Salmon have returned to the East Bay’s water source in record numbers. What does it mean?

The numbers on the Mokelumne River this year is a bright spot in an otherwise dire picture for salmon in the Bay Area.

The Mokelumne River, a 95-mile waterway that supplies a majority of drinking water to the East Bay, earned its name because of the abundance of salmon in its waters. Local legend has it that, many years ago, the rivers were so packed with salmon you could walk from shore to shore along their backs.

Today, after 100 years of industrialization, the Mokelumne (pronounced muh-kaa-luh-mee), which flows from the Sierra Nevada to the Sacramento-San Joaquin River Delta, is a much different river. Salmon now exist there primarily because of human intervention — hatcheries raise many of the salmon that return to its waters.

To draw salmon upstream, water must be released from dams periodically to mimic natural weather patterns. Some hatchery fish are even driven to the San Francisco Bay in trucks in an effort to aid their passage to the ocean and increase the odds that they will one day return.

This modern reality made it all the more unlikely when, last week, the East Bay Municipal Utility District announced a record-breaking fall salmon run in the Mokelumne, the name of which translates to “People of the Fish” in the language of the Miwok, an indigenous group native to the Bay Area. According to EBMUD, over 20,000 salmon have already returned to spawn in the river this year, a figure not seen in 80 years of record-keeping.

“It was just too good of news to keep under our hats,” said Michelle Workman, EBMUD’s Manager of Fisheries and Wildlife. “We’re having a great season.”

The utility district said the record-breaking salmon run is in large part a reflection of its forward-thinking management. Over the past few decades, the agency has undertaken a series of restoration projects and other measures to try to boost the number of salmon spawning in the river — measures that have inarguably benefited the fish. Although the Mokelumne River contributes only about 3% of the freshwater flow into the Sacramento-San Joaquin Delta, its salmon population makes up as much as 50% of the commercial catch off the coast of California.

Yet salmon observers across the state say the record-breaking numbers are unlikely to be a step toward large, more sustainable salmon populations. Instead, the salmon in the Mokelumne this year could just be the fleeting appearance of progress in developed, modern river systems that don’t prioritize the fish’s success.

The numbers on the Mokelumne this year are a bright spot in an otherwise dire picture for salmon in the Bay Area. Historically, millions of salmon would return to the Sacramento River Delta to spawn. Last year, the entire recreational salmon fishery was closed due to historic low salmon abundance. In that context, 20,000 on the Mokelumne doesn’t look so hot.

“There’s this talk about the record-breaking good news, but it’s not ubiquitous for all rivers,” said Scott Artis, the executive director of the Golden Gate Salmon Association, a nonprofit dedicated to restoring the state’s salmon. “And it certainly doesn’t signal the end of the current salmon crisis.”

Artis said he doesn’t question the good work EBMUD has done on the Mokelumne. As part of the agreement to build Pardee and Comanche dams, which provide water to the East Bay, the utility is responsible for producing 3.4 million juvenile salmon that would be lost in the river system otherwise.

“There’s a good ray of hope, some good news that resonates with a bunch of people. But if the light gets shined on that you lose track of the big picture,” Artis said.

According to Keiko Mertz, the policy director at Friends of the River, California’s water management paradigm has long prioritized squeezing as much water as it can out of our rivers, often to the detriment of salmon. In the long run, Mertz said more water needs to be in the rivers in order to restore viable populations of salmon without human intervention.

“All the rivers in the Central Valley are screwed up in one way or another, so the only way you’re going to get fish is by artificial means,” said Peter Moyle, a distinguished professor emeritus of fish and conservation biology at UC Davis. “If we’re going to change that, we have to start talking about changing the operation, or even taking down dams.”

Workman, the EBMUD fish biologist, said it’s hard to compare historical periods. She acknowledges that runs were far lower than historic levels, but also noted that the runs are different, and more adapted to a human environment, where dams allow water managers to keep the rivers flowing in periods in which they otherwise would have run dry.

But Workman, too, agreed that the same positive results haven’t been achieved in all river systems and that hatchery-driven salmon runs are not the long-term goal.

“For me, the goal over the next 100 years is to make sure we’re still supporting the fishery economy in California, but also to improve the number of fish we have spawning in the rivers,” Workman said. “That’s the challenge.”

The reservoirs on the Mokelumne River are the primary drinking water source for 1.4 million customers served by EBMUD in Alameda and Contra Costa counties — so the river is not going to be returned to a wild state anytime soon.

Still, to those invested in the health of California’s rivers, restoring wild salmon runs across the state means restoring fish that have fed communities and the ecosystem for time immemorial. Even today, salmon continue to serve a crucial role in the state’s culture, ecosystem and economy.

That means that a record-breaking salmon run should be celebrated, even as much more work needs to be done, Artis said.

“This is more than just a fishing industry thing, this really is a cultural thing,” Artis said. “It’s people, its wildlife, it’s healthy foods, local foods. If there ever was a keystone species, this is it.”