Urchinomics

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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Drones Pilot Vegetation Mapping

By Michael Hunter Adamson In the world of conservation, as attested to by multiple speakers at a late summer UC Davis event, drones, or UAVs (unmanned aerial vehicles) may be the vehicle of choice for mapping the future of invasive plant management in the Delta. The California Department of Water Resources began using UAVs in earnest after the Oroville dam failure in the winter of 2017, when drones offered visuals no one could get near on the ground. The Blacklock...
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Paddlers Monitor Plovers

By Ashleigh Papp “It sounds fun and glamorous to kayak to work, but it’s not always the case,” says Ben Pearl, plover program director for the San Francisco Bay Bird Observatory. Pearl spends six months of the year in the field researching predator threats, habitat status, and breeding behavior of the local snowy plover population. “All of this habitat used to be tidal marsh and was converted to salt ponds, so the ground is sometimes soft and nearly impossible to...
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Just Shy of Splendor in the Grass

By Jacoba Charles Tobias Rohmer and Ben Chen’s careful work in Hayward’s Cogswell Marsh represents one small moment in the massive, nearly 20-year-old Invasive Spartina Project. To date an initial total of 805 acres of non-native cordgrass, spread across 70,000 acres of the San Francisco Bay’s marshlands, has been reduced to less than 40 net acres. Treatment of the southern section of Cogswell marsh was halted in 2011, however, due to concerns about Ridgway’s rails who’d made homes in the...
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California Sun Podcast Interview with ESTUARY’s Editor Dives into All Things Bay & Delta on the Front Burner Today

This August the California Sun’s Jeff Schechtman interviewed ESTUARY magazine’s editor in chief Ariel Rubissow Okamoto, also a long-time Bay Area science writer, about her personal opinions on the resiliency of the largest estuary on the West Coast, the challenges facing the Sacramento–San Joaquin Delta, and the potential impacts of climate change and sea level rise on the San Francisco Bay.  Listen to the 20-minute podcast here. Mentions: Nutrients, Toxics, Giant Marsh, Adaptation Atlas, Resilience, Sea Level Rise impacts, BCDC...
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Two long-scarce freshwater mammal species are staging a comeback in Bay Area waterways.

The California Department of Fish and Wildlife (CDFW) recently updated its distribution map for the state’s river otters, reflecting sightings by citizen-scientist “otter-spotters.” River Otter Ecology Project director Megan Isadore says the map fills in major gaps in the North Bay and East Bay, increasing otters’ documented range by 4,100 square miles. “It’s interesting to find how well they’re doing in very populated cities,” she says. Absent from the Bay Area for decades, river otters were observed near Tomales in...
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Coyote Valley, an important wildlife corridor connecting the Santa Cruz and Diablo Mountain ranges, would receive new protections under state legislation introduced in April.

AB 948 would create a new Coyote Valley Conservation Program, to be administered by the Santa Clara Open Space Authority. The bill would expand the existing protected area from 7,400 acres to 17,000 acres, and boost new efforts to preserve its resources. Coyote Valley, which drains the ecologically rich upper watershed of Coyote Creek, has long faced development threats as surrounding South Bay communities expand. The area provides critical habitat for critters large and small, which use the valley—especially its...
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Invasive clams and freshwater exports from the Delta have created dramatic and unsustainable changes in the San Francisco Estuary’s foodweb over the past 50 years.

 A study by UC Davis researchers found a 97% decline in phytoplankton, the microscopic foundation of the food chain. “Understanding the causes for the decline in the pelagic [water column] community is essential so that efficient solutions can be implemented,” says Bruce Hammock, a research scientist at the UC Davis School of Veterinary Medicine’s Aquatic Health Program. The invasive clams (Potamocorbula amurensis), originally from Asia, have been over-consuming phytoplankton and zooplankton for more than 30 years, and have long been...
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