here to talk to you about the crisis in our oceans,

but this time perhaps not with a message you've heard before,

because I want to tell you that if the survival of the oceans

depended only on people like me,

scientists trading in publications,

we'd be in even worse trouble than we are.

Because, as a scientist,

the most important things that I've learned

about keeping our oceans healthy and productive

have come not from academia, but from fishermen and women

living in some of the poorest countries on earth.

I've learned that as a conservationist,

the most important question is not, "How do we keep people out?"

but rather, "How do we make sure that coastal people throughout the world

have enough to eat?"

Our oceans are every bit as critical to our own survival

as our atmosphere, our forests or our soils.

Their staggering productivity ranks fisheries with farming

as a mainstay of food production

for humanity.

Yet something's gone badly wrong.

We're accelerating into an extinction emergency,

one that my field has so far failed abysmally to tackle.

At its core is a very human and humanitarian crisis.

The most devastating blow we've so far dealt our oceans

is through overfishing.

Every year, we fish harder, deeper, further afield.

Every year, we chase ever fewer fish.

Yet the crisis of overfishing is a great paradox:

unnecessary, avoidable and entirely reversible,

because fisheries are one of the most productive resources on the planet.

With the right strategies, we can reverse overfishing.

That we've not yet done so is, to my mind,

one of humanity's greatest failures.

Nowhere is this failure more apparent

than in the warm waters on either side of our equator.

Our tropics are home to most of the species in our ocean,

most of the people whose existence depends on our seas.

We call these coastal fishermen and women "small-scale fishers,"

but "small-scale" is a misnomer

for a fleet comprising over 90 percent of the world's fishermen and women.

Their fishing is generally more selective and sustainable

than the indiscriminate destruction

too often wrought by bigger industrial boats.

These coastal people have the most to gain from conservation

because, for many of them,

fishing is all that keeps them from poverty, hunger or forced migration,

in countries where the state is often unable to help.

We know that the outlook is grim:

stocks collapsing on the front lines of climate change,

warming seas, dying reefs, catastrophic storms,

trawlers, factory fleets,

rapacious ships from richer countries taking more than their share.

Extreme vulnerability is the new normal.

I first landed on the island of Madagascar two decades ago,

on a mission to document its marine natural history.

I was mesmerized by the coral reefs I explored,

and certain I knew how to protect them,

because science provided all the answers:

close areas of the reef permanently.

Coastal fishers simply needed to fish less.

I approached elders here in the village of Andavadoaka

and recommended that they close off

the healthiest and most diverse coral reefs to all forms of fishing

to form a refuge to help stocks recover

because, as the science tells us, after five or so years,

fish populations inside those refuges would be much bigger,

replenishing the fished areas outside,

making everybody better off.

That conversation didn't go so well.

(Laughter)

Three-quarters of Madagascar's 27 million people

live on less than two dollars a day.

My earnest appeal to fish less took no account

of what that might actually mean

for people who depend on fishing for survival.

It was just another squeeze from outside,

a restriction rather than a solution.

What does protecting a long list of Latin species names mean to Resaxx,

a woman from Andavadoaka who fishes every day

to put food on the table

and send her grandchildren to school?

That initial rejection taught me that conservation is, at its core,

a journey in listening deeply,

to understand the pressures and realities that communities face

through their dependence on nature.

This idea became the founding principle for my work

and grew into an organization that brought a new approach

to ocean conservation

by working to rebuild fisheries with coastal communities.

Then, as now, the work started by listening,

and what we learned astonished us.

Back in the dry south of Madagascar,

we learned that one species was immensely important for villagers:

this remarkable octopus.

We learned that soaring demand was depleting an economic lifeline.

But we also learned that this animal grows astonishingly fast,

doubling in weight every one or two months.

We reasoned that protecting just a small area of fishing ground

for just a few months

might lead to dramatic increases in catches,

enough to make a difference to this community's bottom line

in a time frame that might just be acceptable.

The community thought so too,

opting to close a small area of reef to octopus fishing temporarily,

using a customary social code,

invoking blessings from the ancestors to prevent poaching.

When that reef reopened to fishing six months later,

none of us were prepared for what happened next.

Catches soared,

with men and women landing more and bigger octopus

than anyone had seen for years.

Neighboring villages saw the fishing boom

and drew up their own closures,

spreading the model virally along hundreds of miles of coastline.

When we ran the numbers,

we saw that these communities, among the poorest on earth,

had found a way to double their money in a matter of months, by fishing less.

Imagine a savings account

from which you withdraw half your balance every year

and your savings keep growing.

There is no investment opportunity on earth

that can reliably deliver what fisheries can.

But the real magic went beyond profit,

because a far deeper transformation was happening in these communities.

Spurred on by rising catches,

leaders from Andavadoaka joined force with two dozen neighboring communities

to establish a vast conservation area along dozens of miles of coastline.

They outlawed fishing with poison and mosquito nets

and set aside permanent refuges

around threatened coral reefs and mangroves,

including, to my astonishment,

those same sights that I'd flagged just two years earlier

when my evangelism for marine protection was so roundly rejected.

They created a community-led protected area,

a democratic system for local marine governance

that was totally unimaginable just a few years earlier.

And they didn't stop there:

within five years, they'd secured legal rights from the state

to manage over 200 square miles of ocean,

eliminating destructive industrial trawlers from the waters.

Ten years on, we're seeing recovery of those critical reefs

within those refuges.

Communities are petitioning for greater recognition

of the right to fish

and fairer prices that reward sustainability.

But all that is just the beginning of the story,

because this handful of fishing villages taking action

has sparked a marine conservation revolution

that has spread over thousands of miles,

impacting hundreds of thousands of people.

Today in Madagascar, hundreds of sites are managed by communities

applying this human rights-based approach to conservation

to all kinds of fisheries, from mud crabs to mackerel.

The model has crossed borders through East Africa and the Indian Ocean

and is now island-hopping into Southeast Asia.

From Tanzania to Timor-Leste, from India to Indonesia,

we're seeing the same story unfold:

that when we design it right,

marine conservation reaps dividends that go far beyond protecting nature,

improving catches

and driving waves of social change along entire coastlines,

strengthening confidence, cooperation

and the resilience of communities to face the injustice of poverty

and climate change.

I've been privileged to spend my career

catalyzing and connecting these movements throughout the tropics,

and I've learned that as conservationists,

our goal must be to win at scale,

not just to lose more slowly.

We need to step up to this global opportunity

to rebuild fisheries:

with field workers to stand with communities

and connect them, to support them to act and learn from one another;

with governments and lawyers standing with communities

to secure their rights to manage their fisheries;

prioritizing local food and job security

above all competing interests in the ocean economy;

ending subsidies for grotesquely overcapitalized industrial fleets

and keeping those industrial and foreign vessels

out of coastal waters.

We need agile data systems

that put science in the hands of communities

to optimize conservation to the target species or habitat.

We need development agencies, donors and the conservation establishment

to raise their ambition to the scale of investment

urgently required to deliver this vision.

And to get there,

we all need to reimagine marine conservation

as a narrative of abundance and empowerment,

not of austerity and alienation;

a movement guided by the people who depend on healthy seas for their survival,

not by abstract scientific values.

Of course, fixing overfishing is just one step to fixing our oceans.

The horrors of warming, acidification and pollution grow each day.

But it's a big step.

It's one we can take today,

and it's one that will give a much-needed boost

to those exploring scalable solutions

to other dimensions of our ocean emergency.

Our success propels theirs.

If we throw up our hands in despair,

it's game over.

We solve these challenges by taking them on one by one.

Our overwhelming dependence on our ocean is the solution

that has been hiding in plain sight,

because there's nothing small about small-scale fishers.

They're a hundred million strong and provide nutrition to billions.

It's this army of everyday conservationists

who have the most at stake.

Only they have the knowledge and global reach needed

to reshape our relationship with our oceans.

Helping them achieve this is the most powerful thing we can do

to keep our oceans alive.

Thank you.

(Applause)