Big is better, we've long been told. Smaller, however, is increasingly proving to be smarter, more sustainable and satisfying when it comes to seafood.

Eco-conscious chefs and home cooks are turning to smaller and lesser-known fish for environmental and health reasons and because they taste good. In so doing, they're reviving interest in sardines, anchovies and herring — a fish trio historically popular but also a nose-wrinkler for a good part of the past century.

Sardines particularly have taken off with chefs. They're turning up on menus across the country.

"Everyone says they have to be politically correct and have to use underutilized species. We say, sardines," said Polly Legendre, culinary director of Clean Fish, a San Francisco company hooking up sustainably run fisheries around the world with American chefs and consumers.

"The sardine is one of the easiest fish to use," she added. "You can grill it, you can do fresh preparations, you can find recipes for it, and it's cheap."

Legendre's job is to change how chefs and consumers think about seafood, moving them toward underutilized fish and eco-friendly fisheries.

"Some people are saying, 'Guess we can't eat our tuna or salmon anymore. Guess we have to eat sardines?' What do you mean have to eat? It's fun," she said. "If you get some fresh sardines, enjoy them. They're fabulous."

Oily fish such as sardines, herrings and anchovies also generate interest because they contain heart-healthy omega-3 fatty acids, said Kate McLaughlin, seafood program director for the Blue Ocean Institute, a conservation group based in East Norwich, N.Y.

Being low on the food chain and living on a diet of plankton, zooplankton and tiny fish, they also carry few of the metals and toxins found in the tissues of larger species. They live relatively short lives and reproduce prodigiously, keeping stocks high.

McLaughlin and Legendre agree the growing consumer buzz on sardines, herring and anchovies is being driven by chefs.

"People will look to a chef, look for guidance, look for OK-ness," Legendre said.

Legendre presents her seafood to chefs as if she's letting them in on a big delicious secret. She thinks chefs have to use the same strategy in approaching customers.

"I've got something awesome and nobody knows about it," she said. "It then becomes cool. Like, 'I, the chef, am letting you, the diner, in on this secret.'"

TURN TO THE PROS

The Monterey Bay Aquarium in California, with its "Seafood Watch," and other aquariums and zoos across the country offer handy wallet guides to help make wise seafood buys. Fish are listed as "best choices," "good alternatives," and "avoid." Monterey's Seafood Watch Program prints seafood guides for every region of the country. These guides are found at seafoodwatch.org, and a free ap can be downloaded to iPhones and the iPod Touch.

The Blue Ocean Institute, a conservation organization based in East Norwich, N.Y., produces a guide with five rankings that details life cycles and sexual maturity of certain fish species, fishing methods used and how the fish affects other species and the aquatic environment. The institute's website is blueocean.org.

The above groups maintain websites and mobile texting services. The Blue Ocean Institute, for example has a "FishPhone" whereby you text "FISH" and the species name to 30644. The answer arrives in less than a minute.

The National Oceanic and Atmospheric Administration has its own seafood facts site called Fish Watch at www.nmfs.noaa.gov/fishwatch.