It's known as the king of sushi in Japan

for its color and texture.

Some of the highest-quality bluefin

are auctioned for millions of dollars

at the Toyosu Market in Tokyo.

At almost 4 million square feet,

the market is a one-stop shop for fish

from all over the world.

Here, tuna is sliced, packaged,

and sold to high-end clientele and grocery stores alike.

But before it's sold, experts must first bid

on the top-tier tuna, which can go for millions.

In 2019, a Japanese restaurant chain paid over $3 million

for a 612-pound tuna.

And at the center of this action are expert tuna scouters

like Takayuki Shinoda.

He's a naka-oroshi, or intermediate wholesaler.

His job is to select the best tuna from around the world

for his customers.

Narrator: But the future of Takayuki's job is in jeopardy.

The population of bluefin tuna

is down 97% over the last decade,

which means there will be less of a need

for naka-oroshi like Takayuki.

Narrator: Takayuki has been a naka-oroshi for 30 years.

Narrator: For him, work starts at 4:30 a.m.

At Toyosu Market,

there's no such thing as a normal business day.

Octopus and squid arrive a day earlier.

Fresh fish like horse mackerel and sardines

come in before midnight.

And truckloads of tuna are dropped off every hour.

Narrator: That's almost $13 million.

And tuna is the market's most popular product.

Each day, the fish make their way from the boat decks

to the auction floor.

But it's more than just the type of tuna you find in a can.

There's bigeye tuna, ideal for sushi and sashimi,

yellowfin tuna, perfect for grilling at restaurants

due to its high fat content,

but most bidders are here for the bluefin.

Between 3 and 5 a.m., wholesale employees lay out tuna

one by one.

Bidders like Takayuki have about 15 minutes

to evaluate dozens of fresh tuna before the auction begins.

Sushi restaurants, supermarkets, and department stores

all depend on naka-oroshi like him.

Takayuki looks at the quality and cost.

Narrator: Any sort of nick or flesh wound

can lower the price by thousands of dollars.

When tuna is reeled in, it can wriggle and writhe,

causing a chemical reaction in the muscles.

The movement speeds up decomposition

and makes tuna sour, soggy, and less tasty.

Narrator: When the bell rings, the bidding begins.

A range of hand signals, known as teyari,

are used to place bids.

An index finger for one and two fingers for two.

But whether that's 1,100 yen a pound or 12,000

depends on the type of fish being auctioned.

In just 10 minutes, the auction's over,

and winning bidders claim their prizes.

Narrator: The tuna then makes its way from the auction floor

to the intermediate wholesale building for filleting.

Toyosu keeps the temperature

between 50.9 and 77 degrees Fahrenheit

to slow decomposition.

Wholesalers also rely on a fleet of small trucks

known as turrets.

They zip through winding corridors

to minimize how long the fish are exposed to air.

Narrator: The Ishiji team works as a unit

to move the heavy tuna onto the cutting table.

To prepare the tuna for cutting, first they wash it,

then remove the ice.

Narrator: Most of Takayuki's high-end customers care about two things

when it comes to raw bluefin tuna: color and taste.

Narrator: It's then brought inside the shop,

where it's divided and filleted.

Customers show up early to get the first pick.

Narrator: Not a single part of the tuna is wasted. Even its eyes.

Narrator: Customers have relied on the market's

high-quality fish products for decades.

Before the market moved to its new location

and was renamed Toyosu, it was known as the Tsukiji market.

Narrator: Tsukiji was the epicenter of seafood.

Its success spurred demand for all types of fish.

Fishing for bluefin tuna in the Western Atlantic

rose by over 2,000% in 1970.

But it was difficult for the market to keep up.

Narrator: Meanwhile, Japanese tuna consumption

was growing significantly.

Narrator: Japan has since placed a quota

on the number of bluefin tuna caught.

But it's a double-edged sword for wholesalers like Takayuki.