SEATTLE (AP) -- We ate stewed clams and clam chowders and all manner of oysters: creamed oysters on toast, oysters in a chafing dish, pan-roasted oysters, broiled oysters on toast, oyster soups, oyster omelets and a rice-and-tomato-based concoction dubbed "a substantial oyster dish."
When a National Marine Fisheries Service biologist perused a Seattle cookbook from 1906, most of the seafood recipes involved shellfish.
A century later, recipes had moved up the ocean food chain. One random cookbook from 2003 contained 13 salmon recipes, five halibut dinners, three meals of tuna, two requiring steelhead and only one recipe that called for clams.
By studying 120 years of Northwest seafood recipes, biologist Phil Levin stumbled on a pattern: He could follow our changing relationship with the sea by scouring what we eat.
"I think it tells us a lot about the social forces that may be driving current environmental problems," Levin said.
Levin, who works at the Northwest Fisheries Science Center, set about researching seafood history when trying to understand declines in rockfish species, three of which were protected last week under the Endangered Species Act. With so little data about the brightly colored bottom-fish, Levin thought cookbooks might offer insight. They did.
He and a partner collected 3,092 recipes from more than 100 cookbooks published in Oregon and Washington between 1885 and 2007. He found nary a rockfish recipe for most of those years.
In fact, 80 percent of the rockfish meals he found only showed up in cookbooks published after 1980 -- about the same time Northwest fishermen really started targeting groundfish. In retrospect, Levin said, that makes perfect sense.
Before that, "they weren't in the marketplace so there really weren't any recipes," Levin said.
That was just one of the intriguing discoveries Levin made in his study, published this spring in the journal Fish and Fisheries. He also noted that the proportion of shellfish among recipes has declined dramatically -- as have populations of native invertebrates such as oysters and abalone. Meanwhile, the overall variety of creatures found in seafood recipes has exploded as the Northwest becomes more culturally diverse -- and as we've fished for more and different stuff.
Levin found gooseneck-barnacle recipes in one modern Whidbey Island cookbook. "I can distinctly remember recipes for pickled bull kelp and periwinkle stew," he said.
But while scientists around the world have documented declines in top ocean predators and a move by fishermen to seek out smaller species -- a phenomenon some have called "fishing down the food web" -- Northwest cookbooks showed a surprising trend.
In 1903, for example, there were lots of recipes for sardines, anchovies and shrimp -- creatures low on the food chain. But modern recipes focus on much bigger fish such as salmon and halibut, a finding Levin said is not necessarily inconsistent.
"It's a reflection of cultural tastes," Levin said. As seafood high on the ocean food chain grows rarer and more expensive, it often also becomes more sought after.
Levin isn't the first to attempt this type of research. A few years ago, world-renowned ecologist Stuart Pimm, a Duke University professor, found he could track global overfishing by comparing editions of "The Joy of Cooking."
In his well-worn 1974 volume, Pimm found eight recipes for cod, four for haddock and 11 for herring. By the 1997 edition, haddock, cod and herring recipes were virtually absent -- just as those species were in decline around the world.
A new fish recipe was added that year -- for orange roughy, a type of deep sea perch only found near underwater volcanoes called seamounts in the Pacific Ocean. Orange roughy had been discovered in the 1980s and would be fished almost to destruction over the next couple of decades.
"Orange roughy exploded on the scene about the same time Madonna did, but its career didn't last anywhere near as long," Pimm said.
Later volumes of the book replaced orange roughy recipes with Chilean sea bass, another species that has been dramatically overfished in recent years.
Pimm and Levin are quick to note there are limits to the scientific conclusions that can be drawn. Recipes are influenced by economic and political pressures and cultural whimsy, and the sample sizes are quite small. But both said recipes and other cultural touchstones still shed light on the ways our ties to the oceans are changing.
"I love watching that show 'The Deadliest Catch,' " Pimm said. "But if you think about it, going to the heart of the Bering Sea in the middle of winter to catch crab? It's incredibly bloody stupid! But it shows how desperate we are to find fish ever farther afield."