February 13, 2019

Estuary’s Question of the Month: What is the weirdest species in the Estuary and why?

A fall flight over the Mexican coast where the Colorado River meets the Sea of Cortez offered me a gut-punching, eye-screwing, visual on the results of impaired flow. The semantics of ‘unimpaired’ and ‘impaired’ flow have laced the language of California water management debates since some engineer invented these politically ‘neutral’ terms long ago. The terms refer to our alteration of freshwater flows from snowmelt and runoff by dams and diversions. But whatever the labels, or whichever estuary you’re referring...
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Pied-billed grebes are providing valuable biocontrol services in the Estuary by consuming red swamp crayfish, an invasive crustacean known to disrupt ecosystems.

Although grebes are primarily fish-eaters (they swallow their own feathers to cushion the sharp bones), this species also consumes significant numbers of crayfish, sometimes detaching the pincers before swallowing the good part. Native to southern swamps and bayous, the red swamp crayfish has been introduced in the Sacramento Valley and San Francisco Delta. According to the US Geological Survey, the species is established at Coyote Hills Regional Park and elsewhere around the Bay. The crayfish preys on the larval stages of...
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Haggles over the what, where, and when of Delta conservation got a reset this January with the state’s release of a new collaborative framework focused on opportunities, not species.

The California Department of Fish & Wildlife’s new Delta Conservation Framework tries to fill the vision vacuum left by former Governor Brown’s early pivot away from the 2013 Bay-Delta Conservation Plan, a plan that touched in some shape or way on 160,000 acres of the Delta. “It was too big and too unwieldy for people to manage, and there were too many questions about its effects, and how it would be implemented – particularly as it related to the Delta...
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A gene tells Chinook salmon whether to return to their native streams to spawn in spring, fall, or sometime in-between, according to new research.

The finding, by UC Davis graduate student Tasha Thompson and colleagues, helps distinguish between spring- and fall-run fish—and could help save spring-run salmon from human-hastened extinction. Fall-run populations enter rivers in autumn and spawn immediately. By contrast, spring-run fish return during peak snowmelt, linger in tributaries through summer, and spawn around the same time as their fall-run brethren. “Spring-run fish are special for a lot of reasons,” Thompson says. Spring-run salmon historically spawned in the upper portion of watersheds, nourishing...
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High Sierra lakes are not immune to climate change, but snowpack provides a moderating effect.

Researchers with the University of California analyzed climate and water-temperature data from 19 lakes scattered throughout the Sierra Nevada, including Emerald Lake in Sequoia-Kings Canyon National Park, where UC runs a long-term study site. They found that summer air temperatures at Emerald Lake are warming 1.5 degrees Fahrenheit per decade — a rate lead author Steven Sadro says is as high as nearly anywhere on the planet. Yet to the researchers’ surprise, says Sadro, an assistant professor of Environmental Science...
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For the first time ever, an annual fish-counting survey has turned up zero Delta smelt—a dire milestone in Bay Area aquatic biology.

This does not mean the fish is extinct—yet—but it does mean that the Sacramento-San Joaquin Delta ecosystem is in disarray. The species, which lives its entire life in the estuary, is a key ecological indicator—and it was prolific until just a couple of decades ago. According to the California Department of Fish and Wildlife’s Fall Midwater Trawl survey, which provides an annual index on abundance for several fish species in the Delta, the Delta smelt index generally averaged several hundred fish...
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A marriage of robotics and artificial intelligence promises to automate the detection of harmful algal blooms, which can trigger shellfish harvesting bans and fill wildlife rescue centers with sickened animals.

The Imaging FlowCytobot (IFCB) takes water samples around the clock and photographs phytoplankton cells floating within. “It’s got a huge amount of potential for figuring out what plankton is in the water column and monitoring for HABs,” says Alexis Fischer, a postdoctoral fellow at the University of California, Santa Cruz with Raphael Kudela. Fischer and colleagues are building a phytoplankton image classifier already capable of identifying more than 90 percent of cells photographed by IFCB at the Santa Cruz Wharf. The...
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In 2019 Los Angeles property owners will see a new addition to their tax bill: a tax on impervious surface area to fund stormwater projects.

Measure W, approved by voters last November, will tax residents 2.5 cents per square foot of impermeable surface on their parcels. The initiative will raise an estimated $300 million per year to fund rain gardens, new parks, and watershed restoration in order to capture and clean the precious rainwater sliding off the county’s concrete and asphalt surfaces. Though the county currently captures and stores enough rain to meet the consumption needs of one million residents, the Measure W tax revenue could...
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About Us

The San Francisco Bay-Delta is named in the federal Clean Water Act as one of 28 “estuaries of national significance." For over 20 years, the San Francisco Estuary Partnership has worked together with local communities and federal and state agencies to improve the health of California’s most urbanized estuary.

San Francisco Estuary Partnership 1515 Clay Street, Suite 1400 Oakland, CA 94612 (510) 622-2304

Association of Bay Area Governments