Of Mice and Marshes: Surveying Salties to Save Them

Of Mice and Marshes: Surveying Salties to Save Them

It’s five in the morning, and Don Edwards San Francisco Bay National Wildlife Refuge remains in the tight velvet grip of night. All is peaceful and quiet, despite the fact that the toll plaza of the Dumbarton Bridge is less than a quarter-mile away. By 5:15, car dome lights and slamming doors have transformed this lonely spot at the watery edge of Newark into a hub of activity. People are taking last sips of coffee, strapping headlamps to their foreheads,...
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California will spend big bucks on beavers to try to boost their numbers and reap some of the benefits—including slowing wildfire—these ecosystem engineers can provide.

After years of advocacy by beaver “believers,” the state has allocated funding for a beaver restoration program. The $1.67 million in license plate funds for fiscal year 2022-23 and $1.44 million the following year represents a new way of thinking about beaver management in California, says Kate Lundquist, of the Occidental Arts & Ecology Center. “Until recently, the Fish and Game Code has focused on recreational and commercial beaver trapping and permitting the depredation of nuisance beaver,” she explains. “I...
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Drought Plan Means Full Lake, Empty River

In the mountains and foothills of California, an enduring drought has depleted the state’s major reserves of water. There is virtually no snowpack, and most of the state’s large reservoirs are less than 40 percent full. But in the central Sierra Nevada, a trio of artificial lakes remain flush with cold mountain water. The largest of them, Hetch Hetchy Reservoir, from which millions of Bay Area residents receive water, is more than 80 percent full. This remarkable plentitude is the...
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Finding Her Way to Fish: Denise Colombano

The path into a career is not always a straightforward one. “I hated school. I mean, hated school,” says Denise Colombano, a postdoctoral fellow and Delta Science Fellow working on fisheries research at UC Berkeley. Today, Colombano feels that it is important to talk about her story as a way of encouraging inclusiveness and opportunity within her field — and in the sciences in general.  “I actually flunked ninth grade, and was attending a continuation school, when my science teacher...
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Over time, the median actual flow to San Francisco Bay in the ecologically critical winter and spring months has declined to less than half of the unimpaired runoff. This bar chart divides actual inflow (the amount that actually made it to the Bay) and unimpaired runoff (the inflow to the Bay that would occur if there were no dams or diversions) into quintiles from wettest to dry, and marks years drier than 2015 (roughly, the driest 2% of years) as “super-critically dry” years. Over the last 54 years, “super-critically dry” runoff conditions in the Bay’s watershed occurred naturally only once, in 1977, but the Estuary received runoff volumes in the super-critical range in 22 years, or 40% of the time. Overall, flow volumes characteristic of the driest 20% of years now occur more than half the time as a result of storage and diversion of runoff for consumptive uses. Source: The Bay Institute, based on data from California Department of Water Resources.

Defining Unimpaired Flows

For the second time in four years, a proposal for a voluntary agreement between agencies and water contractors on flows into and through the Delta from the San Joaquin and Sacramento rivers and their tributaries is wending its way through the State Water Resources Control Board. The proposal, which would replace the regime outlined in the Board’s most recent update to the Bay-Delta Plan, calls for substantially less water remaining in the system than the update, but comparing the two...
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Reorienting to Salmon Recovery

The days when salmon and steelhead teemed in California’s coastal watersheds faded away last century. Today, many populations of the fish are gone or dwindling, the river systems where they spawn drained by diversions or too warm for native fish to survive. Warming trends and drought are squeezing water resources tighter. Nearly all efforts to revive the state’s ailing salmonids have failed, often stalemated by political tensions, and it takes hatcheries and truck transport of juveniles to saltwater to maintain...
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Adrienne Ernst among the Phragmites. Photo: Michael Adamson

Living with a Novel Landscape: Suisun Evolves

Morning at Suisun Marsh is a living watercolor with a soundtrack. Miles of tule and pickleweed populate the foreground, split by canals glinting silver from the sun. In May, the hills undulate across the northern boundary in classic California gold. A red-tailed hawk’s iconic hoarse screech punctuates the insectine buzz as it takes off from a powerline. At 7:40 AM, it’s already 72 degrees and there’s no trace of a breeze. I’ve come to visit the Marsh from downtown Oakland...
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diagram of fish net trawl

Fish monitoring surveys in the San Francisco Estuary net different numbers of different fish species depending upon when and how they sample.

According to a new study published in San Francisco Estuary and Watershed Science, even surveys that target the same part of the water column can come up with significantly different catches. The study’s authors analyzed decades worth of data from the California Department of Fish and Wildlife (CDFW) Fall Midwater Trawl, which spans from San Pablo Bay to the upper Delta; CDFW’s San Francisco Bay Study midwater and otter trawls, covering the South Bay to the central Delta; and the...
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West Coast Salmonids All Tired Out?

West Coast salmon and steelhead populations have declined steeply in the past century – a plight that biologists have primarily blamed on habitat loss. Dams, for instance, block adult fish’s access to historic spawning grounds, and juvenile survival is impacted by streamside development and water diversions. Now, it turns out, microplastic pollution may be a much bigger factor than anyone knew just several years ago. In 2019, scientists with the San Francisco Estuary Institute and the Los Angeles-based nonprofit 5...
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Eyeballing the Fish

Longfin smelt were what hooked Jim Ervin when he first learned about the UC Davis South Bay Fish Survey through a presentation at the 2012 Bay-Delta Science Conference. “They were catching them right there in our effluent channel!” recalls Ervin, a self-trained naturalist and former compliance manager for the San Jose-Santa Clara Regional Wastewater Facility. Intrigued, he contacted the researchers, rode with them on their next survey, and has been part of the project ever since, devoting more time to...
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Will Salmon Simmer Again?

After two critically dry years that coincided with Trump-era rollbacks to environmental protections, some iconic Delta fish are closer than ever to the point of no return. Last fall, for the second year in a row, the fall midwater trawl found zero wild Delta smelt, while a coalition of environmentalists and fishermen is asking a federal court to help prevent a repeat of 2021’s near-obliteration of endangered winter-run Chinook salmon. Their lawsuit is just one of the balls to watch...
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Gone Fishing

As the weekend dawns and California slumbers, the sportfishers descend, like clockwork, on the banks and waves of the San Francisco Bay and Sacramento-San Joaquin Delta. They carry nets for herring or poles for sturgeon, heavy and light tackle, bloodworms or anchovy or any number of delectable morsels to attract the desired target. They tread industrialized East Bay shorelines and marshy Delta banks, hop aboard sporty six-pack boats for more ambitious trips or humbler craft for a leisurely solo excursion....
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South Bay Trawls Show Fish Like Restored Shores

Twelve years ago, scientists at UC Davis began a survey of the southern end of San Francisco Bay — the Lower South Bay — to see how fish responded to the South Bay Salt Ponds Restoration Project. They discovered an unexpectedly diverse and robust aquatic community and a previously unknown spawning ground for the longfin smelt (Spirinchus thaleichthys), listed as endangered in California and a candidate for federal protection because of its declining numbers. The team, led first by Jim...
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Big Boulders, Big Benefits to Coyote Creek Fish

As a source of flowing water, upper Coyote Creek is unreliable at best. Though storms swell its banks in winter, Mediterranean-climate summers shrink this South Bay stream to a series of isolated pools by August. “By October right before the rains come, we’re down to these really small pools that have all the fish in them,” says retired U.S. Environmental Protection Agency ecologist Rob Leidy. Leidy and UC Berkeley fish ecologist Stephanie Carlson began monitoring the annual dry-down of upper...
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Murky Future for Herring

This winter, herring spawns in San Francisco Bay – visible from land as frenzies of birds and pinnipeds and even water discolored by herring milt – have been few and far between, according to recreational fishers who pursue the fish each year using hand-thrown cast nets. With few other eyes on the resource, it seems reasonable to assume that the downward trend in biomass documented through the 2019-2020 winter has continued. But nobody knows for sure. For decades, the California...
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Natives Who Can Rough It

Name a native fish. One that spends lots of time in the Delta. One that’s not a salmon, smelt, or sturgeon. One whose population isn’t plummeting, and in fact seems to be doing just fine. By now the list of possibilities has been shortened severely — though not exhausted. A number of native fish still ply Delta waters in stable numbers, but precisely because there are no restoration projects, monitoring programs, or conservation efforts designed to save them — or...
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Let’s Not Forget Suisun Marsh

I started sampling the fishes of Suisun Marsh in 1979 because one of my UC Davis graduate students was looking for a place to study tule perch, a live-bearing native fish. We found not only a lot of tule perch in the marsh, but also an abundance of other native fishes. Clearly, this was a good place to study species for which we had little information at that time. Two things helped with our new project. First, sampling boats could...
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Hatchery Delta Smelt Released to Wild

On a mild day between rainstorms in mid-December, wildlife biologists outfitted in rubber boots and orange lifejackets load drum after drum of precious cargo onto a small boat docked in Rio Vista, a town on the Sacramento River in the Sacramento-San Joaquin Delta. There is little fanfare but the occasion is nonetheless momentous. The shiny silver drums contain thousands of Delta smelt — finger-size imperiled fish unique to the Delta — that were raised in a conservation hatchery. Today marks...
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Sturdy Sturgeon

A 90-year-old Australian lungfish at San Francisco’s Academy of Sciences has received a lot of press lately, but there is a wild fish species living in the San Francisco Bay that has the potential to live that long or longer — or so we think. While one white sturgeon caught in the Columbia River Basin was estimated to be 104 years old, the life expectancy of white sturgeon, Acipenser transmontanus, which includes the Central Valley population endemic to the San...
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The Complexities of Monitoring Steelhead

For more than two decades, steelhead — listed as federally threatened in 1997 — have been monitored throughout the state. However, until recently that monitoring has been a haphazard affair. Each local jurisdiction has established a different system, using different methods with different degrees of intensity, according to a 2018 study examining monitoring within the Central Valley and its environs. In some areas, primarily the Sacramento River watershed, which drains the vast northern part of the valley, data has been...
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