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.
The University of Florida/IFAS Extension faculty are reintroducing their acclaimed “Panhandle Outdoors LIVE!” series. Conservation lands and aquatic systems have vulnerabilities and face future threats to their ecological integrity. Come learn about the important role of these ecosystems.
The St. Joseph Bay and Buffer Preserve Ecosystems are home to some of the one richest concentrations of flora and fauna along the Northern Gulf Coast. This area supports an amazing diversity of fish, aquatic invertebrates, turtles, salt marshes and pine flatwoods uplands.
This one-day educational adventure is based at the St. Joseph Bay State Buffer Preserve near the coastal town of Port. St. Joe, Florida. It includes field tours of the unique coastal uplands and shoreline as well as presentations by area Extension Agents.
Details:
Registration fee is $45.
Meals: breakfast, lunch, drinks & snacks provided (you may bring your own)
Attire: outdoor wear, water shoes, bug spray and sun screen
*if afternoon rain is in forecast, outdoor activities may be switched to the morning schedule
Space is limited! Register now! See below.
Tentative schedule:
All Times Eastern
8:00 – 8:30 am Welcome! Breakfast & Overview with Ray Bodrey, Gulf County Extension
8:30 – 9:35 am Diamondback Terrapin Ecology, with Rick O’Connor, Escambia County Extension
9:35 – 9:45 am Q&A
9:45- 10:20 am The Bay Scallop & Habitat, with Ray Bodrey, Gulf County Extension
10:20 – 10:30 am Q&A
10:30 – 10:45 am Break
10:45 – 11:20 am The Hard Structures: Artificial Reefs & Marine Debris, with Scott Jackson, Bay County Extension
11:20 – 11:30 am Q&A
11:30 – 12:05 am The Apalachicola Oyster, Then, Now and What’s Next, with Erik Lovestrand, Franklin County Extension
12:05 – 12:15 pm Q&A
12:15 – 1:00 pm Lunch
1:00 – 2:30 pm Tram Tour of the Buffer Preserve (St. Joseph Bay State Buffer Preserve Staff)
2:30 – 2:40 pm Break
2:40 – 3:20 pm A Walk Among the Black Mangroves (All Extension Agents)
3:20 – 3:30 pm Wrap Up
To attend, you must register for the event at this site:
Sargassum washed ashore after a storm on Pensacola Beach. Photo credit: Carrie Stevenson, UF IFAS Extension
I am sure it drives the tourists a little crazy. After daydreaming all year of a week relaxing at the beach, they arrive and find the shores covered in leggy brown seaweed for long stretches. It floats in the shallow water, tickling legs and causing a mild panic—was that a fish? A jellyfish? A shark? Then, of course, high tide washes the seaweed up and strands it at the wrack line, shattering the vision of dreamy white sand beaches.
But for those visitors—and locals—willing to take a closer look, the brown algae known as sargassum is one of the most fascinating organisms in the sea. The next time you are at the beach, pick some up and turn it over in your hands. Sargassum is characterized by its bushy, highly branched stems with numerous leafy blades and berry-like, gas-filled structures. The tiny air sacs serve as flotation devices to keep the algae from sinking. This unique adaptation allows it to fulfill a niche at the top of the water column, instead of growing at the bottom or on another organism.
The sargassum fish blends incredibly well into its home within sargassum mats. It uses handlike pectoral fins to move around. Photo credit: Reef Builders
Sargassum tends to accumulate into large mats that drift through the water in response to wind and currents. These drifting mats create a pelagic habitat that attracts up to 70 species of marine animals. Several of these organisms are adapted specifically to life within the sargassum, reaching full growth at miniature sizes and camouflaged in shape, pattern, and color to blend in. These very specialized fauna include the sargassum crab, the sargassum shrimp, sargassum flatworm, sargassum nudibranch, sargassum anemone, and the sargassum fish! The sargassum fish (Histrio histrio) is in the toadfish family, a group of slow-moving reef fish that pick their way through coral and algae by using their pectoral fins like hands. Sea turtle hatchlings will spend their early years feeding and resting within the relative safety of large mid-ocean sargassum mats.
The small air-filled sacs of sargassum allow it to float on the surface, becoming the basis of a teeming ecosystem. Photo credit: Carrie Stevenson, UF IFAS Extension
Over time the air sacs lose buoyancy and the sargassum sinks, providing an important source of food for bottom-dwelling creatures. If washed ashore, many of the animals abandon the sargassum or risk drying out and dying.
In general, most of the larger, familiar seaweeds like sargassum are brown algae. Brown algae (including kelp and rockweed) have colors ranging from brown to brownish yellow-green. These darker colors result from the brown pigment fucoxanthin, which masks the green color of chlorophyll. Extractions from brown algae are commonly used in lotions and even heartburn medication!
Baby terns on Pensacola Beach are camouflaged in plain sight on the sand. This coloration protects them from predators but can also make them vulnerable to people walking through nesting areas. Photo credit: UF IFAS Extension
The controversial incident recently in New York between a birdwatcher and a dog owner got me thinking about outdoor ethics. Most of us are familiar with the “leave no trace” principles of “taking only photographs and leaving only footprints.” This concept is vital to keeping our natural places beautiful, clean, and safe. However, there are several other matters of ethics and courtesy one should consider when spending time outdoors.
On our Gulf beaches in the summer, sea turtles and shorebirds are nesting. The presence of this type of wildlife is an integral part of why people want to visit our shores—to see animals they can’t see at home, and to know there’s a place in the world where this natural beauty exists. Bird and turtle eggs are fragile, and the newly hatched young are extremely vulnerable. Signage is up all over, so please observe speed limits, avoid marked nesting areas, and don’t feed or chase birds. Flying away from a perceived predator expends unnecessary energy that birds need to care for young, find food, and avoid other threats.
When on a multi-use trail, it is important to use common courtesy to prevent accidents. Photo credit: Carrie Stevenson, UF IFAS Extension
On a trail, the rules of thumb are these: hikers yield to equestrians, cyclists yield to all other users, and anyone on a trail should announce themselves when passing another person from behind.
Obey leash laws, and keep your leash short when approaching someone else to prevent unwanted encounters between pets, wildlife, or other people. Keep in mind that some dogs frighten easily and respond aggressively regardless of how well-trained your dog is. In addition, young children or adults with physical limitations can be knocked down by an overly friendly pet.
Keep plenty of space between your group and others when visiting parks and beaches. This not only abides by current health recommendations, but also allows for privacy, quiet, and avoidance of physically disturbing others with a stray ball or Frisbee.
Summer is beautiful in northwest Florida, and we welcome visitors from all over the world. Common courtesy will help make everyone’s experience enjoyable.
An eastern cottonmouth basking near a creek in a swampy area of Florida. Photo: Tommy Carter
When you think of reptiles you typically think of tropical rainforest or the desert. However, there is at least one member of the three orders of reptiles that do live in the sea. Saltwater crocodiles are found in the Indo-Pacific region as are about 50 species of sea snakes. There is one marine lizard, the marine iguana of the Galapagos Islands, and then the marine (or sea) turtles. These are found worldwide and are the only true marine reptiles found in the Gulf of Mexico.
Sea turtles are very charismatic animals and beloved by many. Five of the seven species are found in the Gulf. These include the Loggerhead, which is the most common, the Green, the Hawksbill, the Leatherback, and the rarest of all – the Kemp’s Ridley.
Many in our area are very familiar with the nesting behavior of these long-ranged animals. They do have strong site fidelity and navigate across the Gulf, or from more afar, to their nesting beaches – many here in the Pensacola Beach area. The males and females court and mate just offshore in early spring. The females then approach the beach after dark to lay about 100 eggs in a deep hole. She then returns the to the Gulf never to see her offspring. Many females will lay more than one clutch in a season.
The largest of the sea turtles, the leatherback. Photo: Dr. Andrew Colman
The eggs incubate for 60-70 days and their temperature determines whether they will be male or female, warmer eggs become females. The hatchlings hatch beneath the sand and begin to dig out. If they detect problems, such as warm sand (we believe meaning daylight hours) or vibrations (we believe meaning predators) they will remain suspended until those potential threats are no more. The “run” (all hatchlings at once) usually occurs under the cover of darkness to avoid predators. The hatchlings scramble towards the Gulf finding their way by light reflecting off the water. Ghost crabs, fox, raccoon, and other predators take almost 90% of them, and the 10% who do reach the Gulf still have predatory birds and fish to deal with. Those who make it past this gauntlet head for the Sargassum weed offshore to begin their lives.
These are large animals, some reaching 1000 pounds, but most are in the 300-400 pound range, and long lived, some reaching 100 years. It takes many years to become sexually mature and typically long-lived / low reproductive animals are targets for population issues when disasters or threats arise. Many creatures eat the small hatchings, but there are few predators on the large reproducing adults. However, in recent years humans have played a role in the decline of the adult population and all five species are now listed as either threatened or endangered and are protected in the U.S. There are a couple of local ordinances developed to adhere to federal law requiring protection. One is the turtle friendly lighting ordinance, which is enforced during nesting season (May 1 – Oct 31), and the Leave No Trace ordinance requiring all chairs, tents, etc. to be removed from the beach during the evening hours. There are other things that locals can do to help protect these animals such as: fill in holes dug on the beach during the day, discard trash and plastic in proper receptacles, avoid snagging with fishing line and (if so) properly remove, and watch when boating offshore to avoid collisions.
If we include the barrier islands there are more coastal reptiles beyond the sea turtles. There are freshwater ponds which can harbor a variety of freshwater turtles. I have personally seen cooters, sliders, and even a snapping turtle on Pensacola Beach. Many coastal islands harbor the terrestrial gopher tortoise and wooded areas could harbor the box turtles. In the salt marsh you may find the only brackish water turtle in the U.S., the diamondback terrapin. These turtles do nest on our beaches and are unique to see. Freshwater turtle reproductive cycles are very similar to sea turtles, albeit most nest during daylight hours.
An American Alligator basking on shore. Photo: Molly O’Connor
The American alligator can also be found in freshwater ponds, and even swimming in saltwater. They can reach lengths of 12 feet, though there are records of 15 footers. These animals actually do not like encounters with humans and will do their best to avoid us. Problems begin when they are fed and loose that fear. I have witnessed locals in Louisiana feeding alligators, but it is a felony in Florida. Males will “bello” in the spring to attract females and ward off competing males. Females will lay eggs in a nest made of vegetation near the shoreline and guard these, and the hatchlings, during and after birth. They can be dangerous at this time and people should avoid getting near.
We have several native species of lizards that call the islands home. The six-lined race runners and the green anole to name two. However, non-native and invasive lizards are on the increase. It is believed there are actually more non-native and invasive lizards in Florida than native ones. The Argentina Tegu and the Cuban Anole are both problems and the Brown Anole is now established in Gulf Breeze, East Hill, and Perdido Key – probably other locations as well. Growing up I routinely find the horned lizard in our area. I was not aware then they were non-native, but by the 1970s you could only find them on our barrier islands, and today sightings are rare.
An eastern cottonmouth crossing a beach. Photo: Molly O’Connor
Then there are the snakes.
Like all reptiles, snakes like dry xeric environments like barrier islands. We have 46 species in the state of Florida, and many can be found near the coast. Though we have no sea snakes in the Gulf, all of our coastal snakes are excellent swimmers and have been seen swimming to the barrier islands. Of most concern to residents are the venomous ones. There are six venomous snakes in our area and four of them can be found on barrier islands. These include the Eastern Diamondback Rattlesnake, the Pygmy Rattlesnake, the Eastern Coral Snake, and the Eastern Cottonmouth. There has been a recent surge in cottonmouth encounters on islands and this could be due to more people with more development causing more encounters, or there may be an increase in their populations. Cottonmouths are more common in wet areas and usually want to be near freshwater. Current surveys are trying to determine how frequently encounters do occur.
Not everyone agrees, but I think reptiles are fascinating animals and a unique part of the Gulf biosphere. We hope others will appreciate them more and learn to live with and enjoy them.
This is one of the most beloved animals on the planet… sea turtles. Discussions and debates over all sorts of local issues occur but when sea turtles enter the discussion, most agree – “we like sea turtles”, “we have nothing against sea turtles”. There are nonprofit groups, professional hospitals, and special rescue centers, devoted to helping them. I think everyone would agree, seeing one swimming near the shore, or nesting, is one of the most exciting things they will ever see. For folks visiting our beaches, seeing the white sand and emerald green waters is amazing, but it takes their visit to a whole other level if they encounter a sea turtle.
The largest of the sea turtles, the leatherback. Photo: Dr. Andrew Colman
They are one of the older members of the living reptiles dating back 150 million years. Not only are they one of the largest members of the reptile group, they are some of the largest marine animals we encounter in the Gulf of Mexico.
There are five species of marine turtles in the Gulf represented by two families. The largest of them all is the giant leatherbacks (Dermochelys coriacea). This beast can reach 1000 pounds and have a carapace length of six feet. Their shell resembles a leatherjacket and does not have scales. Because of their large size, they can tolerate colder temperatures than other marine turtles and found all over the globe. They feed almost exclusively on jellyfish and often entangled in open ocean longlines. There is a problem distinguishing clear plastic bags from jellyfish and many are found dead on beaches after ingesting them. Like all sea turtles, they approach land during the summer evenings to lay their eggs above the high tide line. The eggs incubate within the nest for 65-75 days and sex determination is based on the temperature of the incubating eggs; warmer eggs producing females. Also, like other marine turtles, the hatchlings can be disoriented by artificial lighting or become trapped in human debris, or unnatural holes, on the beach. These animals are known to nest in Florida and they are currently listed as federally endangered and are completely protected.
The large head of a loggerhead sea turtle. Photo: UF IFAS
The other four species are found in the Family Chelonidae and have the characteristic scaled carapace. Much smaller than the leatherback, these are still big animals. The most common are the loggerhead sea turtles (Caretta caretta). As the name suggest, the head of this sea turtle is quite large. Their carapace can reach lengths of four feet and they can weigh up to 450 pounds. The head usually has four scutes between the eyes and three scutes along the bridge connecting the carapace to the plastron. This animal prefers to feed on a variety of invertebrates from clams, to crabs, to even horseshoe crabs. It too is an evening nester and the young have similar problems as the leatherback hatchlings. The tracks of the nesting turtle can be identified by the alternating pattern made by the flippers. One flipper first, then the next. The loggerhead is currently listed as a federally threatened species.
A green sea turtle on a Florida beach. Photo: Florida Sea Grant
The green sea turtle (Chelonia mydas) is called so not for the color of its shell, but for the color of its internal body fat. They are fans of eating seagrasses, particularly “turtle grass” and other plants, which produce the green coloration of the fat. The fat is used to produce a world favorite, “turtle soup”, and has been a problem for the conservation of this species in some parts of the world. At one time, most green turtles nested in south Florida, but each year the number nesting in the north has increased. They can be distinguished from the loggerhead in that (1) their head is not as big, (2) there are only two scales between the eyes, and (3) their flipper pattern in sand is not alternating; green turtles throw both flippers forward at the same time. Green turtles are listed as federally threatened.
A hawksbill sea turtle resting on a coral reef in the Florida Keys. Photo: Molly O’Connor
The hawksbill turtle (Eretmochelys imbricata) is more tropical in distribution. They are a bit smaller, with a carapace length of three feet and a weight of 187 pounds, but their diet of sponges is another reason you do not find them often in the northern Gulf of Mexico. To feed on these, they have a “hawks-bill” designed to rip the sponges from their anchorages. Their shell is gorgeous and prized in the jewelry trade. “Tortoise-shell” glasses and earrings are very popular.
The most endangered of them all is the small Kemp’s Ridley sea turtle (Lepidochelys kempii). This little guy has a carapace length of a little over two feet and weighs in at no more than 100 pounds. These guys are commonly seen in the Big Bend area of Florida but for years no one knew where they nested. That was until 1947 when an engineer from Mexico found them nesting in large numbers (up to 40,000) at one time, in broad daylight in Rancho Nuevo, Mexico. This was problematic for the turtle because the locals would wait for the nesting to be complete before they would take the females and the eggs. Protected today they now face the problem that their migratory path across the Gulf takes them through Texas and Louisiana shrimping grounds, and through the 2010 Deep Water Horizon oil spill field. Not to mention that illegal poaching still occurs. Though all species of sea turtles have had problem with shrimp trawls, the Kemps had a particular problem, which led to the develop of the now required Turtle Excluder Device (T.E.D.S) found on shrimp trawls in the U.S. today. Sea turtles have strong site fidelity for nesting and in the 1980s many Kemp’s Ridley eggs were re-located to beaches in Texas in hopes to move the nesting to other locations. The program had some success and they have been reported to nest in Florida. Their diet consists primarily of crabs but there have been reports of them removing bait from fishing lines fishing from piers over the Gulf. This is species is federally endangered and is considered by many to be the most endangered sea turtle species on the planet.
Turtle friendly lighting. Photo: Rick O’Connor
Sea turtles face numerous human-caused problems including (1) artificial lighting that disorient hatchlings and cause mortality to 50% (or more) of the hatchlings, (2) items left on beaches (such as chairs, tents, etc.) that can impede adults and entrap hatchlings, (3) large holes dug on beaches in which hatchlings fall and cannot get out, (4) marine debris (such as plastics) which they confuse with prey and swallow, (5) boat strikes, sea turtles must surface to breath and can become easy targets, and (6) discarded fishing gear, in which they can become entangled and drown. These are simple things we can correct and protect these amazing Florida turtles.
References
Buhlmann, K., T. Tuberville, W. Gibbons. 2008. Turtles of the Southeast. University of Georgia Press, Athens GA. Pp. 252.
