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At least 109 records · Page 6Linked to original sources
USGS2006

Concurrent assessment of fish and habitat in warmwater streams in Wyoming

Fisheries research and management in North America have focused largely on sport fishes, but native non-game fishes have attracted increased attention due to their declines. The Warmwater Stream Assessment (WSA) was developed to evaluate simultaneously both fish and habitat in Wyoming streams by a process that includes three major components: (1) stream-reach selection and accumulation of existing information, (2) fish and habitat sampling and (3) summarisation and evaluation of fish and habitat information. Fish are sampled by electric fishing or seining and habitat is measured at reach and channel-unit (i.e. pool, run, riffle, side channel, or backwater) scales. Fish and habitat data are subsequently summarised using a data-matrix approach. Hierarchical decision trees are used to assess critical habitat requirements for each fish species expected or found in the reach. Combined measurements of available habitat and the ecology of individual species contribute to the evaluation of the observed fish assemblage. The WSA incorporates knowledge of the fish assemblage and habitat features to enable inferences of factors likely influencing both the fish assemblage and their habitat. The WSA was developed for warmwater streams in Wyoming, but its philosophy, process and conceptual basis may be applied to environmental assessments in other geographical areas. ?? 2006 Blackwell Publishing Ltd.

Fisheries Management and Ecology↗
USGS2013

A novel approach to surveying sturgeon using side-scan sonar and occupancy modeling

Technological advances represent opportunities to enhance and supplement traditional fisheries sampling approaches. One example with growing importance for fisheries research is hydroacoustic technologies such as side-scan sonar. Advantages of side-scan sonar over traditional techniques include the ability to sample large areas efficiently and the potential to survey fish without physical handling-important for species of conservation concern, such as endangered sturgeons. Our objectives were to design an efficient survey methodology for sampling Atlantic Sturgeon Acipenser oxyrinchus by using side-scan sonar and to developmethods for analyzing these data. In North Carolina and South Carolina, we surveyed six rivers thought to contain varying abundances of sturgeon by using a combination of side-scan sonar, telemetry, and video cameras (i.e., to sample jumping sturgeon). Lower reaches of each river near the saltwater-freshwater interface were surveyed on three occasions (generally successive days), and we used occupancy modeling to analyze these data.We were able to detect sturgeon in five of six rivers by using these methods. Side-scan sonar was effective in detecting sturgeon, with estimated gear-specific detection probabilities ranging from 0.2 to 0.5 and river-specific occupancy estimates (per 2-km river segment) ranging from 0.0 to 0.8. Future extensions of this occupancy modeling framework will involve the use of side-scan sonar data to assess sturgeon habitat and abundance in different river systems.

North Carolina, South Carolina↗
USGS2001

Empirical assessment of indices of prey importance in the diets of predacious fish

Determining the importance of prey taxa in the diets of predacious species is a frequent objective in fisheries research. Various indices of prey importance are in common use, and all give different results because of their emphasis on different aspects of fish diets. We explored these differences by empirically comparing four well-known indices-percent weight (%W), percent occurrence (%O), percent number (%N), and percent index of relative importance (%IRI)-as well as a modified %IRI (%MIRI), as applied to an extensive data set on the diets of six fish species in Spirit Lake, Iowa. Correlations among all indices were positive but were weaker among component indices (%W, %O, and %N) than between the two compound indices (%IRI and %MIRI); correlations among component indices were also weaker than correlations of compound with component indices. Correlation strength of %MIRI with the three component indices varied greatly (%N %O %W), whereas the correlation strength of %IRI with component indices was similar. Importance values based on %W, %MIRI, and %N depend more on prey size than those based on %IRI and %O. The %W and %MIRI emphasized the importance of large prey taxa, whereas %N emphasized small prey in diets; %IRI and %O were similarly unbiased with respect to prey size. The %O yielded substantially higher importance values than all other indices. Thus, for use as a general index of dietary importance, we believe %IRI provides the optimal balancing of frequency of occurrence, numerical abundance, and abundance by weight of taxa in fish diets.

Transactions of the American Fisheries Society↗
USGS2019

Growth disparity in sympatric kokanee breeding groups

Growth is arguably the most important dynamic rate function due to its interaction with survival and recruitment. As such, understanding the mechanisms underlying growth is a primary focus of fisheries research. Kokanee Oncorhynchus nerka in Lake Pend Oreille, Idaho, provide an interesting case study for investigating the factors that influence growth. Early‐run and late‐run kokanee occur in Lake Pend Oreille, but early‐run fish generally grow faster than late‐run fish. The observed growth disparity between early‐ and late‐run fish could be due to genetic differences between the two groups. Conversely, a common hatchery practice of slowing growth by reducing feed has been hypothesized to elicit a compensatory growth response in early‐run fish and to explain the size difference between breeding groups. Using two different experiments, we tested the hypotheses that (1) early‐run kokanee are genetically disposed to grow faster than late‐run kokanee at identical water temperatures; and (2) feed restriction elicits a compensatory growth response in early‐run kokanee that explains the observed size difference between breeding groups. Estimates of mean FL, weight, Fulton's condition factor ( K ), and specific growth rate (SGR) were not significantly different ( P ≥ 0.05) between early‐run and late‐run fish in the first experiment. However, water temperature was positively related to mean FL, weight, K , and SGR for both breeding groups. Fish that were subjected to food deprivation exhibited an increased growth rate and obtained weights similar to those of control fish. Overall, our results suggest that early‐ and late‐run fish have similar growth potential, but certain hatchery practices likely provide early‐run fish with an initial advantage in growth, size, or both.

Idaho↗
USGS1991

Acute toxicities to larval rainbow trout of representative compounds detected in Great Lakes fish

In recent years the National Fisheries Research Center-Great Lakes has ranked the potential hazard to fish and invertebrates of various chemical compounds detected in two Great Lakes fishes-- lake trout, Salvelinus namaycush , and walleye, Stizostedion vitreum vitreum (Hesselberg and Seelye 1982). This hazard assessment has included the identification of the potential sources of the compounds, determination of the occurrence and abundance of the compounds in Great Lakes fish, and the determination of acute toxicities of representative compounds of 19 chemical classes (Passino and Smith 1987a). In further studies Smith et al. (1988) focused on 6 of the 19 classes of compounds using the zooplankter Daphnia pulex as the test organism. They ranked the six classes as follows (in decreasing order of toxicity): polycyclic aromatic hydrocarbons (PAHs), alkyl halides, nitrogen-containing compounds, cyclic alkanes, heterocyclic nitrogen compounds, and silicon-containing compounds.

Bulletin of Environmental Contamination and Toxico↗
USGS2007

Effects of antenna length and material on output power and detection of miniature radio transmitters

The optimal antenna of transmitters used in small aquatic animals is often a compromise between efficient radio wave propagation and effects on animal behavior. Radio transmission efficiency generally increases with diameter and length of the conductor, but increased antenna length or weight can adversely affect animal behavior. We evaluated the effects of changing antenna length and material on the subsequent tag output power, reception, and detection of tagged fish. In a laboratory, we compared the relative signal strengths in water of 150 MHz transmitters over a range of antenna lengths (from 6 to 30 cm) and materials (one weighing about half of the other). The peak relative signal strengths were at 20 and 22 cm, which are approximately one wavelength underwater at the test frequency. The peak relative signal strengths at these lengths were approximately 50% greater than those of 30 cm antennas, a length commonly used in fisheries research. Few significant differences were present in distances for the operator to hear or the telemetry receiver to decode transmitters from a boat-mounted receiving system based on antenna length, but the percent of tagged fish detected passing a hydroelectric dam fitted with an array of receiving systems was significantly greater at the antenna length with peak output power in laboratory tests. This study indicates careful choice of antenna length and material of small transmitters can be used to reduce weight and possible antenna effects on animal behavior, to maximize tag output power and detection, or to balance these factors based on the needs of the application. ?? 2007 Springer Science+Business Media B.V.

Conference Paper↗
USGS1992

Immunostimulants, adjuvants, and vaccine carriers in fish: Applications to aquaculture

Use of immunostimulants, adjuvants, and vaccine carriers in fish culture offers a wide range of attractive methods for inducing and building up protection against diseases. Immunostimulants and adjuvants can be administered before, with, or after vaccines to amplify the specific immune response generating elevations of circulating antibody titers and numbers of plaque-forming cells. Special applications of immunostimulants include assisting shower or other regimens to increase topical uptake of vaccines. In addition, immunostimulants may be used alone, inducing elevated activities in the nonspecific defense mechanisms such as increased oxidative activity of neutrophils, augmented engulfment activity of phagocytic cells, or potentiating cytotoxic cells. In cases where disease outbreaks are cyclical and can be predicted, losses may be reduced by elevating the nonspecific defense mechanisms, and the immunostimulants may be used in anticipation of events to prevent losses from diseases. Complete Freund's adjuvant was one of the first immunostimulants used in animals to elevate the specific immune response, and it has also been successfully used in conjunction with injection of fish bacterins. Other adjuvants, immunostimulants, and biological response modifiers that have been used in fisheries research include levamisole, salt baths, and bacterial lipopolysaccharides. Vaccines have been adsorbed to inert particles, such as bentonite on latex beads, to carry the immunogens to maximize in vivo uptake for bath immunization and to facilitate in vitro phagocytosis. Each substance presents special problems in timing and method of administration (injection, immersion, oral—by feed—or flush treatments), dosage adjustments for size and fish species, storage stability, and cost. An additional consideration is that the nonspecific defense mechanisms and immune responses in fish are highly variable among individuals and statistical validation requires appropriate sample numbers and carefully controlled experiments. This article reviews the literature and present concepts of use of immunostimulants, adjuvants, and vaccine carriers in fish. Cautions for use are noted, as some of these potent substances can suppress or alter biological pathways if used inappropriately. Recent research, defining pathways of the action of immunostimulants, adjuvants, and vaccine carriers, helps explain how these substances activate the protective mechanisms in fish. In addition, immunostimulants used alone hold tremendous potential for use in fish farms, hatcheries, and aquaculture facilities to reduce losses from infectious diseases. Research on the immunostimulant, levamisole, and the light oil adjuvants for use in food fish is in progress. Applications for use of these immunostimulants are proposed.

Annual Review of Fish Diseases↗
USGS2026

Fish body midline segmentation using binary search

Body and caudal fin locomotion is ubiquitous in aquatic vertebrates, and kinematic models describing it are used in robotics, biomechanics and fisheries research. This paper presents a new algorithm to translate continuous body midlines of fish into a series of interconnected segments by identifying favorable joint positions along the body. The algorithm employs binary search to generate parsimonious kinematic models, aiming at minimizing the number of segments yet keeping approximation error below a user-defined threshold. To achieve this, the algorithm maximizes the length of each segment by determining the most distal joint position through repetitive shrinking of the search space. Theoretical and empirical analysis using two different datasets show that the binary search algorithm is substantially faster when compared to segment growing algorithm, which employs linear search to generate its models. There is four-fold improvement in computation time when generating models with less than 10 segments, which are typically sufficient to describe fish and fish-inspired robot movements. Furthermore, the multi-segment models generated by the binary search algorithm matched the ground truth models obtained through dynamic programming in over 97% of cases, and on average, contained one fewer segment than those produced by the Ramer–Douglas–Peucker algorithm, which is widely used in curvature simplification tasks. Our findings suggest that the binary search algorithm provides a computationally efficient approach for generating compact kinematic models and may facilitate the analysis of large datasets with high temporal and spatial resolution.

Computers and Electronics in Agriculture↗
USGS2014

The effect of adjusting model inputs to achieve mass balance on time-dynamic simulations in a food-web model of Lake Huron

Ecopath with Ecosim (EwE) is a widely used modeling tool in fishery research and management. Ecopath requires a mass-balanced snapshot of a food web at a particular point in time, which Ecosim then uses to simulate changes in biomass over time. Initial inputs to Ecopath, including estimates for biomasses, production to biomass ratios, consumption to biomass ratios, and diets, rarely produce mass balance, and thus ad hoc changes to inputs are required to balance the model. There has been little previous research of whether ad hoc changes to achieve mass balance affect Ecosim simulations. We constructed an EwE model for the offshore community of Lake Huron, and balanced the model using four contrasting but realistic methods. The four balancing methods were based on two contrasting approaches; in the first approach, production of unbalanced groups was increased by increasing either biomass or the production to biomass ratio, while in the second approach, consumption of predators on unbalanced groups was decreased by decreasing either biomass or the consumption to biomass ratio. We compared six simulation scenarios based on three alternative assumptions about the extent to which mortality rates of prey can change in response to changes in predator biomass (i.e., vulnerabilities) under perturbations to either fishing mortality or environmental production. Changes in simulated biomass values over time were used in a principal components analysis to assess the comparative effect of balancing method, vulnerabilities, and perturbation types. Vulnerabilities explained the most variation in biomass, followed by the type of perturbation. Choice of balancing method explained little of the overall variation in biomass. Under scenarios where changes in predator biomass caused large changes in mortality rates of prey (i.e., high vulnerabilities), variation in biomass was greater than when changes in predator biomass caused only small changes in mortality rates of prey (i.e., low vulnerabilities), and was amplified when environmental production was increased. When standardized to mean changes in biomass within each scenario, scenarios when vulnerabilities were low and when fishing mortality was increased explained the most variation in biomass. Our findings suggested that approaches to balancing Ecopath models have relatively little effect on changes in biomass over time, especially when compared to assumptions about how mortality rates of prey change in response to changes in predator biomass. We concluded that when constructing food-web models using EwE, determining the effect of changes in predator biomass on mortality rates of prey should be prioritized over determining the best way to balance the model.

Lake Huron↗
USGS2009

An expert system for prediction of aquatic toxicity of contaminants

The National Fisheries Research Center-Great Lakes has developed an interactive computer program in muLISP that runs on an IBM-compatible microcomputer and uses a linear solvation energy relationship (LSER) to predict acute toxicity to four representative aquatic species from the detailed structure of an organic molecule. Using the SMILES formalism for a chemical structure, the expert system identifies all structural components and uses a knowledge base of rules based on an LSER to generate four structure-related parameter values. A separate module then relates these values to toxicity. The system is designed for rapid screening of potential chemical hazards before laboratory or field investigations are conducted and can be operated by users with little toxicological background. This is the first expert system based on LSER, relying on the first comprehensive compilation of rules and values for the estimation of LSER parameters.

Book chapter↗
USGS2018

Biogeography of pelagic food webs in the North Pacific

The tufted puffin ( Fratercula cirrhata ) is a generalist seabird that breeds throughout the North Pacific and eats more than 75 different prey species. Using puffins as samplers, we characterized the geographic variability in pelagic food webs across the subarctic North Pacific from the composition of ~10,000 tufted puffin meals (~56,000 prey items) collected at 35 colonies in the Gulf of Alaska (GoA) and Aleutian Archipelago. Cluster analysis of diet species composition suggested three distinct forage fish communities: (i) in the northern GoA, multiple age‐classes of coastal and shelf residents such as capelin, sand lance and herring dominated the food web, (ii) in the western GoA to eastern Aleutians, the shelf community was dominated by transient age‐0 walleye pollock, and (iii) in the western Aleutians, shelf‐edge and mesopelagic forage species such as squid, lanternfish, and Atka mackerel were prevalent. Geographic patterns of abundance of capelin and sand lance in tufted puffin diets were corroborated by independent research fisheries and diets of piscivorous fish, indicating that puffin diets reflect the local abundance of forage species, not just selection of favored species. Generalized additive models showed that habitat characteristics predict, in a non‐linear fashion, forage species distribution and abundance across two large marine ecosystems. We conclude that major biogeographic patterns in forage fish distribution follow gradients in key habitat features, and puffin diets reflect those patterns.

Fisheries Oceanography↗
USGS2016

An expert system for prediction of chemical toxicity

The National Fisheries Research Center- Great Lakes has developed an interactive computer program that uses the structure of an organic molecule to predict its acute toxicity to four aquatic species. The expert system software, written in the muLISP language, identifies the skeletal structures and substituent groups of an organic molecule from a user-supplied standard chemical notation known as a SMILES string, and then generates values for four solvatochromic parameters. Multiple regression equations relate these parameters to the toxicities (expressed as log 10 LC50s and log 10 EC50s, along with 95% confidence intervals) for four species. The system is demonstrated by prediction of toxicity for anilide-type pesticides to the fathead minnow (Pimephales promelas). This software is designed for use on an IBM-compatible personal computer by personnel with minimal toxicology background for rapid estimation of chemical toxicity. The system has numerous applications, with much potential for use in the pharmaceutical industry

Drug Information Journal↗
USGS2023

Using recovered radio transmitters to estimate positioning error and a generalized Monte Carlo simulation to incorporate error into animal telemetry analysis

Background Mobile radio tracking is an important tool in fisheries research and management. Yet, the accuracy of location estimates can be highly variable across studies and within a given dataset. While some methods are available to deal with error, they generally assume a static value for error across all detections. We provide a novel method for making detection-specific error estimates using detections of recovered transmitters (i.e., mortalities or tag expulsion). These data are used to establish the relationship between received signal strength (RSS) and positional error, which can then be used to predict positional error of detections for fish at large. We then show how detection-specific estimates can be integrated into a Monte Carlo framework to analyze movement in ways robust to spatial uncertainty. Results In a telemetry study in a large river (~ 90 m), we recovered 22 transmitters to estimate and model positional error. Error averaged 94 m (range = 1–727 m) for transmitters tracked by researchers on foot using a Yagi antenna, and 200 m (range = 1–1141 m) for transmitters tracked from vehicles using an omnidirectional whip antenna. Transmitters located near roads were tracked more accurately with both methods. Received signal strength was a strong predictor of positional error ( r 2 = 0.86, ground tracking; 0.65, tracking from truck) and was thus used to make detection-specific estimates of error for detections of fish at large. Monte Carlo analysis for a binary movement classification revealed that only 18% of location estimates could be confidently assigned to movement ( p < 0.05); the remainder were associated with stasis or movement that was within the range of positional error. Ignoring positional error led to positive bias of up to 1300% in individual movement estimates and varied seasonally—it was highest when fish were inactive and lowest when fish were most active. Conclusion Using recovered transmitters and RSS models to estimate telemetry error is a viable alternative to staged ‘dummy transmitter’ trials and assuming error is a constant. Our proposed approaches to incorporate detection-specific error estimates into analysis are broadly applicable and can ‘make the most’ out of highly accurate detections while also cautiously extracting spatial information from less-accurate detections.

Animal Biotelemetry↗
USGS2005

Managing water in the West: developing new tools for a critical resource

Rapid population growth in the Western United States over the last century has placed increasing strains on our water supplies and aquatic ecosystems. Historically, water rights have been used to determine the allocation of water in the West, but rules and regulations related to endangered species now often drive how water is released from reservoirs in large rivers such as the lower Colorado and the Columbia. In numerous smaller watersheds, communities are trying to balance the water necessary for human use, irrigation, and the conservation of ecosystems. To assist managers in the face of increasing complexity and uncertainty in water management decision-making, the Western Fisheries Research Center (WFRC) is involved in developing a new generation of integrative tools. Below are some examples of the types of tools that already exist within the WFRC.

Fact Sheet↗
USGS2005

Biological science in Oregon

Fishing is an important part of Oregon's culture. The Western Fisheries Research Center (WFRC) has been conducting research in Oregon for many years to provide information that can be used by managers to help keep fish and other parts of the ecosystem healthy. Below are examples of some of WFRC's studies.

Oregon↗
USGS2005

Aquatic invasive species

Invasive species are plants or animals that are present in an ecosystem beyond their native range. They may have few natural controls in their new environment and proliferate. They can threaten native species and interfere with human activities. The Western Fisheries Research Center (WFRC) has been conducting research to understand how non-native species invade and affect ecosystems, thus aiding management efforts.

Fact Sheet↗
USGS2007

WFRC patrners: our extended family

For more than five decades the Western Fisheries Research Center (WFRC) has worked with partners to provide research findings to managers of aquatic resources. Those partners form an extended family, a network of clients, colleagues, co-investigators, and customers. Our partners include numerous clients in other Department of Interior bureaus such as the U.S. Fish and Wildlife Service, the U.S. Bureau of Reclamation, and the National Park Service. But there is much more--we have partners in other federal agencies, state agencies, and universities. The extended family includes tribal governments, and non-government organizations such as the Nature Conservancy and the Lower Columbia River Estuary Program.

Fact Sheet↗
USGS2012

AquaPathogen X--A template database for tracking field isolates of aquatic pathogens

AquaPathogen X is a template database for recording information on individual isolates of aquatic pathogens and is available for download from the U.S. Geological Survey (USGS) Western Fisheries Research Center (WFRC) website (http://wfrc.usgs.gov). This template database can accommodate the nucleotide sequence data generated in molecular epidemiological studies along with the myriad of abiotic and biotic traits associated with isolates of various pathogens (for example, viruses, parasites, or bacteria) from multiple aquatic animal host species (for example, fish, shellfish, or shrimp). The simultaneous cataloging of isolates from different aquatic pathogens is a unique feature to the AquaPathogen X database, which can be used in surveillance of emerging aquatic animal diseases and clarification of main risk factors associated with pathogen incursions into new water systems. As a template database, the data fields are empty upon download and can be modified to user specifications. For example, an application of the template database that stores the epidemiological profiles of fish virus isolates, called Fish ViroTrak (fig. 1), was also developed (Emmenegger and others, 2011).

Fact Sheet↗