Geology Reports⌕ Search

SEARCH · Geology Reports

Results for “Salmonid”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 199 records · Page 11Linked to original sources
USGS2008

Hydrological response to timber harvest in northern Idaho: Implications for channel scour and persistence of salmonids

The potential for forest harvest to increase snowmelt rates in maritime snow climates is well recognized. However, questions still exist about the magnitude of peak flow increases in basins larger than 10 km2 and the geomorphic and biological consequences of these changes. In this study, we used observations from two nearly adjacent small basins (13 and 30 km2) in the Coeur d'Alene River basin, one with recent, relatively extensive, timber harvest, and the other with little disturbance in the last 50 years to explore changes in peak flows due to timber harvest and their potential effects on fish. Peak discharge was computed for a specitic rain-on-snow event using a series of physical models that linked predicted values of snowmelt input to a runoff-routing model. Predictions indicate that timber harvest caused a 25% increase in the peak flow of the modelled event and increased the frequency of events of this magnitude from a 9-year recurrence interval to a 3-6-year event. These changes in hydrologic regime, with larger discharges at shorter recurrence intervals, are predicted to increase the depth and frequency of streambed scour, causing up to 15% added mortality of bull trout (Salvelinus confluentus) embryos. Mortality from increased scour, although not catastrophic, may have contributed to the extirpation of this species from the Coeur d'Alene basin, given the widespread timber harvest that occurred in this region. Copyright ?? 2008 John Wiley & Sons, Ltd.

Hydrological Processes↗
USGS2026

Increasing artificial light at night enhances salmonid predator foraging efficiency in an urbanized lake

Artificial light at night (ALAN) poses a threat to ecosystems globally. It includes both direct and indirect light, or skyglow, which occurs when ALAN scatters in the atmosphere, extending beyond its original source. We analyzed ALAN trends in Lake Washington, WA, from 2014 to 2023 using Visible Infrared Imaging Radiometer Suite (VIIRS) nighttime light measurements, evaluated the relationship between in situ and satellite measurements, and modeled predator search volumes for a juvenile salmon predator, cutthroat trout ( Oncorhynchus clarki ), as a function of ambient light and turbidity conditions. Open water regions experienced significant increases in ALAN, while nearshore areas primarily showed no or negative trends, revealing the role of skyglow in shaping open water light environments. Using a visual foraging model for cutthroat trout, we found that juvenile salmon at the shallow southern pelagic site experienced light 28 times brighter, resulting in a 168% greater predation vulnerability than those at the northern site. In the Ship Canal, a narrow corridor for outmigrating salmon, predator search volumes were 249% higher than at the southern site. These contrasts in predation vulnerability demonstrate how local conditions influence predator–prey dynamics and provide critical insight for targeting mitigation of both nearshore and distant light sources.

Washington↗
USGS2018

Effects of summer air exposure on the survival of caught-and-released salmonids

Despite the success of catch‐and‐release regulations, exposing fish to air during release has emerged as a growing concern over the past two decades. We evaluated the effect of air exposure during midsummer on survival of Yellowstone Cutthroat Trout Oncorhynchus clarkii bouvieri , Bull Trout Salvelinus confluentus , and Rainbow Trout O. mykiss exposed to catch‐and‐release angling. Fish were sampled by angling on Palisades Creek (August 2016), Sawmill Creek, and the Main Fork of the Little Lost River, Idaho (July−August 2017). After capture, fish were kept underwater while they were measured and individually tagged. Anglers, in groups of two to four, caught study fish and gave them an air exposure treatment of 0, 30, or 60 s. Single‐pass backpack electrofishing was then used to recapture tagged fish and estimate relative survival. In total, 328 Yellowstone Cutthroat Trout were sampled (0 s: n = 110; 30 s: n = 110; 60 s: n = 108), 278 Bull Trout (0 s: n = 92; 30 s: n = 94; 60 s: n = 92), and 322 Rainbow Trout (0 s: n = 103; 30 s: n = 106; 60 s: n = 113). The majority of fish were caught using artificial flies (≥92%) and were hooked in the corner of the mouth, lower jaw, or upper jaw (≥78%) in all three species. No difference in survival was observed among air exposure treatments for all three species. Results from the present study along with those from prior field studies of air exposure times during angling suggest that mortality from exposing fish to air for ≤60 s is not likely a population‐level concern in catch‐and‐release fisheries for these species.

Idaho↗
USGS2008

Performance of a prototype surface collector for juvenile salmonids at Bonneville dam's first powerhouse on the Columbia River, Oregon

During April-July 2000, we radio-tagged and released juvenile Chinook salmon (Oncorhynchus tshawytscha) and steelhead (Oncorhynchus mykiss) to evaluate a prototype surface flow bypass at Bonneville Dam on the Columbia River. The mock bypass, called a prototype surface collector (PSC), had six vertical slot entrances that were each 6 m wide and 12 m deep. The PSC was retrofitted to the upstream face of Bonneville Dam's First Powerhouse. Our objectives were to: (1) assess species-specific differences in movement patterns and behaviour of fish within 6 m of the face of the PSC, (2) estimate the efficiency and effectiveness of the PSC and (3) evaluate factors affecting the performance of the PSC. We found that 60-72% of the fish, depending on species, detected within 6 m of the PSC entered it. Of the fish that passed the First Powerhouse at turbines 1-6, 79-83% entered the PSC. Diel period was a significant contributor to PSC performance for all species, and day of year was a significant contributor to PSC performance for subyearling Chinook salmon. The PSC was twice as effective (%fish/%flow) as the spillway, passing 2.5:1 steelhead and subyearling Chinook salmon and 2.4:1 yearling Chinook salmon per unit of water. If fully implemented, the PSC would increase the percentage of fish that pass the First Powerhouse through non-turbine routes from 65-77% (without the PSC) to 76-85% (with the PSC), depending on species. Published in 2008 by John Wiley & Sons, Ltd.

River Research and Applications↗
USGS2021

Integrated tools for identifying optimal flow regimes and evaluating alternative minimum flows for recovering at-risk salmonids in a highly managed system

Water resource managers are faced with difficult decisions on how to satisfy human water needs while maintaining or restoring riverine ecosystems. Decision sciences have developed approaches and tools that can be used to break down difficult water management decisions into their component parts. An essential aspect of these approaches is the use of quantitative models to evaluate alternative management strategies. Here, we describe four integrated decision support models for evaluating the effect of flows on two life history stages of Chinook salmon ( Oncorhynchus tshawytscha ) and Steelhead ( O. mykiss ). We then use constrained nonlinear optimization to identify optimal flow regimes for the water year type with the least available water. These flow regimes were then used by managers to develop candidate minimum flow strategies that were evaluated using forward simulation and sensitivity analyses. We found that optimal flow regimes differed markedly from existing regulations and varied among species and life history stages. However, evaluation of tradeoffs among the four competing objectives indicated relatively minimal losses for most objectives when the optimal flows were based on equally weighting the objectives. Sensitivity analysis indicated that water temperature was the primary driver of estimated outcomes and suggested that managers consider alternative means of managing temperatures. Decision sciences have created multiple analytical tools and approaches that simplify complex problems, such as water resource management, and we believe that water resource management would benefit from their increased use.

Oregon↗
USGS2021

Capacity of two Sierra Nevada rivers for reintroduction of anadromous salmonids: Insights from a high-resolution view

Historically, anadromous steelhead Oncorhynchus mykiss and spring-run Chinook Salmon O. tshawytscha used high-elevation rivers in the Sierra Nevada of California but were extirpated in the 20th century by construction of impassable dams. Plans to reintroduce the fish by opening migratory passage across the dams and reservoirs can only succeed if upstream habitats have the capacity to support viable populations of each species. To estimate capacity in the Tuolumne and Merced rivers of the central Sierra Nevada, we used a high-resolution approach based on remote sensing and dynamic habitat modeling. Our results suggested that for both species in both systems, sediment grain sizes would support widespread spawning and the water temperatures, depths, and velocities would generate ample capacity for fry and juveniles. However, the unregulated Merced River was consistently too warm for adult Chinook Salmon to hold in the dry season prior to spawning, while the regulated Tuolumne River maintained a cooler, more stable thermal regime with a capacity for thousands of holding adults. In our high-resolution approach, we also discovered several specific physical controls on life history expression, including thermal constraints on the timing of spawning, hydraulic prompts for downstream migration of fry, divergence of the hydraulic niches of steelhead and Chinook Salmon, and a key but uncertain role for thermal tolerance in adult Chinook Salmon. Our results suggested that steelhead reintroduction could succeed in either system and Chinook Salmon could succeed in the Tuolumne River if passage strategies account for large numbers of migrant fry and juveniles driven downstream by winter storms and snowmelt. The Merced River appeared too warm for adult Chinook Salmon, which raises questions about the current limited understanding of thermal tolerance in holding adults. Our study shows how a high-resolution approach can provide valuable insights on specific limiting factors that must be addressed for reintroduction to succeed.

California↗
USGS1989

Preliminary characterization of a virus causing infectious anemia among stocks of salmonid fish in the western United States

Since 1982, anemias occurring in stocks of yearling coho ( Oncorhynchus kisutch ) and chinook salmon (Oncorhynchus tshawytscha ) have been associated with serious losses at hatcheries in the Pacific Northwest, USA. The anemia is often accompanied by infections with external fungus (e.g. Saprolegnia) or the bacterial pathogens Cytophaga psychrophila or Renibacterium salmoninarum (Holt and Rohovec 1984, Leek 1987). The losses associated with the anemia are thought to be caused by these secondary infections. Blood smears that were made from anemic fish and stained with Giemsa or pinacyanol chloride showed erythrocytic inclusions ranging in size from 1 to 8 um and varying in number per cell. Thin sections of infected red blood cells (RBC) examined by electron microscopy revealed virus particles approximately 70 nm in diameter. The virions were scattered in the cytoplasm of the RBC or contained within membrane bound organelles. These virus particles were morphologically distinct from the iridovirus, erythrocytic necrosis virus (ENV), which is also associated with anemia (Holt and Rohovec 1984, Leek 1987). Evidence suggests that the etiological agent of this new anemic disease, termed erythrocytic inclusion body syndrome (EIBS) by Leek (1987), is a previously undescribed virus infecting salmon. The purpose of this study was to experimentally transmit the disease to healthy fish, to determine the blood parameters associated with infection, and to investigate the nature of the virus associated with EIBS.

Book chapter↗
USGS1971

Salmonid viruses: Infectious pancreatic necrosis virus

Epizootics occurred among young trout in France, and the behavior and symptoms suggested infectious pancreatic necrosis (IPN) virus. Specimens preserved in glycerol were sent to the U.S.A. for virological examination. Virus was isolated from four of five lots, but neutralization with antiserum against ATCC VR299 strain IPN virus was incomplete. Electron microscopy, bioassay, histopathology, and serology were used to identify the viruses. The results showed the agents to be new strains of IPN virus with distinctive antigenicity and heretofore unknown lability at 4°C and marked vulnerability to a single freezing and thawing. A method of improving stability in storage was found. Electronmicrographs, tabular and graphic data are presented.

Archiv Fur Die Gesamte Virusforschung↗
USGS1970

Salmonid viruses: Double infection of RTG-2 cells with Egtved and infectious pancreatic necrosis viruses

Egtved and infectious pancreatic necrosis (IPN) viruses were applied at high multiplicity alone and in combination to RTG-2 cells in liquid medium. Procedures were used which selectively suppressed one or the other virus, and the yields were determined after 64 hours at 15°C. The viruses showed an increase of 280 to 450 times the immediate post-adsorption level. Plaques of IPN and Egtved viruses showed some differences which can be helpful in distinguishing between the two agents. Detailed methods and results are given.

Archiv Fur Die Gesamte Virusforschung↗
USGS2011

Species replacement by a nonnative salmonid alters ecosystem function by reducing prey subsidies that support riparian spiders

Replacement of a native species by a nonnative can have strong effects on ecosystem function, such as altering nutrient cycling or disturbance frequency. Replacements may cause shifts in ecosystem function because nonnatives establish at different biomass, or because they differ from native species in traits like foraging behavior. However, no studies have compared effects of wholesale replacement of a native by a nonnative species on subsidies that support consumers in adjacent habitats, nor quantified the magnitude of these effects. We examined whether streams invaded by nonnative brook trout ( Salvelinus fontinalis ) in two regions of the Rocky Mountains, USA, produced fewer emerging adult aquatic insects compared to paired streams with native cutthroat trout ( Oncorhynchus clarkii ), and whether riparian spiders that depend on these prey were less abundant along streams with lower total insect emergence. As predicted, emergence density was 36% lower from streams with the nonnative fish. Biomass of brook trout was higher than the cutthroat trout they replaced, but even after accounting for this difference, emergence was 24% lower from brook trout streams. More riparian spiders were counted along streams with greater total emergence across the water surface. Based on these results, we predicted that brook trout replacement would result in 6–20% fewer spiders in the two regions. When brook trout replace cutthroat trout, they reduce cross-habitat resource subsidies and alter ecosystem function in stream-riparian food webs, not only owing to increased biomass but also because traits apparently differ from native cutthroat trout.

Oecologia↗
USGS2024

Change in growth and prey utilization for a native salmonid following invasion by an omnivorous minnow in an oligotrophic reservoir

Aquatic invasive species can affect food web structure, native fish growth, and production, depending on the traits of the invasive species and the pre-invasion conditions of the ecosystem. Thermal tolerances and behavioral traits can further influence differential exploitation of resources shared between native and invasive species. An unauthorized introduction of redside shiner ( Richardsonius balteatus ) into reservoirs in the Upper Skagit River, Washington, USA caused concern of potential competition, decreased production, and recruitment of rainbow trout ( Oncorhynchus mykiss ). We combined bioenergetics modeling and stable isotope analysis with field data to quantify consumption demand of native and invasive fishes and related consumption to the availability of key zooplankton prey. Per capita consumption on Daphnia by redside shiner was low; however, their high abundance imposed considerable demand on prey resources in Ross Lake. Although monthly consumption demand by the fish community was less than 50% of the monthly production and biomass of Daphnia in Ross Lake, the current Daphnia densities and growth of rainbow trout were considerably lower than before the invasion. These reductions correspond to lower annual consumption of Daphnia . Our study provides insight on mechanisms that influence food web impacts of an invasive omnivore in cold-water reservoirs.

Washington↗
USGS1969

Stress-induced ascorbic acid depletion and cortisol production in two salmonid fishes

Interrenal ascorbic acid and serum cortisol were measured in non-specificity stressed yearling coho salmon and rainbow trout. Interrenal ascorbate was markedly decreased during stress but increased to normal if adaptation occurred. Serum cortisol was elevated by non-specific stress and remained high after interrenal ascorbate had returned to initial levels.

Comparative Biochemistry and Physiology, Part A: M↗
USGS1990

Comparative toxicity of inorganic contaminants released by placer mining to early life stages of salmonids

The acute toxicities of four trace inorganics associated with placer mining were determined, individually and in environmentally relevant mixtures, to early life stages of Arctic grayling ( Thymallus arcticus ) from Alaska and Montana, coho salmon ( Oncorhynchus kitsutch ) from Alaska and Washington, and rainbow trout ( Oncorhynchus mykiss ) from Montana. The descending rank order of toxicity to all species and life stages was copper > zinc > lead > arsenic. For each of the three species, sensitivity to the inorganics was greater in juveniles than in alvenins or in swim-up fry. Arctic grayling from Alaska were more sensitive than the other species tested, including Arctic grayling from Montana. For Arctic grayling, sensitivity to all four inorganics was significantly greater in swim-up fry from Alaska than in alevins from Montana, and sensitivity to arsenic and copper was significantly greater in juveniles from Alaska than in juveniles from Montana. In tests with environmentally relevant mixtures (based on ratios of concentrations measured in streams with placer mining) of these four inorganics, copper was identified as the major toxic component because it accounted for ⩾97% of the summed toxic units of the mixture, and an equitoxic mixture of these inorganics showed less-than-additive toxicity. Total and total recoverable copper concentrations reported in five Alaskan streams with active placer mines were higher than the acutely toxic concentrations, either individually or in mixtures, that the authors found to be acutely toxic to Arctic grayling and coho salmon from Alaska. However, caution should be used when comparing our results obtained in “clear” water to field situations, because speciation and toxicity of these inorganics may be altered in the presence of sediments suspended by placer mining activities.

Ecotoxicology and Environmental Safety↗
USGS2018

Fight and air exposure times of caught and released salmonids from the South Fork Snake River

Catch-and-release regulations are among the most common types of fishing regulations. In recent years, concerns have arisen regarding the exposure of fish to air during catch-and-release angling. The purpose of our study was to quantify the length of time angled fish were exposed to air by anglers in a typical catch-and-release fishery and relate it to the lengths of time reported to produce negative effects. In total, 312 individual anglers were observed on the South Fork Snake River, Idaho, from May through August 2016. Fight time varied from 1.1 s to 230.0 s, and average fight time was 40.0 s (SD = 36.8). Total air exposure times varied from 0.0 s to 91.8 s and averaged 19.3 s (SD = 15.0). Though not statistically significant, a trend in reduced fight times was observed when anglers were guided and increased air exposure times when a net was used and a picture was taken. Results of the current study suggest that anglers expose fish to air for periods that are much less than those reported to cause mortality.

Idaho↗
USGS1999

Influence of bacterial kidney disease on smoltification in salmonids: Is it a case of double jeopardy?

We investigated the effects of a chronic, progressive infection with Renibacterium salmoninarum (Rs), the causative agent of bacterial kidney disease (BKD), on selected aspects of smoltification in yearling juvenile spring chinook salmon (Oncorhynchus tshawytscha). After experimentally infecting fish with Rs using an immersion challenge, we sampled them every two weeks to monitor changes in gill Na+, K+-ATPase (ATPase), cortisol, infection level, mortality, growth, and other stress-related physiological factors during the normal time of parr-smolt transformation in fresh water (i.e., from winter to spring). A progressively worsening infection with Rs did not alter the normal changes in gill ATPase and condition factor associated with smoltification in juvenile chinook salmon. The infection did, however, lead to elevated levels of plasma cortisol and lactate and depressed levels of plasma glucose, indicating that the disease is stressful during the later stages. A dramatic proliferation of BKD was associated with maximal responses of indicators of smoltification, suggesting that the process of smoltification itself can trigger outbreaks of disease. Our results suggest mechanisms that probably influence the reported inability of Rs-infected fish to successfully adapt to sea water.

Aquaculture↗
USGS2008

Mercury concentrations in salmonids from western U.S. National Parks and relationships with age and macrophage aggregates

Mercury accumulation in aquatic foodwebs and its effects on aquatic biota are of growing concern both for the health of the fish and the piscivores that prey upon them. This is of particular concern for western U.S. National Parks because it is known that mountainous and Arctic areas are sinks for some contaminants. The Western Airborne Contaminants Assessment Project seeks, in part, to ascertain mercury concentrations and evaluate effects of contaminants on biota in 14 lakes from 8 National Parks or Preserves. In this paper we report that mercury has accumulated to concentrations in trout that may negatively impact some piscivorous wildlife, indicating potential terrestrial ecosystem effects. Additionally, we show that mercury concentrations increase with age in 4 species of trout, providing evidence of bioaccumulation. Finally, we demonstrate that mercury is associated with tissue damage in the kidney and spleen, as indicated by increases in macrophage aggregates. This finding suggests that mercury, and possibly other contaminants, are negatively affecting the trout that inhabit these remote and protected ecosystems. Our results indicate that mercury is indeed a concern for the U.S. National Parks, from an organismic and potentially an ecosystem perspective. ?? 2008 American Chemical Society.

Environmental Science & Technology↗
USGS2013

Characterizing the thermal suitability of instream habitat for salmonids: A cautionary example from the Rocky Mountains

Understanding a species’ thermal niche is becoming increasingly important for management and conservation within the context of global climate change, yet there have been surprisingly few efforts to compare assessments of a species’ thermal niche across methods. To address this uncertainty, we evaluated the differences in model performance and interpretations of a species’ thermal niche when using different measures of stream temperature and surrogates for stream temperature. Specifically, we used a logistic regression modeling framework with three different indicators of stream thermal conditions (elevation, air temperature, and stream temperature) referenced to a common set of Brook Trout Salvelinus fontinalis distribution data from the Boise River basin, Idaho. We hypothesized that stream temperature predictions that were contemporaneous with fish distribution data would have stronger predictive performance than composite measures of stream temperature or any surrogates for stream temperature. Across the different indicators of thermal conditions, the highest measure of accuracy was found for the model based on stream temperature predictions that were contemporaneous with fish distribution data (percent correctly classified = 71%). We found considerable differences in inferences across models, with up to 43% disagreement in the amount of stream habitat that was predicted to be suitable. The differences in performance between models support the growing efforts in many areas to develop accurate stream temperature models for investigations of species’ thermal niches.

Idaho↗
USGS2016

Feeding ecology of native and nonnative salmonids during the expansion of a nonnative apex predator in Yellowstone Lake, Yellowstone National Park

The illegal introduction of Lake Trout Salvelinus namaycush into Yellowstone Lake, Yellowstone National Park, preceded the collapse of the native population of Yellowstone Cutthroat Trout Oncorhynchus clarkii bouvieri , producing a four-level trophic cascade. The Yellowstone Cutthroat Trout population’s collapse and the coinciding increase in Lake Trout abundance provided a rare opportunity to evaluate the feeding ecology of a native prey species and a nonnative piscivore species after the restructuring of a large lentic ecosystem. We assessed diets, stable isotope signatures, and depth-related CPUE patterns for Yellowstone Cutthroat Trout and Lake Trout during 2011–2013 to evaluate trophic overlap. To evaluate diet shifts related to density, we also compared 2011–2013 diets to those from studies conducted during previous periods with contrasting Yellowstone Cutthroat Trout and Lake Trout CPUEs. We illustrate the complex interactions between predator and prey in a simple assemblage and demonstrate how a nonnative apex predator can alter competitive interactions. The diets of Yellowstone Cutthroat Trout were dominated by zooplankton during a period when the Yellowstone Cutthroat Trout CPUE was high and were dominated by amphipods when the CPUE was reduced. Lake Trout shifted from a diet that was dominated by Yellowstone Cutthroat Trout during the early stages of the invasion to a diet that was dominated by amphipods after Lake Trout abundance had increased and after Yellowstone Cutthroat Trout prey had declined. The shifts in Yellowstone Cutthroat Trout and Lake Trout diets resulted in increased trophic similarity of these species through time due to their shared reliance on benthic amphipods. Yellowstone Cutthroat Trout not only face the threat posed by Lake Trout predation but also face the potential threat of competition with Lake Trout if amphipods are limiting. Our results demonstrate the importance of studying the long-term feeding ecology of fishes in invaded ecosystems.

Wyoming↗