Trans fats, beef, cheese and soft drinks. Cut back on them, a flurry of health studies have warned. This week’s cautionary report comes from the New York City Department of Health, putting sushi and fish with high-mercury content such as tuna and swordfish on the list. How do the city’s top seafood restaurants respond? It’s not a four-alarm fire, but it has ignited plenty of discussion.

Several New York chefs, while they do not anticipate major menu or ordering changes, said the city study would be talked about in staff meetings before service. That way, wait staff and captains are prepared to answer questions from diners.

“I find it hard to believe we’re going to stop serving tuna in New York,” the chef at the Anthos in Midtown, Michael Psilakis, said. “I think that’s premature. If people stop ordering it, well, then it will be a business decision.”

Mr. Psilakis said the restaurant has plenty of options for those worried about consuming foods with high levels of mercury. “If we’re serving an amuse bouche that might be of concern, the staff knows to alert the kitchen so we can make a switch,” he said, explaining that there are always three options available. “As cooks we’re always dealing with public safety. It’s part of our responsibility and in the industry we’re very aware.”

Tuna is high in mercury, like most big fish, because it has a longer life span than many other fish, and accumulates mercury in its body over time from various sources. In general, the smaller and younger a fish is, the less mercury it has. Cod, sole, trout, and crab have lower mercury contents than big fish. Shrimp, salmon, and anchovies have even less.

Even so, the owner of a 60-seat sushi restaurant, 15 East, near Union Square, Marco Moreira, said his flight of five different cuts is a best seller at $75 — and he doesn’t expect that to change. “I think people will continue to eat it,” he said. “We’ve gone through the media blitz on food before. For a while no one ate red meat, and now everyone eats beef.”

The chef and co-owner of the renowned seafood restaurant, Le Bernardin in Midtown, Eric Ripert, had eliminated most of the big fish with the highest levels of mercury — they include Chilean sea bass, grouper, blue fin tuna, and shark — from his repertoire, well before the city study was released. He no longer serves those fish — not because of their mercury content, but because they are endangered.

The only high-mercury fish on Mr. Ripert’s menu is the yellowfin tuna. He touted the city study, adding: “Something like this is good because it proves we need to do something about pollution, and to protect the environment.”

For now, Mr. Ripert said ordering fish is another case of “everything in moderation.” He noted: “If it was some kind of ‘mad fish’ disease it would be a different story altogether.”