|
Nuggets of Bay-Delta news—pearls in the ocean of information—curated by the reporters and editors of ESTUARY News magazine.
|
|
|
Help may be on the way for critically endangered southern resident killer whales, as NOAA Fisheries and the Washington Department of Fish and Wildlife have partnered to produce a list of the west coast Chinook salmon stocks most important to the whale’s survival. This list comes as a part of a special action plan by NOAA to address the three primary threats to the southern resident killer whales: Chemical contaminants, vessel traffic, and lack of prey. The salmon, themselves endangered, are the preferred food source for the whales; identifying the salmon runs—including several Sacramento River and San Joaquin River runs—that most overlap with the range of the southern residents could be crucial to their eventual recovery. “Those fish support not only the commercial fishery but the whales as the salmon migrate north from the Golden Gate,” says Michael Milstein of the National Marine Fisheries Service. “We know they are highly intelligent and they may be handing down information through generations as to where to look for salmon.” In July, marine biologists across the world watched in fascination–and heartbreak–as a female southern resident killer whale refused to abandon her newborn calf for days after it had perished, probably as a result of the mother’s malnutrition. “These whales are truly a ‘West Coast’ population,” Milstein explains. “It’s not about any one stock being more important than the others, but rather the whole range providing them with variety as they travel through areas where they have historically found plenty.” MHA
Photo: John Durban (NOAA Fisheries/Southwest Fisheries Science Center), Holly Fearnbach (SR3: SeaLife Response, Rehabilitation and Research) and Lance Barrett-Lennard (Vancouver Aquarium’s Coastal Ocean Research Institute)
|
|
|
California’s Wild and Scenic Rivers System expanded for the first time in 13 years in June when Governor Edmund G. Brown Jr. signed legislation protecting 37 miles of the upper Mokelumne River. It was the culmination of a long struggle for the Jackson-based Foothill Conservancy and other river advocates. Four years ago, a Mokelumne bill was approved by the state Senate but killed by a parliamentary maneuver that blocked a vote in the Assembly. Despite significant support in Calaveras and Amador counties, the bill was opposed by local water agencies concerned about the potential impact on their water rights. In 2015 Assemblyman Frank Bigelow (R-O’Neals) successfully proposed a state study of the Mokelumne’s suitability for wild and scenic designation. The resulting California Natural Resources Agency report, released in April, recommended protected status with special provisions ensuring water agencies’ existing rights and ability to apply for new rights. “All of the affected water agencies, Foothill Conservancy, Friends of the River, and the Natural Resources Agency worked out language everyone could live with,” says Conservancy president Katherine Evatt. She adds that a credible state study “made it easier for the water agencies to come on board.” Although existing dams will remain in place, they can’t be enlarged, and new onstream dams are barred on 5 segments of the Mokelumne’s north fork and main stem. For more on this story see the upcoming September 2018 issue of Estuary News. JE
Photo courtesy of Foothill Conservancy
|
|
|
|
Nighttime lights on bridges shining into bays and rivers can attract and confuse fish as they migrate at night, leaving them vulnerable to predation. “Well-lighted bridges and dams can create twilight conditions that predators love, especially other fish,” says Peter Moyle, professor emeritus at UC Davis. He recounts that at one point the Red Bluff Diversion Dam was lit up at night and pikeminnow took the opportunity to prey on juvenile salmon. “Opening up the gates helped because the pikeminnow were headed upstream to spawn so didn’t really want to be there, and the juvenile salmon could move past the dam quickly at night.” The Sundial Bridge in Redding is thought to have contributed to low numbers of fall-run Chinook salmon on the Sacramento River between 2011 and 2013. The Bay Institute’s Jonathan Rosenfield agrees that the problem from lights should be mitigated whenever possible but wants to make sure the many other stressors the fish face are not forgotten. Says Rosenfield, “[These fish] are plagued by numerous problems, most of which are related to reservoir and river management.” LOV
|
|
|
California sea lion nurseries are moving north as Año Nuevo Island and the southeast Farallon Islands experience a record-breaking boom in sea lion births. Zalophus californianus have traditionally preferred nurseries in the Channel Islands, but the population of pups born off Northern California’s coast began skyrocketing in 2016. Births at both sites went from a few dozen pups to more than 500. The trend has only intensified since; more than a thousand pups born at the Farallones, and between 500 and 700 at Año Nuevo, in 2017 according to NOAA; similar numbers are expected this year, although final counts are not yet available. Such high census numbers are unprecedented since robust surveys began in 1975. The move appears to coincide with the onset of “the blob,” a marine heat wave that formed off the California coast starting in 2014. California sea lions prey on species that get scarce during warm water conditions. Burgeoning sea lion numbers and the need for more rookery sites could also help explain the expansion to northern nurseries. A coalition of scientists from UC Santa Cruz, the UC Natural Reserve System, and NOAA’s Marine Mammal Laboratory is studying the phenomenon. Great white sharks also have changed their habits during recent warm water conditions. Instead of migrating further south in late fall, young great whites took advantage of the balmy temperatures and lingered near the southern California coast year round. KW
Photo: Patrick Robinson/UCSC
|
|
|
California’s groundwater faces widespread chromium contamination risk resulting from natural, rather than industrial sources. Chromium’s toxic form, known as hexavalent chromium, is used in steel manufacturing, leather tanning, and wood treatment; its lethal effects were popularized in the 2000 movie Erin Brockovich. But today transformation of the benign form of chromium naturally found in soils poses the larger risk, according to a recent Stanford University study. Dr. Debra Hausladen and her colleagues used a statewide groundwater database to trace the origin of 90,000 chromium samples, and discovered toxic chromium from natural sources is affecting a much higher population and area in California than exposure from industrial sources. (The image above shows the concentration of average hexavalent chromium distribution per square kilometer in California groundwater from supply and monitoring wells.) Due to the high occurrence of toxic hexavalent chromium in regions such as Central Valley, the researchers suspect groundwater pumping and other human activities play a role in converting the natural chromium in its benign state to its toxic form. “As we continue to push the need to use and manage groundwater, understanding how these naturally occurring contaminants can jeopardize water becomes really, really important,” Professor Scott Fendorf told the Stanford Report. Last year, the California State Water Resources Control Board withdrew the 10 micrograms per liter hexavalent chromium drinking water standard in adopted in 2014, after a court ruled state regulators failed to adequately consider the economic burden imposed by the chromium standard. Until the new regulation is determined, California will adopt an interim standard of 50 micrograms per liter until a new regulation is determined. IP
Image courtesy of Debra Hausladen and Scott Fendorf
|
|
|
A new online portal from the Delta Stewardship Council offers everyone from scientists to tourists an accessible window into the Delta’s identity and importance. “Although I had studied freshwater and marine ecology, I really was not familiar with the Delta before I started working there,” says 2017 Sea Grant Fellow Heidi Williams, who developed the Beginner’s Guide to the Sacramento-San Joaquin Delta. “I was looking for a way to dive in and learn about the Delta and realized that there wasn’t an easily accessible place to turn for the basics.” As a science communications fellow, Williams suggested to the Council that she create one herself, and spent the next year immersed in Delta-related articles and other materials. “I realized that this needed to be more up-to-date than a lot of that material, because a lot of science and politics have changed and progressed in the last few years,” she says. The guide is comprised of eight main sections: laying the groundwork, history of the Delta, the Delta as place, a Delta tour, the Delta as an ecosystem, Delta challenges, management context, and additional resources. The format is inspired by long-form digital storytelling platforms that have been used effectively by The New York Times and others. It makes extensive use of interactive features such as clickable maps, audio clips, and pull quotes. “The hope is that no matter how much experience someone has with the Delta, they can walk away from this guide having learned something new,” say Williams. CHT
|
|
|
Innovative stormwater management strategies throughout California are pioneering new ways to capture and use stormwater to augment local water supplies and prepare for climate change, according to a new Pacific Institute report. “Stormwater has traditionally been considered a nuisance or danger in terms of flooding and water quality,” says Morgan Shimabuku, lead author of Stormwater Capture in California: Innovative Policies and Funding Opportunities, “But we’re starting to see it as more of a resource with potential for water supply.” Shimabuku notes that stormwater capture is also “a great strategy for adapting to climate change, alleviating the impact of high-intensity rainstorms and reducing dependence on other water sources in times of drought.” The report describes innovations in stormwater management in the Bay Area and beyond, including recent San Francisco ordinances that require builders of projects with large impervious surfaces to install and maintain stormwater capture infrastructure; projects larger than 250,000 square feet must treat and reuse all water, including stormwater, onsite. San Mateo County uses a vehicle registration surcharge to pay for permeable pavement, reducing polluted road runoff and helping to recharge groundwater. Stormwater is part of Santa Monica’s strategy for achieving water independence by 2022, while elsewhere in California it’s being used to recharge groundwater basins. Funding remains a challenge: “In California, state-level entities need to find more funding to support local stormwater capture projects,” says Shimabuku. That could include tapping into federal Clean Water and Drinking Water Revolving Funds that the state disburses. Recent legislation might allow local governments to create stormwater capture fees without voter approval, but that may only be determined once a test case works its way through the courts. JE
|
|
|
|
The latest casualty in America’s opioid epidemic is a small invertebrate that filters pollutants and feeds hungry shorebirds. Biologists testing mussels in the waters around Seattle as part of the Puget Sound Mussel Monitoring Program found oxycodone in mussel tissue for the first time, along with antibiotics, antidepressants, chemotherapy drugs, and heart medications. “We have found evidence that these chemicals are in our nearshore marine waters and are being taken up by marine biota living there,” said Washington Department of Fish & Wildlife biologist Jennifer Lanksbury. She also tested juvenile Chinook salmon in Puget Sound estuaries and found similar results, with the fish being exposed to multiple human medications and other products. The mussels tested were not wild mussels but clean mussels the researchers had transplanted from an aquaculture farm on Whidbey Island to locations near the port of Seattle and the Bremerton shipyard.“Our results do not directly represent contaminants in wild mussels, and they are restricted only to the areas in Puget Sound that we tested,” cautions Lanksbury. She says oxycodone and other human medications likely came from treated wastewater from local sewage treatment plants, stormwater runoff carrying untreated sewage from cities or towns, or even leaking septic tanks in more rural areas. Because marine organisms are being exposed to more than one medication at a time, Lanksbury is concerned that there could be synergistic or multiplicative effects, but she stresses that further testing is needed. LOV
Above: Mussel researcher Jennifer Lanksbury. Photo: Carla Vincent
|
|
|
|
Editor: Cariad Hayes Thronson
Contributors: Michael Adamson, Joe Eaton, Isaac Pearlman, Lisa Owens Viani, Kathleen Wong
|
|
|
|
|
|
