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At least 1,261 records · Page 70Linked to original sources
USGS2011

Joint Ecosystem Modeling (JEM) ecological model documentation volume 1: Estuarine prey fish biomass availability v1.0.0

Estuarine fish serve as an important prey base in the Greater Everglades ecosystem for key fauna such as wading birds, crocodiles, alligators, and piscivorous fishes. Human-made changes to freshwater flow across the Greater Everglades have resulted in less freshwater flow into the fringing estuaries and coasts. These changes in freshwater input have altered salinity patterns and negatively affected primary production of the estuarine fish prey base. Planned restoration projects should affect salinity and water depth both spatially and temporally and result in an increase in appropriate water conditions in areas occupied by estuarine fish. To assist in restoration planning, an ecological model of estuarine prey fish biomass availability was developed as an evaluation tool to aid in the determination of acceptable ranges of salinity and water depth. Comparisons of model output to field data indicate that the model accurately predicts prey biomass in the estuarine regions of the model domain. This model can be used to compare alternative restoration plans and select those that provide suitable conditions.

Florida↗
USGS2014

Discharge, water quality, and native fish abundance in the Virgin River, Utah, Nevada, and Arizona, in support of Pah Tempe Springs discharge remediation efforts

Pah Tempe Springs discharge hot, saline, low dissolved-oxygen water to the Virgin River in southwestern Utah, which is transported downstream to Lake Mead and the Colorado River. The dissolved salts in the Virgin River negatively influence the suitability of this water for downstream agricultural, municipal, and industrial use. Therefore, various remediation scenarios to remove the salt load discharged from Pah Tempe Springs to the Virgin River are being considered. One concern about this load removal is the potential to impact the ecology of the Virgin River. Specifically, information is needed regarding possible impacts of Pah Tempe Springs remediation scenarios on the abundance, distribution, and survival of native fish in the Virgin River. Future efforts that aim to quantitatively assess how various remediation scenarios to reduce the load of dissolved salts from Pah Tempe Springs into the Virgin River may influence the abundance, distribution, and survival of native fish will require data on discharge, water quality, and native fish abundance. This report contains organized accessible discharge, water quality, and native fish abundance data sets from the Virgin River, documents the compilation of these data, and discusses approaches for quantifying relations between abiotic physical and chemical conditions, and fish abundance.

Arizona, Nevada, Utah↗
USGS2015

Exposure-related effects of Pseudomonas fluorescens , strain CL145A, on coldwater, coolwater, and warmwater fish

The exposure-related effects of a commercially prepared spray-dried powder (SDP) formulation of Pseudomonas fluorescens , strain CL145A, were evaluated on coldwater, coolwater, and warmwater fish endemic to the Great Lakes and Upper Mississippi River Basins. Nine species of young-of-the-year fish were exposed to SDP for 24 hours by using continuous-flow, serial-dilution exposure systems at temperatures of 12 degrees Celsius (°C; 2 species; Oncorhynchus mykiss [rainbow trout] and Salvelinus fontinalis [brook trout]), 17 °C (3 species; Perca flavescens [yellow perch], Sander vitreus [walleye], and Acipenser fulvescens [lake sturgeon]), or 22 °C (4 species; Micropterus salmoides [largemouth bass], Micropterus dolomieu [smallmouth bass], Lepomis macrochirus [bluegill sunfish], and Ictalurus punctatus [channel catfish]). Treatments, which were nominal target concentrations of SDP (as active ingredient) of 50, 100, 200, and 300 milligrams per liter (mg/L), were continuously applied for 24 hours by the addition of a test article stock solution into the main water inflow of each exposure system's dilution box. The SDP-treated water was then serially diluted through a series of dilution cells before delivery to the test chambers. The exposure concentrations measured were 61.5 to 81.4 percent of the target concentration. After exposure, fish were monitored for 22 days to assess exposure-related latent effects. Analyses of test animal condition factors and survival revealed that a 24-hour continuous dose of SDP affected all species. Calculated concentrations of SDP that would be lethal to 50 percent of the test animals (LC 50 ) for the coldwater species were 19.2 and 104.6 mg/L for rainbow and brook trout, respectively. The LC 50 's for the coolwater species were 185.4, 176.9 and 8.9 mg/L for yellow perch, walleye, and lake sturgeon, respectively. The LC 50 's for the warmwater species were 173.6, 139.4, and 63.1 for the largemouth bass, smallmouth bass, and channel catfish, respectively. A reliable LC 50 for bluegill sunfish could not be calculated because mortality in the SDP-treated groups did not exceed 20 percent. Further investigations to evaluate the SDP-exposure related effects on freshwater fish at the maximum approved open-water label concentration and exposure duration (100 mg/L for 8 hours) and using the expected lentic application technique (static application) are warranted. The variation in tolerance to P. fluorescens , strain CL145A, exposure observed in this study indicates that fish species community composition should be considered before SDP is applied in open-water environments.

Open-File Report↗
USGS2016

Relative distribution and abundance of fishes and crayfish in 2010 and 2014 prior to saltcedar ( Tamarix ssp.) removal in the Amargosa River Canyon, southeastern California

The Amargosa River Canyon, located in the Mojave Desert of southeastern California, contains the longest perennial reach of the Amargosa River. Because of its diverse flora and fauna, it has been designated as an Area of Critical Environmental Concern and a Wild and Scenic River by the Bureau of Land Management. A survey of fishes conducted in summer 2010 indicated that endemic Amargosa River pupfish ( Cyprinodon nevadensis amargosae ) and speckled dace ( Rhinichthys osculus spp.) were abundant and occurred throughout the Amargosa River Canyon. The 2010 survey reported non-native red swamp crayfish ( Procambarus clarkii ) and western mosquitofish ( Gambusia affinis ) captures were significantly higher, whereas pupfish captures were lower, in areas dominated by non-native saltcedar ( Tamarix ssp.). Based on the 2010 survey, it was hypothesized that the invasion of saltcedar could result in a decrease in native species. In an effort to maintain and enhance native fish populations, the Bureau of Land Management removed saltcedar from a 1,550 meter reach of stream on the Amargosa River in autumn 2014 and autumn 2015. Prior to the removal of saltcedar, a survey of fishes and crayfish using baited minnow traps was conducted in the treatment reach to serve as a baseline for future comparisons with post-saltcedar removal surveys. During the 2014 survey, 1,073 pupfish and 960 speckled dace were captured within the treatment reach. Catch per unit effort of pupfish and speckled dace in the treatment reach was less in 2014 than in 2010, although differences could be owing to seasonal variation in capture probability. Non-native mosquitofish catch per unit effort decreased from 2010 to 2014; however, the catch per unit effort of crayfish increased from 2010 to 2014. Future monitoring efforts of this reach should be conducted at the same time period to account for potential seasonal fluctuations of abundance and distribution of fishes and crayfish. A more robust study design that accounts for variation in capture probability could be implemented to quantify the effects of habitat modifications on abundance of fishes and crayfish.

California↗
USGS2017

Colorado River fish monitoring in Grand Canyon, Arizona; 2002–14 humpback chub aggregations

The humpback chub ( Gila cypha ) is an endangered cyprinid species endemic to the Colorado River. The largest remaining population of the species spawns and rears in the Little Colorado River in Grand Canyon. Construction and operation of Glen Canyon Dam has altered the main-stem Colorado River in Glen and Grand Canyons. Cold, clear water releases from the dam result in a river that is generally unsuitable for successful humpback chub reproduction. During the early 1990s, nine locations within the main-stem Colorado River were identified as humpback chub aggregations—areas with a consistent and disjunct group of fish with no significant exchange of individuals with other aggregations. We monitored main-stem Colorado River aggregations of humpback chub in Grand Canyon during 2010 to 2014 and compared our results to previous investigations. Relative abundance, as described by catch per unit effort (fish per hour) of adult humpback chub at most main-stem aggregations, generally increased from the 1990s to 2014. In addition, distribution of humpback chub in the main-stem Colorado River has increased since the 1990s. Movement of humpback chub between the Little Colorado River and other aggregations likely adds fish to those aggregations. There is clear evidence of reproduction near the 30-Mile aggregation, and reproduction at Middle Granite Gorge and downstream seems likely based on catches of gravid fish and captures of very young fish, especially during relatively warm water releases from Glen Canyon Dam, 2004 to 2011. Humpback chub relative abundance at Shinumo and Havasu Creek inflows increased following translocations of young humpback chub starting in 2009. In light of this information, we modify the original nine aggregations, combining two previously separate aggregations and dropping two locations to form six distinct aggregations of humpback chub. Trends in humpback chub abundance at main-stem aggregations, relative to management actions (for example, translocations) or changing environmental conditions (for example, river warming), informs management of the species across a riverscape scale within the Colorado River.

Colorado↗
USGS2017

Effectiveness of common fish screen materials for protecting lamprey ammocoetes—Influence of sweeping velocities and decreasing flows

In previous tests of the effectiveness of four common fish screen materials for excluding lamprey ammocoetes, we determined that woven wire (WW) allowed substantially more entrainment than perforated plate (PP), profile bar (PB), or Intralox (IL) material. These tests were simplistic because they used small vertically-oriented screens positioned perpendicular to the flow without a bypass or a sweeping velocity (SV). In the subsequent test discussed in this report, we exposed ammocoetes to much larger (2.5-m-wide) screen panels with flows up to 10 ft3 /s, a SV component, and a simulated bypass channel. The addition of a SV modestly improved protection of lamprey ammocoetes for all materials tested. A SV of 35 cm/s with an approach velocity (AV) of 12 cm/s, was able to provide protection for fish about 5–15 mm smaller than the protection provided by an AV of 12 cm/s without a SV component. The best-performing screen panels (PP, IL, and PB) provided nearly complete protection from entrainment for fish greater than 50-mm toal length, but the larger openings in the WW material only protected fish greater than 100-mm total length. Decreasing the AV and SV by 50 percent expanded the size range of protected lampreys by about 10–15 mm for those exposed to IL and WW screens, and it decreased the protective ability of PP screens by about 10 mm. Much of the improvement for IL and WW screens under the reduced flow conditions resulted from an increase in the number of lampreys swimming away from the screen. Fish of all sizes became impinged (that is, stuck on the screen surface for more than 1 s) on the screens, with the rate of impingement highest on PP (39– 72 percent) and lowest on WW (7–22 percent). Although impingements were common, injuries were rare, and 24-h post-test survival was greater than 99 percent. Our results refined the level of protection provided by these screen materials when both an AV and SV are present and confirmed our earlier recommendation that WW screens be replaced with more effective materials. Future work should focus on determining the risks associated with other screen types (for example, rotary drum screens, horizontal flat plate screens) and exploring the effectiveness of higher SV:AV ratios, because it may help expand the range of sizes protected by the best performing materials.

Open-File Report↗
USGS2020

Modeling occupancy of rare stream fish species in the upper Cumberland and Kentucky River Basins

Biological conservation often requires an understanding of how environmental conditions affect species occurrence and detection probabilities. We used a hierarchical framework to evaluate these effects for several Appalachian stream fish species of conservation concern: Chrosomus cumberlandensis (BSD; blackside dace), Etheostoma sagitta (CAD; Cumberland arrow darter), and Etheostoma spilotum (KAD; Kentucky arrow darter). Etheostoma susanae (Cumberland darter) also is present in the study area but was too rare to model in this analysis. In this study, conducted by the U.S. Geological Survey in cooperation with the U.S. Fish and Wildlife Service, fish and habitat data were collected from 205 randomly selected stream sites in the upper Cumberland and Kentucky River Basins (120 and 85 sites, respectively) of Kentucky and Tennessee. Sites were sampled with 10 spatial replicates (2 meter x 5 meter electrofishing zones) to enable estimation of detection probabilities and environmental effects. The best models (that is, lowest Akaike information criterion scores) showed the effects of agriculture (negative) on occurrence of BSD and stream conductivity (negative) on occurrence of CAD and KAD. These effects were statistically more important than measures of basin area, elevation, and substrate size. Conductivity and agriculture showed nonlinear effects on species occurrence, and effects of conductivity were more precise above 400 microsiemens per centimeter than below this threshold. Models incorporated detection-level effects of electrofishing time (positive), flow velocity (negative), sand substrate (positive), and gravel/cobble substrate (negative). Models accounting for detection of BSD estimated occupancy rates similar to the observed proportion of occupied sites (0.10), but the best-supported models for CAD and KAD increased expected occupancy by about 4 percent for each species (from 0.17 to 0.21 for CAD and from 0.07 to 0.11 for KAD). Results of this study provide new inferences for modeling stream fish occurrence and detection processes and highlight the importance of continued monitoring and assessment of rare fish species in Appalachian headwater streams.

Kentucky, Tennessee, Virginia↗
USGS1978

Coal resources of the Fish Creek EMRIA site, Routt County, Colorado

The Fish Creek EMRIA site, an area of about 3.7 square miles (9.6 km2), is located in the southeastern part of the Yampa coal field on the steep to gently dipping beds of the Upper Cretaceous Williams Fork Formation. The Fish Creek coal bed within 200 feet (60 m) of the surface was evaluated by five core holes. Coal resources--measured, indicated, and inferred--within the site are 2,512,000 short tons, 7,970,000 short tons, and 507,000 short tons respectively. The coal has an apparent rank of bituminous C. The average Btu value of three core samples from the site on the as-received basis is 10,790, average ash content is 11.1 percent, and average sulfur content is 1.9 percent. A comparison of the analyses of samples from the Fish Creek coal bed with other Rocky Mountain province coal sample analyses shows that nitrogen, total sulfur, and pyritic and organic sulfur contents are noticeably higher in the Fish Creek coal bed samples. A comparison of other element analyses shows that the Fish Creek coal bed is noticeably higher in As, Cr, F, Fe, Hg, and Sr, and noticeably lower in Th.

Colorado↗
USGS1997

Concentrations of selected trace elements and other constituents in the Rio Grande and in fish tissue in the vicinity of Albuquerque, New Mexico

The State of New Mexico and the Pueblo of Isleta have established surface-water standards for trace elements to control discharges of these contaminants. Before these standards can be meaningfully applied, however, ambient concentrations and loads of trace elements, principally arsenic, need to be determined in the Rio Grande and inflow sources. Arsenic concentrations also need to be determined in the edible portion of fish tissue because the Pueblo of Isleta standard for arsenic is based on fish consumption. Eighteen surface-water sampling sites on a reach of the Rio Grande from the Pueblo of San Felipe to Los Lunas, New Mexico, were sampled quarterly from October 1994 to August 1996. The sites include eight Rio Grande sites, one Jemez River site, five riverside drain sites, and four wastewater- treatment plant outfalls. Trace-element protocol was used to collect and process the samples. Field and laboratory quality-control samples were analyzed, and the results are included in this report. Fish-tissue samples were collected from four of the Rio Grande sites and the Albuquerque Riverside Drain, the Atrisco Riverside Drain, and three lakes at a recreational fishing area on the Isleta Indian Reservation. Arsenic in the Rio Grande is nearly all in the dissolved phase. There was little temporal change in arsenic concentration at the Rio Grande sites. The mean dissolved-arsenic concentration in the Rio Grande increased downstream from 1.8 micrograms per liter at the Pueblo of San Felipe to 3.6 micrograms per liter at Los Lunas. Mean dissolved-arsenic concentrations in the riverside drains were slightly higher (2.8 to 4.5 micrograms per liter) than those in the Rio Grande and were higher still in the wastewater-treatment plant outfalls (7.9 to 16.2 micrograms per liter) and the Jemez River (18.2 micrograms per liter). The mean total-arsenic concentration in fish-tissue samples from the Rio Grande and Albuquerque Riverside Drain was 14.53 micrograms per kilogram.

Open-File Report↗
USGS2004

Fish communities of the Buffalo River Basin and nearby basins of Arkansas and their relation to selected environmental factors, 2001-2002

The Buffalo River lies in north-central Arkansas and is a tributary of the White River. Most of the length of the Buffalo River lies within the boundaries of Buffalo National River, a unit of the National Park Service; the upper 24 river kilometers lie within the boundary of the Ozark National Forest. Much of the upper and extreme lower parts of the basin on the south side of the Buffalo River is within the Ozark National Forest. During the summers of 2001 and 2002, fish communities were sampled at 52 sites in the study area that included the Buffalo River Basin and selected smaller nearby basins within the White River Basin in north-central Arkansas. Water quality (including nutrient and bacteria concentrations) and several other environmental factors (such as stream size, land use, substrate size, and riparian shading) also were measured. A total of 56 species of fish were collected from sites within the Buffalo River Basin in 2001 and 2002. All 56 species also were collected from within the boundaries of Buffalo National River. Twenty-two species were collected from headwater sites on tributaries of the Buffalo River; 27 species were collected from sites within or immediately adjacent to the Ozark National Forest. The list of species collected from Buffalo National River is similar to the list of species reported by previous investigators. Species richness at sites on the mainstem of the Buffalo River generally increased in a downstream direction. The number of species collected (both years combined) increased from 17 at the most upstream site to 38 near the mouth of the Buffalo River. In 2001 and 2002, a total of 53 species of fish were collected from sites outside the Buffalo River Basin. Several fish community metrics varied among sites in different site categories (mainstem, large tributary, small tributary, headwater, and developed out-of-basin sites). Median relative abundances of stonerollers ranged from about 25 to 55 percent and were highest at headwater and developed out-of-basin sites and lowest at mainstem sites. The relative abundances at the headwater and developed out-of-basin sites were significantly different from the relative abundances at the mainstem sites. Percentages of individuals of algivorous/herbivorous, invertivorous, and piscivorous species at headwater sites were significantly lower than values at mainstem and developed out-of-basin sites. Percentages of individuals of invertivorous species at mainstem sites were significantly higher than values at small tributary, headwater, and developed out-of-basin sites. Percentages of top carnivores at mainstem sites were significantly higher than values at tributary and headwater sites. The numbers of darter, sculpin, plus madtom species at mainstem, large tributary, and developed out-of-basin sites were significantly higher than values at other sites, and the values at small tributary sites and headwater sites were each significantly different from values at the other four types of sites. The number of lithophilic spawning species at large tributary sites was not significantly different from values at mainstem and developed out-of-basin sites, but values for small tributary and headwater sites each were significantly different from values for all other categories. Index of biotic integrity scores varied among the site categories. Scores for mainstem sites were significantly larger than all but large tributary site scores. Scores for headwater sites were significantly smaller than mainstem and large tributary site scores. Several analyses of the data described in this report suggest that drainage area is the most important single factor influencing fish communities of the Buffalo River Basin and nearby basins. Species richness increases with increasing drainage area and some species are restricted to smaller streams while other species are more common in larger streams. Some community metrics also are related to land use and related factors

Scientific Investigations Report↗
USGS2005

Water Quality, Fish Tissue, and Bed Sediment Monitoring in Waterbodies of Fort Chaffee Maneuver Training Center, Arkansas, 2002-2004

The Fort Chaffee Maneuver Training Center is a facility used to train as many as 50,000 Arkansas National Guardsmen each year. Due to the nature of ongoing training and also to a poor understanding of environmental procedures that were practiced in the World War II era, areas within Fort Chaffee have the potential to be sources of a large number of contaminants. Because some streams flow on to Fort Chaffee, there is also the potential for sources that are off post to affect environmental conditions on post. This study evaluates constituent concentrations in water, fish tissue, and bed sediment collected from waterbodies on Fort Chaffee between September 2002 and July 2004. Constituent concentrations detected in the three media and measured at nine stream sites and four lake sites were compared to national and regional criteria when available. Two of the larger streams, Big and Vache Grasse Creeks, were sampled at multiple sites. All three sampled media were analyzed for insecticides, PCBs, explosives, and trace elements. Additionally, water samples were analyzed for nutrients and herbicides. The different constituents detected in the three sample media (water, fish tissue, and bed sediment) indicate that land-use activities both on and off post are influencing environmental conditions. Contaminants such as explosives that were sometimes detected in water samples have an obvious relation to military training; however, the occurrence and locations of some nutrients, insecticides, and trace elements suggest that land use both on and off post also could be influencing environmental conditions to some degree. Constituent concentrations at sites on Vache Grasse Creek, and particularly the most upstream site, which was located immediately downstream from an off-post wastewater-treatment facility, indicate that environmental conditions were being influenced by an off-post source. The most upstream site on Vache Grasse Creek had both the highest number of detections and the highest concentrations detected of all sites sampled. Event-mean storm concentrations and storm loads calculated from storm-flow samples at two sites each for Big and Vache Grasse Creeks indicate that storm loads were highest at the two Vache Grasse Creek sites for 24 of the 25 constituents detected. Further evaluation by normalizing storm loads at Big Creek to storm loads at Vache Grasse Creek by stream flow indicate that event loads at Vache Grasse Creek were about two or more times higher than those on Big Creek for 15 of the 25 constituents measured. Low concentrations of arsenic and lead were detected in water samples, but all detections for the two trace elements occurred in samples collected at the upstream site on Vache Grasse Creek. The nickel concentration in fish livers collected from the upstream site on Vache Grasse Creek was 45 percent higher than the median of a national study of 145 sites. Mercury concentrations in edible fish tissue, which are a widespread concern in the United States, exceeded an USEPA criterion for methylmercury of 300 ?g/kg in four of nine samples; however, concentrations are typical of mercury concentrations in fish tissues for the State of Arkansas. Constituent concentrations at some sites indicate that environmental conditions are being influenced by on-post activities. Of the 55 (excluding total organic carbon) organic constituents analyzed in water samples, only 10 were detected above the minimum detection limit but four of those were explosives. Bed-sediment samples from one site located on Grayson Creek, and nearest the administrative and residential (cantonment) area, had detections for arsenic, copper, lead, manganese, nickel, and zinc that were above background concentrations, and concentrations for arsenic and nickel at this site exceeded lowest effect level criteria established by the U.S. Environmental Protection Agency. The site on Grayson Creek also had the only detections of DDT metabolites in bed sedi

Scientific Investigations Report↗
USGS2005

The fishes of Buffalo National River, Arkansas, 2001-2003

During June through September 2001 and 2002, extensive fish community sampling was conducted at 29 sites within the boundaries of Buffalo National River. Samples were collected using backpack, tote barge, and boat electrofishing equipment. Kick seining also was used at all sites. To supplement these results, samples were collected in 2003 from less typical habitats and during other seasons of the year. Ten supplemental samples were collected from the Buffalo River and five samples were collected from tributaries of the Buffalo River. During the 3 years of sampling, 66 species of fish were collected or observed from the 42 sampling sites. Stonerollers, duskystripe shiners, longear sunfish, and rainbow darters were among the more abundant fish species at most sites. Each of these species is common and abundant throughout much of the Ozark Plateaus in creeks and small rivers. Other species (for example, banded sculpin, southern redbelly dace, orangethroat darter, and Ozark minnow) were among the more abundant species at other sites. These species prefer small- to medium-sized, springfed streams or small creeks. A preliminary list of species expected to occur at Buffalo National River provided by the National Park Service incorrectly listed 47 species because of incorrect species range or habitat requirements. Upon revising this list, the inventory yielded 66 of the 78 species (85 percent). Twelve additional species not collected in 2001-2003 may occur at Buffalo National River for two primary reasons--because the species had been collected previously at the park, or because the park occurs within the known species range and habitats found at the park are suitable for the species. Although no fish species collected from Buffalo National River are federally-listed threatened or endangered species, several species collected at Buffalo National River may be of special interest to National Park Service managers and others. Ten species are endemic to the Ozark Plateaus area and most of these ten are restricted to the White River Basin. For some species the Buffalo River is a population stronghold. The yoke darter and Ozark bass are especially abundant in the Buffalo River. In Arkansas, the Ozark shiner is most abundant in the Buffalo River and, although populations of Ozark shiners are declining in Arkansas, this is not typically the case in the Buffalo River. Data from 2001-2003 indicate that gilt darters currently (2005) are less common in the Buffalo River than during the 1970's. Populations of channel catfish (and any other fish species whose movements are inhibited by the cold water temperatures of the White River) may continue to decline without remedial efforts.

Scientific Investigations Report↗
USGS2005

Quantification of fish habitat in selected reaches of the Marmaton and Marais des Cygnes Rivers, Missouri

The U.S. Geological Survey, in cooperation with the Missouri Department of Conservation, undertook a study to quantify fish habitat by using relations between streamflow and the spatial and temporal distributions of fish habitat at five sites in the Marmaton and Marais des Cygnes Rivers in western Missouri. Twenty-six fish habitat categories were selected for nine species under varying seasonal (spring, summer, and fall), diel (summer day and night), and life-stage (spawning, juvenile, and adult) conditions. Physical habitat characteristics were determined for each category using depth, velocity, and channel substrate criteria. Continuous streamflow data were then combined with the habitat-streamflow relations to compile a habitat time series for each habitat category at each site. Fish habitat categories were assessed as to their vulnerability to habitat alteration based on critical life stages (spawning and juvenile rearing periods) and susceptibility to habitat limitations from dewatering or high flows. Species categories representing critical life stages with physical habitat limitations represent likely bottlenecks in fish populations. Categories with potential bottlenecks can serve as indicator categories and aid managers when determining the flows necessary for maintaining these habitats under altered flow regimes. The relation between the area of each habitat category and streamflow differed greatly between category, season, and stream reach. No single flow maximized selected habitat area for all categories or even for all species/category within a particular season at a site. However, some similarities were noted among habitat characteristics, including the streamflow range for which habitat availability is maximized and the range of streamflows for which a habitat category area is available at the Marmaton River sites. A monthly habitat time series was created for all 26 habitat categories at two Marmaton River sites. A daily habitat time series was created at three Marais des Cygnes River sites for two periods: 1941 through 1963 (pre-regulation) and 1982 through 2003 (post-regulation). The habitat category with the highest median area in spring was paddlefish (Polyodon spathula) with normalized areas of up to 2,000 square meters per 100 meters of stream channel. Flathead catfish (Pylodictis olivaris) habitat area generally was the category area most available in summer and fall. Differences in daily selected habitat area time series between pre- and post-regulation time periods varied by species/category and by site. For instance, whereas there was a decline in the distribution of spring spawning habitat for suckermouth minnow (Phenacobius mirabilis) and slenderhead darter (Percina phoxocephala) from pre- to post-regulation periods at all three sites, the 25 to 75 percentile habitat area substantially increased for paddlefish under post-regulation conditions. Potential habitat area for most species was maximized at the Marmaton River sites at flows of about 1 to 10 cubic meters per second, whereas median monthly streamflows ranged from less than 1 to 20 cubic meters per second depending on site and season. Paddlefish habitat was available beginning at higher flows than other categories (4 to 7 cubic meters per second) and also maximized at higher flows (greater than 50 to 100 cubic meters per second). Selected potential habitat area was maximized for most species at the Marais des Cygnes River sites at flows of about 1 to 50 cubic meters per second, whereas median monthly streamflows ranged from 4 to 55 cubic meters per second depending on site and season. The range of streamflows for which selected habitat area was available in summer and fall was substantially less at the channelized Marais des Cygnes River site when compared to the non-channelized sites, and, therefore, the susceptibility of categories to high-flow habitat limitations was greater at this site. The channelized reach was more unifor

Scientific Investigations Report↗
USGS2017

Lake levels and water quality in comparison to fish mercury body burdens, Voyageurs National Park, Minnesota, 2013–15

Within Voyageurs National Park in Minnesota, lake levels are controlled by a series of dams to support a variety of uses. Previous research indicates a link between these artificially maintained water levels, referred to as rule curves, and mercury concentrations in fish owing to the drying and rewetting of wetlands and other nearshore areas, which may release methylmercury into the water when inundated. The U.S. Geological Survey, National Park Service, and University of Wisconsin-La Crosse cooperated in a study to assess the importance of lake-level fluctuation and other factors affecting mercury concentrations in Perca flavescens (yellow perch) in the lakes of Voyageurs National Park. For this study, mercury body burdens were determined for young-of-the-year yellow perch collected from the large lakes within Voyageurs National Park during 2013–15. These mercury body burdens were compared to lake levels and water-quality constituents from the same period. Field properties and profiles of lake water quality indicated that Sand Point, Little Vermilion, and Crane Lakes were anoxic at times near the lake bottom sediments, where sulfate-reducing bacteria may convert mercury to methylmercury. The median dissolved sulfate concentration was highest in Crane Lake, the median total organic carbon concentration was highest in Sand Point Lake, and the median total phosphorus concentration was highest in Kabetogama Lake, all of which is consistent with previous research. All lakes had median chlorophyll a concentrations of 3.6 micrograms per liter or less with the exception of Kabetogama Lake, where the median concentrations were 4.3 micrograms per liter for the midlake sites and 7.1 micrograms per liter and 9.0 micrograms per liter for the nearshore sites. Mercury concentrations in sampled fish varied widely between years and among lakes, from 14.7 nanograms per gram in fish samples from Kabetogama Lake in 2015 to 178 nanograms per gram in fish samples from Crane Lake in 2014. Data from this study can be combined with ongoing hydrologic modeling studies to evaluate trends in the mercury body burden of fish and different water-level management scenarios prescribed by the 2000 Rule Curves and the 1970 Rule Curves.

Minnesota↗
USGS2017

Estimation of the groundwater resources of the bedrock aquifers at the Kettle Moraine Springs State Fish Hatchery, Sheboygan County, Wisconsin

Groundwater resources information was needed to understand regional aquifer systems and water available to wells and springs for rearing important Lake Michigan fish species at the Kettle Moraine Springs State Fish Hatchery in Sheboygan County, Wisconsin. As a basis for estimating the groundwater resources available, an existing groundwater-flow model was refined, and new groundwater-flow models were developed for the Kettle Moraine Springs State Fish Hatchery area using the U.S. Geological Survey (USGS) finite-difference code MODFLOW. This report describes the origin and construction of these groundwater-flow models and their use in testing conceptual models and simulating the hydrogeologic system. The study area is in the Eastern Ridges and Lowlands geographical province of Wisconsin, and the hatchery property is situated on the southeastern edge of the Kettle Moraine, a north-south trending topographic high of glacial origin. The bedrock units underlying the study area consist of Cambrian, Ordovician, and Silurian units of carbonate and siliciclastic lithology. In the Sheboygan County area, the sedimentary bedrock sequence reaches a thickness of as much as about 1,600 feet (ft). Two aquifer systems are present at the Kettle Moraine Springs State Fish Hatchery. A shallow system is made up of Silurian bedrock, consisting chiefly of dolomite, overlain by unconsolidated Quaternary-age glacial deposits. The glacial deposits of this aquifer system are the typical source of water to local springs, including the springs that have historically supplied the hatchery. The shallow aquifer system, therefore, consists of the unconsolidated glacial aquifer and the underlying bedrock Silurian aquifer. Most residential wells in the area draw from the Silurian aquifer. A deeper confined aquifer system is made up of Cambrian- and Ordovician-age bedrock units including sandstone formations. Because of its depth, very few wells are completed in the Cambrian-Ordovician aquifer system (COAS) near the Kettle Moraine Springs State Fish Hatchery. Three groundwater-flow models were used to estimate the water resources available to the hatchery from bedrock aquifers under selected scenarios of well placement and seasonal water requirements and subject to constraints on the effects of pumping on neighboring wells, local springs, and creeks. Model input data (recharge, water withdrawal, and boundary conditions) for these models were compiled from a number of data and information sources. The first model, named the “KMS model,” (KMS stands for Kettle Moraine Springs) is an inset model derived from a published USGS regional Lake Michigan Basin model and was constructed to simulate groundwater pumping from the semiconfined Silurian aquifer. The second model, named the “Pumping Test model,” was constructed to evaluate an aquifer pumping test conducted in the COAS as part of this project. The Pumping Test model was also used to simulate the local effects of 20 years of groundwater pumping from this deep bedrock aquifer for future hatchery operations. The third model, named the “LMB modified model,” is a version of the published Lake Michigan Basin (LMB) model that was modified with aquifer parameters refined in an area around the hatchery (approximately a 5-mile radius circle, corresponding to the area stressed by the aquifer pumping test). This LMB modified model was applied to evaluate regional effects of pumping from the confined COAS. The available Silurian aquifer groundwater resource was estimated using the KMS model with three scenarios—named “AllConstraints,” “Constraints2,” and “Constraints3”—that specified local water-level and flow constraints such as drawdown at nearby household wells, water levels inside pumping well boreholes, and flow in local streams and springs. Each scenario utilized the MODFLOW Groundwater Management Process (GWM) to select three locations from six candidate locations that provided the greatest combined flow while satisfying the constraints. The three constraint scenarios provided estimates of 430 gallons per minute (gal/min), 480 gal/min, and 520 gal/min pumping from three wells—AllConstraints, Constraints2, and Constraints3, respectively. The same three wells were selected for the scenarios that estimated 480 gal/min and 520 gal/min; the scenario that estimated 430 gal/min shared two of these same wells, but the third selected well was different. The available COAS groundwater resource was estimated by two scenarios with each conducted over a period of 20 years with the Pumping Test model and the LMB modified model . The Pumping Test model was used to simulate local effects of pumping, and the LMB modified model was used to simulate regional effects of pumping. The scenarios simulate a range of total and seasonal pumping rates potentially linked to site activities. Scenario 1 simulates two wells completed in the Cambrian-Ordovician aquifer system, each pumping for 8 months at 300 gal/min, followed by pumping for 4 months at 600 gal/min. The average yearly pumping rate of Scenario 1 is 800 gal/min. Scenario 2 simulates three wells completed in the Cambrian-Ordovician aquifer system pumping for 8 months at 200 gal/min, followed by pumping for 4 months at 500 gal/min. The average yearly pumping rate of Scenario 2 is 900 gal/min. The Pumping Test model simulations confirmed that drawdown in the boreholes of the pumping wells at the selected 2-well or 3-well rates will meet the desired condition that the pumping water level remains at least 100 ft above the highest Cambrian-Ordovician unit open to the well. The LMB modified model was used to evaluate the regional drawdown of the pumping from the confined COAS under the same 2-well and 3-well scenarios. At the nearest known existing COAS well, Campbellsport production well #4, the simulated drawdown for Scenario 1 after 20 years of cyclical pumping with two pumping wells averaging a total of 800 gal/min is 16.9 ft, whereas the simulated drawdown for Scenario 2 after 20 years of pumping with three pumping wells averaging a total of 900 gal/min is 19.0 ft. The total deep aquifer thickness at the Campbellsport location is on the order of 620 ft, meaning that the simulated drawdown for either scenario is about 3 percent of the confined aquifer thickness. The models developed as part of this project are archived in the project data release. The archive includes the model input and output files as well as MODFLOW source code and executables. ( Haserodt and others, 2017 ).

Wisconsin↗
USGS2018

Method comparisons for determining concentrations of metals in water samples used in studies of fish migratory histories

Signatures developed from metal concentrations in water and fish bony structures can be used to demonstrate migration of individual fish between connected water bodies. The U.S. Geological Survey (USGS), in cooperation with the National Park Service and the Missouri Department of Conservation, compared two protocols for collecting and analyzing water samples for concentrations of several metals commonly used to develop metal signatures. In 2015, paired seasonal water samples were collected in two study areas incorporating three National Park Service units; paired water samples were collected using USGS protocols and simpler research protocols. Metal concentrations obtained using USGS and research protocols were compared using t-tests, percent differences, and simple linear regression analyses. Graphical plots of median values and measured ranges were used to compare ratios of strontium to calcium (Sr:Ca) and barium to calcium (Ba:Ca) obtained using the different protocols among individual stations within the two study areas. For stations on the Mississippi and St. Croix Rivers, ranges in concentrations of calcium, barium, and strontium (obtained using USGS protocols) were compared between samples collected from 1995 through 2012 and samples collected in this study. Comparisons were used to evaluate the long-term stability of metal concentrations in the environment. Collectively, results presented in this report demonstrated that research protocols provided metal concentration data that were similar to data obtained using USGS protocols for all compared metals except manganese. Holding times of 6–33 weeks prior to filtration and analyses for samples collected using research protocols may have caused greater changes in manganese concentrations compared to other metals. Strontium, barium, and calcium are the metals most commonly used in studies of fish migration, and concentrations of these metals were similar using different protocols. However, rivers within each study area were more easily distinguished from each other using metal concentration data obtained using USGS protocols compared to data obtained using research protocols. Information presented in this report can be used to develop studies that use identified metal signatures in connected water bodies and bony fish structures to demonstrate fish migration.

Mississippi National River and Recreation Area, Na↗
USGS2026

Spatial and temporal trends of mercury in fish from Duck Valley Reservation Reservoirs, southwestern Idaho and northern Nevada, 2007–24

The Shoshone-Paiute (Sho-Pai) Tribes of the Duck Valley Reservation, Nevada, manage reservoirs that support commercial and recreational activities, including robust Oncorhynchus mykiss (rainbow trout) fisheries that attract anglers year-round. Reservoirs are common environments for methylation and bioaccumulation of mercury, which is a potent neurotoxin when elevated levels are consumed. The U.S. Geological Survey (USGS), in cooperation with the Sho-Pai Tribes, measured total mercury concentrations in the muscle tissue of rainbow trout from three Reservation reservoirs in Idaho and Nevada in 2007, 2009, 2013, and 2024. This report highlights spatial and temporal trends of mercury concentrations in rainbow trout in the Duck Valley Reservation reservoirs from 2007 through 2024, and presents limited data on other commonly consumed species, specifically Perca flavescens (yellow perch), Micropterus dolomieu (smallmouth bass), and Micropterus salmoides (largemouth bass). Mercury data are also presented for nearby sites and lower trophic level species. In 2024, two fish sampling methods were used and compared: biopsy muscle plugs and muscle fillets. Results show good agreement between mercury concentrations of biopsy and fillet muscle samples taken from the same fish, with most sample pairs differing by less than 20 percent, though biopsied fish had an unexpectedly high mortality rate. Mercury concentrations increased in Sheep Creek Reservoir during the study period, but no significant trend was observed in Mountain View Reservoir or Lake Billy Shaw. Only 1 rainbow trout out of 160 sampled in the Reservation reservoirs during the study period exceeded the U.S. Environmental Protection Agency’s recommended methylmercury criterion of 0.3 milligram per kilogram of wet weight (mg/kg ww). Largemouth bass, smallmouth bass, and yellow perch had higher mercury concentrations than rainbow trout and may pose a greater risk to consumers. Mercury concentrations in largemouth bass exceeded 0.3 mg/kg ww, although only two fish were sampled, both from Sheep Creek Reservoir. Fish consumption advisories on Tribal lands are determined by the Tribes, and these results may help Sho-Pai managers determine the mercury exposure risk to Tribal members and visiting anglers.

Idaho, Nevada↗
USGS2000

Concentrations of selected trace elements in fish tissue and streambed sediment in the Clark Fork-Pend Oreille and Spokane River basins, Washington, Idaho, and Montana, 1998

Fish tissue and bed sediment samples were collected from 16 stream sites in the Northern Rockies Intermontane Basins study area in 1998 as part of the U.S. Geological Survey National Water-Quality Assessment Program. Bed sediment samples were analyzed for 45 trace elements, and fish livers and sportfish fillets were analyzed for 22 elements to characterize the occurrence and distribution of these elements in relation to stream characteristics and land use activities. Nine trace elements of environmental concern&mdash;arsenic, cadmium, chromium, copper, lead, mercury, nickel, selenium, and zinc&mdash;were detected in bed sediment, but not all of these elements were detected in fish tissue. Trace-element concentrations were highest in bed sediment samples collected at sites downstream from significant natural mineral deposits and (or) mining activities. Arsenic, cadmium, copper, lead, mercury, and zinc in bed sediment at some sites were elevated relative to national median concentrations, and some concentrations were at levels that can adversely affect aquatic biota. Although trace-element concentrations in bed sediment exceeded various guidelines, no concentrations in sportfish fillets exceeded U.S. Environmental Protection Agency screening values for the protection of human health. Correlations between most trace-element concentrations in bed sediment and fish tissue (liver and fillet) were not significant (r<&plusmn;0.50, p>0.05). Concentrations of arsenic, cadmium, copper, lead, mercury, nickel, selenium, and zinc in bed sediment were significantly correlated (r=0.53 to 0.88, p<0.05) with natural mineral deposits and mining activities, but concentrations in fish tissue generally were not correlated with these measures. Regression analysis between mine density and the sum of trace-element concentrations in bed sediment identified two statistically significant relations (r 2 =0.95 and 0.99, p<0.001) that corresponded to trace-element enrichment categories. These strong relations warrant further study using mine density as an explanatory variable to predict trace-element concentrations in bed sediment.

Idaho, Montana, Washington↗