SCIENCE NEWS: Reconsidering IEP sampling programs; Temperature management for salmon; The role of sex and genes in steelhead migration; Survivor: Salmon edition; and more …

Reconsidering IEP Sampling Programs

Dr. Steve Culberson writes, “The Interagency Ecological Program (IEP) has been monitoring in the San Francisco Estuary for a long time. With the passing of IEP’s 50-year Anniversary in 2020, I’ve been doing some reflecting on where we’ve been, and where we’re headed. There’s lots to say (for future blogs, perhaps?!), and recount, and hope for, but one thing is clear to me as the IEP Lead Scientist — we must review and revise our data collection programs.  What do I mean when I say “review and revise our data collection programs?” Well, it’s complicated. But I mean four things at least ... ”  Read more from The View from Here here:  Reconsidering IEP Sampling Programs

Chilling out: Temperature management for salmon at the 2021 Bay Delta Science Conference

For cold-loving fish like salmon, temperature plays a critical role in behavior, survival, and ecology. It’s therefore no surprise that the 2021 Bay Delta Science Conference included a session specifically dedicated to research on the effects of temperature on salmon in the Central Valley. The presentations in this session discussed thermal impacts among different Chinook salmon (Oncorhynchus tshawytscha) populations, and across life stages. The different studies demonstrated just how effective temperature management can be as a tool for improving survival. However, effectively applying this tool requires considering multiple other environmental factors, and the highly variable temperature tolerances among different Chinook populations. … ”  Read more from FishBio here: Chilling out: Temperature management for salmon at the 2021 Bay Delta Science Conference

Ladies Trip – The role of sex and genes in steelhead migration

One challenge of conserving freshwater migratory fish such as salmonids is the diversity of their survival strategies. Some populations are made up of a mix of riverine residents, which spend their whole lives in freshwater, and anadromous migrants, which spend most of their lives at sea and return to rivers to spawn. Among such species, the migratory form is often afforded some protection by law while the resident remains unprotected. This is the case with steelhead and their resident counterparts rainbow trout (Oncorhynchus mykiss) in California. We’ve written before about the many factors that determine whether an O. mykiss will migrate or not, and how their complex ecology makes their partially migratory populations difficult to manage. However, a study in the Canadian Journal of Fisheries and Aquatic Sciences has shown that analyzing two of these factors in combination – sex and genetics – allowed scientists to estimate what proportion of an O. mykiss population is migratory (Kelson et al. 2019). Although the analysis does not provide a perfect prediction of whether an individual will migrate or not, it is a promising approach that highlights the importance of conserving both residents and migrants. ... ”  Read more from Fish Bio here:  Ladies Trip – The role of sex and genes in steelhead migration

Gut detectives: Genetic analysis illuminates potentially missed prey items

Understanding the dynamics of the fish food web means studying what fish eat – which traditionally requires sorting through goopy piles of fish guts and visually identifying prey from body parts. However, a recent study published in the North American Journal of Fisheries Management used genetic analysis of stomach contents to investigate the effects of predation from non-native fish, like striped bass, on native fishes, including listed species such as delta smelt and Chinook salmon (Brandl et al. 2021). While this topic has been previously investigated in the Sacramento-San Joaquin Delta, earlier studies that relied on the visual observation of prey items in stomach contents often found little to no evidence of predation on listed species. However, authors of the recent study used a genetic approach to verify stomach contents of predators, which revealed higher instances of predation on listed species than previous studies. The team also analyzed habitat and water quality data to explore the effect habitat may play in predation. … ”  Read more from Fish Bio here: Gut detectives: Genetic analysis illuminates potentially missed prey items

A blueprint for recovery of endangered wetland plant on California’s Central Coast

La Graciosa thistle (Cirsium scariousum var. loncholepis), a spiny wetland plant with white flowers tinged with a lavender hue, now has a blueprint for recovery, thanks to a draft plan prepared by the U.S. Fish and Wildlife Service and partners.  The endangered thistle lives around the edges of wetlands and riparian areas within coastal dune scrub habitat. It is currently found in only eight locations scattered throughout the iconic Guadalupe-Nipomo Dunes in southwestern San Luis Obispo and northwestern Santa Barbara counties along the Central Coast of California.  Conservation experts say the primary threat to the species is groundwater decline, likely from extraction for urban, agricultural and industrial uses. Climate change exacerbates this threat as drought conditions simply means less water is available. … ”  Read more from the US FWS here: A blueprint for recovery of endangered wetland plant on California’s Central Coast

Are zebra mussels eating or helping toxic algae?

While invasive zebra mussels consume small plant-like organisms called phytoplankton, Michigan State University researchers discovered during a long-term study that zebra mussels can actually increase Microcystis, a type of phytoplankton known as “blue-green algae” or cyanobacteria, that forms harmful floating blooms.  “Microcystis literally means small cell, but numerous cells cluster together in colonies that can float to the surface to form scums,” said Orlando Sarnelle, a professor emeritus with the Department of Fisheries and Wildlife within the College of Agriculture and Natural Resources. “It is one of the most common causes of nuisance algal blooms in nutrient-enriched waters, including Lake Erie where it is a concern for municipal water supplies.” … ”  Read more from Michigan State University here:  Are zebra mussels eating or helping toxic algae?

Survivor: Salmon edition

On a small, grassy point overlooking the lower Fraser River in southwestern British Columbia, a lone angler reels in his line. He checks his lure and gazes out over the broad ribbon of silty water flowing to the sea. Then he casts again. It’s a late August afternoon, and I’m traveling by boat with biologist Dave Scott through the estuary of what is considered one of the world’s greatest salmon rivers. But for the moment, there’s a stillness stretching over the water: the only disturbance is a trail of wakes our boat leaves behind. As we push downstream, I look back at the lone angler perched on the bank. Shoulders slouched, he stands at the water’s edge, line cast, waiting. But the river seems in no hurry to reward his patience.  Salmon tend to be few and far between here in the late summer season, but Scott, a salmon biologist with the Raincoast Conservation Foundation in British Columbia, also knows these are hard times on the river. … ”  Read more from Hakai Magazine here: Survivor: Salmon edition

Model predicts when rivers that cross faults will change course

As tectonic plates slip past each other, the rivers that cross fault lines change shape. The shifting ground stretches the river channels until the water breaks its courses and flows onto new paths.  In a study published July 8 in Science, researchers at UC Santa Cruz created a model that helps predict this process. It provides broad context to how rivers and faults interact to shape the nearby topography.  The group originally planned to use the San Andreas fault in the Carrizo Plain of California to study how fault movement shapes the landscapes near rivers. But after spending hours poring over aerial imagery and remote topographic data, their understanding of how the terrain evolves began to change. They realized that rivers play a more active role in shaping the area than once thought. ... ” Read more from the University of Santa Cruz here: Model predicts when rivers that cross faults will change course

Floods may be nearly as important as droughts for future carbon accounting

Plants play an essential role in curbing climate change, absorbing about one-third of the carbon dioxide emitted from human activities and storing it in soil so it doesn’t become a heat-trapping gas. Extreme weather affects this ecosystem service, but when it comes to understanding carbon uptake, floods are studied far less than droughts – and they may be just as important, according to new research.  In a global analysis of vegetation over more than three decades, Stanford University researchers found that photosynthesis – the process by which plants take up carbon dioxide from the atmosphere – was primarily influenced by floods and heavy rainfall nearly as often as droughts in many locations. The paper, published in Environmental Research Letters on June 29, highlights the importance of incorporating plant responses to heavy rainfall in modeling vegetation dynamics and soil carbon storage in a warming world. … ”  Read more from Stanford News here: Floods may be nearly as important as droughts for future carbon accounting

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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