Juvenile salmonids traverse coastal meta-nurseries that connect rivers via the sea

Ecological Society of America (ESA) | April 30th, 2025

Conventionally, juvenile salmonids are thought to migrate unidirectionally from freshwater systems to marine systems and therefore only inhabit natal drainages. Although

Conventionally, juvenile salmonids are thought to migrate unidirectionally from freshwater systems to marine systems and therefore only inhabit natal drainages. Although scattered evidence suggests juveniles can move bidirectionally between freshwater rivers and the ocean, including into non-natal drainages, such movements have never been documented with high replication. Here, we detected hundreds of movements of juvenile salmonids between drainages that involved 0–22% of cohort emigrants in Washington State and California. Individuals moved up to nine times and between drainages up to 70 km apart. These findings reveal a life-history type of salmonids whose remarkably complex migrations have gone unnoticed. Implicitly, juveniles may use any coastal freshwater habitat accessible from the sea and may not descend from spawning populations of drainages they inhabit. Consequently, typical conservation focused on natal drainages may overlook freshwater habitat elsewhere. A concept of coastal areas as meta-nurseries formed by multiple watersheds connected by the sea may accurately describe anadromous species’ habitat options and better inform management.

Keeping up with the status of freshwater fishes: A California (USA) perspective

Conservation Science and Practice (Wiley) | May 29th, 2021

Klamath Basin Settlement Agreements

Congressional Research Service (CRS) | October 21st, 2015

The Klamath River Basin on the California-Oregon border is a focal point for local and national discussions on water allocation and species protection. Previously, water

The Klamath River Basin on the California-Oregon border is a focal point for local and national discussions on water allocation and species protection. Previously, water and species management issues have exacerbated competition and generated conflict among several interests—farmers; Indian tribes; commercial and sport fishermen; federal water project and wildlife refuge managers; environmental groups; hydropower facility operators; and state, local, and tribal governments. Drought conditions and a call for water by senior water rights holders in 2013 have again brought these issues to the forefront. In 2010, the Secretary of the Interior and the governors of Oregon and California, along with multiple interest groups, announced the results of a multiyear negotiation process to resolve long-standing issues in the basin: two interrelated agreements, supported by the federal government and signed by the two states and numerous other parties. These agreements, known as the Klamath Basin Restoration Agreement (KBRA) and the Klamath Hydroelectric Settlement Agreement (KHSA), together aim to provide for water deliveries to irrigators and wildlife refuges, fish habitat restoration, and numerous other related actions. Generally, the KBRA provides for actions intended to restore Klamath fisheries and for assurances for water deliveries to wildlife refuges and federal project irrigators under certain circumstances, among other things. The KHSA lays out a process that could lead to the removal of four privately owned dams on the Klamath River. This dam removal would be one of the largest and most complex projects of its kind ever undertaken. Some parts of the Klamath agreements are being carried out under existing authorities. Studies to inform a determination on dam removal under the KHSA by the Secretary of the Interior are complete, and some restoration actions have been initiated. However, congressional authorization is required for the most significant components of the agreements to be implemented. The KBRA and KHSA did not address all outstanding issues in the basin. A water rights adjudication by the state of Oregon (in progress since the 1970s) is ongoing. In 2013, the adjudication reaffirmed “time immemorial” tribal water rights in the upper part of the Klamath Basin, confirming that tribal water rights are senior to those of other water rights holders. This resulted in a “call” on water rights (i.e., notice by senior water rights holders that their demands exceed available flows), and led to reductions to water supplies for some junior users during the low water year of 2013. To resolve these issues and prevent such a scenario from occurring again, a separate settlement agreement (the Upper Klamath Basin Settlement Agreement) was negotiated by stakeholders and finalized in April 2014. To be implemented, the agreement would need to be authorized along with the KBRA and KHSA. The KBRA and KHSA were originally set to expire in 2012 if no authorizing legislation was enacted, but they have since been extended (most recently through 2015). Parties may also withdraw individually from the agreements, and several parties initiated this process of withdrawal. In the 114th Congress, S. 133 would authorize the Klamath agreements, including a suite of new federal actions that have received support from disparate parties and are required for the agreements to be implemented. Previous legislation in the 113th Congress (S. 2379) was ordered to be reported out of the Senate Committee on Energy and Natural Resources on November 13, 2014.

Left Out in Drought: California Fish Impacts of the California Drought on Freshwater Ecosystems

Pacific Institute | September 7th, 2022

California is deep into the third year of another major drought. Rural and urban areas again face water use restrictions and financial losses. Less water and hotter tempe

California is deep into the third year of another major drought. Rural and urban areas again face water use restrictions and financial losses. Less water and hotter temperatures also stress ecosystems, increasing the prevalence of wildfires, air pollution, dry streambeds, and loss of wildlife. Impacts to rural and urban areas frequently mask the disproportionate ecological impacts of the drought and the related policy and management responses that have exacerbated those impacts. The lack of acknowledgement and de- prioritization of ecosystem water needs during drought has led to insufficient actions taken to protect the natural systems on which we all depend.

Lessons from California’s 2012–2016 Drought

American Society of Civil Engineers (ASCE) | October 1st, 2018

California’s 5-year drought has ended, even as its aftermath lingers. From 2012–2016 much or all of California was under severe drought conditions, with gre

California’s 5-year drought has ended, even as its aftermath lingers. From 2012–2016 much or all of California was under severe drought conditions, with greatly diminished precipitation, snowpack, and streamflow and higher temperatures. Water shortages to forests, aquatic ecosystems, hydroelectric power plants, rural drinking water supplies, agriculture, and cities caused billions of dollars in economic losses, killed millions of forest trees, brought several fish species closer to extinction, and caused inconvenience and some expense to millions of households and businesses. The drought also brought innovations and improvements in water management, some of which will better prepare California for future droughts. This paper summarizes the magnitude and impacts of the 2012–2016 California drought. The paper then reviews innovations arising from the drought in the larger historical context of water management in California. Lessons for California and for modern drought management are then discussed. Droughts in modern, well-managed water systems serving globalized economies need not be economically catastrophic, but will always have impacts and challenges, particularly for native ecosystems. In California and every other water system, droughts usefully expose weaknesses and inadequate preparation in water management. In this regard for California, managers of ecosystems and small rural water supplies had the most to learn.

Letter to State Water Board re: Flow Criteria that use Percent of Unimpaired Flow

Delta Stewardship Council (Delta Council) | May 22nd, 2012

The proposed use of percent of unimpaired flow is a step toward improving the outlook for fish and other wildlife utilizing the San Joaquin River and its tributaries. Fal

The proposed use of percent of unimpaired flow is a step toward improving the outlook for fish and other wildlife utilizing the San Joaquin River and its tributaries. Fall-run Chinook salmon are likely to benefit from February-through-June flows that are more natural in timing and variability than current flows. Compared with the existing maze of flow standards for the San Joaquin River and its tributaries, unimpaired flow comes closer to approximating natural flow, and it does so more transparently. Caveats include: (1) flow is but one of many stressors affecting fish and wildlife; (2) the choice of flow criteria and metrics needs to serve the broader needs of ecosystems as well as individual species; (3) a chosen percentage of unimpaired flow may fall short of the minimum needed by fish and wildlife in some years; and (4) such critical years are likely to become more common as Sierra Nevada snowpacks diminish as a consequence of climate change. This qualified endorsement is based on our reading of the “Technical Report on the Scientific Basis for Alternative San Joaquin River Flow and Southern Delta Salinity Objectives” (State Water Resources Control Board, February 2012).

Listen to the River: An Independent Review of the CVPIA Fisheries Program

U.S. Bureau of Reclamation (USBR) | December 12th, 2008

In 1992 Congress directed the Department of Interior to develop and implement a program that makes “all reasonable efforts” to ensure and sustain on a long-term basis

In 1992 Congress directed the Department of Interior to develop and implement a program that makes “all reasonable efforts” to ensure and sustain on a long-term basis a doubling of the number of naturally produced anadromous fish in Central Valley rivers and streams by 2002. Doubling did not happen by the legislative goal of 2002, or by 2008, nor is it likely to ever occur unless renewed commitments and improvements are made to the CVPIA program. The specific “doubling” mission itself may make little scientific or policy sense, especially within the time frames demanded. Yet it is also far from clear that the agencies have done what is possible and necessary to improve freshwater conditions to help these species weather environmental variability, halt their decline and begin rebuilding in a sustainable way. A number of the most serious impediments to survival and recovery are not being effectively addressed, especially in terms of the overall design and operation of the Central Valley Project system. Underlying this independent review of the CVPIA anadromous fish program, asked for by the federal agencies, is the question why the CVPIA program has not been successful in achieving its mission. In this report, we identify scientific, institutional and programmatic obstacles to the success of the CVPIA, drawing conclusions from the information provided. Based on these conclusions, we make recommendations to Reclamation and the Service on how these obstacles might be overcome.

Local hydraulics influence habitat selection and swimming behavior in adult California Central Valley Chinook salmon at a large river confluence

Fisheries Research (Elsevier) | February 2nd, 2023

Long-term Monitoring of Pollutants in Fish and Mussels Documents Major Improvements and Persistent Problems

California State Water Resources Control Board (SWRCB) | December 1st, 2007

Of the 390 sites sampled between 1998 and 2003, 32 percent fell into the “low” contamination category. These sites were scattered throughout the state, with

Of the 390 sites sampled between 1998 and 2003, 32 percent fell into the “low” contamination category. These sites were scattered throughout the state, with a particular prevalence in the Sierra Nevada and the area north of San Diego. Unfortunately, the Delta region had relatively few sites with low concentration of pollutants. In general, PCB and DDT levels in fish and mussels across California have declined greatly since the 1970s, and many species have bounced back in response to the decline in DDT levels. However, the report also found that present concentrations of pollutants in fish collected from many California water bodies are high enough to cause concern for possible effects on human health and to have a significant impact on the fishing beneficial use. The report found that fish in 68 percent of the water bodies sampled have “moderate to very high levels of mercury or persistent organics (such as PCBs and organochlorinated pesticides like DDT).” Consumption advisories exist for only a fraction of the water bodies likely to need them. Many water bodies with elevated contaminant levels in fish are near population centers and are popular for fishing. Furthermore, subsistence fishing is increasing, and consumption of contaminated fish is an environmental justice issue.

Long-Term Operations of the Central Valley Project and State Water Project Draft Environmental Impact Statement

U.S. Bureau of Reclamation (USBR) | July 26th, 2024

The Bureau of Reclamation (Reclamation) prepared this Environmental Impact Statement (EIS) for the 2021 Endangered Species Act Reinitiation of Section 7 Consultation on t

The Bureau of Reclamation (Reclamation) prepared this Environmental Impact Statement (EIS) for the 2021 Endangered Species Act Reinitiation of Section 7 Consultation on the Long-Term Operation of the Central Valley Project (CVP) and State Water Project (SWP). This EIS is meant to inform the public and decision-makers on potential federal actions by examining a range of reasonable alternatives and the potential effect on the environment. Reclamation manages the Central Valley Project (CVP). The California Department of Water Resources (DWR) manages the State Water Project (SWP). Collectively, the operation of the CVP and SWP provides flood control and navigation, delivers water to 30 million people, supports 4 million acres of agriculture, maintains 19 wildlife refuges on the Pacific Flyway, protects numerous iconic and endemic species such as Chinook salmon, coho salmon, steelhead, sturgeon, and smelt, generates 4.5 million megawatt hours of electricity, maintains water quality for beneficial uses in the California Bay-Delta, and supports recreation throughout Northern California. This summary provides a succinct overview of the development of alternatives in coordination with other agencies and the public, major conclusions for key environmental resource areas, the identification of avoidance and mitigation measures to address potential impacts, and issues that have been in dispute as raised by the public and other interested parties. This summary provides the material required by the Council on Environmental Quality’s National Environmental Policy Act (NEPA) Implementing Regulations regarding the contents of an EIS summary. Click here to read Maven's Notebook background article to the new DEIS.