The CRISPR technique used to edit DNA has been formulated into a tool that can distinguish between similar-looking California fish species for conservation research. Called SHERLOCK (Specific High-sensitivity Enzymatic Reporter unLOCKing), the tool can tell the difference between species with speed and accuracy. Better yet, it is both inexpensive and can be run while researchers are in the field. “It puts the power in the hands of the field biologist to make the most informed decision versus waiting sometimes days or weeks for lab results,” says Melinda Baerwald, an environmental program manager with the California Department of Water Resources. Traditionally, scientists wishing to verify the identity of a salmon or a smelt had to send samples of fish tissue to...Read More
Standard smelt surveys rely on the use of boat-driven nets, which trap fish by funneling them from the wide mouth of the net to the closed end (known as the cod end). To check their catch, researchers must pull the net and its contents from the water. But this additional handling can harm and even kill the same fish that wildlife agencies are trying to save with the support of robust, long-running monitoring efforts. There may be a better way: According to a new study in the June 2021 issue of San Francisco Estuary and Watershed Science, the use of an underwater camera—the “SmeltCam,” developed about a decade ago by U.S. Geological Survey (USGS) research fish biologist Frederick Feyrer—could provide...Read More
Decades ago, resource managers first learned of declining Delta smelt numbers not through surveys targeting the once-abundant native fish, but rather as a byproduct of long-term monitoring programs for non-native striped bass. Now, the authors of a new study published in the March 2021 issue of San Francisco Estuary and Watershed Science advocate for the use of bycatch data from the recently established Enhanced Delta Smelt Monitoring (EDSM) program to better understand juvenile Chinook salmon distribution. “The scope of [this multi-million dollar Delta smelt survey] has not really been seen before in the Estuary,” says lead author Brian Mahardja, a biologist with the US Bureau of Reclamation, “that’s why there was a call to see what else we can gain...Read More
Scientists know that smelt use tidal ebbs and flows to migrate landward to spawn, but the degree to which external cues influence behavior remains unclear. In a new study published in the March 2021 issue of San Francisco Estuary and Watershed Science, researchers used computer modeling to predict smelt distribution based on hypothesized swimming behaviors. Six increasingly complex behaviors were tested. For example, the “passive” category assumes that smelt do not swim at all, simply drifting with currents and tides. At the other end of the spectrum, the smelt respond to both turbidity and salinity cues. After assigning a behavior to simulated smelt distributed across the Delta, researchers ran a 133-day simulation of water year 2002, then compared the modeled...Read More
In a new study published in the March 2021 issue of San Francisco Estuary and Watershed Science, researchers Lenny Grimaldo, William Smith, and Matthew Nobriga used advanced statistical approaches to understand what factors best predict Delta smelt entrainment at the pumps. The paper builds upon research that Grimaldo conducted in the 2000s, which provided the basis for regulations established in the 2008 Delta smelt Biological Opinion. “This study reinforces previous work that adult Delta smelt salvage is largely explained by hydrodynamics, water clarity (turbidity), precipitation, and sub-adult abundance,” the authors write. Historically, when large numbers of smelt began to appear in the salvage screens of the Delta pumps, pumping would be curtailed. Today, Grimaldo says, the fish are so rare...Read More
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 response to predation pressure from native fish or birds. Was the bass, introduced in the late 19th century, one predator too many, or too effective? Nobriga notes that Delta smelt don’t respond predictably to changing flows: “From what we know...Read More
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 Life Cycle project being rolled out this month; his model of adult smelt entrainment was published in the December issue of San Francisco Estuary and Watershed Science (a separate model for postlarval smelt will appear in another journal). “Adults exhibit...Read More
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 into the early 2000s. Then, in about 2003, numbers of Delta smelt, as well as several other native fishes, began to plunge. To Jonathan Rosenfield, the lead scientist with The Bay Institute, it’s clear what’s going on. “The one thing...Read More
Walk back through time with this selection of early stories from Estuary's first two decades of publication. In those days, the smelt was at the center of lawsuits, regulatory battles, and debates over recovery criteria under the ESA. Little has changed, except there are now far fewer smelt.Read More
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.