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 perhaps because they’re not game fish, or particularly large, or traditionally “charismatic” — theirs are not household names.
To the extent that they are recognized by the general public at all, some are even referred to, somewhat derisively, as “rough” fish: essentially, not a desirable catch. But they are winners in their own way, living reminders of a pre-development Delta, still playing an active role in this highly modified ecosystem.
Who are they, and more importantly, what’s their secret?
Art: Adi Khen
Tule perch
These small yet deep-bodied, often yellowish, barred fish are native to Clear Lake, the Russian River, the San Francisco Estuary, and the low-elevation rivers and streams of the Sacramento-San Joaquin watershed. Tule perch survival in the Delta seems to stem from a few key factors. They give birth to young that are like miniature adults, able to swim away immediately and to feed freely on the same food as their parents. They have a robust physiology as estuary dwellers that allows them to live in a range of salinities. Perhaps most critically, they eat invertebrates that are not favored by other fishes, particularly on the bottom and among the tule reeds, including some non-native amphipods.
“The fish don’t care, as long as it’s nutritious,” says Peter Moyle, distinguished professor emeritus at the UC Davis Center for Watershed Sciences. “It’s an abundant food source that not many other fish are exploiting.”
Dylan Stompe, a fisheries researcher and PhD student at Davis, notes that since tule perch can tolerate totally fresh as well as mixed-salinity water, the Delta population benefits from a stable source upstream in tributary river systems. “More fish are constantly getting fed into the system,” Stompe says. “I think that’s another thing that’s helped them.”
Photo: James Ervin
Prickly sculpin
In addition to a name that tumbles off the tongue, prickly sculpin are fortunate to possess a devil-may-care attitude about housing. They’re happy as a clam in riprap, which lines much of the lower Delta, finding it a perfect place to live and spawn. They’ve also been seen living among old car bodies and other large boulders and stones.
“There’s a variety of invertebrates that live in that environment, and they’re less susceptible to predation when they’re in deep cover like that,” says Moyle, who somewhat famously once wrote that prickly sculpin will even use beer cans as nesting habitat.
Prickly sculpin can deal with a range of temperatures and salinities, including in rivers above the Delta. In fact, these adaptable fish are found up and down the Pacific Coast from Alaska to Southern California, and classified as a species of least concern. “They’re all over the place,” Stompe says.
U.S. Bureau of Reclamation biologist Brian Mahardja notes that prickly sculpin population trends in the Delta aren’t fully understood due to a lack of targeted monitoring. “But because their larvae are pelagic, and we do a lot of pelagic [open water] sampling,” he says, “we at least know that their larval numbers are still relatively high despite all the changes that have happened to the Delta.”
Art: Adi Khen
Threespine stickleback
The tiny threespine stickleback, usually measuring about 1 to 1.5 inches in length, is commonly found in the Suisun Marsh. There it loves weedy tidal ponds, such as those produced by duck clubs, for both feeding and rearing.
The fish plays an interesting part in a novel foodweb in the marsh, which is populated by both native and non-native species, Moyle says. Sticklebacks happily feed on non-native plankton and are in turn an important food of non-native striped bass, which also eat non-native gobies. “These fish behave almost like they’ve been living together forever, even though this relationship is more recent,” Moyle says.
Beyond Suisun, stickleback can be found in decent numbers throughout the Delta and San Francisco Bay, Mahardja notes. In fact, the fish are so adaptable that they are of high interest to researchers studying evolution. “I see this species as being less dependent on the estuary and perhaps more resilient to climate change as a result,” he says.
Photo: James Ervin
Sacramento sucker
Known for its fleshy or “swollen” lips, the slender Sacramento sucker, which can grow to almost two feet in length, is a long-lived benthic omnivore that hangs along the stream or channel bottom, where it feeds on algae, invertebrates, and detritus — “whatever is down there,” Stompe says.
Its success is further aided by productivity. In spring, suckers migrate upstream from the Delta to spawn — often in streams that are low or dry in summer, Moyle notes — and females can lay tens of thousands of eggs per spawning period.
Sacramento sucker populations in the Delta and Suisun Bay are also supported by a healthy base higher in the Sacramento River, which, as with tule perch, is perennially feeding fish back into the system.
And similar to stickleback, Mahardja suggests, Sacramento suckers’ lower reliance on the estuary itself may help it better withstand climate change and further modifications to the Delta ecosystem.
Brian Williamshen holds Sacramento splittail. Photo: Teejay O’Rear.
Sacramento splittail
Of all the fish on this list, the Sacramento splittail, a large minnow, is most at risk. Though currently listed as a species of least concern by the International Union for the Conservation of Nature, it was previously classified as endangered. Similarly, Sacramento splittail were considered threatened by the U.S. Fish and Wildlife Service until 2003; in 2010 the agency ruled that the fish did not warrant protection under the Endangered Species Act. It is currently listed as a species of special concern by the California Department of Fish and Wildlife.
Sacramento splittail’s vulnerability lies in the fact that to reproduce it depends on the floodplain, a Delta habitat that has been heavily modified and largely lost. “When they’re ready to spawn they swim upstream and spawn on floodplains,” especially in the Yolo Bypass and the Consumnes River floodplain, Moyle notes. “Juveniles rear for a short period of time there, then they bail out when flood recedes, then head downstream to Suisun Marsh to grow up and repeat that lifecycle.”
The challenge for splittail, Stompe adds, is that since most historical floodplains in the Delta are gone, they’re reliant on big outflow events to create suitable reproductive habitat. “They need to be able to weather the bad years in order to have a spawning stock and produce a bunch more fish.” Climate change is likely to further challenge the fish through longer droughts and less frequent, more severe flood events.
Detection probability of Sacramento splittail and threespine stickleback in the San Francisco Estuary based on eight surveys between 1980 and 2017 (and expressed as spatial slopes). Red indicates regions of decline, and blue regions of increase, in detection probability. Source: Dylan Stompe
The Big Picture
No working Delta scientists specialize in studying these fish on their own, since the research money goes toward other species — imperiled fish, sport fish, problematic non-natives. What we know about their populations is gleaned from surveys targeting other fish, or, as in the case of the monthly Suisun Marsh Fish Study, now in its 42nd year, the entire community.
Though these five species don’t necessarily live together, looking at them as their own little group reveals common keys to survival. None are pelagic, or open-water fish, like Delta smelt; instead they spend their lives along the bottom or the shore. “There’s no decent water cool-water pelagic habitat left in the Delta,” notes Teejay O’Rear, a field supervisor in Moyle’s lab at Davis who leads sampling and data collection for the Suisun Marsh survey.
Another commonality is that they can tolerate different salinities and temperatures, allowing them to inhabit not only the estuary but also rivers and reservoirs, and rivers above the reservoirs. “Fish can tumble out of there and repopulate when conditions are right,” O’Rear says.
And finally, O’Rear adds, none are “domesticated” (raised in hatcheries) like many local salmon: “They actually know how to find food and how to evade predators and things like that.”
Granted, these fish likely aren’t as abundant in the Delta and upstream habitats as they once were. But they’re not in trouble as far as we can tell, either. Against all odds — despite the alterations to their habitat and a lack of focused efforts to protect them — they’re still hanging in there, in relatively good numbers. “They’re to be paid attention,” Moyle says. “They’re survivors.”
Top photo: Threespine stickleback. Photo: James Ervin
Nate Seltenrich is a freelance science and environmental journalist who covers infrastructure, restoration, and related topics for Estuary. He also contributes to the San Francisco Chronicle, Sonoma and Marin magazines, the journal Environmental Health Perspectives, and other local and national publications, on subjects ranging from public lands and renewable energy to the human health impacts of climate change. He lives in Petaluma with his wife, two boys, and four ducks. www.nate-reports.com
Our magazine’s media motto for many years has been “Where there’s an estuary, there’s a crowd.” The San Francisco Estuary is a place where people, wildlife, and commerce congregate, and where watersheds, rivers and the ocean meet and mix, creating a place of unusual diversity. In choosing to tell the...
Ever since the state and federal water projects were built in the 1930s and 1940s, California has captured snowmelt in foothill reservoirs, and moved the fresh water from dam releases and river outflows to parched parts of the state via aqueducts hundreds of miles long. A convoluted system of ancient...
Though the Clean Water Act did an amazing job of reducing wastewater and stormwater pollution of the San Francisco Estuary, some contaminants remain thorny problems. Legacy pollutants like mercury washed into the watershed from upstream gold mining, PCBs from old industrial sites, and selenium from agricultural drainage in the San...
Hothouse Earth
By Ariel Rubissow Okamoto
Photo by Megan Nguyen
Nothing could be stranger than sitting in the dark with thousands of suits and heels, watching a parade of promises to decarbonize from companies and countries large and small, reeling from the beauties of big screen rainforests and indigenous necklaces, and getting all choked up.
It was day two of the September 2018 Global Climate Action Summit in San Francisco when I felt it.
At first I wondered if I was simply starstruck. Most of us labor away trying to fix one small corner of the planet or another without seeing the likes of Harrison Ford, Al Gore, Michael Bloomberg, Van Jones, Jerry Brown – or the ministers or mayors of dozens of cities and countries – in person, on stage and at times angry enough to spit. And between these luminaries a steady stream of CEOs, corporate sustainability officers, and pension fund managers promising percentages of renewables and profits in their portfolios dedicated to the climate cause by 2020-2050.
I tried to give every speaker my full attention: the young man of Vuntut Gwichin heritage from the edge of the Yukon’s Arctic National Wildlife Refuge who pleaded with us not to enter his sacred lands with our drills and dependencies; all the women – swathed in bright patterns and head-scarfs – who kept punching their hearts. “My uncle in Uganda would take 129 years to emit the same amount of carbon as an American would in one year,” said Oxfam’s Winnie Byanyima.
“Our janitors are shutting off the lights you leave on,” said Aida Cardenas, speaking about the frontline workers she trains, mostly immigrants, who are excited to be part of climate change solutions in their new country.
The men on the stage, strutting about in feathers and pinstripes, spoke of hopes and dreams, money and power. “The notion that you can either do good or do well is a myth we have to collectively bust,” said New Jersey Governor Phil Murphy whose state is investing heavily in offshore wind farms.
“Climate change isn’t just about risks, it’s about opportunities,” said Blackrock sustainable investment manager Brian Deese.
But it wasn’t all these fine speeches that started the butterflies. Halfway through the second day of testimonials, it was a slight white-haired woman wrapped in an azure pashmina that pricked my tears. One minute she was on the silver screen with Alec Baldwin and the next she taking a seat on stage. She talked about trees. How trees can solve 30% of our carbon reduction problem. How we have to stop whacking them back in the Amazon and start planting them everywhere else. I couldn’t help thinking of Dr. Seuss and his truffala trees. Jane Goodall, over 80, is as fierce as my Lorax. Or my daughter’s Avatar.
Analyzing my take home feeling from the event I realized it wasn’t the usual fear – killer storms, tidal waves, no food for my kids to eat on a half-baked planet – nor a newfound sense of hope – I’ve always thought nature will get along just fine without us. What I felt was relief. People were actually doing something. Doing a lot. And there was so much more we could do.
As we all pumped fists in the dark, as the presentations went on and on and on because so many people and businesses and countries wanted to STEP UP, I realized how swayed I had let myself be by the doomsday news mill.
“We must be like the river, “ said a boy from Bangladesh named Risalat Khan, who had noticed our Sierra watersheds from the plane. “We must cut through the mountain of obstacles. Let’s be the river!”
Or as Harrison Ford less poetically put it: “Let’s turn off our phones and roll up our sleeves and kick this monster’s ass.”
4th California Climate Change Assessment Blues
by Isaac Pearlman
Since California’s last state-led climate change assessment in 2012, the Golden State has experienced a litany of natural disasters. This includes four years of severe drought from 2012 to 2016, an almost non-existent Sierra Nevada snowpack in 2014-2015 costing $2.1 billion in economic losses, widespread Bay Area flooding from winter 2017 storms, and extremely large and damaging wildfires culminating with this year’s Mendocino Complex fire achieving the dubious distinction of the largest in state history. California’s most recent climate assessment, released August 27th, predicts that for the state and the Bay Area, we can expect even more in the future.
The California state government first began assessing climate impacts formally in 2006, due to an executive order by Governor Schwarzenegger. California’s latest iteration and its fourth overall, includes a dizzying array of 44 technical reports; three topical studies on climate justice, tribal and indigenous communities, and the coast and ocean; as well as nine region-specific analyses.
The results are alarming for our state’s future: an estimated four to five feet of sea level rise and loss of one to two-thirds of Southern California beaches by 2100, a 50 percent increase in wildfires over 25,000 acres, stronger and longer heat waves, and infrastructure like airports, wastewater treatment plants, rail and roadways increasingly likely to suffer flooding.
For the first time, California’s latest assessment dives into climate consequences on a regional level. Academics representing nine California regions spearheaded research and summarized the best available science on the variable heat, rain, flooding and extreme event consequences for their areas. For example, the highest local rate of sea level rise in the state is at the rapidly subsiding Humboldt Bay. In San Diego county, the most biodiverse in all of California, preserving its many fragile and endangered species is an urgent priority. Francesca Hopkins from UC Riverside found that the highest rate of childhood asthma in the state isn’t an urban smog-filled city but in the Imperial Valley, where toxic dust from Salton Sea disaster chokes communities – and will only become worse as higher temperatures and less water due to climate change dry and brittle the area.
According to the Bay Area Regional Report, since 1950 the Bay Area has already increased in temperature by 1.7 degrees Fahrenheit and local sea level is eight inches higher than it was one hundred years ago. Future climate will render the Bay Area less suitable for our evergreen redwood and fir forests, and more favorable for tolerant chaparral shrub land. The region’s seven million people and $750 billion economy (almost one-third of California’s total) is predicted to be increasingly beset by more “boom and bust” irregular wet and very dry years, punctuated by increasingly intense and damaging storms.
Unsurprisingly, according to the report the Bay Area’s intensifying housing and equity problems have a multiplier affect with climate change. As Bay Area housing spreads further north, south, and inland the result is higher transportation and energy needs for those with the fewest resources available to afford them; and acute disparity in climate vulnerability across Bay Area communities and populations.
“All Californians will likely endure more illness and be at greater risk of early death because of climate change,” bluntly states the statewide summary brochure for California’s climate assessment. “[However] vulnerable populations that already experience the greatest adverse health impacts will be disproportionately affected.”
“We’re much better at being reactive to a disaster than planning ahead,” said UC Berkeley professor and contributing author David Ackerly at a California Adaptation Forum panel in Sacramento on August 27th. “And it is vulnerable communities that suffer from those disasters. How much human suffering has to happen before it triggers the next round of activity?”
The assessment’s data is publicly available online at “Cal-adapt,” where Californians can explore projected impacts for their neighborhoods, towns, and regions.
The results are alarming for our state’s future: an estimated four to five feet of sea level rise and loss of one to two-thirds of Southern California beaches by 2100, a 50 percent increase in wildfires over 25,000 acres, stronger and longer heat waves, and infrastructure like airports, wastewater treatment plants, rail and roadways increasingly likely to suffer flooding.