by Rick O'Connor | Apr 14, 2018
Shoal grass. One of the common seagrasses in Florida.
Photo: Leroy Creswell
For many, it really does not matter. But is there a difference? Yes… there is. Seagrass is what typically washes ashore on the Sound side – seaweed is what we typically see on the Gulf.
So what is the difference?
Seagrasses are actually grasses. They are true plants in the sense they have roots, stems, and leaves. They also produce flowers, but they are so small it is very hard to see them. Pollen and seed dispersal is via the currents. What the observer sees when snorkeling in seagrass meadows are the leaves – in this case called blades. The stems run horizontal beneath the sand, as many grasses in our lawns do. These are called rhizomes, and the roots extend from them. Turtle grass and Shoal grass are the two most common types we have here.
Seaweeds on the other hand, are not true plants because they lack roots, stems, and leaves. They are often called algae and must be submerged in water in order to absorb it. They are either float and drift in the currents, or can attach to hard objects on the seafloor using a structure called a holdfast. June grass and Sargassum are two common types that drift ashore.
So why don’t seagrasses grow in the Gulf?
Like all plants, seagrasses need sunlight. At least 25% of the sunlight reaching the surface must reach the bottom for them to photosynthesize. Near the shore, there is enough sunlight for seagrass, but they cannot tolerate the larger waves that our nearshore Gulf produces – thus they are restricted to the quieter waters of the Sound. We do have seagrasses growing in Big Lagoon, Old River, parts of Pensacola Bay, and even in some of the local bayous. This ecosystem is important to the overall health of our bay. It is known that 80-90% of the commercially and recreationally important finfish and shellfish require seagrasses, or salt marshes, for at least part of their life cycle – so they are important economically as well.
Seaweeds also need sunlight. In rocky areas, you can find them attached in sunlit waters. Much of our area is sand, so we do not see as many forms of seaweed as they do in the Keys or in California. However, we do have floating forms.
March is “Seagrass Awareness Month”. Many people provide opportunities to educate locals about our seagrasses and the issues they are facing. Excessive run-off from parking lots, ramps, homes, etc. – increase the turbidity and decrease the salinity of the water – both of which are detrimental to seagrass health. This run-off also contains pollutants that are problematic – particularly nutrients from fertilizers. The fertilizers trigger algal blooms which block sunlight and, in some cases, smoother the surface of the grass blades. Then there is prop scarring. The shallow waters where they live are also popular spots for boaters to visit. The propeller scarring leaves open tracts throughout the seagrass meadows and, unlike some grasses in our yards, can take years – even decades – to recover. There has been significant loss of seagrass all across the Gulf region, including Pensacola Bay. The loss of seagrass have also affected species such as bay scallop and horseshoe crabs. There are signs of recovery and we need to continue reducing our impact to keep this trend going. Florida Friendly Landscaping, Clean Boater practices, and Living Shorelines are some methods that can help. Contact your local County Extension Office to learn more about these programs.
by Rick O'Connor | Apr 14, 2018
In my job, I get many calls about snakes. Most people want to know how to tell a venomous from a nonvenomous one and how to keep them out of the yard. I was recently reading a new book out by Dr. Sean Graham entitled American Snakes and in the chapter on snake defenses, he provided a long litany of local creatures who consumed snakes – some surprised me. Check this out…
The “cottonmouth” gape of this venomous snakes is a warning. Notice the banded coloration of this individual.
Photo: UF IFAS Wildlife
First, most who do only consume smaller species of snakes – but the list is still surprising. Spiders… spiders were on the list. He specifically called out the black widow – who probably could kill a small snake, but indicated there were others. Scorpions, centipedes, fire ants, carpenter ants, giant water bugs, crayfish, and crabs made the list as well. Some of these may consume snakes only after they are dead – but some can kill small ones.
From the vertebrate world he mentions the larger salamanders (such as the hellbender), and other snakes (such as the short-tailed snake and the coral snake). There are several mammals including shrews, moles, and even the rodents themselves are consumers of snakes! He describes how hoofed mammals (such deer, goat, and horses) do not consume snakes, but can completely destroy one by raising and stopping on them – leaving only small segments remaining. They have found the remains of snakes in the stomachs of all predatory mammals but the snake’s greatest threat are birds… by a long shot. Species from passerines to raptors have been known to kill and consume snakes.
What about venomous snakes – who consumes rattlesnakes and cottonmouths?
There are surprises here as well…
Bullfrogs… bullfrogs basically consume what they can get into their mouths but this includes snakes – and venomous ones as well (though they would be small ones). From the fish world, both the gar and largemouth bass are known to consume venomous snakes.
A coyote moving on Pensacola Beach near dawn.
Photo provided by Shelley Johnson.
Opossums are known to consume at least 12 species of snakes, including venomous ones. They also consume ticks, fire ants, and have a very low occurrence of rabies – a cool animal to have around.
Other mammal consumers of venomous snakes include raccoons, otters, fox, bobcats, coyotes, and black bears. It is understood they must take smaller members of the venomous snake population – but a snake control is snake control.
Most wading birds in our marshes consume snakes, including venomous ones, but it is the red-tailed hawk and the great horned owl that are the masters. Red-tailed hawks are known to consume at least 35 species of snakes, including venomous ones, and – unlike other snake predators – are a larger part of their diet, they seek them out. Great Horned Owls consume at least 13 species, and venomous ones are on the menu.
From the reptile world we begin with the alligator, who has little problem consuming large specimens of both the rattlesnake and the cottonmouth. However, many are snakes… yes, snakes eat snakes and some consume venomous ones. Coral snakes, coachwhips, and cottonmouths have been known to consume other snakes. However, it is the Eastern Indigo and the Kingsnakes who actively seek out venomous species. It is known that kingsnakes have a protein in their blood that makes them immune to the viper’s venoms – and it appears the vipers know this and avoid them. It is not known whether the indigo is immune, but it is known they will seek out venomous snakes and consume. Both of these snakes can take relatively large venomous species.
Of these two, it is the Kingsnake who is the “king” – consuming at least 40 species of snakes. However, both the kingsnakes and the indigo are on the declined. The eastern indigo is currently federally listed as endangered – there has not been a verified record of one in the Florida panhandle since 1997. However, there are anecdotal reports and we encourage anyone who has seen one to send us a photograph. There is an active indigo restoration program going on in Alabama and in the Apalachicola River area. These are the largest native snakes in the U.S. (about 8 feet) and, along with the six-foot kingsnakes, are frequently killed. There is evidence that as the eastern kingsnake populations decline copperhead populations increase, and Vis versa. Some areas near Atlanta are currently experiencing a copperhead “boom”. Clearly, we should reconsider killing both the indigo and kingsnakes. We also understand that habitat loss is another cause of their decline, particularly in the case of the indigo.
When looking at this list of snake consumers we see species that cause other problems – alligators, raccoons, coyotes, and bears have all have had their negative issues. But many we just do not like, such as the opossum, really cause us no harm and control snake populations. Everything has its place in the local environment and not one species seeks out humans for the purpose of harming us – this would include snakes. The negative encounters are for other reasons. But for those who have a deep fear, or are currently experiencing high snake numbers, seeing one of the animals on this in the neighborhood could be a relief.
References
Graham, S. 2018. American Snakes. John Hopkins University Press. Baltimore MD. Pp 293.
O’Connor, M. 2018. Personal communication.
by Rick O'Connor | Mar 10, 2018
As we come to the end of National Invasive Species Awareness Week (NISAW), I need to educate everyone on a potential invasive threat, a classic Early Detection Rapid Response (EDRR) species – the Cuban Treefrog.
is this a Cuban Tree Frog? Do I have to rely on DNA barconding to know for sure – before I decide to euthanize it? Could I be making a mistake?
Image by Dr. Steve A Johnson 2005.
This treefrog was first introduced into to south Florida in the 1920’s. Like lionfish, it quickly became established and began its slow dispersal northward. It is a large predatory frog (reaching about 5”) which began to consume native treefrogs, reducing their populations wherever they were found. In addition to consuming native frogs, Cuban Treefrogs eat snails, millipedes, spiders, and many other small creatures. They can produce a call that is somewhat annoying to many residents where it is found. It is currently listed as established as far north as Gainesville FL.
A few years ago, I received a call from a resident near Big Lagoon in southwest Escambia County. They had just purchased plants from a local chain store to plant in their yard the following day. They had left the plants on the front porch that night and, at some point, noticed this large treefrog on their front door. They wanted to know if this was a non-native frog. It was – it was the Cuban Treefrog. The animal was collected and sent to the University of Florida.
This is a common method of transporting this frog north. They attach to ornamental plants grown in nurseries in south Florida. The plants are loaded on trucks and shipped to the panhandle and locations north and west. There are probably numerous species hitching rides this way, including the Cuban Anole (an invasive lizard). Lucky for us, in many cases these tropical problem species cannot tolerate our cold winters – this could also be said for some of the invasive plants. However, in recent years, the winters have been milder and some of these species are surviving. Most of us know and understand the impact lionfish have had on local small reef fish; no one is interested in another “lionfish problem” in the panhandle.
About a year ago, a second Cuban Treefrog was reported in Crestview.
Early this year I attended an amphibian/reptile conference in north Georgia. There was a presentation given by a scientist from the U.S. Geological Survey in Lafayette LA. He had a call from the Audubon Zoo in New Orleans about a strange frog they had been finding. They had recently purchased palm trees from south Florida for the elephant exhibit. The caretakers of the exhibit began to see strange frogs and reported it. When USGS arrived, they meandered through the park searching. They stopped by the public bathroom to look (a place I have found them in south Florida myself). They happen to pass an electric panel outside the restroom and decided to take a peak – 13 Cuban Treefrogs were within.
They began an exhaustive search and found CTFs everywhere. Most had moved into a public park between the zoo and the river called Riverview. I cannot remember how many they had found but it was in the hundreds, the animals were beginning to establish themselves in this area of New Orleans. USGS is currently working on the problem.
Just a few weeks ago, a Cuban Treefrog was found on Davenport Bayou off Bayou Grande.
There are many reports of single, individual CTFs across the northern Gulf coast, but none were established populations. However, as reports increase we should be looking for these animals and try to keep them under control before they do. No more “lionfish problems”.
How do we do this?
The following link provides information about the frog, how to identify it, how to set traps to determine if the animal is in your neighborhood, and what to do if you do find one. I would include reporting the finding on www.EDDMapS.org. I also recommend as you purchase plants for this spring’s landscaping projects, check the plants carefully for any hitchhikers. This “early detection” method is the most effective way to battle the movement of invasive species.
If you have questions about Cuban Treefrogs, let me know.
Johnson, S.A. 2017. The Cuban Treefrog (Osteopilus septentrionalis) in Florida. University of Florida Extension Electronic Data Information Source (EDIS) document WEC218.
http://edis.ifas.ufl.edu/uw259.
by Rick O'Connor | Mar 9, 2018
Most people know that snakes are ectothermic and the environment is what regulates their body temperature. However, many do not know that they like to maintain their temperature close to 98 F like us. To do this they must move to locations where they can either warm (like basking in the sun or lying on warm asphalt) or cool (like under rocks or logs). Unlike us, their temperature can rise to above 100 F or down close to 30 F with few health problems.
Eastern Diamondback Rattlesnake swimming across the Intracoastal Waterway near Pensacola Beach.
Photo: Andy Barnes
When environmental temperatures become colder, their heart and breathing rates slow significantly. Their blood oxygen levels decrease, and they become very slow and sluggish – a condition we call torpor. There are some advantages to this, such as not having to hunt for food for several weeks or months, but when the air temperatures begin to climb they become more active… Moreover, their hungry.
In the last two weeks, I have had numerous reports of snakes moving around in yards. There have been three records of diamondback rattlesnakes in the Pensacola Beach area alone.
Should I be concerned about doing outdoor activities?
No, not really – but you should be aware. As it warms, snakes will become more active early in the morning and late in the evening. Pit vipers, like rattlesnakes and cottonmouths, actually prefer hunting at night. However, when the temperatures are cool enough for mid-day movement, they will. Food and reproduction (for some species) are on their mind this time of year.
Stay on the trails – snakes typically do not like to be in the open because of predators but they do have to bask to increase their body metabolism; so they may be along the edge. If I am hiking, I tend to look down along the trail when walking. If I want to observe something in the trees, I stop.
These snake movements happen every year, and very people have problems, but with the recent increase in encounters it is could to be aware. I actually think snakes are pretty cool. I enjoy seeing them, especially ones that are not viewed very often like coral snakes and rattlesnakes. You should still go out and enjoy the Pensacola Bay area. It is a great time of year to do it.
by Rick O'Connor | Feb 28, 2018
Lionfish caught on rod and reel. Photo Credit: Alison Rogers
Since the first lionfish was spotted off Pensacola in 2010, panhandle organizations have been busy trying to control the spread of this invasive species. The story is well known to many… the lionfish is a voracious predator, consuming at least 70 different species of small reef fish, including vermillion snapper. They reproduce frequently, producing an average of 25,000 eggs/female every four days – and they breed during most of the year. The densities of these fish on our nearshore and offshore reefs are some of the highest in the South Atlantic region, and they prefer artificial reefs to natural bottom. We know they have spread across the northern Gulf to include all five Gulf states and are found in Mexican waters.
We also know that the primary method of removal is still spearfishing. The state of Florida has an open season on them and provides a program to assist local divers with selling their harvest. There are several rodeo tournaments along the Gulf coast and some traditional fishing tournaments have created a category for them. Education programs about the problem continue and some restaurants have offered them when they can get them.
So how are things going?
Are we on top of controlling the lionfish?
Lionfish at Pensacola Beach Snorkel Reef. Photo Credit: Robert Turpin
Anecdotal reports suggest we have made some impact. Local divers in the Pensacola area report that the shallower public reefs frequented by local divers and dive charters have indicated they are getting harder to find. There have been some tour trips, taking out of town residents diving for lionfish, where they have had to really search to find them. This is certainly encouraging and a numerical assessment of this is needed. However, there are also reports of charter fishing boats catching them on hook and line in deeper waters. They are not catching many, but they do occasionally grab them. When they do, it is usually on live bait and in deep water, 200 feet or so. Local divers seem to agree with this. They too find more lionfish, and some large ones, at depth – too deep to take a typical dive charter trip to remove.
Recent research has shown that lionfish are able, at least in the northern Gulf of Mexico, to swim greater distances than once thought to re-colonize reefs that have been cleaned. One study showed that selected artificial reefs, which were completely cleaned of lionfish, had restored lionfish populations, both young and old fish, within a year. This same study suggests that to keep lionfish at relatively low-density (about 5 lionfish/100 m 2) reefs would need to be cleaned every two months.
Several lionfish derbies occur along the Florida panhandle, but not at the frequency that may be needed to control re-colonization of shallower reefs by lionfish from deeper ones.
Can we increase the number of derbies?
Sure… but those who work on these derbies know the time and financial commitment required to put one on. It could happen that the number of local derbies would increase but we may have to think of other means of controlling lionfish.
One idea is to increase the number who harvest commercially. To do so a diver would need to acquire a saltwater products license from the Florida Fish and Wildlife Conservation Commission (FWC). On their website, they provide the application and a list of approved buyers for the diver to contact. http://www.myfwc.com/Lionfish.
Harvested lionfish. Photo Credit: Bryan Clark
One drawback to the commercial idea is the price. Currently divers require a high price for their catch in order to cover cost and show a profit. These high prices equate to high prices at local restaurants, higher than the public may be willing to pay. One unpublished study shows that some locals are willing to pay more for a lionfish dinner if they know it is helping the environment. Many seafood lovers understand the high cost of lobster, but have not placed lionfish in the same category and are not as willing to pay higher prices; this may have to change. Research continues on developing a lionfish trap that has low by-catch rates. If an effective trap is developed, they could be deployed from vessels, which would not require diving, and could bring prices down.
There is evidence that populations of small reef fish have significantly declined since 2010. Whether this was due to the oil spill, the lionfish invasion, or a combination is still not certain. It is known that local reefs that are cleaned of lionfish are repopulated with both large and small lionfish. We have had some success with removing but we still have work to do.
Reference
Dahl, K.A., W.F. Patterson, R.A. Snyder. 2016. Experimental Assessment of Lionfish Removals to Mitigate Reef Community Shifts on Northern Gulf of Mexico Artificial Reefs. Marine Ecology Progress Series. Vol 558. Pp: 207-221.
