By

Joe Eaton
About the author

Joe Eaton writes about endangered and invasive species, climate and ecosystem science, environmental history, and water issues for ESTUARY. He is also "a semi-obsessive birder" whose pursuit of rarities has taken him to many of California's shores, wetlands, and sewage plants.

Articles by Joe Eaton

Heavy Lifting for Fish

Ted Frink recalls watching Jacques Cousteau’s television specials when he was growing up in coastal Orange County. “I envisioned myself as Cousteau,” says Frink, a fisheries biologist with the California Department of Water Resources (DWR) now approaching retirement. “My folks encouraged my interest in science. I knew I could be a biologist.” That early inspiration sparked a long and varied career, culminating in his work as chief of DWR’s Special Restoration Initiatives Branch and his role in mitigating obstacles to...
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Makeover for Delta Weed Patch & Salt Trap?

What began as a project to convert a submerged Delta island into habitat for endangered native fish has morphed into a multi-benefit package with additional payoffs for water quality and recreation. The collaborative design process for the Franks Tract Futures project brought initially skeptical local stakeholders on board and is being hailed as a model for future initiatives. Yet major uncertainties remain as interested parties explore the challenges of implementing a complex redesign of a big chunk of the Delta....
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Yet another non-native aquatic species may have made itself at home in the Delta.

As described by US Fish and Wildlife Service fish biologist Brian Mahardja and his co-authors in San Francisco Estuary & Watershed Science, the newcomer is an inch-long, minnow-like fish called the bluefin killifish (Lucania goodei), indigenous to Florida and adjacent southeastern states. It was first detected in the Delta Cross Channel during a beach seine survey in October 2017, and subsequently found in Beaver and Hog sloughs and at Decker, Sherman, and Brannan islands. With surveys curtailed by the coronavirus...
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Two recent exercises in modeling the hydrological effects of forest thinning and wildfire are yielding intriguing insights.

Hydrogeologist Fadji Maina and colleague Erica Siirila-Woodburn of the Lawrence Berkeley National Laboratory ran simulations of wildfire effects in the Cosumnes River watershed (see map). “We chose the Cosumnes because it’s one of the largest rivers that has no dam in California,” explains Maina. The most significant findings concerned the way wildfire affects groundwater recharge and storage. “It depends on where the wildfire occurs,” says Maina. The underlying rocks—foothill volcanics or High Sierra granites—make a difference. Consistent with earlier studies, the model also...
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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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Parks and Cities Seek Shore Resilience

By Joe Eaton For Alameda County, climate vulnerability is no abstraction. King tides push the waters of San Leandro Bay into parking lots at Martin Luther King Regional Shoreline. When Diablo winds rattle the eucalyptus, Berkeley and Oakland hill-dwellers recall the conflagrations of 1923 and 1991 and dread the next one. The county feels the bite of both edges of the climate sword: fire and flood. With highways, BART, a major airport and seaport, business parks, and sports complexes, the...
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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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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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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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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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New Regional Rainmaker

By Joe Eaton Environmental issues were important to Michael Montgomery as a young man. Montgomery’s career path led to 33 years with the United States Environmental Protection Agency, where he gained a wealth of experience in navigating complex regulatory landscapes to protect water resources, and ultimately to the San Francisco Bay Regional Water Quality Control Board, where he is now executive officer. “The Bay Area has a strong tradition of coming up with collaborative solutions,” he says. That’s how he...
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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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Tailing a Thrush

By Joe Eaton Researchers like Point Blue Conservation Science ecologist Tom Gardali have equipped Swainson’s thrushes, weighing just over an ounce, with tiny, one-gram GPS tags. If recovered, the tag shows the thrush’s exact winter destination, information vital to border-crossing conservation efforts. “You only get a few readings,” says Gardali, “and you still need to get the tag back. But GPS goes to a spot on the map. This is Holy Grail stuff.”  Sierra/Cascade thrushes were presumed to migrate to...
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Brinkmanship for Frail Smelt

By Joe Eaton Delta smelt had a bad year in 2017. Although scientists are still analyzing the data, the message seems to be that strong freshwater flows alone are not sufficient to allow the population to increase. The resulting sense of urgency has led fish biologists to consider how cultured smelt, raised in hatcheries, could be used to supplement the wild population. “We’ve considered the cultured smelt as a lifeboat,” says California Department of Water Resources biologist Ted Sommer. “Now...
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Jessica Fain got a crash course in resilience planning when Hurricane Sandy hit the East Coast in 2012.

Fain, Planning Director for the Bay Conservation and Development Commission (BCDC) since October, was part of a three-person office in the Waterfront and Open Space Division of New York’s Department of City Planning. “We were doing a small study on adaptation options,” she recalls. “In the middle of that, Sandy hit. Suddenly all eyes were on us.” Fain brings that background to a setting unlike New York in many ways. Instead of five boroughs, for example, she’s dealing with a...
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Getting a Bead on Table Salt

By Joe Eaton Microplastics are present in the San Francisco Bay, and at higher concentrations than Chesapeake Bay or the Great Lakes, according to a San Francisco Estuary Institute study led by Rebecca Sutton. There’s “a lot of uncertainty about potential impacts to people and wildlife,” she says.“[Miicroplastics are] a variable contaminant and challenging to interpret.” What we know is sufficient cause for concern: apart from their physical impacts, plastics can absorb other pollutants and some plastic ingredients are known...
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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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Green Cement Blues

For the last three years, an environmental storm has been brewing in the North Bay city of Vallejo. Some elements of the story are familiar: grassroots activists pitted against a multinational corporate developer, environmental justice versus the lure of new jobs. Add historical preservation, iconic wildlife, political shenanigans, and the unexpected involvement of the California Attorney General’s office, and the mix becomes more complex. An Irish cement company and its local partners want to build a processing plant and a...
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The Nature Conservancy’s venture in growing food crops for wintering cranes on Staten Island is under fire from an unexpected source—the Wetlands Preservation Foundation.

The nonprofit, headed by Stockton tomato packer Dino Cortopassi, is suing TNC and the California Department of Water Resources, which holds a conservation easement on Staten Island, alleging farming practices that cause soil subsidence and threaten levee integrity, and misuse of revenue from farm operations. The 9200-acre farm, acquired by TNC in 2001, is a major destination for migratory greater and lesser sandhill cranes (the latter a California endangered species) as well as Aleutian cackling geese and other birds. As...
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