The Story of Sushi: An Unlikely Saga of Raw Fish and Rice

by Trevor Corson

most yellowtail was shipped headless to save weight.

But the edges of some pieces were dark purple—a sure sign of the presence of iron, and the machinery for employing oxygen for endurance swimming.

baby flatfish swims around looking like a regular fish. It must come as a rude shock when, over the course of just a few days, its cranium, brain, jaw, nose, and eye sockets all suddenly rotate over to one side.

flatfish have less

flavor than most other fish. They don’t get much exercise. They spend most of their time lying around impersonating sand.

While most flatfish muscle lacks a high concentration of flavor elements, it does contain a variety of interesting amino acids.

Eel muscle contains too much collagen—the tough connective tissue—to eat raw.

Cooking gelatinizes the collagen.

emit slime, though slime is actually a sign of clean living, since the mucus protects the eels against bacteria.

Octopus and squid are invertebrates, so they have no bones. To compensate, they hold their muscles together with a tough matrix

of reinforced collagen—three to five times more collagen than fish.

The muscle fibers of octopus and squid are also thin and densely packed, and the animals don’t store fat. Instead, they continue to build muscle, gro...

Octopus and squid once possessed shells. A few hundred million years ago, they looked much like today’s na...

a shell and that uses a bubble of gas inside the shell to stay afloat. Octopus, squid, and nautilus are called cephalopods, which means “head-foot.” Shells offered early cephalopods some protection. But new predators evolved, notably sharks and bony fi...

the water overwhelms its gas bubble and its shell implodes. Shells turned...

The ancestors of octopus and squid lost their shells and gained the ability to escape into the depths. Instead of floating on a bubble of gas, they evolved into muscular swim...

All that swimming required more food, so they evolved into hunters with keen s...

by the time a live octopus goes on sale, the fisherman or fishmonger has usually sliced out the animal’s internal organs. Despite losing its guts, the octopus continues to move around in its tub of water.

This is possible because each of an octopus’s eight tentacles possesses its own brain. These ganglia receive a single command from the primary brain—such as “grab that crab”—and then execute an entire subroutine of action independent of the primary brain’s control. The tentacles require their own brains because their movements are so complex. Lacking a skeletal structure, each tentacle is capable

of infinite degrees and directions...

Like fish, cephalopods counteract the osmotic pressure of the salty ocean by filling their cells partly with free amino acids, but mostly with the amine TMAO, which is tasteless.

Another component they contain in substantial amounts is taurine,

popularly thought to impart strength and virility, and often obtained from ox bile. Taurin was a...

A bluefin tuna can grow to weigh 1,500 pounds. Bluefin inhabit cold waters and their bodies can be up to 15 percent fat, depending on the region and season. Bigeye are smaller, and live in temperate and tropical waters. Yet they swim deep, where the water is relatively chilly, and thus can accumulate up to 8 percent fat. Yellowfin

tuna are about the same size as bigeye. They inhabit warmer waters, and accumulate only about 2 percent fat.

all tuna flesh is red meat.

Bluefin in particular are the reddest.

They are a...

fastest fish in ...

Warm-blooded creatures routinely move and react faster

That worked out to nearly $400 per pound. To be sure, that had been an absurdly extravagant bid, for the best of the best—a winter bluefin caught in the waters near Japan, a type of fish

that accounts for less than 1 percent of the global tuna catch. Moreover, the purchase had been the buyer’s way of celebrating the first day of business in the new millennium, with an ostentatious show of wealth. Even the ridiculously expensive fresh tuna, though, have a drawback—it’s possible for them to be too fresh. After an animal dies, its muscles still live. Muscle

cells contain a local supply of fuel, in the form of crystals of stored sugar called glycogen. Enzymes in the muscle continue to use and break down this fuel. Eating a fish too soon after death is like eating it while it’s still alive. The muscles are still functional. They are firmly bound together and remain r...

Fancy restaurants and sushi shops that serve “fresh kill” sushi from tanks of live fish are not doing their customers any favors. The only sea creatures worth eating straight from the fish tank are eels, squid, and some shellfish—such as giant clam. When the glycogen fuel runs out, the muscles finally fail...

worse to eat. This state is called rigor mortis. But the enzymes in the muscle keep functioning, and begin to digest the proteins that make up the muscles themselves. The meat softens, and the proteins break down into the smaller compounds that provide flavor, such as glutamate and IMP. Beef doesn’t...

after slaughter. Beef producers often age their meat even longer, to allo...

Fish generally need between eight and twenty-four hours after death to develop flavor. Fish flesh ages much more rapidly than the flesh of terrestrial animals—and spoils more quickly—because fish are cold-blooded....

to those in a refrigerator. By contrast, the enzymes of warm-blooded mammals slow down when the flesh cools. Bluefin tuna, however, are warm-blooded and very large, so after they’re killed they take longer to age than other fish. Generally,...

For the sushi chef, bluefin epitomize the fundamental contradiction of serving raw fish. If the meat doesn’t age long enough, it won’t develop sufficient taste. But once rigor mortis is past, the meat rapidly loses firmness and texture. With fish, it is

nearly impossible to achieve perfect flavor and perfect texture at the same time. The sushi chef is locked in a delicate dance of timing with armies of enzymes. Instead of cooking, he practices the art of compromise. There are other challenges to tuna. If a big tuna puts up a long struggle before death, its core temperature can rise so high immediately after death that its

meat can literally cook itself, denaturing the proteins even before rigor mortis sets in. The myoglobin in tuna flesh is also highly susceptible to oxidization. When a molecule of myoglobin loses an electron, it turns from bright red to brown. Much of the tuna served at sushi bars in the United States is...

carboxymyoglobin, another bright red molecule. The Japanese government has outlawed this practice, fearing t...

However, the greatest challenge regarding the bluefin doesn’t involve killing them but, rather, keeping them alive. Bluefin mature slowly. That means fishermen can e...

sushi has taken a severe toll on bluefin around the world, though just how badly they are over-fished remains a subject of debate. Environmental groups now recommend that people avoid eating bluefin altogether. Bluefin ranching operations capture bluefin from the ocea...

bigeye tuna mature faster and so their populations are more resilient to fishing, as are yellowfin.

Meanwhile, researchers are learning to breed bluefin in captivity, and are even considering the use of surrogate

parents for bluefin to increase production of bluefin eggs. So far, scientists have succeeded in implanting primordial trout cells into female salmon, causing the salmon to produce not salmon eggs, but trout eggs. When fertilized by trout sperm, the trout eggs from the salmon grow into healthy tro...

more quickly than trout, so as surrogate parents, they can produce trout eggs mor...

“No one buys a whole tuna—too much meat,” Zoran said. “You can ask for sections: semi-back meat, midsection meat, belly meat. You can ask for just toro—for

seventy or eighty dollars a pound. Or you can ask for a whole side of fish, including toro, in which case the price comes down.”