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At least 1,765 records · Page 98Linked to original sources
USGS2012

Comparing Laser Desorption Ionization and Atmospheric Pressure Photoionization Coupled to Fourier Transform Ion Cyclotron Resonance Mass Spectrometry To Characterize Shale Oils at the Molecular Level

Laser desorption ionization (LDI) coupled to Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was used to analyze shale oils. Previous work showed that LDI is a sensitive ionization technique for assessing aromatic nitrogen compounds, and oils generated from Green River Formation oil shales are well-documented as being rich in nitrogen. The data presented here demonstrate that LDI is effective in ionizing high-double-bond-equivalent (DBE) compounds and, therefore, is a suitable method for characterizing compounds with condensed structures. Additionally, LDI generates radical cations and protonated ions concurrently, the distribution of which depends upon the molecular structures and elemental compositions, and the basicity of compounds is closely related to the generation of protonated ions. This study demonstrates that LDI FT-ICR MS is an effective ionization technique for use in the study of shale oils at the molecular level. To the best of our knowledge, this is the first time that LDI FT-ICR MS has been applied to shale oils.

Energy & Fuels↗
USGS2007

Design and implementation of estimation-based monitoring programs for flora and fauna: A case study on the Cherokee National Forest

Science-based monitoring of biological resources is important for a greater understanding of ecological systems and for assessment of the target population using theoretic-based management approaches. When selecting variables to monitor, managers first need to carefully consider their objectives, the geographic and temporal scale at which they will operate, and the effort needed to implement the program. Generally, monitoring can be divided into two categories: index and inferential. Although index monitoring is usually easier to implement, analysis of index data requires strong assumptions about consistency in detection rates over time and space, and parameters are often biasednot accounting for detectability and spatial variation. In most cases, individuals are not always available for detection during sampling periods, and the entire area of interest cannot be sampled. Conversely, inferential monitoring is more rigorous because it is based on nearly unbiased estimators of spatial distribution. Thus, we recommend that detectability and spatial variation be considered for all monitoring programs that intend to make inferences about the target population or the area of interest. Application of these techniques is especially important for the monitoring of Threatened and Endangered (T&E) species because it is critical to determine if population size is increasing or decreasing with some level of certainty. Use of estimation-based methods and probability sampling will reduce many of the biases inherently associated with index data and provide meaningful information with respect to changes that occur in target populations. We incorporated inferential monitoring into protocols for T&E species spanning a wide range of taxa on the Cherokee National Forest in the Southern Appalachian Mountains. We review the various approaches employed for different taxa and discuss design issues, sampling strategies, data analysis, and the details of estimating detectability using site occupancy. These techniques provide a science-based approach for monitoring and can be of value to all resource managers responsible for management of T&E species.

Proceedings of the Annual Conference of the Southe↗
USGS2024

Nonbreeding waterfowl behavioral response to crewed and uncrewed aerial surveys on conservation areas in Missouri

Monitoring waterfowl populations provides the basis for improving habitat quantity and quality, establishing harvest regulations, and ensuring sustainable waterfowl populations through appropriate management. Waterfowl biologists currently use a variety of population and habitat monitoring methods ranging from informal ground observations to low-level occupied aircraft surveys. Although unoccupied aerial systems (UAS) may provide safer and more precise alternatives to traditional aerial survey techniques that are less disturbing to waterfowl, there is limited information on how waterfowl in winter respond to UAS. We compared the behavioral responses of waterfowl to helicopters and UAS on Missouri Department of Conservation wetland conservation areas October – February 2021-2022. Helicopter surveys were flown using an Airbus H125 helicopter at heights of 100 – 350 m, with UAS surveys flown using a DJI Mavic 2 Pro UAS at 15 – 90 m. Waterfowl behavior was categorized as alert, swim, fly, or abandonment using flock-scan surveys recorded for 10-minute periods before, during, and after the surveys. The percentage of time flocks spent in each behavior during- or post-survey were compared to time spent in those behaviors pre-survey. Waterfowl increased time spent swimming, flying, and abandonment in response to helicopter flights, whereas UAS flights did not influence overall waterfowl behavior. Additionally, waterfowl did not change behavior in response to UAS flights regardless of waterfowl guild (mallard, other duck, or goose) or hunting season (open or closed). Waterfowl did increase flight behavior during UAS flights at 30 m, however, there was no change in behavior at all other UAS survey altitudes. UAS may be a good alternative to traditional waterfowl survey methods and are not likely to affect waterfowl distributions or energy expenditures during the survey periods.

Missouri↗
USGS2021

Field methods for translocating female greater sage-grouse (Centrocercus urophasianus) with their broods

Greater sage-grouse ( Centrocercus urophasianus ) have experienced considerable range contraction and reduced abundance in response to habitat loss and degradation. Translocation is a conservation action that is often used to reintroduce extirpated populations or augment existing small populations. Translocations have had limited success in restoring viable populations of sage-grouse; a lack of success is attributed to long-distance post-release movements away from release sites, reduced survival, and lack of reproductive success of translocated individuals. Translocating female sage-grouse with their chicks (brood translocation) is a technique aimed at promoting breeding area fidelity and reproduction and may be beneficial to population restoration efforts. Furthermore, the ability to capture, relocate, and release individuals while minimizing translocation-induced loss increases the overall probability of restoration success. Accordingly, we developed a protocol to translocate female sage-grouse and their broods simultaneously, using a delayed-release system that included a custom release box and acclimation pen. We tested our protocol across 2 separate restoration projects in North Dakota and California during 2017–2019 with a total of 38 translocated females and 196 chicks. We successfully released 174/196 chicks (88.8%) from 32/38 (84.2%) broods. Our protocol builds on existing translocation methods used to translocate sage-grouse and will likely prove to be a critical technique in restoring sage-grouse populations.

California, North Dakota, Wyoming↗
USGS2006

Detecting compaction disequilibrium with anisotropy of magnetic susceptibility

In clay-rich sediment, microstructures and macrostructures influence how sediments deform when under stress. When lithology is fairly constant, anisotropy of magnetic susceptibility (AMS) can be a simple technique for measuring the relative consolidation state of sediment, which reflects the sediment burial history. AMS can reveal areas of high water content and apparent overconsolidation associated with unconformities where sediment overburden has been removed. Many other methods for testing consolidation and water content are destructive and invasive, whereas AMS provides a nondestructive means to focus on areas for additional geotechnical study. In zones where the magnetic minerals are undergoing diagenesis, AMS should not be used for detecting compaction state. By utilizing AMS in the Santa Barbara Basin, we were able to identify one clear unconformity and eight zones of high water content in three cores. With the addition of susceptibility, anhysteretic remanent magnetization, and isothermal remanent magnetization rock magnetic techniques, we excluded 3 out of 11 zones from being compaction disequilibria. The AMS signals for these three zones are the result of diagenesis, coring deformation, and burrows. In addition, using AMS eigenvectors, we are able to accurately show the direction of maximum compression for the accumulation zone of the Gaviota Slide.

Geochemistry Geophysics Geosystems↗
USGS1999

Beaded-chain collars: A new method to radiotag kangaroo rats for short-term studies

To study burrow use by small mammals, we needed to develop a simple, non-invasive radiotag for the endangered giant kangaroo rat (Dipodomys ingens). We designed and tested a radiocollar made of beaded-chain on 4 captive Heermann's kangaroo rats (D. heermanii). Attachment of the collar required no anesthesia, the collar was easily fitted in 1-2 minutes, and it caused minimal stress to the animals. Once the collar design and attachment technique were perfected on the surrogate animals, we fitted radiocollars on 48 giant kangaroo rats for about 15 days. Upon recapture, 12 animals showed some minor fur or skin abrasion on the neck. Overall, the attachment performed as expected and proved to be a reliable method to radiotrack kangaroo rats during our short-term field study.

Wildlife Society Bulletin↗
USGS1999

Sora rail studies on the Patuxent River, Maryland

The freshwater marshes of the tidal Patuxent River are well known for their annual fall concentration of migrant soras ( Porzana carolina ) and were formerly the most famous rail hunting grounds in the Chesapeake Bay region. Because of concern over the apparent long-term decline in number of soras and the decline in the quality of the Patuxent marshes, especially the loss of wild rice ( Zizania aquatica ), the Maryland National-Capital Park and Planning Commission (MNCPPC), co-steward of the Jug Bay National Estuarine Research Reserve, sponsored rail-related research beginning in 1987. Past efforts focused on developing efficient trapping techniques, age and sex criteria, and monitoring body mass dynamics. Noted progress was made in developing digital playback systems and trap improvements to enhance sora captures. These improvements increased capture success by over an order of magnitude and resulted in capture of 2,315 soras and 276 Virginia rails ( Rallus limicola ) in the 5 year period, 1993-97. Although these methods demonstrate the efficacy of banding large numbers of soras on migration and possibly winter concentration areas, captures at the Patuxent River site have been 70-90% hatching-year birds and recoveries and recaptures have been virtually nonexistent. With the present effort, this outcome precludes population parameter estimation using traditional capture-recapture or recovery model methodologies. In 1996, studies were initiated to employ radio telemetry methods to investigate length of stay, habitat use, survival, and migration characteristics of fall migrant soras. These studies are ongoing and will be continued through 1998 with a grant from the U.S. Fish and Wildlife Service's Webless Migratory Game Bird Research Program and support from the U.S. Geological Survey's Patuxent Wildlife Research Center. Supplemental funding has also been provided by MNCPPC, FWS Region 5, the Maryland Ornithological Society, Quail Unlimited, and Prince Georges Community College. During 1996-97 we developed a successful radio transmitter attachment technique to secure 1.8g radio transmitters over the synsacrum of migrant soras. We modified Rappole and Tipton's (1991) leg-loop attachment method by addition of a waist loop to prevent soras from slipping transmitters over their short tails. Thin gauge (0.6 mm) elastic thread proved ideal for attachment and allowed for girth expansion associated with fattening during stopover. Sixty instrumented soras have been monitored in two years of study from early September until early November. Only a single mortality was recorded and 41 (68%) were confIrmed and another 13 (total 90%) were believed to have migrated from the study area. Only a single bird slipped a radio transmitter. Most birds demonstrated a sedentary nature in the marsh throughout stopover. Average length of stay was 44 days in 1997 (n=29) with peak departure occurring 20-24 October. Departing migrants were detected using a receiver/data-logger monitoring system placed 4 miles down river from the study site. Thirty-six of 37 (97%) soras departed in a 2-hour window of time, beginning 1 hour after sunset. Departure was synchronized with cold fronts on clear, starlit nights. Twenty-five soras were monitored on migration from 8 km to as far away as 770 km. Findings indicate migration flight speeds of 40 to 50 mph and a direct southward orientation from the study site at least until contact with the Atlantic Ocean west of Cape Lookout, North Carolina. We also attempted to monitor passage of migrant soras radio tagged at Iroquois National Wildlife Refuge in western New York by biologist Soch Lor. None were recorded passing a monitoring unit at Haldeman Island in the middle of the Susquehanna River 10 miles north of Harrisburg, Pennsylvania. This further corroborates our findings that when migrating overland, soras move in a direct southward orientation and are not following land features such as major rivers

Book chapter↗
USGS2016

Nonlethal laparoscopic detection of intersex (testicular oocytes) in largemouthbass (Micropterus salmoides) and smallmouth bass (Micropterus dolomieu)

Intersex in wild fish populations has received considerable attention in the scientific literature and public media. Conventional detection of testicular oocytes (TO), the presence of immature oocytes within testis of male fish, employs transverse sectioning of excised testis and is lethal. This present study used a non-lethal laparoscopic technique to collect biopsies of testis from black bass, entering the body cavity via the genital pore. Detection of TO was compared between biopsy and conventional methods using 79 smallmouth bass (SMB) Micropterus dolomieu from 8 sites and 68 largemouth bass (LMB) M. salmoides from 4 sites. Both methods performed similarly at sites where TO severity was moderate or high (6 of 8 SMB sites) while transverse sectioning resulted in superior TO detection at sites where severity was low (2 of 8 SMB sites and all 4 LMB sites). In SMB, TO prevalence by transverse and biopsy methods was strongly correlated across sites (r2 = 0.81) and severity reported by enumeration of TO was moderately correlated across sites (r2 = 0.59). Survival of a subset of LMB (n = 20) to 28-d after laparoscopic surgery was 90%. This research indicates that laparoscopy may be useful for monitoring the prevalence and severity of TO in Micropterus species, particularly when lethal sampling is precluded.

Environmental Toxicology and Chemistry↗
USGS2009

First-order exchange coefficient coupling for simulating surface water-groundwater interactions: Parameter sensitivity and consistency with a physics-based approach

Distributed hydrologic models capable of simulating fully-coupled surface water and groundwater flow are increasingly used to examine problems in the hydrologic sciences. Several techniques are currently available to couple the surface and subsurface; the two most frequently employed approaches are first-order exchange coefficients (a.k.a., the surface conductance method) and enforced continuity of pressure and flux at the surface-subsurface boundary condition. The effort reported here examines the parameter sensitivity of simulated hydrologic response for the first-order exchange coefficients at a well-characterized field site using the fully coupled Integrated Hydrology Model (InHM). This investigation demonstrates that the first-order exchange coefficients can be selected such that the simulated hydrologic response is insensitive to the parameter choice, while simulation time is considerably reduced. Alternatively, the ability to choose a first-order exchange coefficient that intentionally decouples the surface and subsurface facilitates concept-development simulations to examine real-world situations where the surface-subsurface exchange is impaired. While the parameters comprising the first-order exchange coefficient cannot be directly estimated or measured, the insensitivity of the simulated flow system to these parameters (when chosen appropriately) combined with the ability to mimic actual physical processes suggests that the first-order exchange coefficient approach can be consistent with a physics-based framework. Copyright ?? 2009 John Wiley & Sons, Ltd.

Hydrological Processes↗
USGS2016

Stable isotope analyses of oxygen (18O:17O:16O) and chlorine (37Cl:35Cl) in perchlorate: reference materials, calibrations, methods, and interferences

Rationale Perchlorate (ClO 4 − ) is a common trace constituent of water, soils, and plants; it has both natural and synthetic sources and is subject to biodegradation. The stable isotope ratios of Cl and O provide three independent quantities for ClO 4 − source attribution and natural attenuation studies: δ 37 Cl, δ 18 O, and δ 17 O (or Δ 17 O or 17 Δ) values. Documented reference materials, calibration schemes, methods, and interferences will improve the reliability of such studies. Methods Three large batches of KClO 4 with contrasting isotopic compositions were synthesized and analyzed against VSMOW-SLAP, atmospheric O 2 , and international nitrate and chloride reference materials. Three analytical methods were tested for O isotopes: conversion of ClO 4 − to CO for continuous-flow IRMS (CO-CFIRMS), decomposition to O 2 for dual-inlet IRMS (O2-DIIRMS), and decomposition to O 2 with molecular-sieve trap (O2-DIIRMS+T). For Cl isotopes, KCl produced by thermal decomposition of KClO 4 was reprecipitated as AgCl and converted into CH 3 Cl for DIIRMS. Results KClO 4 isotopic reference materials (USGS37, USGS38, USGS39) represent a wide range of Cl and O isotopic compositions, including non-mass-dependent O isotopic variation. Isotopic fractionation and exchange can affect O isotope analyses of ClO 4 − depending on the decomposition method. Routine analyses can be adjusted for such effects by normalization, using reference materials prepared and analyzed as samples. Analytical errors caused by SO 4 2 − , NO 3 − , ReO 4 2 − , and C-bearing contaminants include isotope mixing and fractionation effects on CO and O 2 , plus direct interference from CO 2 in the mass spectrometer. The results highlight the importance of effective purification of ClO 4 − from environmental samples. Conclusions KClO 4 reference materials are available for testing methods and calibrating isotopic data for ClO 4 − and other substances with widely varying Cl or O isotopic compositions. Current ClO 4 − extraction, purification, and analysis techniques provide relative isotope-ratio measurements with uncertainties much smaller than the range of values in environmental ClO 4 − , permitting isotopic evaluation of environmental ClO 4 − sources and natural attenuation.

Rapid Communications in Mass Spectrometry↗
USGS2014

Forecasting the dry‐weather flow of Pond Creek, Oklahoma: A progress report

Pond Creek in west‐central Oklahoma drains an area of 319 sq mi above the gaging station near Fort Cobb, Caddo County. Ground water, contained in the Permian Rush Springs sandstone under water‐table conditions, moves toward the creek at an almost unchanging rate. The discharge of ground water into the creek as dry‐weather flow is modified by evapotranspiration and antecedent overland runoff. Multiple correlations have been computed relating the dry‐weather flow to the water level in a well and to a factor indicative of the rate of evapotranspiration. A method for forecasting the factor indicative of evapotranspiration and one for forecasting the water level in the well during dry weather are given; the result is a method for forecasting the dry‐weather flow of the Creek. Forecasts of dry‐weather flow for seven and 21 days compare favorably with observed flows. The technique may be utilized to extend a forecast for several months.

Oklahoma↗
USGS2010

Estimation of groundwater recharge parameters by time series analysis

A model is proposed that relates water level fluctuations in a Dupuit aquifer to effective precipitaton at the top of the unsaturated zone. Effective precipitation, defined herein as that portion of precipitation which becomes recharge, is related to precipitation measured in a nearby gage by a two-parameter function. A second-order stationary assumption is used to connect the spectra of effective precipitation and water level fluctuations. Measured precipitation is assumed to be Gaussian, in order to develop a transfer function that relates the spectra of measured and effective precipitation. A nonlinear least squares technique is proposed for estimating parameters of the effective-precipitation function. Although sensitivity analyses indicate difficulties that may be encountered in the estimation procedure, the methods developed did yield convergent estimates for two case studies.

Water Resources Research↗
USGS2017

Seventy years of stream‐fish collections reveal invasions and native range contractions in an Appalachian (USA) watershed

Aim Knowledge of expanding and contracting ranges is critical for monitoring invasions and assessing conservation status, yet reliable data on distributional trends are lacking for most freshwater species. We developed a quantitative technique to detect the sign (expansion or contraction) and functional form of range‐size changes for freshwater species based on collections data, while accounting for possible biases due to variable collection effort. We applied this technique to quantify stream‐fish range expansions and contractions in a highly invaded river system. Location Upper and middle New River (UMNR) basin, Appalachian Mountains, USA. Methods We compiled a 77‐year stream‐fish collections dataset partitioned into ten time periods. To account for variable collection effort among time periods, we aggregated the collections into 100 watersheds and expressed a species’ range size as detections per watershed (HUC) sampled (DPHS). We regressed DPHS against time by species and used an information‐theoretic approach to compare linear and nonlinear functional forms fitted to the data points and to classify each species as spreader, stable or decliner. Results We analysed changes in range size for 74 UMNR fishes, including 35 native and 39 established introduced species. We classified the majority (51%) of introduced species as spreaders, compared to 31% of natives. An exponential functional form fits best for 84% of spreaders. Three natives were among the most rapid spreaders. All four decliners were New River natives. Main conclusions Our DPHS‐based approach facilitated quantitative analyses of distributional trends for stream fishes based on collections data. Partitioning the dataset into multiple time periods allowed us to distinguish long‐term trends from population fluctuations and to examine nonlinear forms of spread. Our framework sets the stage for further study of drivers of stream‐fish invasions and declines in the UMNR and is widely transferable to other freshwater taxa and geographic regions.

North Carolina, Virginia↗
USGS2007

Use of the Delphi method in resolving complex water resources issues

The tri-state river basins, shared by Georgia, Alabama, and Florida, are being modeled by the U.S. Fish and Wildlife Service and the U.S. Army Corps of Engineers to help facilitate agreement in an acrimonious water dispute among these different state governments. Modeling of such basin reservoir operations requires parallel understanding of several river system components: hydropower production, flood control, municipal and industrial water use, navigation, and reservoir fisheries requirements. The Delphi method, using repetitive surveying of experts, was applied to determine fisheries' water and lake-level requirements on 25 reservoirs in these interstate basins. The Delphi technique allowed the needs and requirements of fish populations to be brought into the modeling effort on equal footing with other water supply and demand components. When the subject matter is concisely defined and limited, this technique can rapidly assess expert opinion on any natural resource issue, and even move expert opinion toward greater agreement.

Journal of the American Water Resources Associatio↗
USGS2006

Using self-organizing maps to determine observation threshold limit predictions in highly variant data

A significant data quality challenge for highly variant systems surrounds the limited ability to quantify operationally reasonable limits on the data elements being collected and provide reasonable threshold predictions. In many instances, the number of influences that drive a resulting value or operational range is too large to enable physical sampling for each influencer, or is too complicated to accurately model in an explicit simulation. An alternative method to determine reasonable observation thresholds is to employ an automation algorithm that would emulate a human analyst visually inspecting data for limits. Using the visualization technique of self-organizing maps (SOM) on data having poorly understood relationships, a methodology for determining threshold limits was developed. To illustrate this approach, analysis of environmental influences that drive the abundance of a target indicator species (the pink shrimp, Farfantepenaeus duorarum) provided a real example of applicability. The relationship between salinity and temperature and abundance of F. duorarum is well documented, but the effect of changes in water quality upstream on pink shrimp abundance is not well understood. The highly variant nature surrounding catch of a specific number of organisms in the wild, and the data available from up-stream hydrology measures for salinity and temperature, made this an ideal candidate for the approach to provide a determination about the influence of changes in hydrology on populations of organisms.

Conference Paper↗
USGS1980

The comparison of usage and availability measurements for evaluating resource preference

Modern ecological research often involves the comparison of the usage of habitat types or food items to the availability of those resources to the animal. Widely used methods of determining preference from measurements of usage and availability depend critically on the array of components that the researcher, often with a degree of arbitrariness, deems available to the animal. This paper proposes a new method, based on ranks of components by usage and by availability. A virtue of the rank procedure is that it provides comparable results whether a questionable component is included or excluded from consideration. Statistical tests of significance are given for the method. The paper also offers a hierarchical ordering of selection processes. This hierarchy resolves certain inconsistencies among studies of selection and is compatible with the analytic technique offered in this paper.

Ecology↗
USGS2012

Hydrologic and landscape database for the Cache and White River National Wildlife Refuges and contributing watersheds in Arkansas, Missouri, and Oklahoma

A hydrologic and landscape database was developed by the U.S. Geological Survey, in cooperation with the U.S. Fish and Wildlife Service, for the Cache River and White River National Wildlife Refuges and their contributing watersheds in Arkansas, Missouri, and Oklahoma. The database is composed of a set of ASCII files, Microsoft Access® files, Microsoft Excel® files, an Environmental Systems Research Institute (ESRI) ArcGIS® geodatabase, ESRI ArcGRID® raster datasets, and an ESRI ArcReader® published map. The database was developed as an assessment and evaluation tool to use in examining refuge-specific hydrologic patterns and trends as related to water availability for refuge ecosystems, habitats, and target species; and includes hydrologic time-series data, statistics, and hydroecological metrics that can be used to assess refuge hydrologic conditions and the availability of aquatic and riparian habitat. Landscape data that describe the refuge physiographic setting and the locations of hydrologic-data collection stations are also included in the database. Categories of landscape data include land cover, soil hydrologic characteristics, physiographic features, geographic and hydrographic boundaries, hydrographic features, regional runoff estimates, and gaging-station locations. The database geographic extent covers three hydrologic subregions—the Lower Mississippi–St Francis (0802), the Upper White (1101), and the Lower Arkansas (1111)—within which human activities, climatic variation, and hydrologic processes can potentially affect the hydrologic regime of the refuges and adjacent areas. Database construction has been automated to facilitate periodic updates with new data. The database report (1) serves as a user guide for the database, (2) describes the data-collection, data-reduction, and data-analysis methods used to construct the database, (3) provides a statistical and graphical description of the database, and (4) provides detailed information on the development of analytical techniques designed to assess water availability for ecological needs.

Arkansas;Missouri;Oklahoma↗
USGS2021

Evidence for the use of mucus swabs to detect Renibacterium salmoninarum in brook trout

Efforts to advance fish health diagnostics have been highlighted in many studies to improve the detection of pathogens in aquaculture facilities and wild fish populations. Typically, the detection of a pathogen has required sacrificing fish; however, many hatcheries have valuable and sometimes irreplaceable broodstocks, and lethal sampling is undesirable. Therefore, the development of non-lethal detection methods is a high priority. The goal of our study was to compare non-lethal sampling methods with standardized lethal kidney tissue sampling that is used to detect Renibacterium salmoninarum infections in salmonids. We collected anal, buccal, and mucus swabs (non-lethal qPCR) and kidney tissue samples (lethal DFAT) from 72 adult brook trout ( Salvelinus fontinalis ) reared at the Colorado Parks and Wildlife Pitkin Brood Unit and tested each sample to assess R. salmoninarum infections. Standard kidney tissue detected R. salmoninarum 1.59 times more often than mucus swabs, compared to 10.43 and 13.16 times more often than buccal or anal swabs, respectively, indicating mucus swabs were the most effective and may be a useful non-lethal method. Our study highlights the potential of non-lethal mucus swabs to sample for R. salmoninarum and suggests future studies are needed to refine this technique for use in aquaculture facilities and wild populations of inland salmonids.

Pathogens↗