The growth of bluefin tuna ranching, an aquaculture technique promoted as a way of alleviating pressure on wild bluefin populations, has largely wiped out the local sardine season.
As recently as five years ago, local sardines were available for three summer months. The season slated to start next month may be over within a week, Mashiko owner Hajime Sato says.
"It makes me really sad," Sato says. "Most of the stuff now goes to bluefin ranching."
Foreign bluefin ranches use U.S.-caught sardines to fatten juvenile tuna captured from wild stocks. Many sustainable seafood advocates oppose the practice, believing it feeds the global craving for a severely endangered fish and deprives eaters of healthy, affordable sardines.
"Anything small is good," says Sato, who operates a fully sustainable sushi bar. "I always teach people, if you get confused, smaller fish is better."
Sato this week is featuring local smelt, which just became available. The smelt are still too small to cut for sushi or sashimi, but Mashiko is serving the fish fried whole with a sauce of soy, ponzu, and sesame oil.
Sato says he's eaten smelt at a local high-end restaurant where the kitchen chopped off the fishes' heads.
"Of course, people freak out because there are eyes," Sato says. "But, come on: We should be eating everything. The head and bones have such good flavor."