Like "tree-huggers," we fish-huggers are concerned about the environment, specifically the impact of factory trawlers, bottom draggers, the problem of bycatch (e.g., dolphins caught in tuna nets) and industrialized aquaculture. We worry about the byproducts of bad fisheries management or farming, including mercury, antibiotics and colorants in fish. We want to save the fish so we can ... eat them. A little self-interest can, environmentally speaking, be a good thing.

The new book "Fish Forever" by Paul Johnson (Wiley, 2007) is a comprehensive guide to selecting environmentally sustainable fish. Johnson, who operates the Monterey Fish Market in California and who sits on the board of the Seafood Watch program of the Monterey Bay Aquarium, also addresses health issues like mercury and PCBs, parasites, food-borne illnesses and cholesterol content. With this book, we can make not only environmentally sound choices but healthful ones. Not to mention tasty ones - Johnson is a former chef and offers many enticing recipes.

There's a lot to digest (pun intended) in this volume, and an attempt to summarize is doomed to failure. However, the key points are: Be informed and be flexible.

Be informed: Fish sold in the United States must have a country-of-origin label, and many reputable fish markets can now tell you where and how the fish was captured or cultured, and whether it is wild or farmed. But you need to be able to put that in context; farm-raised catfish, for example, is a sustainable wonder, while farm-raised salmon (with the exception of a few "artisan" farms) is not. When it comes to buying shrimp, it's wise to "buy American" owing to bad fish-farming practices in Southeast Asia and Latin America, but grouper from New Zealand is a sound choice. Johnson's book helps sort through these myriad issues. Another source is the Monterey Bay Aquarium Seafood Watch Program at www.mbayaq.org.

Be flexible: If you want to buy healthy, sustainable caught or farmed fish, resign yourself to the fact that many are seasonal. Therefore, if you show up at the supermarket set on buying fresh Alaskan halibut in January, you are going to be disappointed. "Plan your meal around what's fresh at the market that day," counsels Johnson. This is irritating advice to the harried home cook, but consider taking the book with you when shopping for fish. When you find a good choice, you can look up a recipe and know what other ingredients to buy.

Be flexible, part two: Be willing to try alternative, underutilized, well-farmed and well-regulated fish: catfish, for example; also Manila clams (hard-shell clams that are farmed), Boston or Pacific mackerel (high in healthful omega-3 fatty acids, harvested by methods that produce little bycatch or habitat degradation); butterfish (plentiful and underutilized); or black sea bass (now well regulated, parasite-free and not known for accumulating pollutants).

Here are two recipes from Johnson's book. Fish-huggers, rejoice.

PORTUGUESE CLAM BOIL WITH CHORICO AND KALE

1 pound tomatoes

1/4 cup olive oil

1/2 pound chorico (also sold as chorizo) or linguica sausage

1 onion, peeled and chopped

1 red bell pepper, stemmed, seeded and chopped

1 cup dry white wine or white vermouth

1 tablespoon white-wine vinegar

1 pound young kale, chopped

1 large garnet yam, peeled and cut into 1/2-inch pieces (about 1 and 1/2 cups)

3 cups water

4 pounds small hard-shell clams

lemon wedges and chopped fresh cilantro, for garnish

With a sharp knife, cut an X into the bottoms of the skins of the tomatoes. Bring a pot of water to a boil, and boil the tomatoes for 30 to 60 seconds, until the skin begins to loosen. Remove with a slotted spoon and drain. When cool enough to handle, slip off the skins and quarter the tomatoes, removing the seeds. Chop the flesh and set aside.

In a large, heavy pot, heat the oil over medium-high heat and brown the sausages on all sides, 3 to 4 minutes. Transfer to a platter and set aside. Add the onion and bell pepper and cook, stirring, for 2 to 3 minutes. Add the tomatoes, wine (or vermouth) and vinegar, and cook for 3 to 4 minutes. Add the kale, yam and water. Bring to a simmer and cook for 10 minutes.

Meanwhile, scrub the clams under cold running water to remove any dirt. Discard any open clams and add the rest to the pot. Return to a simmer, cover, and cook until the yams are tender and the clams open, 3 to 8 minutes, depending on the clam (Manilas take little time, littlenecks take longer). Slice the sausages into 1/2-inch rounds and return them to the pot. Heat through. Discard any clams that have not opened. Serve in bowls, garnished with a lemon wedge and cilantro.

Yield: 4 servings

Recipe from "Fish Forever" by Paul Johnson (Wiley, 2007)

BLACK-SEA-BASS FILLETS WITH LEMON, OLIVES AND ARTICHOKES

8 small artichokes

1/4 cup all-purpose flour

1-1/2 teaspoons kosher salt

1/4 teaspoon freshly ground black pepper

1 cup good-quality green olives, such as picholines or lucques

2 lemons, preferably organic, scrubbed

4 tablespoons olive oil

2 cloves garlic, peeled and minced

1 teaspoon minced fresh thyme

1 tablespoon minced fresh flat-leaf parsley

1/2 cup dry white wine or white vermouth

4 (5-ounce) black-sea-bass fillets

splash of extra-virgin olive oil, for serving

Bring a medium saucepan of water to a boil. Snap off the tough outer leaves of each artichoke and trim off the top inch of the remaining leaves. Remove the stems and trim the bottoms. Place in the boiling water and cook until tender, about 10 minutes. Drain. Cut the artichokes in half and scrape out the fuzzy "choke" with a teaspoon. If the pieces are larger than bite-sized, cut them in half again.

In a shallow dish, mix together the flour, salt and pepper. Set aside.

Smash the olives with the side of a chef's knife and remove the pits. Set aside.

Trim the ends off one lemon and cut in half lengthwise. Slice the lemon as thinly as possible into half-moon shapes, removing any seeds.

In a small skillet, heat 2 tablespoons of the olive oil over high heat. Pat the artichokes dry and cook, stirring, for 2 to 3 minutes, until browned and crispy at the edges. Reduce heat to medium, add the garlic and cook for 1 minute. Add the lemon slices, olives, thyme and parsley. Then add the juice from the remaining lemon and the wine (or vermouth). Simmer for 2 minutes and set aside.

In a large skillet, heat the remaining 2 tablespoons olive oil over high heat. Dredge the fillets in the seasoned flour and cook for 2 minutes on one side to brown. Turn the fish over and add the artichoke mixture to the pan. Reduce heat to low and simmer gently for about 5 minutes, while spooning the liquids over the fish. Just before serving, add a good splash of your best extra-virgin olive oil.

Yield: 4 servings

Recipe from "Fish Forever" by Paul Johnson (Wiley, 2007)

Marialisa Calta is the author of "Barbarians at the Plate: Taming and Feeding the American Family" (Perigee, 2005). For more information, go to www.marialisacalta.com.