A Fish-Finding Mission

Tourists bring them home as travel keepsakes. But for ecologists tracking fish populations, menus are serving a wider purpose.

Menus taken as souvenirs from seafood restaurants in Hawaii have helped a team of researchers glean important insights into the historical trajectory of the state’s fisheries.

A critical part of that history—a span of forty-five years in the middle of the twentieth century—is obscured by the lack of official records.

“Market surveys and government statistics are the traditional sources for tracking fisheries,” says Kyle Van Houtan Ph.D. ’06, coauthor of the study and an adjunct professor at Duke’s Nicholas School of the Environment. “But when those records don’t exist, we have to be more creative.”

Van Houtan and his colleagues believed that restaurant menus could be a useful indicator of the local supply of ocean fish during Hawaii’s undocumented period. To test that assumption, they gathered a sample of 376 menus dating from 1928 to 1974. Most came from private collectors and library archives, preserved more for their beautiful artwork than their historical or scientific value. Together, the menus illustrate that the prevalence of certain types of fish over others as restaurant dishes likely coincided with their relative abundance in the wild.

For example, reef and other near-shore fish were once a staple of restaurants in the early 1900s. By the time Hawaii was admitted as a state in 1959, however, they composed less than 10 percent of all seafood offerings. Pelagic species like tuna and swordfish, their ocean stocks swelling, quickly grabbed the top spots as menu items. In fact, 95 percent of the menus sampled from 1970 onward featured some variety of these large, offshore fish. Populations of reef fish, by comparison, were in precipitous decline. While still the delight of snorkelers, they have become a rarity in the seafood kitchen. Van Houtan and his fellow ecologists acknowledge that changing tastes probably account for at least some of the evolution in the menus they looked at. Additionally, everything from market dynamics to ocean currents can affect which fish the consumer can order and when. Still, the researchers are convinced that seafood consumption in Hawaii historically has had as much to do with supply as demand. They hope their study encourages other scientists, across disciplines, to seek similar kinds of alternative sources to use with hard data.