SAN FRANCISCO – On a drizzly January morning in the bay, amid a clustering of moored ocean liners and warehouse piers, the crew of a small commercial fishing boat guides a gill net over the stern. As a large winch reels in the mesh, thousands of 6-inch (15 cm) silvery fish rain on to the deck until the boat’s crew, in slickers and boots, are standing ankle-deep in Pacific herring. The catch will be offloaded and sold at Fisherman’s Wharf, several miles north along the San Francisco waterfront, and the boat will soon return for more.

There are plenty of fish to catch, for this is the spawning season of the herring. Each winter, hundreds of millions of the fish enter San Francisco Bay to lay and fertilize their eggs on rocks, pier pilings, kelp and sunken debris, and virtually every participant in the marine food web comes in pursuit: sharks and rays, sturgeon and striped bass, seals and sea lions, gulls, pelicans and cormorants – all feast on the herring. Recreational fishers, often coming down on a rainy evening after work, throw circular, web-shaped cast nets from piers and jetties as they fill buckets and coolers, while just yards from shore the commercial fishers fill their boats.

The fleet will take hundreds of tons of the fish – but very little of their catch will be eaten. The ripe eggs, or roe, of the females are what drives the fishery. Amounting on average to 10-13 percent of total landings, the roe sacs are exported to Japan, to be cured and consumed as the delicacy kazunoko. The remainder of the herring – including all the male fish – has very little value. According to multiple sources, herring carcasses are generally processed in Canada and Asia, and wind up being used as feed for livestock and farmed fish, including bluefin tuna.

Mel Wickliffe, owner of Pier 45 Seafood in San Francisco, says he and several herring fishers in the area have tried diligently to spark interest among local people in eating fresh herring, but with limited success. “[Herring processing] is not the most efficient way to use the fish,” he said. “It bothers me if just one fish comes out of the ocean and isn’t utilized.”

It also bothers Geoff Shester. The California campaign director for the group Oceana, he has been promoting the consumption of small forage fishes, like anchovies and herring, for years.

“This is one of the great failures of the local environmental community – we haven’t made people fully aware that right here in San Francisco Bay there is a superior food product that’s being wasted,” Shester said. “Very few people are eating fish like herring.”

Pacific herring is just one of many commercially targeted species of which much or most of the catch is not consumed. Research published early last year revealed that most wild fish used as livestock or aquaculture feed is of food grade. The same paper reported that 27 percent of all fish caught commercially between 1950 and 2010 were used for purposes other than direct human consumption.

Such use of the world’s fisheries “may represent a challenge to global food security,” wrote the authors, led by Tim Cashion, a PhD student at the fisheries economics research unit of the University of British Columbia.

“If we ate these fish directly, the resources would go farther,” Cashion said in an interview.

Peru’s anchovy haul may be the biggest example of a fishery built on such inefficient practices. Just west of the tropical Andes, a powerful up-welling of cold bottom water loaded with concentrated nutrients feeds an enormous anchovy population, and fishers there catch several million tons of them annually. Cashion says that 90 percent or more is rendered into oil and meal to be fed mostly to farmed fish and shellfish, and to a lesser degree to poultry and pigs.

In California, purse seine fishers haul in between 2,000 and 15,000 tons of anchovy each year. Data on how the fish are used is very limited, but it seems clear that historically, most of the state’s anchovy catch was used for animal feed and bait, and it probably still is.

Shester, the sustainable fisheries advocate Casson Trenor, an author and restaurateur, and Bobby Hayden, a fisheries expert with The Pew Charitable Trusts, all say West Coast anchovy landings are primarily turned into feed for captive bluefin tuna and used for fishing bait. Hayden says just a small quantity is consumed as canned fillets.

Shester feels the fishery is overall wasteful: “The concern here is that you’re taking a very valuable part of the ecosystem that supports fisheries and all kinds of wildlife, removing it from the water and turning it into an end product that’s almost worthless.”

Fishing interests, however, argue that the multitude of end-uses for forage fishes actually reduces waste. Diane Pleschner-Steele, executive director of the California Wetfish Producers Association, says most anchovies caught in California and used for bait and animal feed are not of food-grade quality.

“This market provides for full utilization of the entire catch, with virtually no waste,” she said. She added that California fishing industries are trying to create direct consumption markets for forage fishes.

Rick Mayer, of the Marcus Foods Co.’s fisheries division, a southern California seafood exporter, says such markets are developing. He notes anchovies have historically been used chiefly as feed and bait but that a rebounding population combined with a larger grade of fish in the past 12 months has created some interest overseas in filleting and canning the fish.

The fact that there is so little demand for fresh anchovies and herring in California is one challenge faced by activists and industry players as they try to create markets for small fish. Another problem is that of regulation.

Until a few years ago, it was illegal for nearly all herring caught in California to be sold for any purpose except processing for roe and byproducts. Only during brief periods before and after the core of the spawning season could fishers sell herring for fresh consumption. The idea of that rule, says Ryan Bartling, a biologist with the California Department of Fish and Wildlife, was to protect and maintain the market for herring roe. About five years ago the law changed, with a provision that made it legal for gill netters to sell as much of their catch as they wanted, at any time of the season, to anyone willing to buy it.

“The department recognized that there was a desire locally for fresh herring,” said Bartling, who closely studies and helps regulate the commercial herring fishery.

The change, in Shester’s view, was a step in the right direction, though the action didn’t exactly overhaul the industry. The bulk of the Bay Area catch, which has historically ranged from several hundred to several thousand tons each year, continues to be processed for roe, while very small quantities of herring find their way into the local market. Paul Johnson, co-owner of the Monterey Fish Company in Salinas, says he buys 200-300 lb (90-135 kg) per week during the brief fishing season and sells it “to about a dozen local buyers.”

Commercial fisher Kirk Lombard wants to see further changes made to the state’s herring fishery regulations. Existing rules state that herring can be sold in California only if they are caught with a gill net. These nets, Bartling explains, can be selective for specific sizes of fish. The mesh squares of herring gill nets used in San Francisco Bay must be no smaller than 2 inches (5 cm) to a side, to allow small herring to pass through, and no larger than 2.5 inches (6.3 cm), to prevent larger animals becoming entangled. Lombard, known locally as a guide and guru of seafood foraging, hopes to petition the California Fish and Game Commission to allow commercial fishermen to sell small amounts of herring caught from shore with hand-thrown nets.

“I just think something should be done to have more herring consumed locally,” said Lombard, who advocates the direct consumption of fish and shellfish species low on the food chain.

Ken Bates, a commercial herring fisher in Arcata, is also trying to change existing regulations so that more local fish that is currently exported will be eaten within California. He has spent two years pushing for regulators to allow small-boat fishers using traditional lampara nets to catch and sell sardines exclusively to local markets and restaurants. Bates expects a provision allowing such artisanal fishing to become law this spring, but he still anticipates a challenge in finding people to buy the fish.

“In my area, the only people buying fish like these are a small handful of Portuguese families,” he said. “The general American public has lost touch with these species, and they’re pretty much stuck in small ethnic markets.”

Among restaurants, there is a small stream of interest in herring. Fish in Sausalito, the Chop Bar in Oakland, and Hog Island Oyster Company and Nopa in San Francisco have all served local herring this year.

Shester says eating small forage fishes instead of predators like tuna and billfish, and most farmed fish and shrimp, would make the ocean’s resources go farther and perhaps last longer. He says that eating a pound of farmed shrimp or salmon requires using at least several pounds of fish, often anchovy, as feed.

“So, you have this conundrum where if you just ate more forage fish in the first place, you’d actually be using less, and leaving more in the water,” Shester said. “Fishermen would be getting more money, consumers would be eating healthier seafood, and by eating fish caught in your backyard you’d be lowering your carbon footprint.”

William Sydeman, a senior scientist with the Farallon Institute, says he believes fishing a resource should all but require that it be directly and completely consumed.

“If we’re harvesting anchovies, we should eat anchovies,” he said. “They need to be fished responsibly, and part of that is using them responsibly.”