scholarly journals Pesticide concentrations associated with augmented flow pulses in the Yolo Bypass and Cache Slough Complex, California

2020 ◽  
Author(s):  
James L. Orlando ◽  
Matt De Parsia ◽  
Corey Sanders ◽  
Michelle Hladik ◽  
Jared Frantzich
Keyword(s):  
Yolo Bypass

Early Life History of Fishes in the San Francisco Estuary and Watershed

2004 ◽  
Keyword(s):  
Life History ◽  
San Francisco ◽  
Early Life ◽  
Oncorhynchus Tshawytscha ◽  
San Francisco Estuary ◽  
Sacramento River ◽  
Yolo Bypass ◽  
Species Abundances ◽  
Native Fishes ◽  
Rotary Screw

<em>Abstract.</em>—We examined assemblage patterns of early life stages of fishes for two major tributaries of the upper San Francisco Estuary: (1) Sacramento River channel, and (2) Yolo Bypass, the river’s seasonal floodplain. Over four hydrologically diverse years (1999–2002), we collected 15 species in Yolo Bypass egg and larval samples, 18 species in Yolo Bypass rotary screw trap samples, and 10 species in Sacramento River egg and larval samples. Fishes captured included federally listed species (delta smelt <em>Hypomesus transpacificus </em>and splittail <em>Pogonichthys macrolepidotus</em>) and several game species (American shad <em>Alosa sapidissima</em>, striped bass <em>Morone saxatilis</em>, crappie <em>Pomoxis </em>spp., and Chinook salmon <em>Oncorhynchus tshawytscha</em>). As in other regions of the estuary, alien fish comprised a large portion of the individuals collected in Yolo Bypass (40–93% for egg and larval net samples; 84–98% for rotary screw trap samples) and Sacramento River (80–99% for egg and larval net samples). Overall ranks of species abundances were significantly correlated for Yolo Bypass and Sacramento River, suggesting that each assemblage was controlled by similar major environmental factors. However, species diversity and richness were higher in Yolo Bypass, likely because of a wider variety of habitat types and greater hydrologic variation in the floodplain. In both landscapes, we found evidence that timing of occurrence of native fishes was earlier than aliens, consistent with their life history and our data on adult migration patterns. We hypothesize that Yolo Bypass favors native fishes because the inundation of seasonal floodplain typically occurs early in the calendar year, providing access to vast areas of spawning and rearing habitat with an enhanced food web. Conclusions from this analysis have implications for the management of aquatic biodiversity of tributaries to the San Francisco Estuary and perhaps to other lowland rivers.

Methylmercury production in sediment from agricultural and non-agricultural wetlands in the Yolo Bypass, California, USA

2014 ◽  
Vol 484 ◽  
pp. 288-299 ◽  
Author(s):  
Mark Marvin-DiPasquale ◽  
Lisamarie Windham-Myers ◽  
Jennifer L. Agee ◽  
Evangelos Kakouros ◽  
Le H. Kieu ◽  
...  
Keyword(s):  
Yolo Bypass ◽  
Agricultural Wetlands ◽  
Methylmercury Production

scholarly journals Delivering Food to Hungry Fish in the San Francisco Estuary

2021 ◽  
Vol 9 ◽  
Author(s):  
Laura Twardochleb ◽  
Leela Dixit ◽  
Mallory Bedwell ◽  
Brittany Davis ◽  
Jared Frantzich
Keyword(s):  
Invasive Species ◽  
San Francisco ◽  
Fish Species ◽  
San Francisco Estuary ◽  
Fish Food ◽  
Yolo Bypass ◽  
Delta Smelt ◽  
Endangered Fish ◽  
The Past

The San Francisco Estuary is home to an important endangered fish called delta smelt. Delta smelt eat small, nutritious animals called zooplankton to survive and grow. In turn, zooplankton grow by eating microscopic plant-like organisms called phytoplankton. In the past, the Estuary was full of plankton and delta smelt. Because people have removed water from the Estuary and invasive species now live there, the Estuary no longer has enough plankton to feed delta smelt, making it difficult for them to survive. Scientists have found a unique place in the Estuary, the Yolo Bypass, that has lots of fish food. The problem is that delta smelt do not live in the Yolo Bypass year-round. Scientists are working to solve this problem by sending river or farm water through the Yolo Bypass, to move fish food downstream to feed the hungry delta smelt and other fish species.

scholarly journals Use of a Managed Flow Pulse as Food Web Support for Estuarine Habitat

2021 ◽  
Vol 19 (3) ◽  
Author(s):  
Jared Frantzich ◽  
◽  
Brittany Davis ◽  
Michael MacWilliams ◽  
Aaron Bever ◽  
...  
Keyword(s):  
Resource Management ◽  
San Francisco ◽  
Essential Fatty Acids ◽  
Specific Conductivity ◽  
Sacramento River ◽  
Flow Pulse ◽  
Study Region ◽  
Yolo Bypass ◽  
Estuarine Habitat ◽  
Net Flows

While freshwater inflow has been a major focus of resource management in estuaries, including the upper San Francisco Estuary, there is a growing interest in using focused flow actions to maximize benefits for specific regions, habitats, and species. As a test of this concept, in summer 2016, we used a managed flow pulse to target an ecologically important region: a freshwater tidal slough complex (Cache Slough Complex–CSC). Our goal was to improve estuarine habitat by increasing net flows through CSC to enhance downstream transport of lower trophic-level resources, an important driver for fishes such as the endangered Delta Smelt Hypomesus transpacificus. We used regional water infrastructure to direct 18.5 million m³ of Sacramento River flow into its adjacent Yolo Bypass floodplain, where the pulse continued through CSC. Simulations using a 3-D hydrodynamic model (UnTRIM) indicated that the managed flow pulse had a large effect on the net flow of water through Yolo Bypass, and between CSC and further downstream. Multiple water quality constituents (specific conductivity, dissolved oxygen, nutrients [NO₃ + NO₂, NH₄, PO₄]) varied across the study region, and showed a strong response to the flow pulse. In addition, the lower Sacramento River had increased phytoplankton biomass and improved food quality indices (estimated from long-chain essential fatty acids) after the flow pulse. The managed flow pulse resulted in increased densities of zooplankton (copepods, cladocerans) demonstrating potential advection from upper floodplain channels into the target CSC and Sacramento River regions. This study was conducted during a single year, which may have had unique characteristics; however, we believe that our study is an instructive example of how a relatively modest change in net flows can generate measurable changes in ecologically relevant metrics, and how an adaptive management action can help inform resource management.

scholarly journals Re-Examining Factors That Affect Delta Smelt (Hypomesus transpacificus) Entrainment at the State Water Project and Central Valley Project in the Sacramento–San Joaquin Delta

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Lenny Grimaldo ◽  
William Smith ◽  
Matthew Nobriga
Keyword(s):  
Time Scales ◽  
Central Valley ◽  
The State ◽  
First Flush ◽  
Bypass Flow ◽  
Yolo Bypass ◽  
Delta Smelt ◽  
Water Project ◽  
State Water ◽  
Hypomesus Transpacificus

Managing endangered species is challenging when increased rarity leads to an inability to detect their responses to environmental conditions. In the San Francisco Estuary, the state and federally listed Delta Smelt (Hypomesus transpacificus) has declined to record low numbers, elevating concern over entrainment at the State Water Project (SWP) and Central Valley Project (CVP) water export facilities. The objective of this study was to: (1) revisit previous work on factors that affect adult Delta Smelt collected at the SWP and CVP fish collection facilities using updated conceptual models and a new statistical approach; and (2) to determine factors that affect salvage at time-scales of interest to management. Boosted Regression Tree (BRT) models were applied to salvage data at the SWP and CVP, aggregated into two response categories: a “first flush” response that represented daily salvage from the start of the entrainment window to the 50% midpoint of observed salvage, and a “seasonal” response that included daily salvage from the entire entrainment window. Precipitation, sub-adult abundance, Yolo Bypass flow, and exports best explained first flush salvage at both the SWP and CVP. The seasonal models included a similar set of influential variables, but the relative influence of precipitation was lower compared to the first flush models., Yolo Bypass flow was more influential for seasonal salvage at the SWP, compared to the CVP; Old and Middle River flow was more influential for seasonal salvage at the CVP. Although the rank of variable importance that explains salvage differed slightly between first flush and seasonal time-scales, this study suggests that salvage is most influenced by hydrodynamics, water quality, and population abundance. The application of BRT models to predict salvage is limited, because salvage has been low since federal protections were implemented in 2008. Forecast models that integrate real-time variables with fish behavior models may improve Delta Smelt management.

scholarly journals Re-Examining Factors that Affect Delta Smelt (Hypomesus transpacificus) Entrainment at the State Water Project and Central Valley Project in the Sacramento–San Joaquin Delta

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Lenny Grimaldo ◽  
William Smith ◽  
Matthew Nobriga
Keyword(s):  
Time Scales ◽  
Central Valley ◽  
The State ◽  
First Flush ◽  
Bypass Flow ◽  
Yolo Bypass ◽  
Delta Smelt ◽  
Water Project ◽  
State Water ◽  
Hypomesus Transpacificus

Managing endangered species is challenging when increased rarity leads to an inability to detect their responses to environmental conditions. In the San Francisco Estuary, the state and federally listed Delta Smelt (Hypomesus transpacificus) has declined to record low numbers, elevating concern over entrainment at the State Water Project (SWP) and Central Valley Project (CVP) water export facilities. The objective of this study was to: (1) revisit previous work on factors that affect adult Delta Smelt collected at the SWP and CVP fish collection facilities using updated conceptual models and a new statistical approach; and (2) to determine factors that affect salvage at time-scales of interest to management. Boosted Regression Tree (BRT) models were applied to salvage data at the SWP and CVP, aggregated into two response categories: a “first flush” response that represented daily salvage from the start of the entrainment window to the 50% midpoint of observed salvage, and a “seasonal” response that included daily salvage from the entire entrainment window. Precipitation, sub-adult abundance, Yolo Bypass flow, and exports best explained first flush salvage at both the SWP and CVP. The seasonal models included a similar set of influential variables, but the relative influence of precipitation was lower compared to the first flush models., Yolo Bypass flow was more influential for seasonal salvage at the SWP, compared to the CVP; Old and Middle River flow was more influential for seasonal salvage at the CVP. Although the rank of variable importance that explains salvage differed slightly between first flush and seasonal time-scales, this study suggests that salvage is most influenced by hydrodynamics, water quality, and population abundance. The application of BRT models to predict salvage is limited, because salvage has been low since federal protections were implemented in 2008. Forecast models that integrate real-time variables with fish behavior models may improve Delta Smelt management.

Sign in / Sign up

Export Citation Format

Share Document