Covering 3000 sq km, the Zambezi Delta in Mozambique is one of the most diverse and productive river delta systems in the world. Photo by the European Space Agency.

SCIENCE NEWS: Heating up salmon migration pathways; When ‘eradicated’ species bounce back with a vengeance; Researchers reveal the extent to which rivers across the country are losing flow to aquifers; and more …

Heating up salmon migration pathways

Climate change is turning up the water temperature along migration paths used by anadromous fish species such as Chinook salmon. In a study published in the journal Global Change Biology, researchers predicted the effects of future stream temperatures on Chinook salmon populations (Fitzgerald et al. 2020). They did this by modeling temperature changes in stream networks used for migration and assessed the effects on different life stages of salmon populations with different migration run timings. Their analysis showed that run timing makes a bigger difference than geographic location on how these salmon will be affected by the increasing heat. In particular, fall-run salmon appeared less impacted by thermal stress compared to spring-, winter-, and late-summer run Chinook salmon. In addition, access to cooler historical habitats currently blocked by dams could help mitigate the stress of warming temperatures on these fish. … ”  Read more from FishBio here: Heating up salmon migration pathways

Shasta River Safe Harbor Agreement delivers win for coho salmon and for landowners

Landowners, agencies, and others have made history with a landmark agreement in northern California’s Shasta Valley. The Shasta River Safe Harbor Agreement supports recovery of federally threatened coho salmon while also assuring that a working landscape of farms and ranches will live on.  The voluntary agreement signed in early 2021, culminates an eight-year journey between conservation-minded landowners and the California Department of Fish and Wildlife. Other key partners included California Trout, The Nature Conservancy, and NOAA Fisheries. Through years of education and cooperation, the partners developed a mutual understanding of opportunities for landowners to support recovery of fish protected under the Endangered Species Act and landowners’ needs to maintain viable operations. … ”  Read more from NOAA here:  Shasta River Safe Harbor Agreement delivers win for coho salmon and for landowners

Feds may look at spring-run chinook salmon as genetically distinct

The National Marine Fisheries Service is considering whether the spring-run and fall-run Chinook salmon that occupy the rivers of Northern California and southern Oregon are genetically distinct.  The decision has huge implications for fish populations as the number of spring-run Chinook salmon has plunged to such depths it would almost certainly result in a listing under the Endangered Species Act if seen as a separate species.  “The science is in on that,” said Rich Nawa, an ecologist who petitioned the agency a year ago to consider the spring-run Chinook salmon as genetically distinct. “There are several papers so no one disputes the science, it’s just how to incorporate it into policy at this point.” … ”  Read more from the Courthouse News Service here: Feds may look at spring-run chinook salmon as genetically distinct

When ‘eradicated’ species bounce back with a vengeance

Some invasive species targeted for total eradication bounce back with a vengeance, especially in aquatic systems, finds a study led by the University of California, Davis.  The study, published today in the journal PNAS, chronicles the effort — and failure — to eradicate invasive European green crabs from a California estuary. The crabs increased 30-fold after about 90 percent had been removed. The study is the first experimental demonstration in a coastal ecosystem of a dramatic population increase in response to full eradication.  “A failure in science often leads to unexpected directions,” said lead author Edwin (Ted) Grosholz, a professor and ecologist with the UC Davis Department of Environmental Science and Policy. … ”  Read more from UC Davis here: When ‘eradicated’ species bounce back with a vengeance

Losing Rivers: Researchers reveal the extent to which rivers across the country are losing flow to aquifers

” … The interplay between surface water and groundwater is often overlooked by those who use this vital resource due to the difficulty of studying it. Assistant professors Scott Jasechko and Debra Perrone, of UC Santa Barbara, and their colleagues leveraged their enormous database of groundwater measurements to investigate the interaction between these related resources. Their results, published in Nature, indicate that many more rivers across the United States may be leaking water into the ground than previously realized. … ”  Read more from UC Santa Barbara here: Losing Rivers: Researchers reveal the extent to which rivers across the country are losing flow to aquifers

Field Note: Highlights from the Peter B. Moyle and CalTrout Endowed Professorship

The Peter B. Moyle and California Trout Endowed Professorship was established by a group of donors concerned with the conservation and management of coldwater fishes in California. The endowed chair honors Peter Moyle and the historical and productive working relationship between CalTrout and UC Davis, with an endowment fund resting at over $2 million.  Dr. Andrew L. Rypel was appointed to this professorship as the inaugural holder in 2017, therefore this report reflects year-3 work on behalf of the chair. A total of 13 peer-reviewed scientific publications were produced by the Rypel Lab at UC Davis in 2019-2020. … ”  Read more from Cal Trout here: Field Note: Highlights from the Peter B. Moyle and CalTrout Endowed Professorship

Tetra Tech’s Dr. Sujoy B. Roy discusses modeling and analysis to assess future climate change impacts

Sujoy B. Roy, PhD, a principal engineer in Tetra Tech’s Lafayette, California, office, has more than 25 years of experience in large water-related modeling projects.  “I was drawn to climate change because of the scale and consequences of the problem,” said Dr. Roy. In looking at longer-term infrastructure and future water supply studies, climate considerations are seen less as a separate discipline, and more integrated into ongoing and long-term analyses.  Dr. Roy leads several major interdisciplinary studies related to water resources, water quality, greenhouse gas emissions from water sector projects, and sea level rise impacts, with a particular focus on future growth and climate change. … ”  Read more from CSR Wire here: Tetra Tech’s Dr. Sujoy B. Roy discusses modeling and analysis to assess future climate change impacts

Research Showcase: Hydrological model calibration and rain-on-snow

I am currently a third-year PhD candidate at Indiana University Bloomington, USA, in the Ficklin Hydroclimatology Lab. I use hydrological models to better understand how climate change affects rivers and streams in North America, as part of a collaborative National Science Foundation funded project called HydroClim. I focus on model calibration and rain-on-snow melt simulation. Did you know that there are common pitfalls of calibrating hydrological models with certain time periods of observed data? During my research, I have learned that hydrological models are often calibrated and evaluated without considering how the rivers and streams change over time. … ”  Read more from AGU-3HS here: Research Showcase: Hydrological model calibration and rain-on-snow

Maven’s XKCD Comic Pick of the Week …

 

 


About Science News and Reports: This weekly feature, posted every Thursday, is a collection of the latest scientific research and reports with a focus on relevant issues to the Delta and to California water, although other issues such as climate change are sometimes included. Do you have an item to be included here? Submissions of relevant research and other materials is welcome. Email Maven

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