- [Narrator] They are the birds of the sea, gracefully batting their wings as they glide through the water.

Catching a glimpse of the majestic eagle ray is a highlight for boaters and divers alike.

- [Patrick] It looks like they're flying and their spots really makes them stand out.

- [Cecilia] I'm captivated by these rays.

They're absolutely beautiful.

They're incredibly strong swimmers.

- [Matt] You look at their wings, I mean, it's just like all muscle.

They can hang out in a five-knot current effortlessly.

- [Ariadna] Their capacity of eating hard-shelled prey, that's amazing to me.

(gentle music) - [Narrator] Found mostly in tropical and subtropical waters, eagle rays use a variety of habitats.

- [Matt] They're on the reef, they're in the lagoon, they're in the shallowest of waters.

- [Kim] There's five species of pelagic eagle rays around the world.

The eagle ray that we have in the Atlantic Basin and here in the Gulf of Mexico is the whitespotted eagle ray.

(gentle music) - [Narrator] The whitespotted eagle ray is listed as endangered by the International Union for Conservation of Nature.

- [Matt] However, looking at distinct portions of its range, that status changes, right?

So actually in U.S. waters, the species is of least concern.

As you move through Central and South America, it changes dramatically.

- [Kim] Because in certain places around the world, they're taken in fisheries.

- [Narrator] Despite their designation as globally endangered, relatively little is known about the eagle rays' ecology and life history.

- [Kim] Rays have been very under the radar.

And so we like to say we're gonna start a rayvolution.

- [Narrator] Protected in Florida and Bermuda, these locations make for great study sites of the animals.

- [Cecilia] We're trying to figure out what the feeding behavior and the movement behavior of these rays is like.

- [Kim] And we're learning so much more about them every day, and we need that data for conservation and management.

- [Researcher 1] No tag.

- [Researcher 2] No tag?

- [Narrator] What are scientists learning about whitespotted eagle rays?

And how is technology aiding them in this process?

(dramatic music) - [Announcer] Major funding for this program was provided by The Batchelor Foundation, encouraging people to preserve and protect America's underwater resources.

Additional funding was provided by Trish and Dan Bell and by the Parrot Family Endowment for Environmental Education.

(gentle music) - [Narrator] Sarasota, on Florida's Gulf Coast, is home to Mote Marine Laboratory, where Kim Bassos-Hull has been conducting eagle ray research since 2009.

(gentle music) - We're trying to document what are important habitats for them, what size classes we're seeing.

And then when we do see them, we set a big seine net around them.

And that allows us to at least have them in a controlled circled net that then allows our divers to go in and get them and bring them on board.

(playful music) - You got her now, Kim?

(playful music) - [Narrator] Extra care needs to be taken to avoid an accidental sting by one of the venom-coated barbs near the animal's tail.

- [Kim] It's a female.

- [Narrator] And each animal is checked for a so-called PIT tag.

- And those PIT tags are similar to the microchips we put in your pets, like your dogs and your cats.

So if it doesn't have a tag, it means it has not been caught before.

So we then put a PIT tag in, and it allows us to detect if we've had a recapture months or years down the line.

Then the next thing we do is we take a genetics clip.

Those are really important for us to look at population structure.

- [Researcher 1] 8.5.

- [Researcher 2] 8.5, okay.

- [Narrator] The team also weighs and measures each ray.

- [Researcher] 54.2.

- [Narrator] And collects a series of samples to study its blood and microbiome.

Next, they take photographs of the animal.

- [Kim] Spotted eagle rays have unique spot patterns and that allows us to do photo ID and create a catalog and keep track of them over time.

- [Researcher] Little male.

- [Narrator] To study the eagle ray's movements and habitat use, the researchers also implant an acoustic tag in the animal's abdominal cavity.

- When you turn a shark or a ray upside down, they calm down and they go into almost, we like to say a trance-like state, that's when we perform this acoustic tag surgery.

Most stitches heal within, you know, a series of days.

And acoustic tags are passive coded transmitters that work within a system of receivers that are out in the environment.

These receivers can receive that unique coded tag signal to them and allow us to look at how the animals move.

We strategically place those receivers, for instance at creek mouths, throughout the bay, and we have them in all of our passes between the estuary out to the Gulf of Mexico, 'cause we wanna see if animals are going in and outta the estuary.

And then we have a series that are like curtains along the coast, so if animals swim up and down the coast, we can catch them in our curtain gate.

And then we have ones all the way to about 50 miles offshore.

So if our rays swim outside of our array within like say the Sarasota area, they go into other researchers' arrays.

(gentle music) - [Narrator] Kim and her team manage 80 receivers that are part of larger networks of receivers that cover the entire state of Florida and beyond.

Scientists studying the movements of all kinds of fish maintain receivers along different parts of the networks and share recorded data with each other.

- So we've learned a lot about migration patterns of the eagle rays, because of the shared data.

(water splashing) - [Narrator] To access the information, researchers need to pull up the receivers at regular intervals and download the data.

- It's like Christmas for us.

Like what ray have we seen that we've tagged and when did we tag it?

- [Narrator] Kim and her team discovered that the rays are in the Sarasota area between March and October.

- The beauty of the acoustic tagging is we have learned where those rays go during those winter months.

They go south, they go down to Charlotte Harbor, they go down to the Florida Keys.

We even had one of our rays go as far as Cancun, like off the coast of Mexico.

We wanna understand what are the drivers of movement.

Are they going for social reasons?

Are they leaving because of a certain temperature?

Is it food driven?

We found that the migration patterns on the east coast versus west coast rays were very different.

East coast rays, where there's less temperature variation, seem to stay in the Indian River Lagoon year-round.

Only when a cold front came, did they go offshore into the Atlantic.

(playful music) (boat engine roaring) - [Narrator] Kim closely collaborates and his team of researchers at FAU Harbor Branch in Fort Pierce, on Florida's east coast.

- When we started this work off, the Atlantic coast was pretty much, you know, an empty basket, right?

We had no information.

- One of the things that we're interested in, as a driver of movement, is what food and what prey resources are available.

- [Narrator] Eagle rays feed on clams and snails that live on the seafloor.

To get at the meat, they crunch the shells like a nutcracker.

- [Matt] You have teeth that are fused together as one plate, a top and a bottom one.

- Almost like a conveyor belt of teeth that they're able to take these hard-shelled prey and crush them.

And the coolest thing is that they spit out the shell parts and only ingest the meaty parts.

- [Narrator] The bottom tooth plate has a pointed spade tip at the end, just like a shovel.

- [Kim] They can like dig into the sand or dig into the mud, 'cause some of their prey, such as clams, actually bury themselves.

They might be down like six inches.

- [Narrator] It's difficult to analyze the amount and type of the rays' prey by looking at their stomach contents, since the shells have been removed.

So the researchers devised a unique method to study the animals' diet.

- [Kim] We did a short-term capture of the rays and brought them in.

We have specialized research tanks here at Mote, and then we were able to feed them a variety of diet of their wild prey.

And the reason that we did that is we wanted to understand the different acoustic properties of when they're eating these prey items.

(clam crushing) So when they're eating a clam, it sounds very different from when they're eating, for instance, a snail.

- And we've recorded hundreds and hundreds of feeding events there from many different individuals of eagle rays.

- [Narrator] Using AI, the researchers trained a computer to - We've already found that we can tell differences between spotted eagle ray predation on a clam or a conch or a nerite.

- And our next step is to take that exciting research out to the wild.

(lively music) - [Narrator] To do so, the team traveled to Bermuda, where they work closely with their colleagues at the Bermuda Aquarium, Museum and Zoo.

(lively music) - It's one of the longest running aquariums in the world.

And then we also have our Natural History Museum.

- That's its main function, really, to get people to understand what Bermuda is in terms of its natural history.

But the other roles we have are really to support research.

(boat engine starting) (gentle music) (boat engine roaring) (water splashing) - [Narrator] The Bermuda Aquarium, Museum and Zoo is located on Harrington Sound, which is frequented by the rays.

- All of our previous studies have shown that they spend lots of time in there, often several months continuously.

- We're trying to figure out what the feeding behavior and the movement behavior of these rays is like.

How they spend their day versus their night, where, when, and what they like to eat, and how much they're affecting the animals that live in the sound.

- [Narrator] The aquarium staff assist the team in capturing the rays.

- Our job principally is to provide the boat support.

- We have quite a few boats available with good platforms that they can easily deploy nets from.

- We'll try to spot them from the bow of the boat as the water's really clear, and we can usually see them in the depths where we were able to fish.

- But it's often a cat and mouse game.

It's never as straightforward as it seems.

(lively music) - [Narrator] To capture the rays, the team uses the same methods as their colleagues in Sarasota.

- And then fill it with water and then fill it with water from the bucket.

(Researcher) Where did the bucket go.

- [Narrator] Once an animal is on the boat, the researchers begin their work-up.

- [Cecilia] So we collect information on the width and length of the animal, as well as the sex of the animal, and whether it's mature or not.

Then we'll also take genetic fin clips so that we can find out, you know, how this population compares to the Florida population and other populations of eagle rays.

- [Matt] We will inject the animal with a PIT tag.

- [Narrator] And if a ray is the right size, the researchers will also equip it with a highly specialized, temporary tag.

- We wanna tag a big enough animal that it won't be a stressor or any kind of hindrance to their swimming or feeding, preferably over a meter in width.

- This is the first venture into this kind of multi-sensor tagging process for this particular species.

- [Narrator] The tag is placed on the animal with suction cups.

- [Matt] This species is really conducive for suction cup attachments, because its skin is so smooth, actually.

In fact, its skin is almost like the skin of a dolphin.

So we added a little retainer strap to hold the tag down to the animal's head.

And the retainer strap basically is two sets of very soft hooks that attach to the spiracular cartilage of the animal.

And those straps go over and are held together by a galvanic timed release.

- That galvanic timed release slowly disintegrates as a result of the saltwater reacting with it.

And it should fall apart about 24 hours later, causing those hooks to fall out.

And then the suction cups will eventually naturally pop off on their own.

- [Narrator] The tag records a variety of data while attached to the animal.

- [Matt] So we've got motion sensors on it.

- They will allow us to record how the animal was moving and where, whether it's deep, very shallow, how warm the water is and what it's doing.

- And so those things are all getting recorded simultaneously, along with the time.

There's a light sensor, and we have a hydrophone.

So it's listening to all the sounds being generated, either by the animal or its surroundings, and then a video camera that's looking forward.

So giving you a very unique perspective of what the animal's doing.

- [Narrator] The tag also gets picked up by 11 stationary receivers located at different depths and in different habitats throughout the sound and in the inlet.

Each time a ray swims by one of these receivers, the time and location is recorded.

This data can then be combined with the information collected by the tag.

- [Matt] That ability to link the behavior and habitat to where the animal actually is, is absolutely crucial for our project.

(playful music) - [Narrator] Once the tag comes off the ray, it floats up to the surface.

- [Cecilia] And it will float in an orientation that puts a little antenna of our satellite transmitter out of the water, as well as a wet-dry sensor.

So as soon as that sensor's dry, the transmitter will start telling satellites overhead where it is.

So we then hone in on wherever the tag is, using a ground interception antenna that will hear those transmissions that are meant for the satellites, and guide us to where they're coming from by direction and signal strength.

So we'll get near where the tag was from the satellite transmission data, and then we will just sort of be guided by our instruments on the ground to a closer location.

And then we just have to look and see our bright pink little package floating there.

- [Narrator] Locating the floating tag is like finding a needle in a haystack.

- [Cecilia] It's incredibly stressful to look for those tags, they're very expensive, but more importantly, the data is invaluable.

- [Matt] What's that.

Is that pink?

- Where?

- It's pink.

It's sort of exciting at the same time, to be honest, because it's a little like a giant Easter egg hunt.

It's a very expensive Easter egg hunt at the same time, but, you know, you're so excited to get data back that sometimes, you know, the stresses of the situation, you know, is overcome by all of that energy.

- Way to go Ce.

- [Narrator] Between October of 2022 and the end of 2023, the team successfully deployed 9 tags which have led to exciting discoveries.

- Whenever I open the videos from these tags, I have this really great rush knowing that I'm seeing something that no one has ever seen before.

We finally know where this animal was when it ate that.

How deep was it?

What was the bottom like?

What did it sound like?

Were there other rays around?

We've seen rays trailing other rays, as well as being part of larger groups of rays, maybe three at a time or four.

- The video camera has shown interactions with certain habitats that we weren't really expecting.

- Now we can see behaviors like looking for food, but not necessarily finding food.

Have they changed their swimming behavior when they appear to be looking for food?

- It's like a dream come true, because as scientists who are interested in studying these animals, like, you know, short of being able to be underwater and attach yourselves to them, like this is it, right?

This is the way to break through and discover these behaviors that are basically concealed to us.

- [Narrator] Using sound recordings to understand the rays' diet and feeding patterns can also shed light on how eagle rays interact with shellfish aquaculture operations.

- That kind of information could, you know, potentially lead to less interactions with the industry.

(lively music) (water sloshing) - [Narrator] To test this, the team at Mote is working closely with Sarasota Bay Watch.

- Sarasota Bay Watch is an organization of citizens who are actively working for the environment.

We have this project with clam restoration, the southern hard clam.

- [Narrator] Native to the area, these clams were once abundant, but their numbers declined due to overfishing.

- [Ernesto] We wanna put them back again so the clams will produce babies, and they repopulate those sites.

- [Narrator] The filter-feeding clams serve an important ecological role by improving water quality.

- [Ernesto] These clams, their filter power is very strong.

20 gallons per clam a day.

- [Narrator] Sarasota Bay Watch received permits from the state to put clams in places where they occurred historically.

- We determine if the location is good by doing testings.

And once we determine the clams will survive, and they will grow, then we put large quantities.

We're talking 60,000 clams.

(lively music) - We collected preliminary data at those sites before they released clams.

So we put receivers out, we put hydrophones out, we were able to get a baseline prior to the restoration, and then we were able to get some data after the clams were put in the water.

What we noticed is when the clam restorations were first done, we did see sort of an uptick in a few of our acoustic tagged rays visiting those sites.

This is probably, you know, if the clams hadn't buried themselves yet, it's almost like a buffet of clams in the area.

But one of the things that's really cool that we're learning is by looking at the diet of the eagle rays.

They don't really eat a lot of the hard clams.

They eat a lot of other stuff.

And one of the things that rays eat are some of the whelks, banded tulips, some of the conchs.

So rays can actually be helping manage some of these shellfish beds and industries by like eating some of the other predators of the clams.

(water bubbling) (lively music) - [Narrator] Researchers are also hoping to identify eagle ray nurseries in Sarasota and in the Indian River Lagoon.

- Really there's been no nursery work on the species, mainly because there's very few places, I think, where you can reliably study them.

- We don't know where the rays are born.

And so a way to help recover populations of a species that is globally declining, is to discover those nursery habitats, so we can create protected boundaries for this area.

So I'm trying to determine where these protected areas should be in Florida coastal waters.

For this study, rays between 40 to 80 centimeters disc width, we are considering a pup.

(lively music) In the Indian River Lagoon, we use gillnets, (lively music) and then we wait like 30 minutes, and that's how we capture little ones here.

- It's a little different than the way Mote captures them.

They tend to see eagle rays in waters that are a bit clearer.

Once the ray is captured, we take a lot of the similar measurements we take for the adults, and then we'll proceed with the surgery to implant them with acoustic transmitters.

- We internally tag the rays with two tags.

- [Narrator] One tag communicates with the stationary receivers set up throughout the lagoon that record the time and date each time a pup swims by over the course of two years.

- Really to understand how long that habitat serves as a nursery for.

- [Narrator] The second tag allows Ari to actively track a pup from a boat.

- [Matt] The active tracking vessel has a special mount on it, with a pole, for the hydrophone system.

The hydrophone is connected to a deck box, which serves as the receiver.

And, basically the receiver gives you information, in real time, in terms of the strength of the signal, which is a strong indication of how far away the ray is, as well as the date and the time.

And we'll manipulate the direction of the hydrophone to give us the strongest bearing on where the animal is.

And we'll continuously move in that direction to stay as close as possible to the ray.

- [Narrator] Ari and her colleagues try to follow the pup for 24 hours.

- It's because I'm interested in their behavior, how that changes in relationship to time, like their activities during the day and also at night.

So we're trying to focus and figure out what the hotspots are, pretty much where they spend the majority of their time.

- [Narrator] And the hard work is paying off.

Ari is already making some interesting discoveries.

- Their behavior is somewhat similar in both areas, despite being so different in terms of water clarity and the tides.

- [Narrator] The pups are moving more than expected and are spending time in surprising places.

- [Ariadna] 55.8.

Some of the preliminary data is showing that little rays, they love deeper waters, like the channels, and also they love bridges, in Sarasota Bay and also here.

We were not expecting to see little ones in the channels, because those are areas with high traffic of predators.

- [Narrator] Many species of fish seek refuge around shallow mangrove roots when they are little, because these areas are difficult for large predators to access.

Ari is hoping that her research will help explain why eagle ray pups also frequent adult habitats like the deep channels.

- [Ariadna] I think it helps to be in turbid, darker waters where predators cannot see you very well.

(lively music) (water burbling) (gentle dramatic music) - [Narrator] Eagle rays have long captivated people with their stunning appearance and elegant movements.

- What I think is really fascinating about studying eagle rays is that we have learned a lot, but we still have a lot to learn.

- There seems to be like nothing about them that isn't interesting, which I think keeps me going.

We have an amazing opportunity here in Florida, because they are in such great shape here that we can learn a lot and apply to other areas in Central and South America where they're not doing as well, so that those people have the information they need to better manage that species.

- [Kim] And we can contribute towards finding out more information and helping with their conservation.

(gentle dramatic music) (lively music) - [Announcer] Major funding for this program was provided by The Batchelor Foundation, encouraging people to preserve and protect America's underwater resources.

Additional funding was provided by Trish and Dan Bell and by the Parrot Family Endowment for Environmental Education.

(upbeat music)