At Athens Grill in Riverhead, the moussaka is made with...

At Athens Grill in Riverhead, the moussaka is made with both ground beef and lamb. (April 20, 2012) Credit: Newsday/Erica Marcus

It was Friday night, I was at a Greek restaurant and I was jonesing for fish. The menu at Athens Grill in Riverhead, however, offered grilled sardines as an appetizer, Pacific halibut as a main and that was it. Where, I wondered, was the whole grilled branzino, the sauteed tilapia, the herb-crusted salmon, to name a few of the usual seafood suspects one typically encounters in Mediterranean restaurants?

We ordered the sardines and they were fantastic, as was a very correct Greek country salad, made with cucumbers, onions, cherry tomatoes (surprisingly flavorful) and creamy, barrel-aged feta. I snagged a welcome taste of my companion’s lamb “porterhouses” (what we used to call loin chops). For my own main, I went for the moussaka, which was sweet with  vegetables and meat, topped with a thick layer of creamy béchamel.

A few days later, I got chef-owner John Mantzopoulos on the phone, and the first thing I asked him was “What, no salmon?” Mantzopoulos responded that although there had been wild Pacific salmon in the market that week, it was too expensive. “What, no farmed salmon?” was my follow-up. No, Mantzopoulos doesn’t serve farmed salmon. He doesn’t serve any farmed fish, and that’s why neither tilapia nor branzino graces his menu.

“I try to buy whatever is running,” he said. “For the last two weeks, the halibut from Alaska has been great. This time of year — before a lot of local fish starts — it’s tough.” Mantzopoulos lives in Greenport, and his favored fish routine is to swing by Southold Seafood on the way to work to see what the local fishermen have landed. “In a few weeks, it’s going to be whole porgy, red snapper, striped bass, whiting,” he promised.

Mantzopoulos opened Athens Grill in 2005 and has been slowly shifting the focus away from souvlaki and mass-market gryros and toward the simple, clear flavors of his native Greece as well as the Mediterranean cuisines of Italy, France, Spain and North Africa. “I've been fighting this gyro thing for the past two years,“ he said. “Now, I only serve it for lunch.“

Athens Grill is at 33 E Main St., Riverhead, 631-727-1301.