Oct. 23 (Bloomberg) -- Reading a restaurant menu is a prized skill among experienced travelers. Now it's proving valuable to ecologists.

Researchers working to save endangered marine life have unearthed U.S. restaurant menus dating back to the 1850s in a bid to track evolving demands for different types of fish. It's part of a 10-year project to find out what types of fish populated the world's oceans, how fishing practices have affected them, and what can be done to save those have become endangered.

``Previously historians and biologists would have said, `Well, there is no way that we could know' '' fish populations dating back 150 years, said Poul Holm, a professor of history and civilization at the University of Southern Denmark. ``What we have discovered is that it is actually possible.''

Restaurant menus are the latest historical artifact, along with tax records and fishermen's log books, being employed by researchers participating in the international Census of Marine Life, Holm and colleague Glenn Jones of Texas A&M University said in a report presented today at a conference in Denmark.

More than 1,700 scientists from 73 countries are contributing to the $15 million marine census project, designed to assess the diversity, distribution and abundance of ocean life and explain how it changes over time.

Culinary Archives

Their work with the menus demonstrates that prices rise and fall not only with supply, but sometimes with exaggerated effects at times of high demand. That makes clear that conquering human behavior -- specifically the desire to have something unusual -- may be toughening the job of saving endangered species.

``It seems to confirm that many people simply want to eat something that is rare,'' said Jones, a paleo-oceanographer at Texas A&M.

The restaurant menus are critical because they provide one of the oldest and most reliable sets of data on what types of fish were consumed 150 years ago, Jones said. Marine biologists hadn't thought previously to check them, while curators of culinary archives hadn't realized their value, he said.

Records of fish wholesalers also are valuable, but many don't date back as far as the restaurant menus, Jones said. Fishermen's logs are older, though many are unreliable due to the tendency to underreport catches to avoid taxes and penalties, he said.

Abalone

The menus reveal such trends as spikes in the price of abalone on San Francisco menus at the same time stocks of the slow-growing mollusk were decimated along the California coast.

Abalone appeared on the city's menus in the 1920s and its inflation-adjusted price held steady at about $7 in 2004 currency until climbing in the 1930s and 1950s, at periods when it was over-harvested. The price has jumped since then at rates seven to 10 times faster than inflation, the researchers said.

California banned commercial abalone fishing in 1997. Most restaurants import it from Australia and New Zealand, priced at $50 to $70 per plate, the researchers said.

That price history is typical of other endangered fishes, and differs from foods such as chicken, which is mass-produced and has had roughly the same inflation-adjusted price for the past 150 years, Jones said.

The danger with depleting fish stocks is that it alters the ecosystem and makes it difficult if not impossible for some types of fish to recover, even after governments enact bans, Holm said. Consumers have had much of that problem hidden from them, as restaurants respond to dwindling stocks by seeking foreign suppliers, he said.

Market Forces

``Unfortunately we are at the end of that period,'' Holm said. ``The ocean's resources are being depleted, we probably are at the end of that gold mining period.''

Such species as orange roughy or Chilean sea bass have been ``fished out in a matter of only 10 years,'' and already are becoming endangered species, he said.

In other instances, fishermen are becoming accustomed to catching much-smaller versions, Jones said. Halibut used to reach 300 pounds back in 1910, while the fish known as ``scrod'' is essentially a juvenile codfish or haddock, he said.

The National Oceanic and Atmospheric Administration said in an annual report in August that more than a quarter of known U.S. fish stocks are considered overfished. Those subject to overfishing include Atlantic sea scallop, summer flounder, black rockfish and large coastal sharks, it said.

The Bush administration announced a proposal last month for reauthorizing the Magnuson-Stevens Fishery Conservation and Management Act that it described as promoting ``greater use of market-based systems for fisheries management.''

Fisheries Management

That plan, however, would allow overfishing of already depleted fish populations through such changes as lengthening the allowable time frames for rebuilding fish populations, according to the National Environmental Trust, a Washington-based environmental advocacy group.

Market forces over the decades have ``reacted to demand by depleting sea life one after another,'' said Carl Safina, president of the Blue Ocean Institute, a conservation organization based in Cold Spring Harbor, New York.

``The price spikes mostly reflect sudden declines, and are one measure of a long history of poor fisheries management,'' Safina said.

Some companies have tried to help through a group called the Seafood Choices Alliance, a Washington-based association of fishermen, wholesalers, retailers and restaurant chefs who avoid endangered fish and try to encourage their customers to do the same.

``Fishing really intensively and then moving on once we've wiped it out is really having catastrophic effects biologically on species,'' said Joey Ritchie Brookhart, spokeswoman for the group, whose member restaurants include Jardiniere in San Francisco, Le Bernardin in New York City and the Rattlesnake Club in Detroit.

To contact the reporter on this story: Paul Basken in Washington at pbasken@bloomberg.net

Last Updated: October 23, 2005 15:30 EDT