Eat More Fish. The Right Fish. Here’s How.

At the sloping end of Barton Seaver's quiet street in South Freeport, Maine, floats the Freeport Town Wharf. Seaver—director of Harvard University's Sustainable Seafood and Health Initiative, National Geographic Fellow, and former chef-restaurateur—can walk five minutes down to the pier, cast a hooked line into the Harraseeket River, and head home with flopping-fresh alewife, a type of herring, to hot-smoke with applewood on the backyard grill. You've probably never heard of alewife, and that's the problem.

If his line were long enough to stretch out through Casco Bay and into the Gulf of Maine, Seaver could hook a pearl-fleshed, succulent cod. But the latest data make it unlikely, and even illegal: Federal scientists estimated last fall that Gulf of Maine cod had dropped to a scant 3% or 4% of its target population levels, a historic low. Commercial fishermen saw a major revenue stream run dry as regulators consequently slashed the Gulf's legal cod catch by 75% through most of 2015 and banned recreational cod fishing outright.

The New England cod crisis is local (and nothing new), one story among many about the plight of threatened fish stocks worldwide. For centuries, we've feasted on a slight fraction of the tens of thousands of fish species swimming in the seas. "We've told the oceans what we're willing to eat rather than ask what they're willing to provide," Seaver says. We demanded New England cod, bluefin tuna, snapper, and grouper, and right down every link of the commercial food chain, fishermen, wholesalers, chefs, and retailers complied. So sustainability—fish caught or farmed with minimal harm to the ocean, responsibly managed for us to enjoy for generations—suffers.

For home cooks, fish is an infrequent investment, often pricey, and Seaver understands the reluctance to shell out for something different. "You're going to go with what you know."

Indeed, fishermen chase what pays. "People know just a few—salmon, swordfish, bass," says Wayne Samiere, CEO of Hawaii-based Honolulu Fish Company and a former marine biologist. "There are millions and millions of pounds of great eating fish out there. We don't harvest them because no one has asked us to."

Seaver says it'll take courage from retailers and chefs—tastemakers with the power to create consumer cravings for lesser-known yet sustainable species like dogfish and Acadian redfish (often called "trash fish" because fishermen can't find a market for them). They may not become regular fish-counter fare for many years, he says. Still, change is under way.

Consider herring—a smaller fish that's sweet, aromatic, and richly flavored, like sardines. For years it was mostly sold canned, pickled, smoked, or slathered with sour cream in a deli case. New England fishermen relegated reeking, sun-baked barrels of herring to lobster bait.

"We started getting calls from chefs for fresh herring in 2012," says Nick Branchina, marketing director for Browne Trading Company in Portland, Maine, a specialty seafood retailer and wholesaler for the likes of Manhattan's legendary seafood restaurant Le Bernardin. "When we first tried to buy it from the fishermen, we were laughed off the dock."

But progressive chefs knew fresh-cooked herring was delicious, diners agreed, and retailers now see growing demand for the fish, which fishing boats net sustainably in the Northwest Atlantic. What's more, fishermen can sell pristine herring for six times more as a gourmet ingredient than lobster chum. "We have to sustain fishermen as much as fish," Seaver says.

Samiere sees similarities with monchong (aka pomfret), a Pacific bycatch species he calls "massively abundant." Bycatch is accidental by definition: It snags in the nets and lines of commercial boats targeting other species. Until recently, fishermen just threw the dead bycatch overboard. Now they can find paying markets for it, and if the particular bycatch population is healthy, that's a small win for fishermen, sustainability, and diners.

Chefs and distributors like Samiere are leading the way. Some chefs are going beyond promoting; they're policing. New concerns about Atlantic wild striped bass populations led 10 big-name American chefs to launch the #saveourstripers campaign in May, reducing demand and boosting awareness by taking stripers off their menus.

Now it's time for consumers to take action. Here's how to make a difference as a home cook: Check the latest intel from reliable seafood advocacy groups (see "Go with the Current," left), ask smart questions at the fish counter, and be adventurous. "As fishermen are charged with responsible harvesting," Seaver says, "we're responsible to try something new and to use our creativity to sustain oceans and fishermen.