Researchers Discover Peaceful Turtle Playground in the Sargasso Sea

A tagged green sea turtle.

A tagged green sea turtle.
Photo: Gustavo Stahelin, UCF MTRG; Permit number NMFS – 19508

Off the coast of Florida lie marigold meadows floating in the ocean; they’re trails of sargassum, a seaweed that bobs on the surface of the water. Amid those frilly ocean mats, young sea turtles grow up, learning about life in an oasis protected from predators.

Advertisement

In 2012, a research team scooped up 21 newly hatched green turtles and brought them to their lab. They were kept there for about three months, until their shells were about the side of salad plates. Then, the researchers fastened a non-invasive marine adhesive to the turtles’ shells (one that wouldn’t bother the turtles as they grew and moved about the ocean) and stuck them with trackers about the size of an AA battery.

“Since this was the first time any green turtle of this age/size had been tagged and satellite tracked, we used lab-reared turtles to get an initial idea of where they go, to make it easier to target areas offshore where they might be found,” said Kate Mansfield, a biologist at the University of Central Florida and director of the marine turtle research group there, in an email.

A turtle on a mission. Even if it doesn’t know it.

A turtle on a mission. Even if it doesn’t know it.
Photo: Kate Mansfield, UCF MTRG; Permit number NMFS – 19508.

The turtles’ haven is within the Sargasso Sea, a warm, borderless water mass off the southeastern United States, named for the sargassum that occupies it. Mansfield and her team knew that the turtles have an internal compass that makes sense of Earth’s magnetic field; previous research had mimicked the field in the North Atlantic gyre, and the turtles hovered inside the lab-based ‘gyre.’ Given this, the team figured the turtles would likely stay within the real, much more massive oblong gyre that sits off the coast.

Not only did the turtles keep within the currents, they stayed within the sea that occupies the center of the gyre, according to the new study published in the Proceedings of the Royal Academy B. Following their release in December 2012, the turtles slowly made their way out to sea. One got as high up the seaboard of New Jersey before turning back toward warmer waters. Over the next few months, though, the turtles all headed for the Sargasso Sea, something the researchers didn’t expect.

The team thinks that the water’s temperature, combined with the bounty of food sources and the sargassum’s coverage from predators make it an ideal nursery for the turtles. The behavior would also resemble the activity of loggerhead, hawksbill, and Kemp’s ridleys, all of which hang out in the North Atlantic, and the latter two of which Mansfield has observed hanging out in sargassum in the Mexican gulf. Less is known, though, about the duration of the turtles’ stays in the region.

Advertisement

The turtles will lie on the mats of sargassum.

The turtles will lie on the mats of sargassum.
Photo: Gustavo Stahelin, UCF MTRG; Permit number NMFS – 19508.

“The big question,” Mansfield said, “is how long these species may spend offshore in their oceanic stage.”

Advertisement

Mansfield’s team is now engaged in that next step; rather than launching turtles naive to the ocean into the great blue yonder, they’re picking them up from the sea and seeing where they go from there. Those turtles will not only show that next stage in the animals’ oceanic treks, but they’ll also have the benefit of not starting the first few months of their life in lab—they are wholly products of their natural environment.

Though not shell-shocking, the turtles’ trajectories from shore have shed new light on the trips these animals take to sea. I wouldn’t blame the little critters if they just continued to hang out on that sargassum. It looks relaxing.

Advertisement

Florida Bans Sale of Invasive Reptiles as Iguanas and Snakes Take Over

A 14-foot, 95-pound, female Burmese python captured in Naples, Florida.

A 14-foot, 95-pound, female Burmese python captured in Naples, Florida.
Image: Robert F. Bukaty (AP)

The Florida Fish and Wildlife Conservation Commission is clamping down on invasive reptiles, making it illegal for Floridians to breed or sell these problematic creatures except in special circumstances.

Advertisement

In an effort to protect local ecology, economy, and human health, the state is making it illegal for Floridians to breed or sell such animals as Burmese and scrub pythons, Green anacondas, Nile monitors, green iguanas, and tegus, among several other invasive species. Finalized on February 25, the new rules are meant to improve the regulations on the ownership of invasive reptiles in Florida, and they’re expected to go into effect later this summer.

“Stringent biosecurity measures are required for those entities in possession of Prohibited species to limit escapes,” declares the Florida wildlife commission in its guidelines.

These reptiles are becoming a major menace in the state, ravaging sensitive ecosystems and wreaking havoc in urban environments. The Burmese python, for example, is now endemic in the Everglades, where it consumes a wide variety of prey. Green iguanas have been plaguing home and business owners for years, digging up gardens, damaging sidewalks and seawalls, and occasionally popping up in toilets (yes, seriously). Green iguanas also carry salmonella. So bad is this problem, that the wildlife commission has urged homeowners to kill green iguanas “whenever possible” and without the need for permits.

As the new guidelines stipulate, pet owners will have 90 days to comply with the rules once they go into effect. Except in situations involving requirements to improve outdoor enclosures, which give owners 180 days to comply.

Possession of these animals may be permitted under special circumstances, such as for educational purposes or for “eradication/control activities,” which the Florida wildlife commission describes as a “targeted, systematic effort to remove an entire population of a nonnative species or to contain or otherwise manage the population of an invasive species so as to minimize its spread and impacts.”

Advertisement

Green iguanas and tegus are still being permitted for personal use (i.e. pets), but those cases will require special permits. These animals can be owned for the duration of their lives, but the commission will only include animals that were owned prior to the new rules going into effect. Owners will have to make sure these animals are marked with a Passive Integrated Transponder (PIT) tag, and they’ll have to renew their permits annually.

Some pet owners in Florida won’t be happy with the new guidelines, and some breeders will likely have to revise their business plans. Sucks, but the environment is important, as is property, not to mention human health and safety.

Advertisement

Scientists Don’t Know Why All These Sea Creatures Are Swimming in Circles

A green sea turtle hatchling swimming in a tank at the turtle conservancy section of Aquaria KLCC in Kuala Lumpur, Malaysia.

A green sea turtle hatchling swimming in a tank at the turtle conservancy section of Aquaria KLCC in Kuala Lumpur, Malaysia.
Photo: Tengku Bahar (Getty Images)

Marine researchers in Japan and elsewhere have discovered yet another enigma of the aquatic world. In a new paper out Thursday, they detail their finding that various species of large sea animals, from turtles to sharks to seals, swim in circles for no clear reason. This circling could have several purposes for the animals, such as aiding their navigation or foraging for food, the researchers say.

Advertisement

According to the researchers, recent advances in technology have allowed scientists to get a fuller picture of how animals in the ocean move through their environment with much better precision than before. Lead author Tomoko Narazaki, from the University of Tokyo, and his colleagues decided to put this tech to good use by looking at the movements of green sea turtles during their nesting season, when female turtles return to their birthplace to lay eggs.

They moved turtles from their nesting location to elsewhere, so that they could observe how they navigated back to the original spot. But once they did, they spotted a peculiar pattern: the turtles would often circle at a relatively constant speed at least twice around, then go back to their normal swimming as they ventured back home.

Curious, Narazaki told others in his field about the discovery. Eventually, he teamed up with some of these researchers to look back at movement data that had been collected earlier about a range of other marine animals across different branches of the evolutionary tree. And sure enough, they found the same sort of circling behavior pop up repeatedly. These circling animals included fish (tiger sharks), birds (king penguins), and mammals (Antarctic fur seals and Cuvier’s beaked whales).

Their work is published in iScience.

“All of the data used in our study was initially collected for different purposes (e.g., to study foraging behavior of sharks etc.). Data of each species was analyzed by different co-authors for different aspects,” Narazaki told Gizmodo in an email. “So, it took a while for us to realize that this circling is a common behavior across many species—until we collaborated.”

An illustration of how different marine animals circle, based on the study’s findings

An illustration of how different marine animals circle, based on the study’s findings
Illustration: Narazaki, et al/iScience

On the surface, circling is hardly practical for these animals’ survival, since the most energy-efficient way to travel anywhere in the ocean is usually a straight line. So that probably means it has one or more important functions that are worth the extra effort. Right now, though, all the team has are some educated guesses as to what’s going on, which may vary between different species.

Advertisement

The sharks, for instance, seem to circle most often around where they get food, indicating that it provides some advantage in hunting. Meanwhile, other research has shown that some species of whales will use circling in groups as a way to create “bubble nets” to catch their small fish prey. But feeding likely isn’t the only purpose for circling.

In at least one male tiger shark, the team found evidence that circling was part of its courtship ritual in front of a female. Seals and penguins seem to circle most often near the water’s surface or outside of their typical foraging hours, both of which indicate it isn’t part of their feeding technique. The team also cited earlier research that found northern elephant seals will circle during their drift dives—lazy, passive dives that help them rest or process their last meal.

Advertisement

In the turtles, the circling may help them reorient their navigation skills, which rely on smell, sight, and sensing magnetic fields. The turtles would frequently circle just before the last stretch of their journey, and for a while, too. One turtle was observed to circle a whopping 76 times before moving on.

“Given that similar circling behavior was observed across a wide variety of marine megafauna taxa, it might be possible that it is a behavioral convergence having similar purposes,” Narazaki said. “But, for now, the purpose and the function of this behavior remain unknown.”

Advertisement

Of course, we know that lots of animals on land circle for various reasons (just ask your nearest dog before he poops). But the obscurity of the vast ocean means there are probably all sorts of behaviors commonplace among these animals that we simply haven’t gotten to see yet. By studying the how and why of marine circling more closely, the researchers hope to illuminate this almost alien world a bit more.

“For the next step, we would like to examine animal movements in relation to animals’ internal state and environmental conditions to examine why they circle,” Narazaki said. “Some hypothesis-testing experiments would be necessary to understand the function and mechanism underlying circling movements.”

Advertisement

Thousands of Stunned Sea Turtles Are Being Rescued From the Texas Freeze

Illustration for article titled Thousands of Stunned Sea Turtles Are Being Rescued From the Texas Freeze

Photo: Eric Gay (AP)

The abnormally cold temperatures in Texas aren’t just affecting people. They’re also causing sea turtles to freeze up in the ocean, leaving volunteers scrambling around-the-clock to save thousands of the creatures washing up on the Gulf Coast.

Each year, volunteers can expect to rescue some turtles through a few cold snaps, but this year is something else. Temperatures dropped big time this week as Texas is in the midst of a historic freeze, which spelled trouble for the turtles. As of Monday evening, Texas Fish and Wildlife reported that nearly 2,000 cold-shocked sea turtles had been rescued–the majority along the Lower Laguna Madre lagoon on the Texas coast.

Advertisement

Turtles are reptiles, meaning that they can’t regulate their internal body temperature. When it gets really cold, they get really cold, too. The waters along South Padre Island, a slim barrier island that hugs the southern Texas coast along the Gulf of Mexico, and the nearby Laguna Madre are normally balmy enough to keep turtles native to the region active. Among the species that roam the normally temperature waters are endangered green sea turtles.

But when temperatures drop below 50 degrees Fahrenheit (10 degrees Celsius), sea turtles can’t cope. They become hypothermic, stop swimming and float to the surface. Cold stunned sea turtles like this are especially vulnerable to accidents from boats, shock, or predators–and often need to be rescued by humans and given a place to warm up.

“We’re undergoing one of the largest cold stun events the island has seen in more than a decade,” Wendy Knight, the executive director of the nonprofit turtle rescue Sea Turtle, Inc., which works hand-in-hand with Texas Fish and Wildlife to rescue and rehabilitate the turtles, said in a video posted to Instagram Monday.

The scale of the rescue currently underway is so large that Sea Turtle, Inc. quickly ran out of space to keep the reptiles and turned to the town for help. As of Monday, rescuers began using the city of South Padre Island’s convention center as a kind of turtle hotel. Footage posted to social media shows turtles placed end-to-end along the convention center. Though they look dead, sea turtles (and other reptiles) can spring back to life after warming up enough to regain their motor skills.

Advertisement

There may still be trouble ahead as the cold weather continues, though. Volunteers reported on Twitter Tuesday that the convention center was running out of empty floor space for the turtles. And rolling blackouts that have hit largely part of Texas also knocked out power to the Sea Turtle, Inc. headquarters, Knight said on Instagram, which has lost power to its five enormous tanks used to warm up rescued turtles.

Even under more ideal circumstances, the road to recovery can sometimes be long for turtles. Rescuers along Cape Cod pick up stunned Kemp’s ridley sea turtles from the bay and beaches every winter and rehabilitate them before shipping them back south to warmer waters that the species also call home. That process can take anywhere from months to even years. With the Texas turtles, at least more hospitable weather should be back by early next week.

Advertisement

If you’re in Texas and spot a stunned turtle, there’s a special state hotline: call 1-866-Turtle-5 to save a turtle life.