The leatherback sea turtle is the largest of the five species that have been found in the northern Gulf of Mexico. With a carapace (top shell) length between 6-7 feet and weighing between 800-1000 pounds it is truly a magnificent creature. Any encounter with them is amazing.
Most encounters occur with fishermen or divers who are out searching for artificial reefs to fish or dive. Though very rare, they have been known to nest in this area. They feed exclusively on jellyfish and will follow them close to shore if need be. But what do leatherbacks do with most of their time? Do they hang offshore and follow jellyfish in? Do they circle the entire Gulf of Mexico and we see them as they pass? Based on past studies, many encounters with this turtle occur in the warmer months. They often become entangled in commercial fishing longlines set in the central Gulf of Mexico. But what do they do during the fall and winter? One of the tagging projects presented at a recent workshop tried to answer that question.
The project was led by Dr. Christopher Sasso of the National Oceanic and Atmospheric Administration. The tag chosen for this was a satellite tag. Since the leatherback must surface to breath air, and often is found near the surface following jellyfish, orbiting satellites would be able to follow them. As we mentioned in Part 1, catching the creature is step 1, and catching a six-foot 1000-pound sea turtle is no easy task.
The team used a spotter aircraft to locate the turtles. Once found, the pilot would radio the chase boat who would zip in with a large net. The net was connected to a large metal hoop and was designed to give way once it was around the turtle. Once in the net the turtle was hauled onto a small inflatable boat where the work of tagging could be done. They would measure the animal, take blood samples, place a PIT tag within them (similar to a microchip in your pet) and then attach the satellite tag by a tether to the tail end of the turtle before releasing it. The entire operation took less than 30 minutes.
Between 2015-2019 19 leatherbacks were tagged in the northern Gulf. 17 of these were females and 2 were males. Data obtained from these tags ranged between 63 and 247 days at liberty. The behavior the team noticed was divided into foraging behavior (feeding on jellyfish) and transiting behavior (direct swimming ignoring all).
The turtles foraged in this part of the Gulf until the fall season. At that point most of them moved south along the Florida shelf, past the western peninsula of the state, heading towards the Keys. A few chose to swim directly south against the Loop Current, and a small number remained in the area.
Those moving along the Florida shelf appeared to be foraging as they went. Those crossing the open Gulf may have foraged some but seemed to be focused on getting south to the nesting beaches. Almost all of the turtles entered the Caribbean on the east side of the Yucatan channel, following the currents, with their final destination being their nesting beaches. When they returned, they did so in the warmer months and used the western side of the channel – again following the currents – until they once again reached the northern Gulf and foraging began again. One interesting note from this study, the two males tagged did not leave the Gulf.
The tagging studies do show that leatherbacks use the Gulf of Mexico year-round. They usually head south to the Caribbean when it gets colder and use the currents to do so. It is during the warmer months we are most likely to see them here foraging on jellyfish. It is an amazing experience to encounter one of these large turtles. I hope you get to experience it one day.
Satellite tracks of leatherback movement in the GoM. Red (2015), Blue (2018), Black (2019).
Image: Sasso (et.al.) 2021.
Reference
Sasso, C.R., Richards, P.M., Benson, S.R., Judge, M., Putman, N.F., Snodgrass, D., Stacy, B.A. 2021. Leatherback Sea Turtles in the Eastern Gulf of Mexico: Foraging and Migration Behavior During the Autumn and Winter. Frontiers in Marine Science., Vol. 8., https://doi.org/10.3389/fmars.2021.660798.
Diamondback terrapins are the only resident turtle within brackish water and estuarine systems. Their range extends from Massachusetts to Texas but, prior to 2005, their existence in the Florida panhandle was undocumented. The Panhandle Terrapin Project was developed to first determine whether terrapins exist in the panhandle (Phase I) and, if so, what is their status (Phase II and III).
The project began at the Marine Science Academy at Washington High School (in Pensacola) in 2005. Between 2005 and 2010 the team was able to verify at least one record in each of the panhandle counties. For Phase II we used what we called the “Mann Method” to determine the relative abundance of terrapins in each area. To do this we needed to conduct assessments of nesting activity in each county. In 2012 the project moved from Washington High School to Florida Sea Grant. At that time, we developed a citizen science program to conduct Phase II of this project. Effort first focused on Escambia and Santa Rosa counties, but in recent years has included Okaloosa County. Florida Sea Grant now partners with the U.S. Geological Survey (based out of Gulf County) to assist with Phase II and lead Phase III, which is estimating populations using mark-recapture methods, as well as satellite tagging to better understand movements and habitat use. The focus of Phase III has been Gulf County, but tagging has occurred in Okaloosa and Escambia counties.
Over the years we have trained 271 volunteers who have conducted thousands of hours of nesting surveys and helped obtain a better picture of the status of diamondback terrapins in the Florida panhandle. Here are the 2023 project results.
Results from 2023
We trained 67 volunteers; 35 (52%) of which participated in at least one nesting survey.
The volunteers conducted 196 surveys logging 212 hours.
During those surveys terrapins (or terrapin sign) were encountered 43 times; a Frequency of Encounter (FOE) of 22%.
Three terrapins were tagged. Two from Okaloosa and one from Escambia. All but two of the nine primary survey beaches saw nesting activity (78%). One new nesting beach was discovered.
Escambia County
Two nesting beaches. 47 surveys. 7 encounters (FOE = 15%).
The Mann Method assumes the sex ratio is 1:1 (male: female) but recent studies suggest the ratio may be as high as 5:1 (male: female). Based on these two rations the number of terrapins estimated to be using these beaches ranged from 4-36.
One terrapin (“Dollie”) was tagged. Fire ants and torpedo grass were reported on some beaches.
Santa RosaCounty
Three nesting beaches. 68 Surveys. 14 encounters (FOE = 21%).
The number of terrapins estimated to be using these beaches ranged from 6-30.
No terrapins were captured, though one was seen nesting. No invasive species were reported from the nesting beaches.
OkaloosaCounty
Four nesting beaches. 67 surveys. 21 encounters (FOE = 31%).
The number of terrapins estimated to be using these beaches ranged from 2-66.
Two terrapins were tagged (“Kennedy” and “Molly”). Phragmites were reported from all beaches.
Walton County
Walton county currently does not have a volunteer coordinator and surveys are not occurring at this time. We are working with an individual who may take the lead on this.
BayCounty
This team is just beginning and currently there are no primary beaches. The team focused on five beaches encountering terrapin nesting activity on one of them. They conducted a total of 14 surveys encountering terrapin tracks on 1 of those (FOE = 7%). The estimated number of terrapins using this beach ranged from 4-12.
Baldwin County Alabama
Due to the proximity of terrapin habitat and nesting beaches at the Alabama/Florida line, and the possibility of terrapins using habitat in both states, a team was developed in Baldwin County Alabama this year. The team began conducting Phase I surveys and encountered one deceased terrapin. No nesting beaches have been identified at this time.
Summary
The results of this year’s surveys suggest that, based on the number of nesting beaches we know of, there are anywhere from 2-66 terrapins utilizing them. Again, two of the primary beaches did not have nesting activity this year. USGS tagging studies will provide better population estimates and a better understanding of how these animals are utilizing these habitats. The current population estimate for Gulf County is a little over 1000 individuals and most are showing relatively small range of habitat utilization, although two individuals in the western panhandle moved from one county to the neighboring one.
Training for volunteers occurs in March of each year. If you are interested in participating, contact Rick O’Connor – roc1@ufl.edu.
Recently I was walking along the shore of Santa Rosa Sound near Park West searching for horseshoe crab nesting. I did not find any nesting activity, but the beach was covered with small comb jellies. These creatures reminded me of my childhood days on Pensacola Beach when we used to throw them at each other – “football jellyfish” we would call them. Now that I am an adult, I understand throwing comb jellies was not a good thing, but as a kid it was the thing to do. I mean, these are jellyfish that do not sting. How cool is that. It occurred to me that many reading this article also experienced comb jellies as a kid the way I did, but probably know very little about the animal that was bringing them enjoyment. So, let’s learn a little more about this magical creature.
Comb jellies do not sting and they produce a beautiful light show at night.
The typical jellyfish we encounter at the beach is in the Phylum Cnidaria. They have gelatinous bodies made of a material called mesoglea. They have only one opening into their gut – the mouth, which serves both taking food in and releasing waste. They have a thin tissue called the velum which they undulate allowing them to slowly pulsate through the water column. Extending from their “bell” are tentacles armed with cells called cnidoblast (where they get their phylum name) which house a coiled harpoon possessing a drop of venom called a nematocyst. They use these nematocysts to paralyze their prey, which – depending on the jellyfish and the type of venom they have – range from small planktonic creatures to decent sized fish. To find their prey is a trick. They do have nerves but lack a central nervous system (brain) and so they are aware of what is going on around them, and can react, but memory and thought is not high on their ability list. The tentacles extend into the water column hoping to accidentally snag something to eat. Another thing about cnidarians, is that some do not look like jellyfish at all. Some, like the sea anemones and corals, look more like flowers attached to rocks extending their tentacles up into the water column hoping to get lucky.
The nonvenmous comb jelly.
Photo: Bryan Fluech
Our friend the comb jelly is in the Phylum Ctenophora. They too have a gelatinous mesoglea body with only a mouth. However, their method of swimming is different. Instead of an undulating velum, they have grooves along their sides that house a row of cilia (hair-like structures) that move in a pattern similar to you running your finger over the bristles of a hair comb. These are called ctenes and is where the animal gets its common name “comb jelly”. Some species have tenacles, but our local one does not. Either way there are no cnidoblast or nematocysts. Rather they move through the water column, usually with their mouths facing upwards, collecting planktonic food and, in some cases, other comb jellies. They also lack a brain but have the nerve net and they also possess a structure called a statocyst that lets them know whether they are upside down or not. In this group there are only medusa (the swimming form), the polyps (flower-like form) found in cnidarians is not found in this group. However, they do something that our local jellyfish do not do. They emit light. The cells that do this are located in the grooves where the ctenes are located. The light they produce is blue in color and is magical when hundreds are doing this at night. They use oxygen to produce this light. It first appears bright, but as the oxygen is used it becomes dimmer.
We saw them as something to play with when we were kids. We see them now as a neat member of our marine community and a magical part of living at the beach. Comb jellies are just cool.
They’re consumed worldwide, from 5-star exclusive restaurants overseas to your flip-flop beach bars right here in the Florida Panhandle. They have many different preparation techniques, such as plain and simple with a squeeze of lemon and a dash of hot sauce to “dip-your-bread-innit” chargrilled parmesan Cajun garlic butter (recipe below). However, many of their consumers actually don’t know what an oyster is, and as luck would have it, here’s a quick oyster 101!
Anatomy
Many people ask me what exactly an oyster is? Before becoming an oyster farmer, I always referred to them as “rocks with tasty meat in them,” but I couldn’t be further from the truth. Oysters are actually complex individuals that go through many metamorphoses and transitions throughout the first 2-4 weeks of their life, this includes a period of free-swimming followed by walking around with its “foot.” Let us look under an oyster’s top shell and identify some key organs.
The anatomy of Crassostrea virginica (Eastern oyster) – Thomas Derbes
Mantle – A very thin, dark, fleshy layer of tissue that surrounds the oyster’s body. This is where shell formation begins!
Hinge – The shucker’s worst nightmare. This, along with the adductor muscle, is responsible for the opening and closing of the shell.
Adductor Muscle – Helps keep the oyster shut and protected from any predators. This part must be severed in order to fully open the oyster.
Gills – Thin, delicate structures found inside the body of the oyster. They serve a crucial role in respiration and feeding. Gills are shaped like tiny, finger-like projections that provide a large surface area for oxygen extraction, and they also trap and transport food towards the mouth.
Heart – Oysters have a simple circulatory system with a three-chambered heart that pumps colorless hemolymph throughout their body to distribute nutrients and oxygen.
Biology
Crassostrea virginica (or as we know them, the Eastern oyster) is a native species of oyster that is commonly found along the eastern coast of the USA, from the upper New England states all the way to the southernmost tip of Texas. Eastern oysters prefer an estuarine environment (mid-salinity) but can be found in some coastal areas with higher salinities, especially in south Florida. As filter feeders, they trap nutrients like plankton and algae from the environment and require a habitat that can handle their filtering power (30 gallons per day).
The first 2 – 3 weeks of an oyster’s life is completely different than most people expect from an oyster. Females and males coordinate their spawning time with different cues and release massive amounts of eggs and sperm into the water. This type of spawning behavior is considered batch spawning, and a majority of the fertilized eggs perish before adulthood due to predation and other environmental causes. Once fertilized, the fertilized eggs go through multiple divisions and approximately 12-24 hours later, the free-swimming trochophore larvae are formed. These larvae swim around in the water column for 2-3 weeks, developing their shell and forming into a veliger, which closely resembles their adult stage. Once ready to settle, the pediveliger is formed. The pediveliger has a “foot” and walks around the bottom, looking for a suitable place to settle (usually another oyster). Once a suitable location has been found, the foot will secrete a substance to cement them into place and the pediveliger will metamorphose into a juvenile oyster, also known as spat. Oysters can grow very rapidly after their settlement, with oysters reaching 3 inches (usual harvest size) within 18 months.
Oysters have been known to establish massive reefs in estuaries, but their numbers have been on a rapid decline across the southern USA since the 1960s. These oyster reefs provided a massive natural, biological filter in the bays, and also were home to many juvenile and adult fish and crustaceans. Currently, there are many agencies and foundations that have oyster restoration at the top of their agenda, and the future is looking brighter for the oyster populations.
The Oyster Life Cycle – Maryland Sea Grant
Pearls of Wisdom
I hope this quick oyster 101 helped shed light on the otherwise unknown life of the Eastern oyster. With the holidays coming up, make sure you grab some oysters to shuck and share with family and friends, and look at their shocked faces when you bust out all this wonderful oyster knowledge. Who knew that an oyster was much, much more than a “rock with some meat in it.”
Chargrilled “DYBI” Oysters Kissed With Flame – Thomas Derbes
Sliced Bread (Baguette, Wonder, any bread honestly)
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Shuck Oysters – Many instructional videos online, and make sure you use an actual oyster knife, clam knives are no good!
Add butter to pan/pot. Melt the butter on medium, then add everything but the oysters and cheese to the butter.
Start your grill, charcoal/wood is best for adding a smoky flavor. Once the butter mixture is made, add oysters to the grill and spoon your butter mixture into the oysters.
Mix the cheeses together and add the cheese mixture to the oysters once the butter is spooned on. For a little razzle-dazzle, mix 1 cup of panko into the cheese mixture.
Cook oysters until bubbling. Make sure to not overcook the oysters, and once you seed the mixture bubbling, they are good to remove.
Eat the oysters and dip your bread in the shell to soak up the juices. You won’t regret it.
For many who grew up in the Pensacola area October meant flounder gigging season. This once popular past time involved going out at night along the shores of Santa Rosa Sound with flounder lights and gigs seeking a local favorite flounder. Everyone has their favorite recipe for this fish but in this article, we are going to focus on the fish – maybe something you did not know about it.
In the northern Gulf of Mexico, flounder are flatfish with the two eyes on the left side of the head. Locally, flatfish with eyes on the right side are called soles. We do have native soles, but all species are too small to be a food option. If you are not familiar with the “two eyes on one side of the head” idea, yes – flounder hatch from the egg looking like a normal fish, an eye on each side of the head. But earlier in development one eye slides across to the other side. This is a weird transformation and there are probably videos online, so you see how this happens – check them out. The reason for this transformation is to improve depth perception. Eyes close together give the animal binocular vision. Binocular vision does not have a wide viewing range, can basically see what is in front of it but not so much what is behind it, but it does give the animal good depth perception, it can tell how far away the prey actually is, and this is important when hunting.
Once the eyes have shifted to the left side of the head, flounders lose the pigments on the side without eyes, which becomes white, and the fish lays on its side – white side down. The cells on the “eye side” have chromatophores that allow the fish to change color to match the sand on the bottom. Another important feature of being a successful hunter. Most of know they will bury themselves in this sand as well. With their binocular vision, camouflaged body, and sharp teeth, they lie in wait to ambush predators.
You may also be surprised at how many different kinds of flounder are found in the northern Gulf of Mexico. There are 21 species listed, and they range in size from the small Spiny Flounder which can reach an average length of 3 inches, to the Southern Flounder which attains a length of 3 feet. The Gulf flounder and Southern flounder are two species that are popular seafood targets, but any decent sized flounder will do.
Flounder are found in a variety of habitats ranging from shallow seagrass beds nearshore, near structure just offshore, to artificial reefs and the base of bridges, to depths of 1200 feet in the Gulf of Mexico. Many species spend the warmer months in the estuaries moving offshore when the weather cools down to spawn. Hard northerners can trigger a mass migration and a great time for commercial and recreational fishermen alike.
It is flounder season. Whether you prefer to catch your own or buy from the local seafood market I think will enjoy one of the variety of ways to prepare this fish.
A flounder scurrying across the seafoor.
Photo: NOAA
Growing up in the South, I was exposed to many “Old Wives’ Tales,” ranging from not cleaning your house or clothes on New Year’s Day to the one that everyone, including the northern states, knows, “don’t consume oysters in months without an R.” While most “tales” are full of superstition, the “R” tale was one of biosecurity, and was mainly truthful until two new types of “R” came about; Regulations and Refrigeration. The tale came about due to the rise in food poisonings from shellfish in the warmer summer months that do not contain a “R,” such as June and July. The rise in food poisoning came about from the practices used by the oyster “tongers” at the time. Commercial harvest of wild oysters is a very labor-intensive job that requires long days on the water and constant tonging, measuring, and sorting of oysters as they come off the bottom. During the summer, the oysters would sit on the deck of the boat for hours in the heat, causing microorganisms and bacteria to flourish inside the closed oyster. Bacteria, like Vibrio, would replicate to harmful levels inside of the oysters and when consumed by a human, could cause life-threatening illnesses.
That was then, and this is now. While the consumption of wild Florida oysters during the summer is not allowed (closed harvest season for wild oysters during the summer in Florida), you can still find oysters from all over the US, and farmed oysters from Florida are still allowed to be consumed during the summer. Biosecurity is a major factor involving food production and aquaculture, and without biosecurity, the consumption of Florida-farmed oysters would be prohibited. Oyster farmers in Florida must follow a very rigorous biosecurity plan that includes State-issued harvest times, water-to-refrigeration requirements, reporting of harvest and planting, and twice-daily temperature monitoring requirements. The regulations for harvest times and refrigeration requirements have scientific backing, showing a statistical difference in Vibrio concentrations between properly handled oysters and neglected oysters, with properly handled oysters having little to no concentrations of Vibrio. For instance, during the summer months, oyster farmers must have oysters harvested and in the cooler before 11am and down to 45°F within 2 hours of storing in cooler.
A farmer returns early morning from the lease with harvest oysters covered by burlap. This keeps the oysters “cool.” (Photo by: Thomas Derbes)
While there is an increased concentration of harmful bacteria during these warmer months, properly cared-for oysters help limit the growth and proliferation of the bacteria. Another myth is that Vibrio doesn’t exist in cold, winter waters. Vibrio can exist year-round, and people with health risks, including immune-suppressed patients and those with diabetes, should exercise extreme caution when consuming raw seafood. When purchasing seafood for personal consumption, make sure to bring a cooler with ice and place your seafood above the ice, making sure to not allow any fresh water to touch the seafood. When storing seafood at home, make sure they are in a container that can breathe, and cover with a moist paper towel to keep their gills wet. Oysters are typically good for 10-14 days after the harvest date, so make sure you check the tags and consume within time.
Next summer, when you see farmed oysters on the menu, remember the new R’s and order a couple dozen for the table. The need for support from your local oyster farmer is most needed during those months without R, so slurp them down all summer and thank your local oystermen and women!
Locally Farmed Oyster with French Mignonette (Photo by: Kelly Derbes)
Easy French Mignonette Recipe
Recipe for 2doz Oysters
¼ cup Red Wine Vinegar
¼ cup Champagne Vinegar
1 tablespoon of Finely Chopped Shallot
1 teaspoon of Fresh Crushed Black Pepper
Juice of ½ Lemon
Combine all ingredients together. Spoon over shucked, chilled raw oysters.
