The fate of fish populations around the world may rest in the hands of chefs and diners as well as policy-makers and oceanographers, experts said in San Diego last week.

Mounting evidence from fishermen and ocean scientists shows an alarming drop in ocean fish populations. According to the Web site of the Monterey Bay Aquarium, ocean fishermen increased their catch 400 percent between 1950 and 1994 by doubling the number of boats and using more effective fishing gear. In 1989, the world's catch leveled off at just over 82 million metric tons of fish per year. That's all the ocean can produce, says the Web site.

So far there is little consensus about how to reverse the depletion of the ocean's fish stocks. One approach, simple in theory but complex in practice, is to stop selling, serving and buying certain fish.

Pascal Vignau, chef-owner of Savory restaurant in Encinitas, said he stopped serving Chilean sea bass -- also called Patagonian toothfish -- three years ago after hearing its numbers were dropping near endangered levels.

Many diners, however, might not have heard about the declining fish populations until recent news reports, and many people probably remain unaware about a fish shortage at all, since grocery stores and menus still feature plenty of fish.

To increase awareness, the annual Marine Technology and Ocean Science Conference, held in Mission Valley last week included a panel discussion on the issue.

"I think it's a great thing," Vignau said between preparing fish entrees for guests at the Scripps Institute of Oceanography centennial celebration Sept. 25, held a few hours after the Mission Valley forum. "It's creating a good awareness for people on the numbers of fish."

The forum was organized by Passion Fish, a nonprofit Oakland-based organization that promotes "sustainable wild fisheries," or managing what is fished to prevent endangerment or extinction.

Marine Room chef Bernard Guillas of Encinitas, the only chef on the 11-person panel, expressed some frustrations with the challenge of trying to stay abreast of the issue.

"This is the trouble we have," he said. "We gather a lot of information, and sometimes conflicting information. We need a scientific community to really give us accurate information. We don't want black today, white tomorrow, and then we're going to go pink."

Guillas said he had heard that Chilean sea bass was endangered, and then later learned that it was not officially endangered or threatened.

Confusing categories

Some groups are trying to clear up the confusion. The London-based Marine Stewardship Council certifies stores and brands that sell only fish with healthy populations. Whole Foods Markets, which has outlets in La Jolla and Hillcrest, is the only area store listed.

But consumers can keep track of which fish are not in danger with wallet-size guides created by the Monterey Bay Aquarium in partnership with the Seattle Aquarium. The cards classify fish in three categories and colors: best choices (green), caution (yellow) and avoid (red).

Blue Ocean Institute and the Audubon Society also have lists, which don't always agree.

The Monterey Bay Aquarium list, for example, names 21 fish as abundant, while the shorter Blue Ocean Institute names only 10. Monterey Bay names lists mahi-mahi under "caution," while Blue Ocean Institute calls it abundant.

Panelist Sam King, president and CEO of King's Sea Co., noted the discrepancies.

"A card like this is scary," he said about the Monterey Bay list. "I think it's wrong. I think it's a political statement. A card like this will divide rather than bring people together."

The card catagorized Atlantic salmon as a fish to avoid, and King agreed there are serious problems with the fish, but he disagreed with placing mahi-mahi under the "caution" category.

"Mahi-mahi is the fastest growing fish out there," he said. "I've never heard of a problem with it."

Enlisting the consumer

Despite some discrepancies, the various lists have more similarities than differences. Even so, the bigger challenge may be getting people to pay attention to them.

Panel member and nutritionist Chris Speed said 80 percent of people haven't decided what they will have for dinner by 6 p.m., and the decision about whether to buy wild or farmed salmon probably will be based on price.

Two-thirds of consumers buy their fish in restaurants rather than at stores, and those restaurant owners often aren't sure about the source of their fish, said Michael Sutton, director of the Ocean Conservation Program.

"If you go to a typical white-tablecloth restaurant and ask, 'Where is your fish from?' you know what they're going to say?" Sutton asked the panel. "'The truck.'"

Sutton said the lists that classify fish for consumers are a good start, "but just a start."

While there may not be absolute agreement on the value of such cards or lists, there is wide acknowledgement that something bad is happening to the ocean fish population, according to the film "Empty Oceans, Empty Nets," produced by the nonprofit organization HabitatMedia.org and shown before the forum.

While people may not believe that oceans could be at risk of losing fish populations, marine scientist Carl Safina said in the film that the ocean is in a sense a desert, with large, desolate areas containing little life.

As fishing technology has improved and the world's population has grown, more fish are being caught. Fishing boats have begun working in remote areas that were never fished before, and the film quotes fishermen from Asia, Africa, the United States and other areas who say they have to fish much longer to catch as much as they did just a few years ago.

Consumers haven't noticed the problem yet because there still is plenty of affordable fish in the marketplace. The reason, according to the film, is that markets are selling smaller fish or fish that once were considered inedible.

The film said that by-catch, or fish that are caught by accident while hunting for another fish, is one of the reasons fish populations are diminishing. About 20 million metric tons of fish are discarded as by-catch annually, according to the film, which claimed that 5 pounds of marine life are discarded for each pound of shrimp caught.

Positive steps

Panel member Wally Pereyra, chairman of Arctic Storm Management Group, Inc. and vice chairman of the Virginia-based National Fisheries Institute, the leading trade association for the fish and seafood industry, said he has seen fisheries taking positive steps by working together to monitor catches and track data as a way of controlling by-catches.

Panelist Linda Sheehan, director of the Pacific Regional Office of the Ocean Conservancy, said sanctuaries that prohibit fishing are one solution.

"I don't see how it can hurt," she said. "The scientific consensus so far is it can only help."

John LaGrange, a professional fisherman and president of the Eureka-based American Fishermen's Research Foundation, disagreed.

"Fishing is part of the world's food supply," he said. "If we set it aside, we'll have to replace it with another source."

But with fisheries closing and people losing jobs, LaGrange said it is important to acknowledge the problem.

"When you have a record of dismal failure, it does make sense to pay attention from time to time," he said.

But there is hope, said Michael Sutton, director of the Ocean Conservation Program.

"The oceans have an incredible ability to recover," he said. "We still have time."

Contact staff writer Gary Warth at gwarth@nctimes.com or (760) 740-5410.