Translator: Tanya Cushman Reviewer: Peter van de Ven
On May 1, 2005,
the fishermen of Hat Khrai village, in Northern Thailand,
were out on the river before dawn.
It was the one time of year to catch the Mekong giant catfish,
a fish that Thais call "pla buek," or "buffalo fish."
Among Thai fishermen, no fish inspires more folk tales,
and the villagers of Hat Khrai
have been telling stories about pla buek for centuries.
These fishermen had watched their fathers,
they had grown up watching their fathers
pull dozens of Mekong giant catfish out of the river every year.
And they themselves had caught some,
but it had been three years since anyone, anywhere in Thailand,
had caught a wild Mekong giant catfish.
And it was clear that their numbers were declining dramatically.
Some people questioned
whether or not there were any pla buek left to catch.
Together, the men ventured out onto the muddy waters of the Mekong,
unfurling their long nets across the river.
They'd been out on the water for less than 15 minutes
when the great fish announced itself with four whacks of its tail.
The fishermen knew immediately what had tangled in their net.
It was a pla buek.
No other fish grew as big,
and this one was enormous.
It took the fishermen over an hour to pull the fish to shore.
And by then, the fish had lost its brute force, its brute strength,
that it exhibited out on the river.
When one of the men thread a thick rope through the fish's mouth and gills,
the toothless giant, bruised and exhausted,
put up little resistance.
It took eight men to lift the fish out of the water,
to measure and weigh it.
The fish measured 9 feet in length
and it weighed 646 pounds.
The fishermen didn't know it at the time,
but they had just broken the record
for the largest freshwater fish in the world.
Or had they?
At the time, I was working in the Mekong Basin.
I was doing research that I'd started as part of my PhD.
And media around the world reported on this 646-pound catch,
but no one was reporting of anyone ever catching a larger fish.
So the catch made me curious.
I asked myself,
"What is the world's largest freshwater fish?"
We know that the African elephant is the world's largest terrestrial animal,
that the blue whale is the largest creature in the sea,
that the whale shark is the largest marine fish.
But as I started digging,
I realized that no one had ever looked at giant freshwater fish
on a global scale.
And it was because of this curiosity and my inability to find answers
that I started to search for the world's largest freshwater fish.
Together with the National Geographic Society
and the University of Nevada, Reno,
it's become a ten-year-plus scientific adventure
to six continents
to find, study and protect the world's largest freshwater fish.
And it's been an adventure that stretched across the globe,
from some of the most remote places on earth
to our own backyards.
And it's also become a race against the clock
to try to find and protect these giant fish
before they disappear forever.
What I found has been amazing,
more incredible than I ever imagined.
Beneath the surface of the world's rivers and lakes
swim dozens of species of mysterious aquatic giants.
These are the real-life Loch Ness Monsters of the freshwater world.
There are about 30 species of what I call megafish,
freshwater fish that grow to over 6-feet length
or weigh more than 200 pounds,
and it's a diverse assemblage of unknown, poorly understood creatures,
like the giant Siamese carp.
This is a fish,
a 600-pound relative of the goldfish,
that has scales that are the size of the palm of my hand.
Or the giant freshwater stingray,
a stingray in fresh water that can grow to 15 feet in length
and has a venomous barb on the base of its tail
that's as long as my forearm.
There are two other species of freshwater ray that grow almost as big.
And one species in Northern Australia
was only described in 2008.
So these are enormous creatures
that play important roles in aquatic environments,
yet their numbers are dwindling,
threatened by overfishing and habitat loss,
pollution, climate change.
Over 70% of these giant fish are now at risk of extinction.
So why are these fish,
like this giant goonch catfish in India,
why are these fish disappearing?
And honestly, why should we care?
Well, the big fish - often these big fish face the biggest threats.
They're the first to be affected by overfishing, by dams,
by pollution a lot of times.
And so they're indicators, these big fish are indicators of river health.
And it's not just big fish; it's small fish too.
It's all fish.
The troubled story of these large fish
underscores an environmental crisis that's facing our lakes and rivers today,
where the rate of biodiversity loss, freshwater biodiversity loss,
is greater than the biodiversity loss that we see in the oceans or on land.
And it's not just fish.
It's people too.
You take the Mekong River as one example.
The Mekong river is the most productive river on earth.
Over 2 million tons of fish are harvested from the Mekong River every year.
And as the big fish disappear from the Mekong,
it's an indication
that the overall harvest is at risk as well.
And that it turn threatens the livelihoods and food security
of millions of people living along the Mekong river.
These fish are culturally important.
Giant Siamese carp,
giant seven-striped barb, giant catfish
are carved into the walls of the ancient Angkor Wat temples
in Cambodia.
These are fish that are so significant
that they play central roles in religion and ceremony,
that these extraordinary animals,
they have the ability to change the way that we view the world.
I remember the first time I saw one of these fish -
and I hope some of you are feeling the same way right now -
the first time I saw one of these fish, something inside me shifted,
and my world became a bigger place.
It became a better place.
So what can we do to save these amazing animals?
First, I think we have to acknowledge that they have an image problem.
(Laughter)
So first, I think we have to acknowledge that they have an image problem.
We tend to dismiss these fish as ugly.
Let's be honest:
we tend to dismiss these fish as ugly
or think of them as food
or fear them as dangerous.
But they're much more than that.
They are found in many of the world's great rivers.
In the Mississippi, in the Amazon, the Yangtze, the Nile, the Colorado.
Like us, they need clean water to survive.
They clearly illustrate threats to aquatic systems,
and they can be used to show the link between river health and human health.
We need to change the way that we think about freshwater fish.
As sharks have shown, over the last 40 years,
it is possible to change lack of awareness and even fear
to appreciation and respect.
You think about - for those of you that were around -
think about how we thought about sharks when the movie "Jaws" came out.
And now, 40 years later,
thanks to the work of thousands of people around the world,
people's perceptions of sharks has changed.
And three of the largest shark species, including the great white,
are now globally protected.
And an important part of this is education and outreach.
This is a photo of Cambodian children
reading a book about the ecology and conservation of Mekong giant catfish.
Ten years ago, when I was just starting this work,
I would talk to people or show people photos of these fish,
and people hadn't heard of them.
Today, when I speak to students, even young children,
a lot of them can name these fish.
And we need to come together.
These fish, they don't have many friends.
They need more friends,
and so we need to come together, form partnerships,
and especially, engagement with fishermen.
Those can be important conservation tools.
An example of this is what's happened in Alaska,
where fishermen, local businesses and environmental groups
have come together to protect Bristol Bay,
which is home to one of the largest populations of salmon on earth.
Or what's happening in Mongolia,
where scientists, religious leaders and fishermen
have come together
to take the lead in protecting the world's largest trout species.
And then, finally, we need action,
direct action to help protect aquatic habitats,
help either maintain or restore free-flowing rivers,
and help save these iconic yet critically endangered megafish.
If you google "dam removal,"
you can see an example of one of the kinds of actions
that are being adopted more and more frequently recently
to help protect these rivers and fish.
I was back in the Mekong late last year,
and I witnessed first hand people coming together
to try to create a world where megafish and humans can coexist.
While Cambodians were celebrating Independence Day,
a group of fishermen outside of Phnom Penh made a very special catch.
They caught the first Mekong giant catfish of 2015.
And that's evidence
that this extremely rare fish still occurs in Cambodia
and it's still making its annual spawning migration
in the free-flowing stretches of the Mekong.
We tagged and released this fish, alive, downstream of the fishermen's nets
as part of a partnership
between the fishermen,
the Cambodian department of fisheries
and scientists.
To release the fish, I dove into the water with it
to try to guide the big fish down into deeper water.
And about 15 feet below the surface,
my ears popped,
it was silent, it was dark,
and I'd reached the point where my world ended
and the world of that fish began.
In the end, I've learned that the search for the world's largest freshwater fish
is about far more than finding the big one.
It's the story of the health of our rivers and lakes.
It's the story of people who depend on fish and fresh water to survive.
And it's the story of how we perceive our world
and how the existence of these amazing fish
makes our lives richer and earth a better home,
not just for us, but for all life, big and small.
Thank you very much.
(Applause)