Sacramento pikeminnow and introduced striped bass in the middle Sacramento River eat a surprisingly similar diet, says a new study in San Francisco Estuary and Watershed Science.

Sacramento pikeminnow and introduced striped bass in the middle Sacramento River eat a surprisingly similar diet, says a new study in San Francisco Estuary and Watershed Science.

Both species have been implicated in the decline of vulnerable native species in the river, particularly juvenile Chinook salmon, says lead author Dylan Stompe, a PhD student and researcher at the University of California at Davis. For eight months in 2017, Stompe and fellow researchers with the California State University at Chico and the California Department of Fish and Wildlife surveyed a 35 kilometer reach of the river outside Chico for the two predatory fish. They baited hooks with with...
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Should the striped bass be a suspect in the decline of the Delta smelt?

Writing in the March issue of San Francisco Estuary and Watershed Science, US Fish and Wildlife Service biologists Matt Nobriga and Will Smith suggest that the smelt’s baseline might have shifted long before anyone was paying attention, and striped bass predation may have constrained its numbers before recent water diversions and food web changes added their effects. The smelt’s historic abundance is unknown; systematic surveys didn’t begin until 1959. But it’s thought to have evolved its boom-and-bust life history in...
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Beaver dams may offer wildfire protection to western watersheds, in addition to providing better-known benefits such as groundwater recharge, wetland and habitat creation, and riparian restoration.

A new study by California State University Channel Islands professor Emily Fairfax analyzed satellite-derived vegetation indices of riparian areas and beaver dams mapped via Google Earth. At the same time, Fairfax analyzed data for large (over 30,000 acre) wildfires that had occurred between 2000 and 2018 in California, Wyoming, Colorado, Idaho, and Oregon, and compared the fate of beaver-dammed areas to areas without dams. Fairfax found that riparian corridors within 100 meters of beaver ponds were buffered from wildfires. “In...
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A new project should dramatically improve conditions for endangered steelhead trout in the lower reaches of Alameda Creek.

The project is part of a long-term effort to restore steelhead to Alameda Creek. Last year, for the first time in decades, the San Francisco Public Utilities Commission began releasing water from a newly retrofitted dam, effectively reviving an important tributary stream. Also in 2019, the Alameda County Flood Control District began construction of a key fish ladder at the BART line crossing that will allow adult steelhead to access the river’s headwaters. The new fish passage enhancement plan focuses...
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A resurgence of dinoflagellates, which can cause harmful algal blooms, may be in the cards for some bays along the U.S. West Coast.

A resurgence of dinoflagellates, which can cause harmful algal blooms, may be in the cards for some bays along the U.S. West Coast. Scientists at UC Santa Cruz have been monitoring phytoplankton weekly at the town’s Municipal Wharf since 2002. In 2018, Alexis Fischer, then a postdoctoral fellow at UC Santa Cruz, augmented these observations with an Imaging FlowCytobot (IFCB) that photographed wharf phytoplankton hourly. She also developed a machine learning classification algorithm to automate identification of the organisms. In...
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New archaeological evidence from the South Bay strengthens the case that Chinook salmon spawned naturally in the Guadalupe River.

Albion Environmental, a Santa Cruz research consulting firm, and researchers from Santa Clara University analyzed thousands of fish bones excavated from a 19th century indigenous village on Mission Creek, a historical Guadalupe River tributary long since buried under modern urban development. In an abstract of their research, which has not yet been published, the authors describe using DNA sequencing on 55 confirmed salmonid bones. They identified 52 as belonging to steelhead trout and three as Chinook salmon. Whether Chinook occurred...
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A grassroots effort to move migrating newts across a Marin County road has drawn to a close, but organizers hope it leads to a more permanent solution.

For roughly half a mile, the two-lane road in a hilly rural area west of Petaluma travels alongside a large, natural body of water called Laguna Lake. On the other side is an oak woodland: the perfect place for California and rough-skinned newts, which spend the dry season in moist terrestrial habitat under leaf litter and wood debris or inside animal burrows. After seeing a number of native newts flattened along the road on rainy winter evenings, a small group...
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Urchinomics

By Alastair Bland As purple urchins have multiplied, kelp forests, already stressed by unusually warm water, have collapsed. Norwegian company Urchinomics proposes to capture the overpopulated urchins, fatten them up in circulating seawater tanks, and sell them to restaurants—hopefully in volumes sufficient to dent the urchin armies and allow a kelp comeback. Greater Farallones National Marine Sanctuary press liaison MaryJane Schramm says combatting the urchin takeover “goes directly to our mandate to maintain or restore ecosystem balance.” Citizen science, she...
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Kinky Fish Spines Linked to Selenium

By Joe Eaton Scientists with the U.S. Geological Survey and the National Oceanic and Atmospheric Administration are using new tools to track selenium, with the Sacramento splittail, a California-endemic fish, as an indicator species. Robin Stewart, lead author of a new paper on splittail and selenium, is one of the region’s most seasoned current experts on bioaccumulation of metals in estuarine species. In some sampled splittail, selenium levels exceeded the proposed EPA protective criteria for fish ovaries. Liver levels, not...
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Tracking Curlews Cross-Country

By Joe Eaton This winter, Jay Carlisle, director of the Intermountain Bird Observatory, teaming with Nils Warnock of Audubon Canyon Ranch and netting expert David Newstead of Coastal Bend Bays and Estuaries Program, caught two long-billed curlews and outfitted them with transmitters. Those birds may reveal where the wintering curlews on the California coast and Bayshore are coming from. While many grassland birds are experiencing catastrophic declines, long-billed curlews had appeared to be an exception. “It’s such a habitat generalist...
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Dam Tweaks Yield Results

By Alastair Bland “After one year of flows, we’re seeing lots of rainbow trout,” says Brian Sak of the San Francisco Public Utilities Commission (SFPUC). For the first time ever, cold water is flowing steadily through Calaveras Dam in southern Alameda County, and into the creek canyon below. The return of rainbow trout to Calaveras Creek marks a milestone in an ongoing, multi-agency restoration of Alameda Creek, which drains more than 600 square miles of the East Bay. Since the...
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Dennis McEwan finished work on the 430-acre Yolo Flyway Farms Tidal Habitat Restoration Project in September 2018. A month later, he retired.

The timing was no accident; he’d delayed his departure from the California Department of Water Resources (DWR) to see the project through after helping to launch it ten years earlier. But even from the very beginning of his career, McEwan had been committed to doing all he could for declining species in and around the Delta. That “calling,” as he put it, began with 25 years at the California Department of Fish and Game (now Fish and Wildlife) supporting Pacific...
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A career spent monitoring imperiled fish has given Randy Baxter a strong sense of the vulnerability of aquatic ecosystems.

“We’ve overtaxed the system,” he says. Baxter officially retired from the California Department of Fish and Wildlife last August, but still works two or three days a week as a “reemployed annuitant”—a big change from supervising a staff of 14 studying the threatened longfin smelt and other native fish. The reduced schedule gives him more time to fish, in California and on British Columbia’s Skeena River, and tend his orchids and carnivorous plants. Chicago-born Baxter grew up in Pacifica with...
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Bob Fujimura spent his entire career with the California Department of Fish and Wildlife.

Bob Fujimura spent his entire career with the California Department of Fish and Wildlife. From 1987 until his retirement in late 2018, Fujimura served in a variety of roles at the department—but he is likely best known for heading up its long-term monitoring of native fishes in the Bay and Delta. Beginning in the mid-2000s, he oversaw annual smelt surveys with far-reaching implications for management and conservation, including the Spring Kodiak Trawl, which determines the relative abundance and distribution of...
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Manmade features in the Delta, including riprap-armored banks, water diversion pipes, pilings, and woody debris, may be sending juvenile native fishes into the jaws of finned invaders.

“We know from a decade of doing survival studies that migrating juvenile salmon are dropping out of the system pretty much everywhere in the Delta,” says UC Santa Cruz fisheries biologist Brendan Lehman. “Physical habitat features are potentially aggregating predators and prey in ways detrimental to salmon smolts and steelhead.” The scientists report in the December 2019 San Francisco Estuary and Watershed Science that artificial light and submerged aquatic vegetation pose the most severe and widespread risks to native fishes....
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Levels of pyrethroid insecticides spike sharply in the North Delta’s Cache Slough during winter rainstorms, rendering the water so toxic that it decimates laboratory populations of a half-inch crustacean called Hyalella azteca.

However, according to a study reported in the September 2019 San Francisco Estuary and Watershed Science, Hyalella collected in the wild from Cache Slough are resistant to pyrethroids. Genetic analysis revealed that, collectively, Hyalella in the slough have four mutations for pyrethroid resistance. They also have a fifth mutation for resistance to organophosphates and likely carbamates, two additional major classes of pesticides that are applied extensively on agricultural and urban lands. “Hyalella are special,” explains co-author Helen Poynton, a molecular...
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Researchers hope new computer models will help clarify the effects of entrainment on the population of endangered Delta smelt.

Entrainment at the South Delta pumps of the State Water Project and the Central Valley Project has been a concern for years, but disentangling its impact on the dwindling smelt population from those of other environmental and water management factors isn’t easy, and operational differences between the SWP and CVP facilities complicate analysis. Now, US Fish and Wildlife Service statistician Will Smith has developed computer models for entrainment effects on different smelt life stages, part of a larger Delta Smelt...
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While the acreage of wetland restoration projects is growing throughout the Delta, scientists are still working to understand how best to help these areas become fully functioning, complex habitat as quickly and successfully as possible.

A study published in September’s San Francisco Estuary and Watershed Science shed light on some essential questions about what triggers seed generation in wetland habitat. “Wetland restoration practices can be enhanced by a solid understanding of basic plant life history and species ecology,” says co-author Taylor Sloey of Yale-NUS College in Singapore. The researchers looked at three questions: what seeds are present in the seed bank (the viable seeds that accumulate naturally in the soil), and how exposure to cold...
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Not So Picky Marsh Mouse

The endangered salt marsh harvest mouse (informally “Salty”) is a poster child for tidal marsh restoration in San Francisco Bay. But recent research, presented by University of California at Davis postdoc Katie Smith in a State of the Estuary conference session on tidal wetlands, suggests we’ve misinterpreted what the mouse needs. “It’s been managed as a habitat specialist,” she said, based on assumptions that it requires tidal wetlands and a diet of pickleweed. However, hours of mouse-tracking around the Bay...
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Speakers discuss issues facing Estuary wildlife and their wetland habitats, as well as drones and other new tools that will help future management.

Fish and Wildlife Check-up State of the Estuary Conference presentations featuring decades of data on fish, ducks, seabirds, and cetaceans revealed both hopeful and alarming trends. “The loss of federal funding for the midwinter waterfowl survey, usually conducted using small aircraft, has researchers looking at drone-based alternatives,” said waterfowl biologist Susan De La Cruz of the US Geological Survey. The overall community condition of the Estuary’s fish (abundance, distribution, diversity, proportion of native to non-native species) has declined, reported the...
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