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Right now,
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beneath a shimmering blue sea,
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millions of fish are having sex.
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(Cheers)
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And the way they're doing it
and strategies they're using
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looks nothing like what we see on land.
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Take parrotfish.
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In this species, all fish are born female,
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and they look like this.
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Then later in life,
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she can transition into a male
and she'll look like this.
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But it's not just
a spectacular wardrobe change.
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Her body can reabsorb her ovaries
and grow testes in their place.
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In just a few weeks,
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she'll go from making eggs
to producing sperm.
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It's pretty impressive,
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and in the ocean it's also pretty common.
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In fact, I bet nearly all of you
have at some point had a seafood dish
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made up of an individual
that started life as one sex
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and transitioned to another.
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Oysters?
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Grouper?
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Shrimp?
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Seeing some heads nodding, yeah.
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But not all fish that change sex
start as females.
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Those clown fish we know
from "Finding Nemo"?
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They're all born male.
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So in the real world,
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when Nemo's mother died,
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Nemo's dad Marlin
would have transitioned into Marlene --
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(Laughter)
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and Nemo would have likely mated
with his father turned mother.
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(Laughter)
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You can see --
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(Laughter)
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Yeah.
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You can see why Pixar
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took a little creative license
with the plotline, right?
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(Laughter)
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So sex change in the ocean
can happen in either direction
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and sometimes even back and forth,
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and that's just one of the many
amazing strategies animals use
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to reproduce in the ocean.
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And trust me when I say
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it's one of the least surprising.
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Sex in the sea is fascinating,
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and it's also really important,
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and not just to nerdy
marine biologists like me
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who are obsessed with understanding
these salty affairs.
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It matters for all of us.
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Today, we depend on wild caught fish
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to help feed over two billion people
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on the planet.
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We need millions of oysters and corals
to build the giant reefs
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that protect our shorelines
from rising seas and storms.
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We depend on medicines that are found
in marine animals to fight cancer
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and other diseases.
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And for many of us,
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the diversity and beauty of the oceans
is where we turn for recreation
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and relaxation and our cultural heritage.
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In order for us to continue
to benefit from the abundance
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that ocean life provides,
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the fish and coral and shrimp of today
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have to be able to make fish
and shrimp and coral for tomorrow.
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To do that, they have to have
lots and lots of sex.
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And until recently,
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we really didn't know
how sex happened in the sea.
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It's pretty hard to study.
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But thanks to new science and technology,
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we now know so much more
than even just a few years ago,
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and these new discoveries
are showing two things.
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First, sex in the sea is really funky.
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Second, our actions are wreaking havoc
on the sex lives of everything
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from shrimp to salmon.
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I know. It can be hard to believe.
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So today, I'm going to share a few details
about how animals do it in the deep,
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how we may be interrupting
these intimate affairs,
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and what we can do to change that.
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So, remember those sex-changing fish?
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In many places in the world,
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we have fishing rules
that set a minimum catch size.
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Fishers are not allowed
to target tiny fish.
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This allows baby fish to grow
and reproduce before they're caught.
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That's a good thing.
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So fishers go after the biggest fish.
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But in parrotfish, for example,
or any sex changer,
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targeting the biggest fish means
that they're taking out all the males.
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That makes it hard for a female fish
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to find a mate
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or it forces her to change sex sooner
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at a smaller size.
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Both of these things can result
in fewer fish babies in the future.
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In order for us to properly care
for these species,
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we have to know if they change sex,
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how, and when.
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Only then can we create rules
that can support these sexual strategies,
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such as setting a maximum size limit
in addition to a minimum one.
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The challenge isn't that we can't think
of these sex-friendly solutions.
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The challenge is knowing
which solutions to apply to which species,
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because even animals we know really well
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surprise us when it comes
to their sex lives.
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Take Maine lobster.
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They don't look that romantic,
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or that kinky.
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They are both.
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(Laughter)
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During mating season,
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female lobsters want to mate
with the biggest, baddest males,
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but these guys are really aggressive,
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and they'll attack any lobster
that approaches, male or female.
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Meanwhile, the best time
for her to mate with the male
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is right after she's molted,
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when she's lost her hard shell.
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So she has to approach this aggressive guy
in her most vulnerable state.
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What's a girl to do?
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Her answer?
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Spray him in the face
repeatedly with her urine.
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(Laughter)
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Under the sea, pee
is a very powerful love potion.
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Conveniently, lobsters' bladders
sit just above their brains,
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and they have two nozzles
under their eye stalks
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with which they can shoot
their urine forward.
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So the female approaches the male's den
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and as he charges out
she lets loose a stream of urine
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and then gets the hell out of there.
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Only a few days of this daily dosing
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is all it takes for her scent
to have a transformative effect.
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The male turns from an aggressive
to a gentle lover.
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By the week's end,
he invites her into his den.
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After that, the sex is easy.
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So how are we interrupting
this kind of kinky courtship?
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Well, the female's urine
carries a critical chemical signal
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that works because
it can pass through seawater
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and lobsters have a smell receptor
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that can detect and receive the message.
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Climate change is making
our oceans more acidic.
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It's the result of too much
carbon dioxide entering seawater.
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This changing chemistry
could scramble that message,
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or it could damage
the lobsters' smell receptors.
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Pollution from land
can have similar impacts.
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Just imagine the consequence
for that female
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if her love potion should fail.
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These are the kinds of subtle
but significant impacts we're having
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on the love lives of these marine life.
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And this is a species we know well:
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lobsters live near shore in the shallows.
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Dive deeper, and sex gets even stranger.
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Fanfin anglerfish live at about
3,000 feet below the surface
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in the pitch-black waters,
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and the males are born
without the ability to feed themselves.
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To survive, he has to find a female fast.
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Meanwhile, the female,
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who is 10 times bigger than the male,
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10 times,
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she lets out a very strong pheromone
with which to attract mates to her.
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So this tiny male is swimming
through the black waters
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smelling his way to a female,
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and when he finds her,
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he gives her a love bite.
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And this is when things get really weird.
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That love bite triggers
a chemical reaction
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whereby his jawbone
starts to disintegrate.
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His face melts into her flesh,
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and their two bodies start to fuse.
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Their circulatory systems intwine,
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and all his internal organs
start to dissolve
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except for his testes.
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(Laughter)
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His testes mature just fine
and start producing sperm.
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In the end, he's basically
a permanently attached
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on-demand sperm factory for the female.
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(Laughter)
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It's a very efficient system,
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but this is not the kind
of mating strategy
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that we see on a farm, right?
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I mean, this is weird.
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It's really strange.
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But if we don't know
that these kinds of strategies exist
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or how they work,
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we can't know what kind of impacts
we may be having, even in the deep sea.
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Just three years ago,
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we discovered a new species
of deep sea octopus
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where the females lay their eggs
on sponges attached to rocks
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that are over two and a half miles deep.
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These rocks contain rare earth minerals,
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and right now there are companies
that are building bulldozers
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that would be capable of mining
the deep sea floor for those rocks.
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But the bulldozers
would scrape up all the sponges
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and all the eggs with them.
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Knowingly, and in many cases unknowingly,
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we are preventing successful sex
and reproduction in the deep.
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And let's be honest,
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dating and mating is hard enough
without somebody coming in
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and interrupting all the time, right?
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I mean, we know this.
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So today, while I hope you will leave here
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with some excellent bar trivia
on fish sex --
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(Laughter)
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I also ask that you remember this:
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we are all far more intimately connected
with the oceans than we realize,
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no matter where we live.
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And this level of intimacy
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requires a new kind
of relationship with the ocean,
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one that recognizes and respects
the enormous diversity of life
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and its limitations.
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We can no longer think of the oceans
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as just something out there,
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because every day we depend on them
for our food security,
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our own health and wellness,
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and every other breath we take.
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But it is a two-way relationship,
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and the oceans can only continue
to provide for us
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if we in turn safeguard
that fundamental force of life in the sea:
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sex and reproduction.
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So, like any relationship,
we have to embrace some change
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for the partnership to work.
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The next time you're thinking
about having seafood,
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look for sustainably caught
or farmed species
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that are local and low on the food chain.
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These are animals
like oysters, clams, mussels,
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small fish like mackerel.
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These all reproduce like crazy,
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and with good management
they can handle a bit of fishing pressure.
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We can also rethink
what we use to wash our bodies,
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clean our homes,
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and care for our lawns.
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All of those chemicals
eventually wash out to sea
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and disrupt the natural chemistry
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of the ocean.
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Industry also has to play its part
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and take a precautionary approach,
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protecting sexual activity
where we know it exists
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and preventing harm in the cases
where we just don't yet know enough,
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like the deep sea.
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And in the communities where we live,
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the places we work,
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and the country in which we vote,
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we must take bold action
on climate change now.
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(Applause)
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Thank you.
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(Applause)