been found in the US, this disease has recently been detected in the Dominican Republic and Haiti.
This concern has led to a new monitoring program in Florida specifically for ASF in counties bordering the Gulf. USDA APHIS will begin trapping wild hogs in these counties in order to monitor populations for ASF. Landowners, both public and private, can benefit from this monitoring program. Professional trappers will be employed to remove wild hogs for this monitoring effort. For more information on this program, contact Buddy Welch, North Florida Assistant District Supervisor, USDA Wildlife Services, ASF Surveillance at edgar.welch@usda.gov.
Sounder of hogs in a corral trap. Photo Credit: Jennifer Bearden
Without question, Cogongrass is the most troublesome invasive plant that I (and my clients) deal with. Here in Northwest Florida, we have a lot of it, and it is very difficult to manage. It has been my observation that the difficulty of management and limited early success often lead to frustration and ultimately a loss of interest in control efforts on the part of landowners/managers. This is the absolute worst-case scenario, as diligence over time is paramount to successfully managing cogongrass. With all this in mind, optimizing the impact of the initial control effort is crucial both in terms of biology (efficacy on the plants) and psychology (keeping the landowner encouraged and motivated). If you have cogongrass to fight, take every step you can to get the absolute best results you can, out of every treatment, especially the first one.
Cogongrass is highly invasive, difficult to control and widespread in Northwest Florida.
Phot Credit: Mark Mauldin
The following is a discussion of some of the steps you can take to maximize the efficacy of your control efforts.
1) Timing Matters
Cogongrass is best treated with a fall-spring, one-two punch. Mid-summer and mid-winter treatments are not advisable. NOW is the time to treat. As I write this it is mid-October with rain on the way – by the time this is published the front will have passed and the timing will be perfect. If you ask me the absolute best time of year to treat cogongrass, I will tell you, without hesitation, “October through November, before first frost, with good soil moisture”. Spray now and be prepared to spray again in the spring when you have at least 12 inches of green leaf and good soil moisture. With that one-two successfully delivered you should see significant reduction in the size of the infestation by this time next year. Keep repeating the spring-fall process until you can no longer find any cogongrass.
Getting good herbicide coverage over all of the characteristically lime green foliage of cogongrass is essential for good control.
Photo Credit: Mark Mauldin
2) Coverage & Leaf Area are Crucial
To make the most out of each treatment you must maximize the amount of chemical you get into the plant. This is done by getting thorough coverage on as much green leaf area as possible. Make sure you have plenty of green leaves (at least 12inches) and spray them like you’re painting a wall. You don’t want runoff, but you want every square inch of leaf covered with spray. Don’t mow or burn for at least 30 days after you spray. Cogongrass can be hard to spot, especially if it is growing mixed with other grasses/green foliage. Look diligently to find the edge of the patch and then spray 10ft past the known edge on all sides of the patch.
3) Get the Spray Mixture Right
Notice, I didn’t say pick the right chemical. There’s more to it than that. The following recommendations will be based on using the active ingredient glyphosate. (Imazapyr is also very effective on cogongrass, but due to its soil activity it is inherently more complicated to use and ensure the safety of desirable plants near the treatment area. I am not comfortable recommending imazapyr without first seeing the site where it is to be applied and discussing the risk to other vegetation with the landowner. Glyphosate must enter a plant through a green leaf making it much easier for applicators to ensure the safety of desirable vegetation.)
Generally speaking, the efficacy of glyphosate will increase if a water conditioner and surfactant are included in the spray solution. To clarify, this would be 3 separate products going into the spray tank – one herbicide and two adjuvants. The preferred water conditioner would be a 34% liquid Ammonium Sulfate (AMS) product and the surfactant would be an 80/20 Non-ionic surfactant (NIS). These products should be available anywhere ag chemicals are sold (not the garden center at a big box store) under many different name brands. Selecting a glyphosate product can be somewhat confusing, simply because there are so many different products on the market. The product amounts listed below are based on a 41%, 3lbs acid equivalent (ae) per gallon glyphosate product. This is a relatively common formulation, but there are many others available. All can be effective; it is just a matter of value and correctly adjusting the rate to match the formulation you are using.
An example mixture for treating a small patch with a hand-held single nozzle sprayer:
Fill spray tank ½ – ¾ full of water (run agitation if available)
For each gallon of spray solution you are making add:
3.2oz of 34% AMS water conditioner (add this first and let it completely mix before proceeding)
5oz of 41% 3lbs ae glyphosate herbicide
0.5oz of 80/20 NIS
Finish filling spray tank
For a broadcast application using a tractor mounted sprayer or other similar equipment, mix a spray solution such that 1 gallon of 41%, 3lbae glyphosate herbicide is applied per acre. Ideally this would be delivered in 10-20 gallons of water (be sure spray equipment is properly calibrated). Add a liquid AMS water conditioning product at 2% v/v before adding herbicide to the tank. Add a non-ionic surfactant (80/20 NIS) at 1qt per 50-100 gallons of spray solution after the herbicide has been added.
I understand that nobody likes to have to deal with all the numbers, especially the various formulations of glyphosate. Unfortunately, that’s just part of it… There are so many different products out there that the numbers are necessary to communicate the recommendations in a way that is widely applicable. Please don’t hesitate to contact me or your local UF/IFAS Extension Agent for assistance sourcing vegetation management products or tailoring the recommendations to match the specific products you have on hand. The most important thing is to get the mixture right and make the application be as effective as possible.
It’s a national program where volunteers gather at a public space to help remove invasive weeds. In many cases they target one specific species. This year in Escambia County we plan to target beach vitex on Pensacola Beach. If there is not an event in your community, you can still participate by removing invasive weeds from your own private property. Here is how…
Target one specific species. Maybe Chinese tallow, Japanese climbing fern, or other possible invasive weeds in your community. If you are not sure which weeds are invasive, check with your local county extension office.
Read how to best manage. Each species may use different methods and herbicides to treat. Maybe you do not want to use herbicides, not a problem, by visiting the website of the University of Florida’s Center for Aquatic and Invasive Plants, you can find fact sheets that will give you not only the different herbicides that can be effective, but other non-herbicide management ideas.
Decide what you are going to do with the weeds afterwards. Fragments and seeds from these weeds can generate new populations. You make sure you dispose of the plant properly to not create a bigger problem.
Pick a nice day, collect all your supplies, and do it.
Let us know! Contact me (Rick O’Connor roc1@ufl.edu) and let us know which species you removed and how much.
If you are in Escambia County and want to participate in our event this year, we will be removing beach vitex from public areas on Pensacola Beach. You will need gloves, loppers or clippers, and a 5-gallon bucket. Here is our schedule…
Oct 4 12:00pm Quietwater Boardwalk. Meet at the seashell.
Oct 12 12:00pm The Bike Path near the Sugar Bowl. Meet at parking lot 27A (Allen Levin Way).
Oct 18 12:00pm The sewer lift station on Via DeLuna just west of the west entrance into
Sugar Bowl.
Oct 25 12:00pm Bike Path near Portofino. Meet at parking lot 27B.
If you plan to come to one of these, let me know! Rick O’Connor at roc1@ufl.edu.
Vitex beginning to take over bike path on Pensacola Beach. Photo credit: Rick O’Connor
Miami is ground zero for invasive species in this state. But the Florida panhandle is no stranger to them. Where they are dealing with Burmese pythons, melaleuca, and who knows how many different species of lizards – we deal with Chinese tallow, Japanese climbing fern, and lionfish. The state spends hundreds of thousands of dollars each year battling and managing these non-native problem species. By definition, invasive species cause environmental and/or economic problems, and those problems will only get worse if we do not spend the money to manage them. Those who work in invasive science and resource management know that the most effective way to manage these species is to detect them early and respond rapidly.
The Invasive Species Curve
Invasive species have made their way to the coastal waters and dunes of the barrier islands in the Florida panhandle. Beach vitex, Brown anoles, and Chinese tallow are found on most. Recently on Perdido Key near Pensacola, we found a new one – cogongrass.
Cogongrass (Imperata cylindrica) was accidentally introduced to the Gulf coast via crates of satsumas entering the port of Mobile in 1912. It began to spread from there and has covered much of the upland areas of the southeastern U.S. It has created large problems within pasture lands, where livestock will not graze on it, and in pine forest where it has decreased plant and animal biodiversity as well as made prescribed burning a problem – it burns hot, hot enough to actually kill the trees. The impacts and management of this plant in that part of the panhandle has been known for a long time. The Department of Agriculture lists it as one of the most invasive and noxious weeds in the country.
Cogongrass seedheads are easily spotted in spring.
Photo credit: Mark Mauldin
Two years ago cogongrass was discovered growing around a swimming pool area at a condo on Perdido Key. To be considered an invasive species you must (a) be non-native to the area – cogongrass is certainly non-native to our barrier islands, (b) have been introduced by humans (accidentally or intentionally) – strike two, we THINK it was introduced by mowers. This is a common method of spreading cogongrass, mowing an area where it exists, then moving those mowers to new locations without cleaning the equipment. We do not know this is how it got to the island, but the probability is high. Third, it has to be causing an environmental and/or economic problem. It certainly is north of the I-10, but it is not known what issue it may cause on our barrier islands. Could it negatively impact protected beach mice and nesting sea turtle habitat? Could alter the integrity of dunes to reduce their ability to hold sand and protect properties. Could it overtake dune plants lowering both plant and animal diversity thus altering the ecology of the barrier island itself? We do not know. What we do know is that if we want to eradicate it, we need to detect it early and respond rapidly.
According to EDDMapS.org – there are 75 records of cogongrass on the barrier islands, and coastal beaches of the Florida panhandle. This is most likely under reported. So, step one would be to conduct surveys along your islands and beaches. Florida Sea Grant and Escambia County of Marine Resources are doing just that. EDDMaps reports five records on Perdido Key and four at Ft. Pickens. It most likely there is more. A survey of the northeast area of Pensacola Beach (from Casino Beach east and north of Via De Luna Drive) has found two verified records and two unverified (they are on private property, and we cannot approach to verify). Surveys of both islands continue.
The best time to remove/treat cogongrass is in the fall. The key to controlling this plant is destroying the extensive rhizome system. In the upland regions, simple disking has been shown to be effective if you dig during the dry season, when the rhizomes can dry out, and if you disk deep enough to get all of the rhizomes. Though the rhizomes can be found as deep as four feet, most are within six inches and at least a six-inch disking is recommended. Depending on the property, this may not be an option on our barrier islands. But if you have a small patch in your yard, you might be able to dig much of it up.
Chemical treatments have had some success. Prometon (Pramitol), tebuthurion (Spike), and imazapyr have all had some success along roadsides and in ditches north of I-10. However, the strength of these chemicals will impede new growth, or plantings of new plants, for up to six months. There are plants that are protected on our islands and on Perdido Key any altering of beach mouse habitat is illegal. We certainly do not want to kill plants that are holding our dunes. If you feel chemical treatment may be needed for your property, contact the county extension office for advice.
Most recommend a mixture of burning, disking, and chemical treatment. But again, this is not realistic for barrier islands. Any mechanical removal should be conducted in the summer to remove thatch and all older and dead cogongrass. As new shoots emerge in late summer and early fall herbicides can then be used to kill the young plants. Studies and practice have found complete eradication is difficult. It is also recommended not to attempt any management while in seed (in spring). Tractors, mowers, etc. can collect the seeds and, when the mowers are moved to new locations, spread the problem. If all mowing/disking equipment can be cleaned after treatment – this is highly recommended.
Step one would be to determine if you have cogongrass on your property, then seek advice on how to best manage it. For more information on this species, contact your local extension office.
