Linkage of In Vitro Assay Results With In Vivo End Points, Phases 1 and 2

San Francisco Estuary Institute (SFEI) | April 3rd, 2017

Our results clearly show that it is possible to establish linkages between the screening level in in vitro assays and higher order endpoints in fish that are infl

Our results clearly show that it is possible to establish linkages between the screening level in in vitro assays and higher order endpoints in fish that are influenced by estrogen, such as growth and gonadal sex differentiation (Table 1). As expected, the in vitro responses are the most sensitive endpoints tested and using them as a monitoring tool can provide a margin of safety for aquatic organisms that may be more sensitive to estrogenic chemicals than Menidia. Moreover, the margin of safety provided, represented by the ratio of in vivo to in vitro EC50s ranged from 0.9 to 9 for the potent estrogen E2 to 1.2 for E1 and 2.4 to 3.4 for NP (Table 1). There were no significant effects on growth, but merely trends, by any of the chemicals tested, suggesting that a higher “n” may be required to see appropriate effects on this endpoint. Using more concentrations for in vivo tests can refine these ratios.

Linking river management to species conservation using dynamic landscape-scale models

River Research and Applications (Wiley) | March 23rd, 2012

Efforts to conserve stream and river biota could benefit from tools that allow managers to evaluate landscape-scale changes in species distributions in response to water

Efforts to conserve stream and river biota could benefit from tools that allow managers to evaluate landscape-scale changes in species distributions in response to water management decisions. We present a framework and methods for integrating hydrology, geographic context and metapopulation processes to simulate effects of changes in streamflow on fish occupancy dynamics across a landscape of interconnected stream segments. We illustrate this approach using a 482 km2 catchment in the southeastern US supporting 50 or more stream fish species. A spatially distributed, deterministic and physically based hydrologic model is used to simulate daily streamflow for sub-basins composing the catchment. We use geographic data to characterize stream segments with respect to channel size, confinement, position and connectedness within the stream network. Simulated streamflow dynamics are then applied to model fish metapopulation dynamics in stream segments, using hypothesized effects of streamflow magnitude and variability on population processes, conditioned by channel characteristics. The resulting time series simulate spatially explicit, annual changes in species occurrences or assemblage metrics (e.g. species richness) across the catchment as outcomes of management scenarios. Sensitivity analyses using alternative, plausible links between streamflow components and metapopulation processes, or allowing for alternative modes of fish dispersal, demonstrate large effects of ecological uncertainty on model outcomes and highlight needed research and monitoring. Nonetheless, with uncertainties explicitly acknowledged, dynamic, landscape-scale simulations may prove useful for quantitatively comparing river management alternatives with respect to species conservation.

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.

Losses of Sacramento River Chinook Salmon and Delta Smelt to Entrainment in Water Diversions in the Sacramento-San Joaquin Delta

University of California, Davis (UC Davis) | June 30th, 2008

Pumping at the water export facilities in the southern Sacramento-San Joaquin Delta kills fish at and near the associated fish-salvage facilities. Correlative analyses of

Pumping at the water export facilities in the southern Sacramento-San Joaquin Delta kills fish at and near the associated fish-salvage facilities. Correlative analyses of salvage counts with population indices have failed to provide quantitative estimates of the magnitude of this mortality. I estimated the proportional losses of Sacramento River Chinook salmon (Oncorhynchus tshawytscha) and delta smelt (Hypomesus transpacificus) to place these losses in a population context. The estimate for salmon was based on recoveries of tagged smolts released in the upper Sacramento River basin, and recovered at the fish-salvage facilities in the south Delta and in a trawling program in the western Delta. The proportion of fish salvaged increased with export flow, with a mean value around 10% at the highest export flows recorded. Mortality was around 10% if pre-salvage losses were about 80%, but this value is nearly unconstrained. Losses of adult delta smelt in winter and young delta smelt in spring were estimated from salvage data (adults) corrected for estimated pre-salvage survival, or from trawl data in the southern Delta (young). These losses were divided by population size and accumulated over the respective seasons. Losses of adult delta smelt were 1–50% (median 15%) although the highest value may have been biased upward. Daily losses of larvae and juveniles were 0–8%, and seasonal losses accumulated were 0–25% (median 13%). The effect of these losses on population abundance was obscured by subsequent 50-fold variability in survival from summer to fall.

Making the Delta a Better Place for Native Fishes

Orange County Coastkeeper | March 1st, 2018

The Sacramento-San Joaquin Delta is the heart of California’s water delivery system, connecting the precipitation-rich regions of the north with the dry farmlands and

The Sacramento-San Joaquin Delta is the heart of California’s water delivery system, connecting the precipitation-rich regions of the north with the dry farmlands and demanding urban areas of the south and coast, including the Bay Area. Scarce water resources create conflicts between people and fishes; as demand by people for water grows, less water is available for the environment. This white paper explores the ways to keep the native fishes, and the functional ecosystems they require, from disappearing. Our analysis is fish-oriented because salmon, smelt, and other declining fishes are major drivers of decisions on where to focus aquatic restoration efforts.  The goals of this white paper are to first provide a brief introduction to the Delta and then to describe why restoration of native fishes and natural processes is such a challenge in this system. We follow this with some general guidelines for restoration projects in the Delta and apply those guidelines with a project evaluation tool. We used this tool to evaluate 26 projects, mostly part of EcoRestore, to provide insights to help determine action items. We then present 17 action items, listed below, some of which can be accomplished fairly quickly, some that will take longer, and few that will have to be continuous. But taken together, our recommended actions could significantly improve the welfare of native fishes and help to create a novel aquatic ecosystem with many desirable features.

Making the Most of Water for the Environment: A Functional Flows Approach for California’s Rivers

Public Policy Institute of California (PPIC) | August 25th, 2020

In California, water and land management activities have substantially altered river flows and degraded river channels and their floodplains. The result has been a precip

In California, water and land management activities have substantially altered river flows and degraded river channels and their floodplains. The result has been a precipitous decline in native fish populations, including the collapse of valued salmon fisheries, and widespread imperilment of freshwater biodiversity. Environmental flows—flows in rivers and streams necessary to sustain ecosystem health—are essential to reversing these trends. Yet many rivers in California lack environmental flows. And for those rivers with such protections, environmental flows are typically established at static minimum levels, which fail to preserve the natural seasonal and interannual variability of flow that sustains healthy ecosystems. A new approach to managing environmental water is needed. 

Managing diversions in unregulated streams using a modified percent-of-flow approach

Freshwater Biology (Wiley) | August 22nd, 2017

In Mediterranean-type river systems stream flows are naturally low in summer and autumn. This pattern is often exacerbated by over-exploitation of water resources during

In Mediterranean-type river systems stream flows are naturally low in summer and autumn. This pattern is often exacerbated by over-exploitation of water resources during the dry season, which has implications for managing flows for both environmental and human needs. Mediterranean systems are characterised by strong inter- and intra-annual variability with almost all precipitation occurring in winter months followed by summer droughts with little or no rainfall, and extreme year-to-year variation ranging from intense winter storms to year-round drought (Gasith & Resh, 1999; Power, Kupferberg, Cooper, & Deas, 2015; Power, Parker, & Dietrich, 2008). The seasonal pattern of precipitation in Mediterranean climatic regions results in water availability and demand being out-of-phase; precipitation and runoff occur (almost exclusively) in winter when human demands are lowest, and precipitation is virtually non-existent in summer months when human demand is greatest (Kondolf & Batalla, 2005; Merenlender & Matella, 2013). As a result, rivers in Mediterranean climates tend to have a high degree of alteration with streamsdiverted and dammed to provide scarce water for human use (Kondolf, Podolak, & Grantham, 2013; Marr et al., 2009; Moyle, 2013). While the biophysical responses to alterations of land use, vegetation and hydrology are similar in Mediterranean and other climatic regions, the magnitude of responses tends to be intensified in Mediterranean systems. For example prolonged dry season flows may result in lower dissolved oxygen, higher temperatures and concentration of contaminants among other impacts (Cooper, Lake, Sabater, Melack, & Sabo, 2013). Climate change and increasing frequency and severity of drought promise to increase the conflict between human needs and ecological needs over time (Arthington, 2012).