When Theodore C. Bestor haunts the wharves of New England and the Tsukiji Wholesale Seafood Market in Tokyo, he's not just looking for really fresh fish.

What the Cornell University social anthropologist is learning about Japanese expectations for imported seafood may aid the U.S. trade balance. And he could make the arrival of the "perfect" tuna a more regular occurrence for Japanese sushi chefs.

"Reliable air freight -- the jet transport of fresh seafood -- changed everything in the past 10 to 15 years," said Bestor, associate professor of anthropology in Cornell's College of Arts and Sciences and acting director of the university's East Asia Program. "Narita International Airport is now considered Japan's leading fishing port and a major commodity is jumbo Atlantic bluefin tuna from Cape Cod, Montauk or Spain's Canary Islands. Japanese buyers have made connections in the U.S. and American fishermen have discovered where to get top yen for their catches, but there's still plenty of room for misunderstanding."

Japan's appetite for sushi has propelled tuna prices into the stratosphere, and because Japanese fishermen cannot fish within America's 200-mile limit, American fishermen from New Jersey to the Gulf of Maine are scrambling for the bonanza. A prime tuna at the Tsukiji (pronounced "skee-jee") market is worth a small fortune. A recent record is $90,000 for a single, spectacular bluefin, and auction prices of $10,000 to $15,000 are not unusual.

"For an American fisherman, hitting a couple of good tuna a year can put a new roof on the house or a new pickup in the garage," Bestor observed. But if Americans want to keep more of the $10,000-per-fish in their pockets, by cutting out the middleman and dealing directly with Japanese markets, they need to learn about culture as well as tuna, the anthropologist believes.

"The differences between fish and the 'ideal' fish are not recognizable to most American eyes. We are accustomed to eating fish fried and broiled with sauces and oils that can disguise the differences," Bestor said. "To us, it doesn't matter if the fish was caught yesterday or three days ago, but it does when a Japanese consumer is eating the fish raw and unadorned."

Wholesale buyers at the Tsukiji market, where $7.8 billion worth of fish changed hands in 1994, are particularly choosy, the anthropologist learned. They sniff, they taste and they press the flesh of the bluefin between their fingers to find the ideal fat content. They look for the proper color and structure of the fish, which is sliced at the tail to offer a "window" on its entire inside.

But external appearance is at least as important, Bestor notes as he tries to explain the Japanese concept of kata to American fishermen.

"Kata is the notion of the ideal form. It is the ideal of a flawless specimen of silver salmon or a shipment of lobster that is perfectly matched in color, weight and claw size," he said. "Kata also is the process that results in an ideal outcome -- the fluid and precise moves of a master sushi chef as he fillets a block of tuna," Bestor said, "or the way he arranges a tray of sea urchin roe." (Virtually all sushi chefs are men in Japan, the anthropologist adds. "Some Japanese explain this by saying that a woman's hands are warmer and would spoil the raw fish.")

"We would say, 'You're going to cut the thing up! What does it matter if its shape isn't perfect?' But it does matter. Anything not ideal is regarded as slightly substandard," Bestor said. "Many Japanese consumers are uneasy about fresh food and they shop with 'nervous eyes.' Even blemishes having no possible link to nutritional value -- if the cherry stems aren't uniform in length, if the cucumbers aren't straight or the fish's tail is scarred -- are cause for rejection."

Japanese standards for the kata of tuna may seem as arbitrary as the ideal number of spots on a purebred dog, the anthropologist said. Some may have their basis in the facts of tuna biology: If the color of tuna is "off," for example, it may have been feeding on less-than-optimum food in the ocean or may suffer from internal parasites.

"But whether there is an external 'objective' fact behind the evaluation of tuna or not, if Japanese buyers and consumers have clear preferences for certain kinds of tuna, these standards become facts," Bestor emphasized. "American fishermen have to learn what those cultural facts are."

This notion is difficult to convey to veteran American fishermen, Bestor said. "Thirty and 40 years ago when some of them started, tuna was sold for cat food at seven cents a pound."

Tuna isn't just cat food anymore, and seafood ranks among the top sources of export income (along with lumber, wheat and commercial aircraft) in U.S. trade with Japan. So the anthropologist reports his findings in the American fisheries trade press.

He also guides U.S. trade missions to Japan and Korea. In one mission last year with representatives of 12 American seafood suppliers, two-thirds had never done business with Asian buyers before and they were eager to explore what potential customers wanted.

"The American suppliers saw that the Japanese buyers weren't kidding. Tokyo is full of perfect seafood, and if they are going to compete, they have to meet the standards. This is not a scheme to beat the prices down. This is the search for highly uniform products that meet the ideal of perfection."

Bestor didn't start out to practice "applied anthropology." His interest in the strategies people use to maintain equitable and stable social order in highly competitive economic environments originally led him to the Tsukiji market. In research funded by the National Science Foundation, he studied the time-tested system of seafood auctions and sales that occupy 60,000 sellers and buyers every business day and feed 22 million residents of metropolitan Tokyo.

Then he began to learn why American seafood has trouble in Japanese markets. Bestor heard complaints of Alaska salmon scarred by pitchfork handling and California lobster tails so varied in size that they would have caused an envious uproar at the Japanese wedding banquet. ("Lobster claws are never served because they resemble scissors, and it's bad form to mention anything that can cut at a wedding," he said.)

Subsequent research in Japanese seafood markets and in American fisheries, as well as his education and outreach efforts, are supported in part by the New York Sea Grant Institute. Teaching at Cornell, he covers urban markets and the organization of food supplies in the course "Anthropology of the City." He also leads an Anthropology Department freshman writing seminar on food and culture, "You Are What You Eat."

"If I can improve Americans' understanding of what is expected from exported seafood and help build trusting, balanced trading relationships where profits are more evenly distributed, I'll be happy," Bestor said.

In the meantime, he added "I've learned where to get the best sushi in Tokyo at 5 a.m."