SCIENCE NEWS: Rumble in the river: brook vs. bull trout; Delta smelt on the brink; Hydrologic models may misidentify snow as rain; New method to track genetic diversity of salmon, trout; A promising forecast for predictive science; and more …

Rumble in the river: brook vs. bull trout

In the fictional world of trout wrestling, one of the most uneven matchups would pit brook trout (Salvelinus fontinalis) against bull trout (Salvelinus confluentus). When squaring off in their aquatic ‘ring,’ the invasive and scrappy ‘brookies’ are bullies, outcompeting the native bull trout by eating all the food, hogging the best shelter and generally pushing them around. Brook trout are also opportunists, taking advantage of and spawning with bull trout.  Such a fish face-off recently occurred in the Upper Sprague River watershed north of Klamath Falls, Oregon. The U.S. Fish and Wildlife Service office in Klamath Falls received reports from an angler of brook trout in tributaries of the Sprague River where none had been previously documented. … ”  Read more from the US FWS here: Rumble in the river: brook vs. bull trout

A tiny fish is on the brink of extinction. Does it matter that another just like it is thriving?

California’s tiny delta smelt is not a terribly impressive fish at first glance, and not really at second glance either. It’s about the length and width of a finger, silvery and kind of see-through – looks a bit like a sardine.  They’re not particularly clever or cute, but Mandi Finger, a University of California Davis population geneticist, says the delta smelt do have one weird characteristic going for them.  “They smell amazing,” she said. “They smell like the best version of cucumbers you could ever imagine.”  No one knows why, not for certain.  “I know they smell great though. They really do,” Finger said. “I’ve gotten to smell a delta smelt, you know, before they were all gone.” … ”  Read more from WHYY here: A tiny fish is on the brink of extinction. Does it matter that another just like it is thriving?

Traditional hydrologic models may misidentify snow as rain, new citizen science data shows

Normally, we think of the freezing point of water as 32°F – but in the world of weather forecasting and hydrologic prediction, that isn’t always the case. In the Lake Tahoe region of the Sierra Nevada, the shift from snow to rain during winter storms may actually occur at temperatures closer to 39.5°F, according to new research from the Desert Research Institute (DRI), Lynker Technologies, and citizen scientists from the Tahoe Rain or Snow project.  The new paper, which published this month in Frontiers in Earth Science, used data collected by 200 volunteer weather spotters to identify the temperature cutoff between rain and snow in winter storms that occurred during the 2020 season. Their results have implications for the accuracy of water resources management, weather forecasting, and more. … ”  Read more from the Desert Research Institute here:  Traditional hydrologic models may misidentify snow as rain, new citizen science data shows

Researchers demonstrate new method to track genetic diversity of salmon, trout

Scientists at Oregon State University and the U.S. Forest Service have demonstrated that DNA extracted from water samples from rivers across Oregon and Northern California can be used to estimate genetic diversity of Pacific salmon and trout.  The findings, just published in the journal Molecular Ecology, have important implications for conservation and management of these species, which are threatened by human activities, including those exacerbating climate change. … ”  Read more from Oregon State University here: Researchers demonstrate new method to track genetic diversity of salmon, trout

Advancing steelhead monitoring in the San Joaquin Basin

Studying steelhead (Oncorhynchus mykiss) populations in the rivers of California’s Central Valley has long challenged scientists and managers due to the species’ diverse and complex life history. Although recent initiatives such as the Central Valley Steelhead Monitoring Program (CVSMP) have sought to improve our understanding of steelhead in the Sacramento River Basin, no such concerted efforts have been developed for the San Joaquin River Basin. To begin addressing this gap, the Delta Science Program recently hosted a virtual workshop entitled Monitoring Steelhead Populations in the San Joaquin Basin. Over 200 participants, including experts from state and federal agencies, academia, NGOs, and private consultancies, came together to learn about current steelhead monitoring programs in other watersheds, assess the status of ongoing steelhead monitoring in the Central Valley, and identify opportunities for interagency and stakeholder partnerships to implement an efficient and sustainable steelhead monitoring plan for the San Joaquin Basin. By identifying key gaps in knowledge and defining current management challenges, the workshop outcomes will be used to help develop and design an improved approach to steelhead monitoring in the long overshadowed southern half of the Central Valley. … ”  Read more from FishBio here:  Advancing steelhead monitoring in the San Joaquin Basin

New model reveals how two radically different communities coexist beneath the canopies of California’s iconic kelp forests

Walk along the beach after a winter storm and you’ll see a shore littered with wracks of giant kelp, some 30 to 40 feet long — evidence of the storm’s impact on coastal kelp forests.  Less apparent to the casual beachgoer is what happens to the submarine forests after the storm’s fury dies down. This is precisely the topic of a new study led by Raine Detmer(link is external), a graduate student at UC Santa Barbara. She developed a mathematical model describing the effects of severe storms on kelp forest ecosystems, particularly the seafloor, or benthic, communities. The research, published in Ecology(link is external), reveals an ecosystem whose variability is key to its diversity. … ”  Read more from UC Santa Barbara here: New model reveals how two radically different communities coexist beneath the canopies of California’s iconic kelp forests

Fish food on the floodplain

CalTrout’s science-based approach to grow fish food on floodplains, as part of our Integrate Wild Fish and Working Landscapes initiative, is featured in a new paper in the publication Ecosphere by Ecology Society of America. The article, Understanding community assembly rules in managed floodplain food webs, was authored by members of UC Davis’ Center for Watershed Sciences and California Trout. In summary, it demonstrated that long duration inundation in all types of off-channel floodplain habitat in the Central Valley (bypasses, rice fields, wetlands, flooded ground from levee breaches) consistently results in predictable and rapid set-up of abundant zooplankton assemblages that are high quality forage for native fish species.  … ”  Continue reading from CalTrout here: Fish food on the floodplain

Salmon Smolts: Here Today, Guano Tomorrow

For four months, University of British Columbia master’s student Zachary Sherker tried to solve the case of the missing tracking devices.  From 2008 to 2018, researchers and salmon hatchery staff inserted more than 100,000 tiny passive integrated transponder tags into the abdomens of wild and hatchery-raised salmon smolts to follow their migration to the Pacific Ocean. But thousands of the tags mysteriously vanished.  Across the Pacific Northwest, wild salmon populations are in peril. As many as 50 percent of juvenile salmon in the Cowichan River on southeastern Vancouver Island, British Columbia, for example, die during their downstream migration. But what exactly happens to them, and which predators pick them off, whether birds, mammals, or other fish, has been the subject of ongoing—and sometimes quite heated—debate. … ”  Read more from Hakai Magazine here: Salmon Smolts: Here Today, Guano Tomorrow

For selenium in rivers, timing matters

Selenium contamination of freshwater ecosystems is an ongoing environmental health problem around the world. A naturally occurring trace element, selenium levels are high in some geologic formations like sedimentary shales that form much of the bedrock in the Western United States. Soils derived from this bedrock, and weathering of shale outcrops, can contribute high levels of selenium to surrounding watersheds.  New research out this week in Environmental Science & Technology from UConn Assistant Professor of Natural Resources and the Environment Jessica Brandt with Travis Schmidt and colleagues at the United States Geological Survey (USGS) investigates some of the complexities of selenium and how it moves through the ecosystem  during runoff events and as a result of seasonal irrigation of selenium-enriched soils. … ”  Read more from the University of Connecticut here: For selenium in rivers, timing matters

A promising forecast for predictive science

Leaders at the U.S. Geological Survey (USGS) expect the proliferation of networked devices, inexpensive sensors, and drones to make an explosion of massive data sets available to Earth scientists. At the same time, advances in cloud computing and artificial intelligence will enable more powerful models for understanding these data and using them to project into the future. This is the outlook from the USGS 21st-Century Science Strategy 2020–2030. The report, released in January, describes USGS’s growth from its foundation in traditional observational science to a resource for predictive tools that can guide decision-makers in the management of natural resources and environmental hazards. … ”  Read more from EOS here: A promising forecast for predictive science

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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