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Thank you so much. I'm going to try to take you

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on a journey of the underwater acoustic world

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of whales and dolphins.

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Since we are such a visual species,

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it's hard for us to really understand this,

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so I'll use a mixture of figures and sounds

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and hope this can communicate it.

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But let's also think, as a visual species,

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what it's like when we go snorkeling or diving

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and try to look underwater.

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We really can't see very far.

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Our vision, which works so well in air,

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all of a sudden is very restricted and claustrophobic.

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And what marine mammals have evolved

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over the last tens of millions of years

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is ways to depend on sound

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to both explore their world

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and also to stay in touch with one another.

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Dolphins and toothed whales use echolocation.

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They can produce loud clicks

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and listen for echoes from the sea floor in order to orient.

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They can listen for echoes from prey

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in order to decide where food is

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and to decide which one they want to eat.

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All marine mammals use sound for communication to stay in touch.

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So the large baleen whales

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will produce long, beautiful songs,

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which are used in reproductive advertisement

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for male and females, both to find one another

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and to select a mate.

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And mother and young and closely bonded animals

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use calls to stay in touch with one another,

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so sound is really critical for their lives.

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The first thing that got me interested in the sounds

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of these underwater animals,

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whose world was so foreign to me,

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was evidence from captive dolphins

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that captive dolphins could imitate human sounds.

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And I mentioned I'll use

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some visual representations of sounds.

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Here's the first example.

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This is a plot of frequency against time --

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sort of like musical notation,

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where the higher notes are up higher and the lower notes are lower,

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and time goes this way.

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This is a picture of a trainer's whistle,

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a whistle a trainer will blow to tell a dolphin

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it's done the right thing and can come get a fish.

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It sounds sort of like "tweeeeeet." Like that.

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This is a calf in captivity

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making an imitation

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of that trainer's whistle.

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If you hummed this tune to your dog or cat

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and it hummed it back to you,

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you ought to be pretty surprised.

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Very few nonhuman mammals

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can imitate sounds.

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It's really important for our music and our language.

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So it's a puzzle: The few other mammal groups that do this,

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why do they do it?

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A lot of my career has been devoted

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to trying to understand

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how these animals use their learning,

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use the ability to change what you say

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based on what you hear

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in their own communication systems.

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So let's start with calls of a nonhuman primate.

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Many mammals have to produce contact calls

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when, say, a mother and calf are apart.

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This is an example of a call produced by squirrel monkeys

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when they're isolated from another one.

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And you can see, there's not much

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variability in these calls.

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By contrast, the signature whistle

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which dolphins use to stay in touch,

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each individual here has a radically different call.

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They can use this ability to learn calls

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in order to develop more complicated and more distinctive calls

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to identify individuals.

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How about the setting in which animals need to use this call?

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Well let's look at mothers and calves.

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In normal life for mother and calf dolphin,

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they'll often drift apart or swim apart if Mom is chasing a fish,

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and when they separate

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they have to get back together again.

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What this figure shows is the percentage of the separations

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in which dolphins whistle,

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against the maximum distance.

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So when dolphins are separating by less than 20 meters,

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less than half the time they need to use whistles.

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Most of the time they can just find each other

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just by swimming around.

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But all of the time when they separate by more than 100 meters,

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they need to use these individually distinctive whistles

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to come back together again.

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Most of these distinctive signature whistles

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are quite stereotyped and stable

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through the life of a dolphin.

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But there are some exceptions.

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When a male dolphin leaves Mom,

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it will often join up with another male

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and form an alliance, which may last for decades.

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As these two animals form a social bond,

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their distinctive whistles actually converge

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and become very similar.

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This plot shows two members of a pair.

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As you can see at the top here,

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they share an up-sweep, like "woop, woop, woop."

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They both have that kind of up-sweep.

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Whereas these members of a pair go "wo-ot, wo-ot, wo-ot."

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And what's happened is

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they've used this learning process

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to develop a new sign that identifies this new social group.

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It's a very interesting way that they can

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form a new identifier

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for the new social group that they've had.

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Let's now take a step back

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and see what this message can tell us

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about protecting dolphins

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from human disturbance.

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Anybody looking at this picture

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will know this dolphin is surrounded,

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and clearly his behavior is being disrupted.

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This is a bad situation.

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But it turns out that when just a single boat

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is approaching a group of dolphins

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at a couple hundred meters away,

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the dolphins will start whistling,

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they'll change what they're doing, they'll have a more cohesive group,

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wait for the boat to go by,

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and then they'll get back to normal business.

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Well, in a place like Sarasota, Florida,

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the average interval between times

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that a boat is passing within a hundred meters of a dolphin group

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is six minutes.

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So even in the situation that doesn't look as bad as this,

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it's still affecting the amount of time these animals have

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to do their normal work.

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And if we look at a very pristine environment like western Australia,

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Lars Bider has done work

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comparing dolphin behavior and distribution

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before there were dolphin-watching boats.

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When there was one boat, not much of an impact.

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And two boats: When the second boat was added,

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what happened was that some of the dolphins

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left the area completely.

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Of the ones that stayed, their reproductive rate declined.

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So it could have a negative impact on the whole population.

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When we think of marine-protected areas for animals like dolphins,

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this means that we have to be

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quite conscious about activities that we thought were benign.

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We may need to regulate the intensity

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of recreational boating and actual whale watching

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in order to prevent these kinds of problems.

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I'd also like to point out that sound

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doesn't obey boundaries.

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So you can draw a line to try to protect an area,

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but chemical pollution and noise pollution

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will continue to move through the area.

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And I'd like to switch now from this local,

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familiar, coastal environment

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to a much broader world of the baleen whales and the open ocean.

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This is a kind of map we've all been looking at.

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The world is mostly blue.

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But I'd also like to point out that the oceans

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are much more connected than we think.

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Notice how few barriers there are to movement

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across all of the oceans compared to land.

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To me, the most mind-bending example

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of the interconnectedness of the ocean

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comes from an acoustic experiment

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where oceanographers

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took a ship to the southern Indian Ocean,

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deployed an underwater loudspeaker

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and played back a sound.

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That same sound

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traveled to the west, and could be heard in Bermuda,

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and traveled to the east, and could be heard in Monterey --

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the same sound.

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So we live in a world of satellite communication,

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are used to global communication,

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but it's still amazing to me.

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The ocean has properties

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that allow low-frequency sound

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to basically move globally.

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The acoustic transit time for each of these paths is about three hours.

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It's nearly halfway around the globe.

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In the early '70s,

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Roger Payne and an ocean acoustician

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published a theoretical paper

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pointing out that it was possible

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that sound could transmit over these large areas,

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but very few biologists believed it.

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It actually turns out, though,

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even though we've only known of long-range propagation for a few decades,

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the whales clearly have evolved,

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over tens of millions of years,

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a way to exploit this amazing property of the ocean.

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So blue whales and fin whales

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produce very low-frequency sounds

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that can travel over very long ranges.

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The top plot here shows

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a complicated series of calls

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that are repeated by males.

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They form songs, and they appear to play a role in reproduction,

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sort of like that of song birds.

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Down below here, we see calls made by both males and females

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that also carry over very long ranges.

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The biologists continued to be skeptical

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of the long-range communication issue

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well past the '70s,

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until the end of the Cold War.

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What happened was, during the Cold War,

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the U.S. Navy had a system that was secret at the time,

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that they used to track Russian submarines.

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It had deep underwater microphones, or hydrophones,

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cabled to shore,

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all wired back to a central place that could listen

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to sounds over the whole North Atlantic.

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And after the Berlin Wall fell, the Navy made these systems available

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to whale bio-acousticians

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to see what they could hear.

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This is a plot from Christopher Clark

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who tracked one individual blue whale

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as it passed by Bermuda,

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went down to the latitude of Miami and came back again.

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It was tracked for 43 days,

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swimming 1,700 kilometers,

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or more than 1,000 miles.

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This shows us both that the calls

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are detectable over hundreds of miles

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and that whales routinely swim hundreds of miles.

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They're ocean-based and scale animals

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who are communicating over much longer ranges

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than we had anticipated.

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Unlike fins and blues, which

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disperse into the temperate and tropical oceans,

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the humpbacked whales congregate

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in local traditional breeding grounds,

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so they can make a sound that's a little higher in frequency,

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broader-band and more complicated.

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So you're listening to the complicated song

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produced by humpbacks here.

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Humpbacks, when they develop

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the ability to sing this song,

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they're listening to other whales

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and modifying what they sing based on what they're hearing,

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just like song birds or the dolphin whistles I described.

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This means that humpback song

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is a form of animal culture,

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just like music for humans would be.

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I think one of the most interesting examples of this

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comes from Australia.

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Biologists on the east coast of Australia

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were recording the songs of humpbacks in that area.

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And this orange line here marks the typical songs

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of east coast humpbacks.

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In '95 they all sang the normal song.

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But in '96 they heard a few weird songs,

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and it turned out that these strange songs

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were typical of west coast whales.

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The west coast calls became more and more popular,

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until by 1998,

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none of the whales sang the east coast song; it was completely gone.

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They just sang the cool new west coast song.

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It's as if some new hit style

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had completely wiped out

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the old-fashioned style before,

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and with no golden oldies stations.

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Nobody sang the old ones.

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I'd like to briefly just show what the ocean does to these calls.

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Now you are listening to a recording made by Chris Clark,

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0.2 miles away from a humpback.

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You can hear the full frequency range. It's quite loud.

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You sound very nearby.

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The next recording you're going to hear

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was made of the same humpback song

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50 miles away.

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That's shown down here.

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You only hear the low frequencies.

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You hear the reverberation

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as the sound travels over long-range in the ocean

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and is not quite as loud.

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Now after I play back these humpback calls,

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I'll play blue whale calls, but they have to be sped up

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because they're so low in frequency

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that you wouldn't be able to hear it otherwise.

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Here's a blue whale call at 50 miles,

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which was distant for the humpback.

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It's loud, clear -- you can hear it very clearly.

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Here's the same call recorded from a hydrophone

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500 miles away.

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There's a lot of noise, which is mostly other whales.

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But you can still hear that faint call.

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Let's now switch and think about

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a potential for human impacts.

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The most dominant sound that humans put into the ocean

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comes from shipping.

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This is the sound of a ship,

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and I'm having to talk a little louder to talk over it.

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Imagine that whale listening from 500 miles.

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There's a potential problem that maybe

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this kind of shipping noise would prevent whales

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from being able to hear each other.

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Now this is something that's been known for quite a while.

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This is a figure from a textbook on underwater sound.

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And on the y-axis

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is the loudness of average ambient noise in the deep ocean

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by frequency.

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In the low frequencies, this line indicates

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sound that comes from seismic activity of the earth.

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Up high, these variable lines

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indicate increasing noise in this frequency range

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from higher wind and wave.

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But right in the middle here where there's a sweet spot,

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the noise is dominated by human ships.

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Now think about it. This is an amazing thing:

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That in this frequency range where whales communicate,

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the main source globally, on our planet, for the noise

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comes from human ships,

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thousands of human ships, distant, far away,

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just all aggregating.

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The next slide will show what the impact this may have

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on the range at which whales can communicate.

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So here we have the loudness of a call at the whale.

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And as we get farther away,

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the sound gets fainter and fainter.

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Now in the pre-industrial ocean, as we were mentioning,

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this whale call could be easily detected.

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It's louder than noise

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at a range of a thousand kilometers.

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Let's now take that additional increase in noise

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that we saw comes from shipping.

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All of a sudden, the effective range of communication

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goes from a thousand kilometers to 10 kilometers.

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Now if this signal is used for males and females

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to find each other for mating and they're dispersed,

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imagine the impact this could have

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on the recovery of endangered populations.

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Whales also have contact calls

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like I described for the dolphins.

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I'll play the sound of a contact call used

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by right whales to stay in touch.

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And this is the kind of call that is used by,

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say, right whale mothers and calves

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as they separate to come back again.

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Now imagine -- let's put the ship noise in the picture.

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What's a mother to do

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if the ship comes by and her calf isn't there?

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I'll describe a couple strategies.

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One strategy is if your call's down here,

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and the noise is in this band,

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you could shift the frequency of your call out of the noise band

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and communicate better.

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Susan Parks of Penn State has actually studied this.

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She's looked in the Atlantic. Here's data from the South Atlantic.

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Here's a typical South Atlantic contact call from the '70s.

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Look what happened by 2000 to the average call.

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00:13:52,000 --> 00:13:54,000
Same thing in the North Atlantic,

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in the '50s versus 2000.

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Over the last 50 years,

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as we've put more noise into the oceans,

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these whales have had to shift.

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It's as if the whole population had to shift

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from being basses to singing as a tenor.

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It's an amazing shift, induced by humans

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over this large scale,

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in both time and space.

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And we now know that whales can compensate for noise

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by calling louder, like I did when that ship was playing,

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by waiting for silence

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and by shifting their call out of the noise band.

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Now there's probably costs to calling louder

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or shifting the frequency away from where you want to be,

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and there's probably lost opportunities.

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If we also have to wait for silence,

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they may miss a critical opportunity to communicate.

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00:14:34,000 --> 00:14:36,000
So we have to be very concerned

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about when the noise in habitats

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00:14:38,000 --> 00:14:40,000
degrades the habitat enough

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00:14:40,000 --> 00:14:43,000
that the animals either have to pay too much to be able to communicate,

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00:14:43,000 --> 00:14:45,000
or are not able to perform critical functions.

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It's a really important problem.

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And I'm happy to say that there are several

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00:14:50,000 --> 00:14:53,000
very promising developments in this area,

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00:14:53,000 --> 00:14:56,000
looking at the impact of shipping on whales.

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00:14:56,000 --> 00:14:58,000
In terms of the shipping noise,

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00:14:58,000 --> 00:15:01,000
the International Maritime Organization of the United Nations

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has formed a group whose job is to establish

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guidelines for quieting ships,

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to tell the industry how you could quiet ships.

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00:15:08,000 --> 00:15:10,000
And they've already found

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that by being more intelligent about better propeller design,

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you can reduce that noise by 90 percent.

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00:15:16,000 --> 00:15:19,000
If you actually insulate and isolate

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00:15:19,000 --> 00:15:21,000
the machinery of the ship from the hull,

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00:15:21,000 --> 00:15:24,000
you can reduce that noise by 99 percent.

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00:15:24,000 --> 00:15:27,000
So at this point, it's primarily an issue of cost and standards.

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If this group can establish standards,

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00:15:29,000 --> 00:15:32,000
and if the shipbuilding industry adopts them for building new ships,

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we can now see a gradual decline

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00:15:34,000 --> 00:15:36,000
in this potential problem.

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00:15:36,000 --> 00:15:39,000
But there's also another problem from ships that I'm illustrating here,

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00:15:39,000 --> 00:15:41,000
and that's the problem of collision.

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00:15:41,000 --> 00:15:44,000
This is a whale that just squeaked by

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00:15:44,000 --> 00:15:47,000
a rapidly moving container ship and avoided collision.

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00:15:47,000 --> 00:15:49,000
But collision is a serious problem.

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00:15:49,000 --> 00:15:52,000
Endangered whales are killed every year by ship collision,

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00:15:52,000 --> 00:15:55,000
and it's very important to try to reduce this.

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I'll discuss two very promising approaches.

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The first case comes from the Bay of Fundy.

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00:16:00,000 --> 00:16:02,000
These black lines mark shipping lanes

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00:16:02,000 --> 00:16:04,000
in and out of the Bay of Fundy.

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00:16:04,000 --> 00:16:06,000
The colorized area

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00:16:06,000 --> 00:16:09,000
shows the risk of collision for endangered right whales

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00:16:09,000 --> 00:16:11,000
because of the ships moving in this lane.

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00:16:11,000 --> 00:16:14,000
It turns out that this lane here

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00:16:14,000 --> 00:16:17,000
goes right through a major feeding area of right whales in the summer time,

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00:16:17,000 --> 00:16:20,000
and it makes an area of a significant risk of collision.

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00:16:20,000 --> 00:16:22,000
Well, biologists

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00:16:22,000 --> 00:16:24,000
who couldn't take no for an answer

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00:16:24,000 --> 00:16:26,000
went to the International Maritime Organization

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and petitioned them to say,

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"Can't you move that lane? Those are just lines on the ground.

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00:16:30,000 --> 00:16:32,000
Can't you move them over to a place

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00:16:32,000 --> 00:16:34,000
where there's less of a risk?"

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00:16:34,000 --> 00:16:36,000
And the International Maritime Organization responded very strongly,

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00:16:36,000 --> 00:16:38,000
"These are the new lanes."

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00:16:38,000 --> 00:16:40,000
The shipping lanes have been moved.

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00:16:40,000 --> 00:16:43,000
And as you can see, the risk of collision is much lower.

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00:16:43,000 --> 00:16:45,000
So it's very promising, actually.

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00:16:45,000 --> 00:16:47,000
We can be very creative about thinking

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00:16:47,000 --> 00:16:49,000
of different ways to reduce these risks.

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00:16:49,000 --> 00:16:51,000
Another action which was just taken independently

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00:16:51,000 --> 00:16:54,000
by a shipping company itself

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00:16:54,000 --> 00:16:57,000
was initiated because of concerns the shipping company had

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00:16:57,000 --> 00:17:00,000
about greenhouse gas emissions with global warming.

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00:17:00,000 --> 00:17:03,000
The Maersk Line looked at their competition

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00:17:03,000 --> 00:17:06,000
and saw that everybody who is in shipping thinks time is money.

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00:17:06,000 --> 00:17:08,000
They rush as fast as they can to get to their port.

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00:17:08,000 --> 00:17:10,000
But then they often wait there.

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00:17:10,000 --> 00:17:12,000
What Maersk did is they worked ways to slow down.

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00:17:12,000 --> 00:17:15,000
They could slow down by about 50 percent.

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00:17:15,000 --> 00:17:18,000
This reduced their fuel consumption by about 30 percent,

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00:17:18,000 --> 00:17:20,000
which saved them money,

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00:17:20,000 --> 00:17:23,000
and at the same time, it had a significant benefit for whales.

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00:17:23,000 --> 00:17:26,000
It you slow down, you reduce the amount of noise you make

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00:17:26,000 --> 00:17:28,000
and you reduce the risk of collision.

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00:17:28,000 --> 00:17:30,000
So to conclude, I'd just like to point out,

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00:17:30,000 --> 00:17:32,000
you know, the whales live in

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00:17:32,000 --> 00:17:34,000
an amazing acoustic environment.

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00:17:34,000 --> 00:17:36,000
They've evolved over tens of millions of years

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00:17:36,000 --> 00:17:38,000
to take advantage of this.

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And we need to be very attentive and vigilant

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00:17:41,000 --> 00:17:43,000
to thinking about where things that we do

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00:17:43,000 --> 00:17:45,000
may unintentionally prevent them

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from being able to achieve their important activities.

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At the same time, we need to be really creative

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in thinking of solutions to be able to help reduce these problems.

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I hope these examples have shown

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00:17:55,000 --> 00:17:57,000
some of the different directions we can take

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in addition to protected areas

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00:17:59,000 --> 00:18:02,000
to be able to keep the ocean safe for whales to be able to continue to communicate.

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Thank you very much.

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(Applause)