On the coast of Northern Ireland, a vast plateau of basalt slabs and columns called the Giant’s Causeway stretches into the ocean.
The scientific explanation for this is that it’s the result of molten lava contracting and fracturing as it cooled in the wake of a volcanic eruption.
But an ancient Irish myth has a different accounting.
According to legend, the giant Finn MacCool lived happily on the North Antrim coast with his wife Oonagh.
Their only disturbance came from the taunts and threats of the giant Benandonner, or the red man, who lived across the sea in Scotland.
The two roared insults and hurled rocks at each other in dramatic shows of strength.
Once, Finn tore up a great clump of land and heaved it at his rival, but it fell short of reaching land.
Instead, the clump became the Isle of Man, and the crater left from the disturbed earth filled with water to become Lough Neagh.
The giants’ tough talk continued, until one day Benandonner challenged Finn to a fight, face to face.
And so the Irish giant tossed enough boulders into the sea to create a bridge of stepping stones to the Scottish coast.
Finn marched across in a fit of rage.
When Scotland loomed before him, he made out the figure of Benandonner from afar.
Finn was a substantial size, but at the sight of his colossal enemy thundering towards him, his courage faltered.
With one look at Benandonner’s thick neck and crushing fists, Finn turned and ran.
Back home, with Benandonner fast approaching, Finn trembled as he described his enemy’s bulk to Oonagh.
They knew that if he faced Benandonner head on, he’d be crushed.
And so Oonagh hatched a cunning plan - they needed to create an illusion of size, to suggest Finn was a mountain of a man whilst keeping him out of sight.
As Benandonner neared the end of the bridge, Oonagh stuffed her husband in a huge cradle.
Disguised as an enormous baby, Finn lay quiet as Benandonnner pounded on the door.
The house shook as he stepped inside.
Oonagh told the enraged visitor that her husband wasn’t home, but welcomed him to sit and eat while he waited.
When Benandonner tore into the cakes placed before him, he cried out in pain for he’d shattered his teeth on the metal Oonagh had concealed inside.
She told him that this was Finn’s favorite bread, sowing a seed of doubt in Benandonner’s mind that he was any match for his rival.
When Finn let out a squawk, Benandonner’s attention was drawn to the gigantic baby in the corner.
So hefty was the infant swaddled under piles of blankets, Benandonner shuddered at the thought of what the father would look like.
He decided he’d rather not find out.
As he fled, Benandonner tore up the rocks connecting the shores, breaking up the causeway.
What remains are two identical rock formations: one on the North Antrim coast of Ireland and one at Fingal’s Cave in Scotland, right across the sea.
If you were to jump into any random spot in the ocean, you would probably see something like this.
Empty of large animals.
Because we have taken them out of the water faster than they can reproduce.
Today I want to propose a strategy to save ocean life, and the solution has a lot to do with economics.
In 1999, a little place called Cabo Pulmo in Mexico was an underwater desert.
The fishermen were so upset not having enough fish to catch that they did something that no one expected.
Instead of spending more time at sea, trying to catch the few fish left, they stopped fishing completely.
They created a national park in the sea.
A no-take marine reserve.
When we returned, 10 years later, this is what we saw.
What had been an underwater barren was now a kaleidoscope of life and color.
We saw it back to pristine in only 10 years.
Including the return of the large predators, like the groupers, the sharks, the jacks.
And those visionary fishermen are making much more money now, from tourism.
Now, when we can align economic needs with conservation, miracles can happen.
And we have seen similar recoveries all over the world.
I spent 20 years studying human impacts in the ocean.
But when I saw firsthand the regeneration of places like Cabo Pulmo, that gave me hope.
So I decided to quit my job as a university professor to dedicate my life to save more ocean places like this.
In the last 10 years, our team at National Geographic Pristine Seas has explored, surveyed and documented some of the wildest places left in the ocean and worked with governments to protect them.
These are all now protected, covering a total area half the size of Canada.
(Applause) These places are the Yellowstones and the Serengetis of the sea.
These are places where you jump in the water and are immediately surrounded by sharks.
(Laughter) And this is good, because the sharks are a good indicator of the health of the ecosystem.
These places are time machines that take us to the ocean of 1,000 years ago.
But they also show us what the future ocean could be like.
Because the ocean has extraordinary regenerative power, we have seen great recovery in just a few years.
We just need to protect many more places at risk so they can become wild and full of life again.
But today, only two percent of the ocean is fully protected from fishing and other activities.
And that's not enough.
Studies suggest that we need at least 30 percent of the ocean under protection not just to save marine life, but to save us, too.
Because the ocean gives us more than half of the oxygen we breathe, food, it absorbs much of the carbon pollution that we throw in the atmosphere.
We need a healthy ocean to survive.
Now, is there a way to accelerate ocean protection?
I think so.
And it involves us looking at the high seas.
Now, what are the high seas?
Now coastal countries have authority over 200 nautical miles from shore.
Everything beyond those areas are called the high seas.
In dark blue on this map.
No country owns the high seas, no country is responsible for them, but they all are, so it's a little like the Wild West.
And there are two main types of fishing in the high seas.
At the bottom and near the surface.
Bottom trawling is the most destructive practice in the world.
Super trawlers, the largest fishing vessels in the ocean, have nets so large that they can hold a dozen 747 jets.
These huge nets destroy everything in their paths -- including deep corals that grow on sea mounds, which can be thousands of years old.
And fishing near the surface targets mostly species that migrate between the high seas and country's waters, like tuna and sharks.
And many of these species are threatened because of too much fishing and bad management.
Now, who fishes in the high seas?
Until now, it was difficult to know exactly, because countries have been very secretive about the long-distance fishing.
But now, satellite technology allows us to track individual boats.
This is a game-changer.
And this is the first time we are presenting the data that you are going to see.
I'm going to show you the tracks of two boats over the course of a year, using a satellite automated identification system.
This is a long-liner, fishing around the southern coast of Africa.
After a few months fishing there, the boat goes to Japan to resupply, and shortly after, here it is, fishing around Madagascar.
This is a Russian trawler fishing, probably, for cod, in Russian waters, and then across the high seas of the north Atlantic.
Thanks to Global Fishing Watch, we have been able to track over 3,600 boats from more than 20 countries, fishing in the high seas.
They use satellite positioning and machine-learning technology to automatically identify if a boat is just sailing or fishing, which are the white spots here.
So with an international group of colleagues, we decided to investigate not only who fishes in the high seas, but who benefits from it.
My colleague, Juan Mayorga, at the University of California, Santa Barbara, has produced detailed maps of fishing effort, which means how much time and fuel is spent fishing in every pixel in the ocean.
We have a map for every country.
China, Taiwan, Japan, Korea and Spain alone account for almost 80 percent of the fishing in the high seas.
When we put all of the countries together, this is what we get.
Because we know the identity of every boat in the database, we know its size, its tonnage, the power of its engines, how many crew are on board.
With this information, we can calculate fuel costs, labor costs, etc.
So for the first time, we have been able to map the costs of fishing in the high seas.
The darker the red, the higher the costs.
Thanks to our colleagues at the University of British Columbia, we know how much every country is actually fishing.
And we know the price of the fish as it comes off the vessel.
Combined with the data on effort, we have been able to map the revenue of fishing the high seas.
The darker the blue, the higher the revenue.
We have costs, and we have revenue.
So for the first time, we have been able to map the profitability of fishing in the high seas.
Now I'm going to show you a map.
Red colors mean we are losing money by fishing in that part of the ocean.
Blue colors mean it's profitable.
Here it is.
It seems mostly profitable.
But there are two more factors we have to take into account.
First, recent investigations reveal the use of forced labor, or slave labor, in high seas fishing.
Companies use it to cut costs, to generate profits.
And second, every year, governments subsidize high seas fishing with more than four billion dollars.
Let's go back to the map of profits.
If we assume fair wages, which means not slave labor, and we remove the subsidies from our calculation, the map turns into this.
Fishing is truly profitable in only half of the high seas fishing grounds.
In fact, on aggregate, subsidies are four times larger than the profits.
So we have five countries doing most of the fishing in the high seas and the economics are dependent on huge government subsidies, and for some countries, on human rights violations.
What this economic analysis reveals, is that practically the entire high seas fishing proposition is misguided.
What sane government would subsidize an industry anchored in exploitation and fundamentally destructive?
And not so profitable, anyway.
So, why don't we close all of the high seas to fishing?
Let's create a giant high seas reserve, two-thirds of the ocean.
A modeling study from -- (Applause) A modeling study from colleagues at UC Santa Barbara, suggests that such reserve would help migratory species like tuna recover in the high seas.
And part of that increased abundance would spill over into the countries' waters, helping to replenish them.
That would also increase the catch in these waters, and so would the profits, because the cost of fishing would be lowered.
And the ecological benefits would be huge, because these species of large predators, like tuna and sharks, are key to the health of the entire ecosystem.
Therefore, protecting the high seas would have ecological, economic and social benefits.
But the truth is that most fishing companies don't care about the environment.
But they would make more money by not fishing in the high seas.
And this would not affect our ability to feed our growing population, because the high seas provide only five percent of the global marine catch, because the high seas are not as productive as near-shore waters.
And most of the catch of the high seas is sold as upscale food items, like tuna sashimi or shark fin soup.
The high seas catch does not contribute to global food security.
So how are we going to do it?
How are we going to protect the high seas?
As we speak, negotiators at the United Nations are beginning discussions on a new agreement to do just that.
But this cannot happen behind closed doors.
This is our greatest opportunity.
And we all should ensure that our countries will support the protection of the high seas and get rid of subsidies to industrial fishing.
In 2016, 24 countries and the European Union agreed to protect the Ross Sea, the wildest places in Antarctica, full of wildlife like killer whales, leopard seals, penguins.
And this included fishing nations, like China, Japan, Spain, Russia.
But they decided that protecting such a unique environment would be worth more than exploiting it for relatively little benefit.
And this is exactly the type of cooperation and willingness to set aside differences that we are going to need.
We can do it again.
If 20 years from now, our children were to jump into any random spot in the ocean, what would they see?
A barren landscape, like much of our seas today, or an abundance of life, our legacy to the future?
Thank you very much.
(Applause) Thank you.
(Applause)