♪ Narrator: From above, the ocean seems like a vast, serene expanse-- peaceful, boundless, and still.

But beneath the surface, human activity has turned these waters into a cacophony-- roaring engines, pounding propellers, commercial fishing, and relentless sonar pulses that disrupt ecosystems, scattering marine life, and interfering with essential feeding and breeding behaviors.

For species that depend on sound to survive, like whales, dolphins, and countless fish, the noise can be detrimental.

Scientists and researchers today are peering into the depths to uncover the impact noise pollution has on our waters and what can be done.

[Click] ♪ Announcer: This presentation is made possible in part by... A grant from Anne Ray Foundation, a Margaret A. Cargill Philanthropy.

Man: Coming up on your right a little bit.

Oh, you got it.

Woman: Oh, yeah.

Man: There's a couple more right up to your right there, right there.

What we're trying to do out here is figure out how we as humans are affecting the day-to-day lives of the dolphins out here.

Man: This is the first experiment that's been conducted with sound exposure with these large-group, socially-gregarious species.

♪ Narrator: California provides essential habitat to a large variety and abundance of whales, dolphins, porpoises, and other marine mammals.

But this research isn't just specific to Catalina Island.

The waters off Dana Point in Orange County boast the highest density of dolphins per square mile globally, attracting nearly half a million individuals and even megapods of up to 10,000 dolphins.

With its abundant whale and dolphin populations and active naval bases across the Channel Islands and California coast, these waters make the ideal place to conduct research.

Off the waters of Catalina Island, a crew of researchers is conducting a study-- the impact of sonar on marine mammals.

With integrated drone photography, strategically placed recorders, and visual observations, the crew is measuring the different aspects of behavior for dolphins in responses during controlled exposure experiments of mid-frequency active Navy sonar.

Man: Good morning, everybody.

Woman: Morning.

Man 2: Morning, Tom.

Tom: Got ya.

Woman: Sound pollution, or noise pollution, is maybe not a word that people tend to think of, but sound is actually one of the noxious stimuli that can come in and harm the animals that are living in a particular space.

The ocean is not a quiet place.

There's lots of noise in the ocean that occurs naturally, but when we start to bring in high levels of noise or continuous or unpredictable sources of noise, that's when we can start to think about how we are kind of changing the physical space that animals have to use.

[Inaudible voice over radio] Selene: We know that dolphins use sound as their primary sensory modality because they spend so much of their time underwater.

So, below 100, 200 meters, it's dark.

So, they can't really use sight the way we use sight to navigate through our environment, communicate with one another.

So, a great example is echolocation clicks.

So, that's what dolphins use to forage.

They emit a sound, and they listen for that echo, and it allows them to identify object size, type.

They're very good at figuring out what it is from just that bounce.

[Sonar pinging] Narrator: Naval vessels use passive sonar to listen for enemy ships, and active sonar to send out acoustic pulses over long distances.

[Sonar pinging] Even after traveling dozens of miles and losing significant power, sonar pulses can still be audible and negatively impact marine life.

♪ To get an idea of the noise that animals are hearing and feeling underwater from a nearby powerful sonar, think about standing directly next to a jet engine during takeoff, going to a rock concert and being next to the speaker, or having a firecracker right by your ear.

There are natural sounds that we can hear in the air that also impact underwater marine life, like the crack of lightning or an earthquake.

[Lightning cracking] But water changes everything, affecting pressure, travel distance, and how we measure sound.

And it's not just volume-- it's repeated exposure.

Certain whale and dolphin species who depend on echolocation can suffer a range of hearing and behavioral effects, even at great distances from the sound source.

♪ Man: Sonar is used for Navy to interrogate and understand what's out in the water.

[Sonar pinging] They've got a job to do, to look for a variety of things in the water.

You know, it could be submarines or other crafts.

Over time, there have been stranding events during a sonar exercise.

You can debate, but there's definitely been associated with Navy sonar.

So, that's the core part of our program, is to better understand the effects of sonar.

Film narrator: Below deck, the Valiant has a great strength in the most highly classified of instruments-- a sonar device.

Narrator: World War I saw the use of sonar on a large scale for military purposes.

A sound pulse would be emitted by a device, travel through water until it hit an object, and bounce back to a receiving device.

By the Second World War, sonar's use became widespread in military, scientific, and commercial detection and navigation.

Today, naval sonar pings, which are one of the loudest sounds ever put into the seas, are joined by the engine and propeller sounds of over 105,000 merchant fleet ships and millions of private commercial fishing boats across the world.

There were several triggering events that brought the issue of sonar specifically to the public eye.

Some of the early strandings that happened in the Mediterranean, and particularly in the Bahamas around 2000, really got people's attention that there were these mortal events that happened around these training exercises.

The concern that we have is repeated exposures and how it translates.

Do you want me to head that way?

Brandon: Sure.

Okay.

Brandon: They said they had a couple groups of common dolphins.

Yeah.

Brandon: Might be them, but... Tom: See the-- there's the boat on the radar.

Brandon: Okay.

And I was noticing bird splash behind it.

Brandon: Okay.

It's behind the boat?

Tom: Yeah, just slightly behind it.

That thing... I'm right at him now.

Not a big pod.

Yeah, they're really spread.

But there's quite a few of them.

You get some good splashing out here to the right.

Want to angle a little more to the right, Tom?

One of the sort of interesting things about being an acoustician is we actually spend a lot of time looking at sounds instead of listening to them.

And so, what I have here is a visual representation of some sound recorded off of Catalina.

It's a really great program and helps us analyze our data.

It has time on the x-axis and intensity on the y-axis.

All those little wiggly lines are just showing the change in the sound wave over time.

This sound that I'm playing here is from the pre-exposure period, so there's no sonar happening during this time.

You can see there's multiple animals vocalizing in here and making all sorts of fun whistle sounds.

[Clicks and whistles] So, the sort of Rice Krispie, poppy sounds, those are the echolocation clicks, and then the high-pitched, squeaky sounds are the whistles.

I'll play it again without talking.

[Clicks and whistles] And I'm gonna jump forward and get into showing the exposure period.

And there is our first sonar ping.

And so, you can see whistling activity before the sonar ping is pretty low.

The sonar ping is that really bright-red sound there.

It shows up-- it's totally saturating our waveform up there-- it's visible there-- and then after that is this huge burst increase in whistles.

And so, that lasts 1.6 seconds, and then that sound ends, and then right after that, you can see there's just an explosion of whistles.

There's some echolocation clicks going on in the background, but, really, the whistling activity right after that sonar sound increases.

♪ Narrator: Lead scientist Brandon Southall has been researching the impacts of sonar since 1995.

Brandon: There's four species we're working with.

We've seen two of the four.

And just the ones we're focusing on are bottlenose dolphins.

One of the unique things about this project is it's pulling together four different methods that have been used in other contexts and that have been applied to ask different kinds of questions in a way that they haven't been integrated before.

So, here, you can see a picture of Catalina Island.

This is the sort of northwest tip of the island.

This is about 6 miles, just for reference.

So, there's three boats and a shore station.

We have our theodolite station, which is the shore base station, we have the drone, which is based from a boat that's following near the animals, we have the sound source, which is on another boat, and we have the acoustic buoys, or the passive acoustic monitoring, that's on a third boat.

It's definitely an orchestrated process.

So, Office of Naval Research, ONR, is the S&T, Science and Technology, branch of the Navy.

We do basic and early applied research on a variety of topics, and, in my case, it's a marine mammal and biology program.

The Navy's got a mission, you know, national security for our country, and so, they want to be able to do this in an environmentally friendly and responsible way.

The Navy's really driven to be good stewards of the environment.

Brandon: The earliest studies that I was involved in in the field were some of the first ones for looking at military sonar directly.

And, you know, we were putting tags on animals and tracking their movement and their behavior.

Selene: I think the ultimate goal is to understand how it may be causing long-term population level effects.

So, if an animal has to stop foraging or swim further or faster than it usually does, that takes up energy.

And if animals are expending more energy than they can gain, then that may have a long-term detrimental effect about their survival, their ability to reproduce, and that population.

Woman: They look a little bigger.

Woman 2: Yeah, they look bigger, and they've got a blow on them.

Brandon: I work closely with how animals behave and how they are affected by various kinds of human disturbance.

We try to do science that leads to actionable conclusions and outcomes to help people do what they need to do in a way that minimizes the impact on protected species and the environment.

There's one Tursiops, at least, so... yeah.

[Laughs] Brandon: The focus of our subsequent study is to look at things like avoidance, changes in foraging, social changes in group composition, and things that helped us refine the kind of questions we asked in subsequent studies.

Because they're complicated behaviors.

The animals may be doing multiple things at the same time, but it helped us refine the way that we were asking the questions by understanding the nature of these responses from the early studies.

It's not just that we're adding other noise types to the environment-- we're adding very loud sounds, sometimes very pervasive sounds that may travel hundreds or thousands of kilometers through the ocean.

[Series of explosions] We are adding noise that is unlike sounds that these animals have evolved to cope with in their natural habitats.

Humans having difficult experiences with noise pollution-- sometimes painful, annoying, and problematic noise that causes you to leave an area-- animals have to deal with those same types of problems.

Under the Marine Mammal Protection Act and the Endangered Species Act and the National Environmental Policy Act, a big part of what's required of Navy is to estimate the number of animals that they're affecting.

I get the feeling they might be coming together.

Woman: Hope so.

Let's take a closer look from the boats on the water.

Typically, one of the small boats will then, you know, evaluate the group and get a read of which direction that they're going.

Here, you see the boat with the three recorders on it.

They'll continue-- they'll track the animal.

We're still getting information from the people on the shore team.

As you can see from here, it's fixed at specific locations where they're observing.

Once this recorder's in place, that typically initiates the process of beginning the experiment.

Once the command boat gets the drone up and the drone is over the group, that initiates a window of time that's about 30 minutes, where we can run the experiment.

When you look at environmental impact statements, the number of takes that are happening, the oceanic dolphins rank the highest as far as the number of animals that are potentially harassed or changed their behavior.

Fleur: What we realized is that we really need to observe these animals at a group level.

And that gives you a really good overview and a large zoomed-out picture so that we can actually observe the whole group at once.

As we're continuing to track them, the boat that's deploying the acoustic recorders continues to move with the group, drops a second one, ultimately drops a third one.

We position the sound source boat, which is in red here, in a specific location and orientation, relative to the animals.

So, each of these, called the elements-- there's 14 of them total-- and they're stacked like this, in this vertical array, and it allows us to amplify the sound, and so, together, they produce a much louder sound than each of them would be able to do individually.

Brandon: There can be one of three things that happens.

The boat can deploy the sound source in the water but not turn it on, which we call a "no noise control," or it can make what we call a "simulated sonar signal."

The third thing that could happen, which is, we could deploy an operational sonar from a Navy source, in this case a Navy helicopter.

That continues through the whole three phases of the experiment, go into this window of tens of minutes where we're collecting biopsy samples from these groups of dolphins, still with information from the shore team about how this group is moving, whether there's other animals that may have come around the island that we don't know about.

Then that's the end of the experiment.

The land team has-- they have two jobs.

One of them is to find a group that would be a good candidate for us, and the other one, once they've located and put us in the right place-- the team on the water-- their job is then to monitor the movement of the whole overall group.

Fleur: To observe these animals, we use high-power binoculars, so that we can watch them up to about 7km from shore.

Usually, they're actually nearby.

For that, we have developed a protocol that we record behavioral parameters every minute to see how behavior changes, or not, over the course of an experiment.

I need your help to find them, if you guide me a little bit.

Moby is on the much right of Valkyrie.

I moved a little bit.

Oh, okay.

I think they're back.

Hannah: You got them?

Fleur: I think so.

We also record their location from this elevated cliff, actually using an apparatus that's called a theodolite.

And that measures, essentially, horizontal and vertical angle to the animals.

And if you don't know exactly where you are yourself, from that, you can actually translate that to the position of the animals at that time.

[Fleur over radio] For your information, there's been a large group of common dolphins foraging in shore.

They've moved off to the east now.

But I'll let you know in case they move back in.

[Radio clicks] [Man over radio] That sounds good.

We have [inaudible] kind of headed the same direction as this group.

Brandon: The boat that has the sound buoys is generally ahead of the group and slowly maneuvering to position the location of the buoys.

Narrator: Meanwhile, on the hydrophone boat, scientists are preparing instruments for the test.

Selene: This is called a sound trap.

It's an acoustic recorder.

So, it will record the sounds that the dolphins are making underwater.

This part right here is the hydrophone, which is basically an underwater microphone.

And then all the electronics and batteries are just in this little package.

We have it hooked up to a buoy and float, and so, it'll just drift along at the surface during the experiment.

[Man over radio] Moving the-- the pieces around here, and we're getting into position, and thinking about getting-- getting going.

Yeah, and there were a couple of [inaudible] sort of geared to us.

I picked it up just to... [inaudible] Man: James, did you copy buoy two, please?

James: Yeah, and just so you know, I do have a Tursiops right here.

[Man over radio] Roger.

They're not moving very quickly.

[Man over radio] James, what is your range to media?

Can you see that?

James: Range is 647 meters.

Brandon: The third piece is the sound source boat, and that's farther away.

[Man over radio, inaudible] Brandon: We have a general distance that we are trying to present the sound from, that's based on sound modeling, that tells us what is the level of sound we're gonna get at the animals based on that location and aspects of the ethymetry.

So, that's a lot of pieces in-- in real time.

The boat that has the drone flying over it is the one that's typically going behind the group, and the drone is reaching out ahead of the group to get the imagery above.

So, once those things are right, then it's starting to move the chess pieces in place.

Once the drone goes up, that initiates the 30-minute sequence that says, "We've gotten on top of the animals.

We're starting the sequence now."

[Man over radio] These guys are moving pretty good.

If you've got a solid feed on them, I'm going to peel off on the inshore side.

[James over radio] Roger.

Selene: So, we start with a 10-minute pre-exposure period.

That's when we just monitor the animals' current baseline behavior-- what they're doing when we find them out in the environment.

We're monitoring their surface and swimming behavior with the drone and with visual observations, and then we're also monitoring their acoustic activity.

Then, after that 10-minute baseline period is over, then we start to introduce the sound.

We play 24 sonar pings-- one ping every 25 seconds.

That takes 10 minutes.

[Ping] And during that, we're collecting all the same data streams that we're collecting during the baseline period.

[Pinging] And then once the 10-minute baseline period is over, we start a 10-minute post-exposure period, where we continue to monitor all three data streams.

Selene: And we'll have one more.

[Pinging] Okay, so now we'll power it down.

[Drone humming] Almost all types of science like this, especially bioacoustics research, things that touch on animal communication and social behavior, it really relies on an underlying understanding of species biology.

So, a side benefit of these types of behavioral response studies is a deeper knowledge of animal behavior, animal biology that we don't have and we don't necessarily have the opportunity to get.

♪ Brandon: After the sound is over, the group on the shore continues to monitor the group.

We go through the last 10-minute phase that ends the post-exposure sequence.

Hannah: Oh, they're behind Valkyrie.

Fleur: Oh, yeah.

Hannah: Yeah.

♪ Control T.

[Beep] Brandon: And then, effectively, the exposure part and the post-exposure part of the experiment is over.

[Over radio] Staying on this line and bumping our speed a little bit.

Hannah: Good copy.

Brandon: And a period of time after that, the source boat becomes the biopsy boat.

They go into biopsy mode.

Hannah: ...starting the... Fleur: In biopsy.

Yeah.

Hannah: Okay.

Sweet.

Brandon: And, typically, we fly the drone again to get images of the biopsy sampling.

Michael: Over a number of years, we've developed the ability to look at the physiological stress response in animals.

So, through the use of blubber biopsies, we're able to look at how animals are responding physiologically when they're exposed to a sound source.

Narrator: To collect blubber biopsies remotely, scientists typically send a small dart, capturing a plug of skin and blubber the size of a pencil eraser.

The dart then bounces off the animal, keeping the sample intact for retrieval.

This is the method used in this study, which identifies physiological impacts of minutes to hours of sonar exposure.

Scientists examine gene expression patterns and cortisol levels, essentially measuring the amount of stress on the dolphin.

Brandon: The assumption initially was, these animals aren't bothered by military sonar.

I think the thing we can tell the Navy the most from the work that we've done is, first, these animals appear to be more sensitive than we assumed that they were, based on imperfect information.

It pretty clearly depicts that these animals are more sensitive to sonar than we thought that they were.

Narrator: Current research by this team has spanned decades, with published updates as early as 2007.

This study, because the way it's set up and combining all these level of observations on this species really greatly advances our ability to understand this species.

And though we're getting at understanding their responses, I think it's really a significant step forward in understanding what these animals do and why they do it.

Big picture, I think we've shown that these animals are more sensitive to sound exposure and specifically mid-frequency sonar exposure than we previously thought they were.

So, what we see here is a visual depiction of the sound exposure experiment that we did.

On this plot is a map of the center of the distribution of the animals from the track of the drone, as well as the observations from our observers on the hill.

So, this is the 10 minutes that comes before the sound exposure event, and the blue line here is sequential points that are taken from the drone.

And when I click on the controlled exposure experiment or the sound transmission, you can see the location of the vessel that's projecting it.

The radius of the blue circle is one kilometer, 1,000 meters, about two-thirds of a mile away.

I can scroll along here and show-- show the time, and right at the beginning of that track, the animals make about a 50-degree turn to the left.

So, we would interpret that as a directed avoidance response.

Where the animals turned, there's a few deviations in the track, but generally, they're pointed away from the sound source.

So, it appears that the animals turned away from the source and sped up during it, and that turn in speed continued into the post-exposure period afterwards.

Michael: Understanding the significance of those responses is really the biggest step, then developing the mitigation measures, changing those mitigation measures if needed.

Fleur: What we have done here is opened up the floor for research on small cetaceans.

So, I do think we need to conduct these studies also in other places around the world.

Brandon: Our hope with doing these types of studies is to be able to provide some of the first direct data to the Navy and to the decision makers that regulate these things.

And if there are ways that we can reduce the sound in general that we put into the ocean, the less likely we'll be to impact the animals that live there.

Narrator: This team began with a question: "Are dolphins affected by sonar?"

It led to one of the most groundbreaking marine mammal studies attempted.

These scientists peered below the surface and discovered that dolphins indeed notice and react.

They speed up, become more vocal, and change course, signaling a level of sensitivity not understood before.

New insight into dolphin behaviors is leading to changes in naval exercises.

The Navy now is determining areas to avoid sonar testing during specific seasons, to better protect their oceanic neighbors.

But there is still much left to explore and learn.

♪ Announcer: This presentation is made possible in part by... a grant from Anne Ray Foundation, a Margaret A. Cargill Philanthropy.