Rick Moonen In the 1980s, when Rick Moonen was starting out as a chef in New York City, few people thought about how our seafood choices affected the oceans. But year after year, as he worked for some of the city's most prestigious restaurants, Moonen saw the size and quality of the fish he purchased steadily declining.

By 1998, when he was asked to join the "Give Swordfish a Break" campaign, the first large-scale effort to get chefs and consumers involved in fish conservation, he was ready to take action. "I realized that there were some major changes going on," he says. "At the Fulton Fish Market I used to see swordfish that were 200 pounds or more all the time—I used to buy them. But it got to the point where it was more common to find fish that were 100 pounds or less."

He joined the swordfish campaign and went on to become a passionate and vocal advocate for sustainable seafood. Today, at his Las Vegas restaurant, Rick Moonen's rm seafood in the Mandalay Bay Resort and Casino, Moonen works hard to spread the word about the Seafood Watch program and encourages his customers to eat a variety of seafood. "If the ocean collapses, so do we," he says. "We've focused too much on a few fish—we put so much pressure on these species that they become endangered. To me, it's all about diversity—don't have tuna three times a week."

Moonen echoes this idea in his award-winning, 2008 cookbook, Fish Without a Doubt: The Cook's Essential Companion. "I wanted to write a book to help people get more comfortable with fish," he says, "and hopefully they'll start having tilapia once in a while, or barramundi; fish other than tuna, salmon and shrimp." This month's featured recipe for "chicken-fried," trout is a case in point. If trout isn't available, or isn't to your liking, Moonen recommends substituting any freshwater or fairly lean fish such as tilapia, barramundi, pacific cod or halibut.

When he's not cooking, or writing books, Moonen can often be found encouraging other chefs to learn about sustainability and the Seafood Watch program. In Las Vegas, tens of thousands of pounds of shrimp are consumed each day, so there's a lot of work to be done to bring about change. But Moonen is undeterred.

"There's been more of a mentality shift here recently than I saw over the years in New York City; I'm seeing more chefs who are willing to do something. If we can turn Las Vegas into a more sustainable model, no one has an excuse not to follow suit—I kind of like the challenge."