BUENOS AIRES — One of the most potent signs of Peru's growing prestige and cultural weight may be the spread of its food, and especially ceviche, the raw fish salad relished by gourmets the world over. Here in Buenos Aires, it may even threaten the rule of an earlier international arrival: sushi.

Author Gabriel Rotbaum, who has a Peruvian wife, writes in De la nostalgia al orgullo(From Nostalgia to Pride) that Peruvian cuisine has become a veritable trend, and it's no accident that ceviche has barged its way onto menus in the trendy Palermo district, where sushi has been a favorite in recent decades.

"I had stopped entering Peruvian eateries because they were always closed with the curtains down," he says. "Then I realized the restaurants were for their own community. There are about 30 of them in a five-block radius of the Abasto area in central Buenos Aires."

He says Peruvians began to migrate to Buenos Aires in earnest in the 1990s, trickling in almost one at a time. "In food terms, we've come halfway," Rotbaum says. "There are about 350,000 Peruvians in Argentina, the vast majority living in the capital and its environs." Migrants, he adds, try to ease their move away from home, "and food is crucial to that."

That could be a problem for sushi, which up to now has occupied the capital's fascinating foreign food seat. It is indeed the "love of the exotic" that has taken Argentine diners to Peruvian food, Rotbaum says, "as happened before with other ethnic foods." The exotic element has market value, he says. "Now you have Peruvian restaurants in Palermo charging between 300 and 500 pesos (roughly 18-20 euros) per head. You can get a Peruvian meal, a traditional dish, for about 70 pesos here in Abasto."

Ceviche? No, mainly chicken. "Chicken is the most traditional Peruvian meal," Rotbaum says. "The thing with food is it's more firmly tied to social class than nationality. Buenos Aires society was fairly hostile to Latin Americans migrating here, even if society has changed since the 1990s." And, he notes, "I don't know if any place in Palermo will serve you a Peruvian-marinated chicken."

But you'll get ceviche for sure. It's increasingly seen on fusion-type menus in Palermo, though like sushi, it remains a starter rather than a main dish.

Buenos Aires is the city with the most Peruvian restaurants outside of Peru: 250. Rotbaum observes that, curiously, Peruvian food is indebted to Japanese cuisine, which arrived in Peru with Japanese migrants at the turn of the 20th century. "The Japanese brought Peruvian cooking the experience of learning to work fish and giving it a new identity," he says. And in Buenos Aires, sushi paved the way. "Who would have eaten raw fish before?" he asks.

What's next in Argentina, I ask Rotbaum. "Mexican food, but not tacos," he says. "Mexican cuisine has 300 national dishes. We just eat the tacos."

So is that the end of sushi? No, he says, "because sushi has now become a take-away dish, and that's crucial for settling in."