Estuary News

March 2020

Where have all the Herring Gone?

Pete has fished San Francisco Bay for nearly all of his 60 years. A lifelong San Francisco resident who keeps his last name to himself, he recalls herring runs in the 1970s the likes of which rarely, if ever, occur anymore.

“I remember herring spawns that went from Oyster Point all the way to the Golden Gate Bridge,” says Pete, a former commercial fisherman, referring to the point near Brisbane. He also remembers massive spawns that stretched contiguously from the Tiburon peninsula out the Golden Gate to Point Bonita.

Today, the fish still return. Each year between December and March, schools of Pacific herring, Clupea pallasii, lay and fertilize their eggs in the Bay’s shallow waters. When the fish gather at sites like Point Richmond, China Basin, and the Sausalito waterfront, so do frenzied birds and pinnipeds, all feasting on the sardine-sized fish. As the female herring lay their eggs on rocks, pier pilings, and eel grass, the males release clouds of sperm that color the water a chalky gray.

Fishermen also attend large herring spawns. Recreational anglers fill buckets and coolers using hand-thrown nets, while commercial gillnetters, who sell the bulk of their catch for various industrial purposes, fill boats.

But these spawns are a pale shadow of the massive events of the past. Veteran fishermen say they’ve watched northern California’s herring, which also spawn in Tomales and Humboldt bays, dwindle away.

“You used to see herring breezing the surface on the open ocean,” says Tom Baty, a naturalist and lifelong resident of Inverness who has fished the Point Reyes area since the 1960s. “But we don’t anymore, and we don’t find them in salmon bellies anymore, either.”

Today, a San Francisco Bay herring spawn tends to be a comparatively isolated event — often limited to a single cove or a mile of shoreline. 

Population figures from the California Department of Fish and Wildlife illustrate a long downward trend, accented by periodic spikes in abundance. Average returns through the 1980s, reported in estimated spawning biomass, hovered in the 50,000-ton range. By the 1990s, biologists’ estimates — which they base on density and extent of egg deposition during spawn events — had dipped into the 30,000-ton range.

The fish staged a comeback of sorts early this century, with a record-smashing spawn in 2005-2006 and another surge beginning in 2010, when estimated abundance spiked to circa-1980s levels for four years.

But then the numbers plunged to new depths, and since 2015 the herring have trickled into the Bay. Returns have not exceeded 18,000 tons for six winters in a row, and last year saw just 8,030 tons — the second lowest biomass on record. (The lowest, 4,800 tons, came in 2008-2009 and is generally believed to have been the result of the 2007 Cosco Busan oil spill.)

San Francisco Herring Biomass 1979-2019. Source: CDFW

This season, based on visible spawning events and accounts from recreational fishermen trying fruitlessly to catch the herring, seems to have been one of the worst years on the books.

No one is sure what’s ailing these oily, nutritious pillars of the food web, but different sources have different theories. Some blame overfishing, while the California Department of Fish and Wildlife contends that the harvest rate is sustainable. The department sets commercial catch quotas at less than 10 percent of the previous year’s estimated biomass. It’s a squishy management system, but the department’s herring team believe it works. Commercial fishing, they say, likely dented herring stocks several decades ago. Using nets, the Bay’s herring fleet used to catch thousands of tons of herring every year. Landings peaked in the late ‘90s at 12,000 tons.

But the department, whose biologists declined to be interviewed by phone, says the more recent decline has probably been due to unfavorable ocean conditions. 

“Since the early 1990s, environmental conditions off the coast of California have been more variable than in previous decades, with more rapid shifts between warm and cool conditions,” Fish and Wildlife’s herring team wrote in an emailed statement. “This oceanographic variability has been reflected in the increasing variance of the spawning biomass of the San Francisco Bay Herring stock.” 

Today, the fleet generally catches a few hundred tons of herring each winter. The females’ roe is sold to Japan as a delicacy while the rest of the catch, including the male herring, is treated as little better than trash. Industry sources say it’s mostly used as livestock and aquaculture feed.

“Zoo food,” Baty recalls, was the euphemism that fishermen and Fish and Game staff used for such herring.

Kirk Lombard, a sustainable fishing advocate who has gained some local fame as a seafood foraging guide, believes the commercial fishery should have been closed years ago, when the herring population showed signs of stress.

“If the fishery has gotten so bad that they’re putting limits on the recreational catch,” Lombard says, referring to a decision to do so last year, “then why is there even a commercial fishery at all?” 

This is not the first time that an apparent decline in herring population has prompted concerns. In 2003, the Department of Fish and Game itself (now Fish and Wildlife) sounded the alarm. By the department’s estimates, the Bay’s herring population had crashed, and at a public meeting in Los Angeles in August of that year, department biologist Becky Ota recommended that the California Fish and Game Commission close the fishery. Fishermen lashed back. They contended a closure was unnecessary and that Fish and Game was using flawed methods for counting fish and eggs and was underestimating the biomass. The commission sided with the industry and voted to maintain a generous quota.

CDFW science aid samples herring spawn on Richardson Bay shoreline in Marin County in 2019-2020 season. Photo: CDFW

A few years later, estimated biomass spiked to its record high of 145,000 tons. Fishermen who had argued just three years before that the department’s methods for estimating population were flawed now stood by the sky-high figure as evidence that the population was healthy. Commercial fishing continued, even as herring numbers subsequently waned. 

Some scientists, like William Sydeman of the Farallones Institute, stand by the department’s diagnosis of the ailing herring population — that the dip in herring numbers is the result of depressed ocean productivity. In recent years, warmer surface waters have weakened upwelling cycles, depriving the food web of the cold, nutrient-packed bottom water that drives the growth of plankton, on which herring and anchovies feed.

But Sydeman says he isn’t sure what’s causing the reduced ocean productivity.

“Is it part of an ocean-warming cycle that will reverse naturally, or is it related to human-caused warming?” he says.

Herring are struggling elsewhere, too. Up the coast, all the way to Alaska, populations have shriveled. A once-productive fishery in southern Alaska collapsed in the 1990s. It has failed to rebound, prompting a grim theory that the ecosystem, perhaps more plastic than elastic, has simply re-stabilized as one without herring.

In British Columbia, activists have called for a ban on industrial herring fishing, which they blame for the decline in several distinct populations. Pacific Wild, a group based in Victoria, has argued that fishery managers, by using the year 1950 as the baseline for abundance, are misevaluating the health and stability of herring populations. The group contends that historical abundance of the fish was far greater than presumed and that 1950s numbers represent a depleted fishery.  

In fact, shifting baselines is a problem that affects fisheries everywhere. The phenomenon occurs when successive generations of people lose sight of past abundance levels and end up misinterpreting a depleted population of animals for a thriving one. It’s a dangerous process that can cause misguided management and further depletion.

In the case of California’s herring, accounts from experienced fishermen remind us of what once was.

“You could see these massive, massive spawns, where it seemed like they’d go on for miles,” says Baty, recalling winter herring runs in Tomales Bay in the 1960s, when he was a boy.

There has been essentially no fishing pressure on the Tomales Bay population for many years, but Baty thinks heavy commercial harvest in the past pushed Tomales Bay’s herring into what ecologists call a “predator pit.” Facing growing numbers of pinnipeds and cormorants, the fish just can’t recover, he believes.

Jon Warrenchuk, a Juneau-based scientist with the advocacy group Oceana, suspects a range of factors are responsible for ailing herring runs. 

“It’s the cumulative impacts of climate change, ocean acidification, habitat loss, predation, and the lingering effects of past and present industrial fishing,” he says.

To Lombard, the ambiguity surrounding the herring collapse is exactly why fishery overseers need to act cautiously and, at least temporarily, close the commercial fishery. “Given the state of the environment, global warming, and the deplorable state of fisheries,” Lombard says, “do we have the leisure anymore to assume that natural cycles are causing this and that the herring will just come back?”

Pacific Herring Fishery, Cal Fish & Wildlife

Related Prior ESTUARY stories

Hopeful Outlook for Pacific Herring, March 2018 Estuary News

Other Fish Tales

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Top Photo: Commercial gill net fishing boat this herring season. Photo: CDFW

About the author

A native to San Francisco, Alastair Bland is a freelance journalist who writes about water policy in California, rivers and salmon, marine conservation and climate change. His work has appeared at NPR.org, Smithsonian.com, Yale Environment 360 and News Deeply, among many other outlets. When he isn't writing, Alastair is likely riding his bicycle uphill as fast as he can.

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