Marissa Wulff
Marissa Wulff is a Biologist at the California Water Science Center.
Marissa Bauer Wulff is a biologist with the U.S. Geological Survey’s California Water Science Center, where she researches and assists in projects relating to aquatic biology and ecology. Marissa has been involved in ecosystem modeling for the Sacramento-San Joaquin Delta as well as flow-regime and aquatic mercury studies. Marissa is currently involved in research looking at the effects of climate change on selected fish species of the San Francisco Bay-Delta.
Science and Products
Aquatic Ecology Group
The California Water Science Center's Aquatic Ecology Group is making great strides in research and reporting.
Post Carr Fire Bioassessment Data, Whiskeytown National Recreation Area, Shasta County, California, 2020
This data release contains data collected during August 2020 for the post Carr fire Bioassessment project at Whiskeytown National Recreation Area, Shasta County, California. Data includes sediment and habitat characteristics, water chemistry, and biological conditions of tributaries to Whiskeytown Lake and Clear Creek below the dam. Samples were also collected to assess concentrations of metals in
Santa Ana River Native Fish Population and Habitat Data, Santa Ana River, California, 2022
This dataset includes 2022 reach fish data and reach habitat data collected to support development of the upper Santa Ana River Habitat Conservation Plan for the Santa Ana Sucker (Catostomus santaanae) and the Arroyo Chub (Gila orcutti) in the Santa Ana River, California.
Post-Fire Stream Assessment Data, Napa and Sonoma County, California, 2017-2018
In October 2017, the Atlas, Nuns, and Tubbs wildfires in Napa and Sonoma Counties, CA burned approximately 133 thousand acres. Multiple watersheds were affected by the fires, with up to 95% of some watersheds being burned. Post-fire assessments were conducted at 10 sites within Napa and Sonoma Counties to assess the effects of fire on sediment, water quality, and ecology. This data release contain
Data used in projected air and water temperatures for selected regions of the upper San Francisco Estuary and Yolo Bypass under 20 scenarios of climate change 2020-2099
Understanding the effects of climate change is a substantial challenge in estuarine systems because the mixing of freshwater and ocean water adds complexity to climate change projections. Such climate change projections have been conducted in the San Francisco Estuary as part of the U.S. Geological Survey's CASCaDE Project. In this project, we assessed downscaled air temperature data from 10 Globa
Santa Ana River Native Fish Population and Habitat Data, Santa Ana River, California, 2020
This dataset includes 2020 reach fish data and reach habitat data collected to support development of the upper Santa Ana River Habitat Conservation Plan for the Santa Ana Sucker (Catostomus santaanae) and the Arroyo Chub (Gila orcutti) in the Santa Ana River, California.
Data used in projected flow analysis in Yolo Bypass under 20 scenarios of climate change
Yolo Bypass is an ecological feature of the Bay-Delta ecosystem in California that provides floodplain habitat for spawning and rearing of Sacramento Splittail (Pogonichthys macrolepidotus) and rearing of juvenile Chinook Salmon (Oncorhynchus tshawytscha) when inundated. We used outputs from 10 climate change models for two Representative Concentration Pathways (RCPs) for greenhouse gas concentrat
SAR 2018 Native Fish Population and Habitat Study, Santa Ana and San Gabriel Rivers, California
This dataset includes 2018 reach fish data and reach habitat data collected to support development of the upper Santa Ana River Habitat Conservation Plan for the Santa Ana Sucker (Catostomus santaanae) and the Arroyo Chub (Gila orcutti) in the Santa Ana and San Gabriel Rivers, California.
SAR 2019 Native Fish Population and Habitat Study, Santa Ana River, California
This dataset includes 2019 reach fish data and reach habitat data collected to support development of the upper Santa Ana River Habitat Conservation Plan for the Santa Ana Sucker (Catostomus santaanae) and the Arroyo Chub (Gila orcutti) in the Santa Ana River, California.
SAR 2017 Native Fish Population and Habitat Study, Santa Ana River, California
This dataset includes: 1) microhabitat use data for fish 100 mm and larger; 2) reach fish data; and 3) reach habitat data for the Santa Ana Sucker (Catostomus santaanae) and the Arroyo Chub (Gila orcutti) in the Santa Ana River, California. Habitat availability data was not collected in 2017.
SAR 2016 Native Fish Population and Habitat Study, Santa Ana River, California
Data included in this dataset include: 1) population estimate data; 2) microhabitat use data; and 3) microhabitat availability data for the Santa Ana Sucker (Catostomus santaanae) and the Arroyo Chub (Gila orcutti) in the Santa Ana River, California.
Native Fish Population and Habitat Study, Santa Ana River, California, 2015
Data included in this dataset include: 1) population estimate data; 2) microhabitat use data; and 3) microhabitat availability data for the Santa Ana Sucker (Catostomus santaanae) and the Arroyo Chub (Gila orcutti) in the Santa Ana River.
Microhabitat use of native Santa Ana sucker and arroyo chub in an effluent-dominated southern California stream
A significant amount of the base flow of the Santa Ana River, located within California's arid Los Angeles metropolitan region, originates from two wastewater treatment facilities: the Rialto wastewater treatment facility and Rapid Infiltration and Extraction facility. The Santa Ana sucker (Pantosteus santaanae, syn. Catostomus santaanae) and arroyo chub (Gila orcuttii) are two native species list
Authors
Brock Huntsman, Larry R. Brown, Jason May, Kai Palenscar, Kerwin Russell, Heather Dyer, Marissa L. Wulff, Brett Mills, Chris Jones
Chapter 1: General conceptual model for climate change in the Upper San Francisco Estuary
This report is a collaboration by many state and federal agencies working in the Upper San Francisco Estuary to analyze the potential impacts of climate change to different ecosystems found here. Management stategies for ecological values in the face of climate change require reliable and focused information. In this technical report, our focus is on the Upper San Francisco Estuary (SFE), which co
Authors
Eva Bush, Bruce Herbold, Larry R. Brown
Floodplains and climate change
Floodplains are landscape features that are periodically inundated by water from adjacent rivers (Opperman et al. 2010). Ecologically, functional floodplains are characterized by three primary elements: connectivity, flow regime, and spatial scale. Water quantity flowing over floodplains can vary greatly. Based on a flood’s effects on the floodplain, three flood categories have been defined: flood
Authors
Annika Keeley, Shruti Khanna, Nicole Kwan, Bryan G. Matthias, Catarina Pien, Marissa L. Wulff
Gill-net selectivity for fifteen fish species of the upper San Francisco Estuary
Gill-net size selectivity for 15 fish species occurring in the upper San Francisco Estuary was estimated from a data set compiled from multiple studies which together contained 7,096 individual fish observations from 882 gill net sets. The gill nets considered in this study closely resembled the American Fisheries Society’s recommended standardized experimental gill nets for sampling inland waters
Authors
Marissa L. Wulff, Frederick V. Feyrer, Matthew J. Young
Joint-species analysis reveals potential displacement of native fishes by non-native fishes within the Santa Ana River, California
Accurate estimates of abundance are a cornerstone for resource managers to make effective decisions for fish conservation. However, multiple sampling methods often are required to sample fish communities, and ignoring the detection process can create substantial bias in latent state parameter estimation (e.g., abundance, survival). We developed a joint-species N-mixture model that integrated snork
Authors
Brock Huntsman, Larry R. Brown, Kai Palenscar, Chris Jones, Kerwin Russell, Heather Dyer, Brett Mills, Marissa L. Wulff, Jason May
Assessment of interim flow water-quality data of the San Joaquin River restoration program and implications for fishes, California, 2009-11
After more than 50 years of extensive water diversion for urban and agriculture use, a major settlement was reached among the U.S. Departments of the Interior and Commerce, the Natural Resources Defense Council, and the Friant Water Users Authority in an effort to restore the San Joaquin River. The settlement received Federal court approval in October 2006 and established the San Joaquin River Res
Authors
Marissa L. Wulff, Larry R. Brown
Upper Clear Creek watershed aquatic chemistry and biota surveys, 2004-5, Whiskeytown National Recreation Area, Shasta County, California
The U.S. Geological Survey, in cooperation with the National Park Service and Whiskeytown National Recreation Area, performed a comprehensive aquatic biota survey of the upper Clear Creek watershed, Shasta County, California, during 2004-5. Data collected in this study can provide resource managers with information regarding aquatic resources, watershed degradation, and regional biodiversity withi
Authors
Marissa L. Wulff, Jason T. May, Larry R. Brown
Concentrations of mercury and other metals in black bass (Micropterus spp.) from Whiskeytown Lake, Shasta County, California, 2005
This report presents the results of a reconnaissance study conducted by the U.S. Geological Survey (USGS) to determine mercury (Hg) and other selected metal concentrations in Black bass (Micropterus spp.) from Whiskeytown Lake, Shasta County, California. Total mercury concentrations were determined by cold-vapor atomic absorption spectroscopy (CVAAS) in fillets and whole bodies of each sampled fis
Authors
Jason T. May, Roger L. Hothem, Marissa L. Bauer, Larry R. Brown
Associations of benthic macroinvertebrate assemblages with environmental variables in the upper Clear Creek watershed, California
Benthic macroinvertebrates are integral components of stream ecosystems and are often used to assess the ecological integrity of streams. We sampled streams in the upper Clear Creek drainage in the Klamath—Siskiyou Ecoregion of northwestern California in fall 2004 (17 sites) and 2005 (original 17 plus 4 new sites) with the objectives of documenting the benthic macroinvertebrate assemblages support
Authors
Larry R. Brown, Jason T. May, Marissa Wulff
Effects of hydrologic infrastructure on flow regimes of California's Central Valley rivers: Implications for fish populations
Alteration of natural flow regimes is generally acknowledged to have negative effects on native biota; however, methods for defining ecologically appropriate flow regimes in managed river systems are only beginning to be developed. Understanding how past and present water management has affected rivers is an important part of developing such tools. In this paper, we evaluate how existing hydrologi
Authors
Larry R. Brown, Marissa L. Bauer
Cliff swallows Petrochelidon pyrrhonota as bioindicators of environmental mercury, Cache Creek Watershed, California
To evaluate mercury (Hg) and other element exposure in cliff swallows (Petrochelidon pyrrhonota), eggs were collected from 16 sites within the mining-impacted Cache Creek watershed, Colusa, Lake, and Yolo counties, California, USA, in 1997-1998. Nestlings were collected from seven sites in 1998. Geometric mean total Hg (THg) concentrations ranged from 0.013 to 0.208 ??g/g wet weight (ww) in cliff
Authors
Roger L. Hothem, Bonnie S. Trejo, Marissa L. Bauer, John J. Crayon
Mercury and trace elements in crayfish from northern California
We collected two species of crayfish, Pacifastacus leniusculus and Procambarus clarkii, from Cache and Putah Creeks, California, and analyzed them for mercury and trace elements. Trace elements were higher in carcasses in 40 cases, higher in tails in 5 cases, and not different in 35 cases; no concentration exceeded levels considered harmful. Mercury concentrations were similar among sites, with no
Authors
R. L. Hothem, D.R. Bergen, M.L. Bauer, J.J. Crayon, A.M. Meckstroth
Non-USGS Publications**
Pintor, L. M., Sih, A. and Bauer, M. L. (2008), Differences in aggression, activity and boldness between native and introduced populations of an invasive crayfish. Oikos, 117: 1629–1636. doi:10.1111/j.1600-0706.2008.16578.x
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Science and Products
- Science
Aquatic Ecology Group
The California Water Science Center's Aquatic Ecology Group is making great strides in research and reporting. - Data
Post Carr Fire Bioassessment Data, Whiskeytown National Recreation Area, Shasta County, California, 2020
This data release contains data collected during August 2020 for the post Carr fire Bioassessment project at Whiskeytown National Recreation Area, Shasta County, California. Data includes sediment and habitat characteristics, water chemistry, and biological conditions of tributaries to Whiskeytown Lake and Clear Creek below the dam. Samples were also collected to assess concentrations of metals inSanta Ana River Native Fish Population and Habitat Data, Santa Ana River, California, 2022
This dataset includes 2022 reach fish data and reach habitat data collected to support development of the upper Santa Ana River Habitat Conservation Plan for the Santa Ana Sucker (Catostomus santaanae) and the Arroyo Chub (Gila orcutti) in the Santa Ana River, California.Post-Fire Stream Assessment Data, Napa and Sonoma County, California, 2017-2018
In October 2017, the Atlas, Nuns, and Tubbs wildfires in Napa and Sonoma Counties, CA burned approximately 133 thousand acres. Multiple watersheds were affected by the fires, with up to 95% of some watersheds being burned. Post-fire assessments were conducted at 10 sites within Napa and Sonoma Counties to assess the effects of fire on sediment, water quality, and ecology. This data release containData used in projected air and water temperatures for selected regions of the upper San Francisco Estuary and Yolo Bypass under 20 scenarios of climate change 2020-2099
Understanding the effects of climate change is a substantial challenge in estuarine systems because the mixing of freshwater and ocean water adds complexity to climate change projections. Such climate change projections have been conducted in the San Francisco Estuary as part of the U.S. Geological Survey's CASCaDE Project. In this project, we assessed downscaled air temperature data from 10 GlobaSanta Ana River Native Fish Population and Habitat Data, Santa Ana River, California, 2020
This dataset includes 2020 reach fish data and reach habitat data collected to support development of the upper Santa Ana River Habitat Conservation Plan for the Santa Ana Sucker (Catostomus santaanae) and the Arroyo Chub (Gila orcutti) in the Santa Ana River, California.Data used in projected flow analysis in Yolo Bypass under 20 scenarios of climate change
Yolo Bypass is an ecological feature of the Bay-Delta ecosystem in California that provides floodplain habitat for spawning and rearing of Sacramento Splittail (Pogonichthys macrolepidotus) and rearing of juvenile Chinook Salmon (Oncorhynchus tshawytscha) when inundated. We used outputs from 10 climate change models for two Representative Concentration Pathways (RCPs) for greenhouse gas concentratSAR 2018 Native Fish Population and Habitat Study, Santa Ana and San Gabriel Rivers, California
This dataset includes 2018 reach fish data and reach habitat data collected to support development of the upper Santa Ana River Habitat Conservation Plan for the Santa Ana Sucker (Catostomus santaanae) and the Arroyo Chub (Gila orcutti) in the Santa Ana and San Gabriel Rivers, California.SAR 2019 Native Fish Population and Habitat Study, Santa Ana River, California
This dataset includes 2019 reach fish data and reach habitat data collected to support development of the upper Santa Ana River Habitat Conservation Plan for the Santa Ana Sucker (Catostomus santaanae) and the Arroyo Chub (Gila orcutti) in the Santa Ana River, California.SAR 2017 Native Fish Population and Habitat Study, Santa Ana River, California
This dataset includes: 1) microhabitat use data for fish 100 mm and larger; 2) reach fish data; and 3) reach habitat data for the Santa Ana Sucker (Catostomus santaanae) and the Arroyo Chub (Gila orcutti) in the Santa Ana River, California. Habitat availability data was not collected in 2017.SAR 2016 Native Fish Population and Habitat Study, Santa Ana River, California
Data included in this dataset include: 1) population estimate data; 2) microhabitat use data; and 3) microhabitat availability data for the Santa Ana Sucker (Catostomus santaanae) and the Arroyo Chub (Gila orcutti) in the Santa Ana River, California.Native Fish Population and Habitat Study, Santa Ana River, California, 2015
Data included in this dataset include: 1) population estimate data; 2) microhabitat use data; and 3) microhabitat availability data for the Santa Ana Sucker (Catostomus santaanae) and the Arroyo Chub (Gila orcutti) in the Santa Ana River. - Publications
Microhabitat use of native Santa Ana sucker and arroyo chub in an effluent-dominated southern California stream
A significant amount of the base flow of the Santa Ana River, located within California's arid Los Angeles metropolitan region, originates from two wastewater treatment facilities: the Rialto wastewater treatment facility and Rapid Infiltration and Extraction facility. The Santa Ana sucker (Pantosteus santaanae, syn. Catostomus santaanae) and arroyo chub (Gila orcuttii) are two native species listAuthorsBrock Huntsman, Larry R. Brown, Jason May, Kai Palenscar, Kerwin Russell, Heather Dyer, Marissa L. Wulff, Brett Mills, Chris JonesChapter 1: General conceptual model for climate change in the Upper San Francisco Estuary
This report is a collaboration by many state and federal agencies working in the Upper San Francisco Estuary to analyze the potential impacts of climate change to different ecosystems found here. Management stategies for ecological values in the face of climate change require reliable and focused information. In this technical report, our focus is on the Upper San Francisco Estuary (SFE), which coAuthorsEva Bush, Bruce Herbold, Larry R. BrownFloodplains and climate change
Floodplains are landscape features that are periodically inundated by water from adjacent rivers (Opperman et al. 2010). Ecologically, functional floodplains are characterized by three primary elements: connectivity, flow regime, and spatial scale. Water quantity flowing over floodplains can vary greatly. Based on a flood’s effects on the floodplain, three flood categories have been defined: floodAuthorsAnnika Keeley, Shruti Khanna, Nicole Kwan, Bryan G. Matthias, Catarina Pien, Marissa L. WulffGill-net selectivity for fifteen fish species of the upper San Francisco Estuary
Gill-net size selectivity for 15 fish species occurring in the upper San Francisco Estuary was estimated from a data set compiled from multiple studies which together contained 7,096 individual fish observations from 882 gill net sets. The gill nets considered in this study closely resembled the American Fisheries Society’s recommended standardized experimental gill nets for sampling inland watersAuthorsMarissa L. Wulff, Frederick V. Feyrer, Matthew J. YoungJoint-species analysis reveals potential displacement of native fishes by non-native fishes within the Santa Ana River, California
Accurate estimates of abundance are a cornerstone for resource managers to make effective decisions for fish conservation. However, multiple sampling methods often are required to sample fish communities, and ignoring the detection process can create substantial bias in latent state parameter estimation (e.g., abundance, survival). We developed a joint-species N-mixture model that integrated snorkAuthorsBrock Huntsman, Larry R. Brown, Kai Palenscar, Chris Jones, Kerwin Russell, Heather Dyer, Brett Mills, Marissa L. Wulff, Jason MayAssessment of interim flow water-quality data of the San Joaquin River restoration program and implications for fishes, California, 2009-11
After more than 50 years of extensive water diversion for urban and agriculture use, a major settlement was reached among the U.S. Departments of the Interior and Commerce, the Natural Resources Defense Council, and the Friant Water Users Authority in an effort to restore the San Joaquin River. The settlement received Federal court approval in October 2006 and established the San Joaquin River ResAuthorsMarissa L. Wulff, Larry R. BrownUpper Clear Creek watershed aquatic chemistry and biota surveys, 2004-5, Whiskeytown National Recreation Area, Shasta County, California
The U.S. Geological Survey, in cooperation with the National Park Service and Whiskeytown National Recreation Area, performed a comprehensive aquatic biota survey of the upper Clear Creek watershed, Shasta County, California, during 2004-5. Data collected in this study can provide resource managers with information regarding aquatic resources, watershed degradation, and regional biodiversity withiAuthorsMarissa L. Wulff, Jason T. May, Larry R. BrownConcentrations of mercury and other metals in black bass (Micropterus spp.) from Whiskeytown Lake, Shasta County, California, 2005
This report presents the results of a reconnaissance study conducted by the U.S. Geological Survey (USGS) to determine mercury (Hg) and other selected metal concentrations in Black bass (Micropterus spp.) from Whiskeytown Lake, Shasta County, California. Total mercury concentrations were determined by cold-vapor atomic absorption spectroscopy (CVAAS) in fillets and whole bodies of each sampled fisAuthorsJason T. May, Roger L. Hothem, Marissa L. Bauer, Larry R. BrownAssociations of benthic macroinvertebrate assemblages with environmental variables in the upper Clear Creek watershed, California
Benthic macroinvertebrates are integral components of stream ecosystems and are often used to assess the ecological integrity of streams. We sampled streams in the upper Clear Creek drainage in the Klamath—Siskiyou Ecoregion of northwestern California in fall 2004 (17 sites) and 2005 (original 17 plus 4 new sites) with the objectives of documenting the benthic macroinvertebrate assemblages supportAuthorsLarry R. Brown, Jason T. May, Marissa WulffEffects of hydrologic infrastructure on flow regimes of California's Central Valley rivers: Implications for fish populations
Alteration of natural flow regimes is generally acknowledged to have negative effects on native biota; however, methods for defining ecologically appropriate flow regimes in managed river systems are only beginning to be developed. Understanding how past and present water management has affected rivers is an important part of developing such tools. In this paper, we evaluate how existing hydrologiAuthorsLarry R. Brown, Marissa L. BauerCliff swallows Petrochelidon pyrrhonota as bioindicators of environmental mercury, Cache Creek Watershed, California
To evaluate mercury (Hg) and other element exposure in cliff swallows (Petrochelidon pyrrhonota), eggs were collected from 16 sites within the mining-impacted Cache Creek watershed, Colusa, Lake, and Yolo counties, California, USA, in 1997-1998. Nestlings were collected from seven sites in 1998. Geometric mean total Hg (THg) concentrations ranged from 0.013 to 0.208 ??g/g wet weight (ww) in cliffAuthorsRoger L. Hothem, Bonnie S. Trejo, Marissa L. Bauer, John J. CrayonMercury and trace elements in crayfish from northern California
We collected two species of crayfish, Pacifastacus leniusculus and Procambarus clarkii, from Cache and Putah Creeks, California, and analyzed them for mercury and trace elements. Trace elements were higher in carcasses in 40 cases, higher in tails in 5 cases, and not different in 35 cases; no concentration exceeded levels considered harmful. Mercury concentrations were similar among sites, with noAuthorsR. L. Hothem, D.R. Bergen, M.L. Bauer, J.J. Crayon, A.M. MeckstrothNon-USGS Publications**
Pintor, L. M., Sih, A. and Bauer, M. L. (2008), Differences in aggression, activity and boldness between native and introduced populations of an invasive crayfish. Oikos, 117: 1629–1636. doi:10.1111/j.1600-0706.2008.16578.x**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.