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Frank J. Rahel - One of the best experts on this subject based on the ideXlab platform.
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Single‐Pass Electrofishing Predicts Trout Abundance in Mountain Streams with Sparse Habitat
North American Journal of Fisheries Management, 1998Co-Authors: Carter G Kruse, Wayne A Hubert, Frank J. RahelAbstract:Abstract Fish abundances in mountain streams are typically estimated over a reach with multiple-pass-removal Electrofishing techniques, but such estimates are time consuming and they potentially harm fish. Recent research has indicated that a single Electrofishing pass can provide an index of trout abundance in some streams, but applicable circumstances were not clarified. We sampled 30 stream reaches in northwestern Wyoming to determine if the number of trout captured with a single Electrofishing pass could be used to predict trout abundance as estimated by a multiple-pass-removal maximum-likelihood model. Stream width, depth, channel slope, instream cover, and substrate were also assessed to determine their possible influences on the relationship between the number of fish captured with a single pass and multiple-pass estimates. We found that trout samples from a single Electrofishing pass accurately indexed the abundance of trout in small mountain streams with little instream cover and low fish densiti...
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single pass Electrofishing predicts trout abundance in mountain streams with sparse habitat
North American Journal of Fisheries Management, 1998Co-Authors: Carter G Kruse, Wayne A Hubert, Frank J. RahelAbstract:Abstract Fish abundances in mountain streams are typically estimated over a reach with multiple-pass-removal Electrofishing techniques, but such estimates are time consuming and they potentially harm fish. Recent research has indicated that a single Electrofishing pass can provide an index of trout abundance in some streams, but applicable circumstances were not clarified. We sampled 30 stream reaches in northwestern Wyoming to determine if the number of trout captured with a single Electrofishing pass could be used to predict trout abundance as estimated by a multiple-pass-removal maximum-likelihood model. Stream width, depth, channel slope, instream cover, and substrate were also assessed to determine their possible influences on the relationship between the number of fish captured with a single pass and multiple-pass estimates. We found that trout samples from a single Electrofishing pass accurately indexed the abundance of trout in small mountain streams with little instream cover and low fish densiti...
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evaluation of depletion removal Electrofishing of brook trout in small rocky mountain streams
North American Journal of Fisheries Management, 1996Co-Authors: Paul D Thompson, Frank J. RahelAbstract:Abstract We evaluated the effectiveness of three-pass depletion Electrofishing for removing introduced brook trout Salvelinus fontinalis from small mountain streams that contained native populations of Colorado River cutthroat trout Oncorhynchus clarki pleuriticus. Estimates based on depletion indicated removal efficiencies of 73–100% for age-0 brook trout and 59–100% for older brook trout. Estimates based on the number of fish caught 1 year later indicated removal efficiencies of 42–83% for age-0 brook trout and 92–96% for older fish. The lower removal efficiencies for age-0 brook trout reflected the difficulty in spotting small fish in streams with overhanging vegetation, undercut banks, and large woody debris. Because small brook trout were not captured as effectively as larger trout, a single Electrofishing pass the year after depletion-removal Electrofishing helped further reduce brook trout numbers. Although brook trout were not eradicated from any of the study streams, a year after treatment brook ...
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Comparison of Streamside Visual Counts to Electrofishing Estimates of Colorado River Cutthroat Trout Fry and Adults
North American Journal of Fisheries Management, 1991Co-Authors: Michael A. Bozek, Frank J. RahelAbstract:Abstract Streamside visual counts and depletion-removal Electrofishing were compared for estimating fry and adult abundances of Colorado River cutthroat trout Oncorhynchus clarki pleuriticus. Visual counts of fry were significantly correlated (R = 0.92) with three-pass depletion-removal Electrofishing estimates of abundance. Streamside visual counts were generally lower than Electrofishing estimates, except in streams having turbulent water, where Electrofishing was difficult. Disturbance of fry by observers reduced estimates obtained with the visual counts; however, visual counts can be a useful method for estimating the abundance of cutthroat trout fry in small streams with shallow water. For adults, correlations between streamside visual counts and Electrofishing population estimates were low, and therefore visual counts were not considered a viable method for older fish.
Daniel Boisclair - One of the best experts on this subject based on the ideXlab platform.
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a comparison of Electrofishing and visual surveying methods for estimating fish community structure in temperate rivers
River Research and Applications, 2015Co-Authors: Camille J Macnaughton, Gabriel Lanthier, Simonne Harveylavoie, Caroline Senay, Guillaume Bourque, Pierre Legendre, Daniel BoisclairAbstract:Studies attempting to describe fish community structure in shallow riverine environments typically rely on Electrofishing and/or visual (snorkelling) surveys, but few have addressed the relative efficiencies of these two methods at estimating fish density and biomass across wide ranges of geography, taxonomy and life history stages. Multiple paired Electrofishing and visual surveys were conducted in 18 temperate Canadian rivers in order to obtain community-wide density and biomass estimates from both methods. Partial canonical multivariate analyses were applied to the paired fish community matrices comparing the results of both surveying methods at the taxonomic levels of family, genus and species, as well as size classes within families and species, to assess the particular effectiveness of each sampling method. Although Electrofishing estimates of family and species richness were generally greater, snorkelling surveys tended to generate higher density and biomass estimates for different size classes of many salmonid and cyprinid species. Moreover, mean river biomass estimates derived from visual surveying matched those obtained from our best mean river biomass estimates arising from the two methods combined. This study provides empirical evidence that Electrofishing and visual survey methods generate different types of information when assessing fish community structure at the family level or by size classes. Our results provide ample background information for determining the most accurate sampling method for a particular fish community assemblage, which is fundamental to fisheries management and research. Copyright © 2014 John Wiley & Sons, Ltd.
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comparison between Electrofishing and snorkeling surveys to describe fish assemblages in laurentian streams
Environmental Monitoring and Assessment, 2014Co-Authors: Jeanmartin Chamberland, Gabriel Lanthier, Daniel BoisclairAbstract:We evaluated the relative performance of Electrofishing and visual surveys (snorkeling) for estimating the abundance of combinations of fish species and size classes in rivers. We also assessed the effect of environmental conditions on potential differences between the results obtained using these two sampling methods. Sampling sites were distributed in the Laurentian region of Quebec. Both methods were used while sections were blocked. Three snorkelers swam the river sections upstream while identifying and counting fish of each species and size classes. Three-pass Electrofishing was performed in the same sites and abundances were estimated with a maximum likelihood depletion model. Greater abundances of fish were observed by snorkeling than by Electrofishing at all sites. Snorkeling species richness was higher or equal to Electrofishing richness in, respectively, 60 % and 40 % of sampled sites. Differences in the fish communities observed by both sampling methods were not related to environmental conditions. The results of our work are therefore contrary to that of most published studies that suggested the use of Electrofishing over visual surveys. This study highlights that conclusions derived from previous work on sampling gear comparisons may not be generalisable; rather survey methods might benefit from being selected based on fish community composition.
Michael R. Meador - One of the best experts on this subject based on the ideXlab platform.
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Effectiveness of Seining after Electrofishing to Characterize Stream Fish Communities
North American Journal of Fisheries Management, 2012Co-Authors: Michael R. MeadorAbstract:Abstract The richness and composition of species collected uniquely to Electrofishing and subsequent seining efforts were examined at 271 stream sites across the USA by using wadeable Electrofishing methods (backpack or barge Electrofishing) or boat Electrofishing followed by seining. Seining after wadeable Electrofishing resulted in the collection of new species at 42% of sites, whereas seining after boat Electrofishing resulted in the collection of new species at 87% of sites. Mean percentage of total observed fish species richness that was collected uniquely by seining was 6% (representing one new species, on average) after wadeable Electrofishing compared with 18% (four new species, on average) after boat Electrofishing. Shannon–Wiener diversity index values were not significantly different between data from combined sampling (Electrofishing and seining) and data from wadeable Electrofishing (P = 0.490) but were significantly different between boat Electrofishing and combined sampling (P = 0.004). Sei...
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single pass versus two pass boat Electrofishing for characterizing river fish assemblages species richness estimates and sampling distance
Transactions of The American Fisheries Society, 2005Co-Authors: Michael R. MeadorAbstract:Abstract Determining adequate sampling effort for characterizing fish assemblage structure in nonwadeable rivers remains a critical issue in river biomonitoring. Two-pass boat Electrofishing data collected from 500–1,000-m-long river reaches as part of the U.S. Geological Survey's National Water-Quality Assessment (NAWQA) Program were analyzed to assess the efficacy of single-pass boat Electrofishing. True fish species richness was estimated by use of a two-pass removal model and nonparametric jackknife estimation for 157 sampled reaches across the United States. Compared with estimates made with a relatively unbiased nonparametric estimator, estimates of true species richness based on the removal model may be biased, particularly when true species richness is greater than 10. Based on jackknife estimation, the mean percent of estimated true species richness collected in the first Electrofishing pass (pj,sj ) for all 157 reaches was 65.5%. The effectiveness of single-pass boat Electrofishing may be greate...
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Effects of Electrofishing Gear Type on Spatial and Temporal Variability in Fish Community Sampling
Transactions of The American Fisheries Society, 2003Co-Authors: Michael R. Meador, Julie P McintyreAbstract:Abstract Fish community data collected from 24 major river basins between 1993 and 1998 as part of the U.S. Geological Survey's National Water-Quality Assessment Program were analyzed to assess multiple-reach (three consecutive reaches) and multiple-year (three consecutive years) variability in samples collected at a site. Variability was assessed using the coefficient of variation (CV; SD/mean) of species richness, the Jaccard index (JI), and the percent similarity index (PSI). Data were categorized by three Electrofishing sample collection methods: backpack, towed barge, and boat. Overall, multiple-reach CV values were significantly lower than those for multiple years, whereas multiple-reach JI and PSI values were significantly greater than those for multiple years. Multiple-reach and multiple-year CV values did not vary significantly among Electrofishing methods, although JI and PSI values were significantly greatest for backpack Electrofishing across multiple reaches and multiple years. The absolute d...
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assessing the efficacy of single pass backpack Electrofishing to characterize fish community structure
Transactions of The American Fisheries Society, 2003Co-Authors: Michael R. Meador, Julie P Mcintyre, Kenneth H PollockAbstract:Abstract Two-pass backpack Electrofishing data collected as part of the U.S. Geological Survey's National Water-Quality Assessment Program were analyzed to assess the efficacy of single-pass backpack Electrofishing. A two-capture removal model was used to estimate, within 10 river basins across the United States, proportional fish species richness from one-pass Electrofishing and probabilities of detection for individual fish species. Mean estimated species richness from first-pass sampling ([pcirc], s1) ranged from 80.7% to 100% of estimated total species richness for each river basin, based on at least seven samples per basin. However, [pcirc], s1 values for individual sites ranged from 40% to 100% of estimated total species richness. Additional species unique to the second pass were collected in 50.3% of the samples. Of these, cyprinids and centrarchids were collected most frequently. Proportional fish species richness estimated for the first pass increased significantly with decreasing stream width fo...
Michael J Hansen - One of the best experts on this subject based on the ideXlab platform.
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Relationship between Electrofishing Catch Rate and Adult Trout Abundance in Wisconsin Streams
North American Journal of Fisheries Management, 2011Co-Authors: Paul S. Bergman, Michael J Hansen, Nancy A. NateAbstract:Abstract The relative quickness and cost effectiveness of single-pass Electrofishing samples (catch per effort [CPE]) argues for their use over multiple-pass estimates for enumerating stream fish populations. However, CPE can be an imprecise index of fish abundance and therefore may be less useful than more-precise indices of abundance, such as those obtained from mark–recapture or depletion methods, for assessing trout populations. We evaluated the use of single-pass Electrofishing samples (catch/mi) as abundance (number/mi) predictors of adult brook trout Salvelinus fontinalis and brown trout Salmo trutta in Wisconsin streams by quantifying the relationship between Electrofishing CPE and adult trout abundance. First, we tested for linearity of the relationship between CPE and adult trout abundance while accounting for measurement error. Next, we explained the residual variability in the relationship using physical and biological attributes of surveyed streams. We found that the relationship between CPE ...
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Electrofishing catchability of walleyes largemouth bass smallmouth bass northern pike and muskellunge in wisconsin lakes
North American Journal of Fisheries Management, 2005Co-Authors: Casey W. Schoenebeck, Michael J HansenAbstract:Abstract We sought to determine whether Electrofishing catchability was density dependent and varied with physical and biological factors for walleyes Sander vitreus, largemouth bass Micropterus salmoides, smallmouth bass M. dolomieu, northern pike Esox lucius, and muskellunge E. masquinongy in Wisconsin lakes. Electrofishing catch rate (number of fish caught per shoreline mile) was linearly related to population density (number of fish per acre) in spring for largemouth bass, northern pike, and muskellunge and in fall for walleyes, largemouth bass, and smallmouth bass. In contrast, gear saturation caused the Electrofishing catch rate to be nonlinearly related (hyperstable) to population density for walleyes and smallmouth bass during spring. Catchability was higher during spring than fall for walleyes, largemouth bass, and smallmouth bass. Catchability of walleyes during fall was positively related to the percentage of littoral zone, whereas catchability of largemouth bass, smallmouth bass, and muskellun...
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a reexamination of the relationship between Electrofishing catch rate and age 0 walleye density in northern wisconsin lakes
North American Journal of Fisheries Management, 2004Co-Authors: Michael J Hansen, Steven P Newman, Clayton J EdwardsAbstract:Abstract We quantified the relationship between the population density (number/acre) of age-0 walleyes Sander vitreus (formerly Stizostedion vitreum) and Electrofishing catch per effort (CPE; number/mi) in 19 Wisconsin lakes to update a 1982 analysis by Serns, who used linear regression through the origin to develop a model from a small data set that has been widely used to estimate age-0 walleye density from Electrofishing CPE. We added new data, explicitly tested for the linearity of the relationship, and accounted for the effect of measurement errors. We found that Electrofishing CPE was nonlinearly related to the population density of age-0 walleyes, which indicated that the catchability of age-0 walleyes to Electrofishing declined with population density. The measurement errors in Electrofishing CPE were more than nine times as great as those in age-0 walleye population density, so that the parameters of the relationship between Electrofishing CPE and age-0 walleye density were accurately estimated b...
Wayne A Hubert - One of the best experts on this subject based on the ideXlab platform.
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Snorkeling As an Alternative to Depletion Electrofishing for Assessing Cutthroat Trout and Brown Trout in Stream Pools
Journal of Freshwater Ecology, 2003Co-Authors: Michael P. Joyce, Wayne A HubertAbstract:ABSTRACT We compared abundance and length structure estimates of cutthroat trout (Oncorhynchus clarki) and brown trout (Salmo trutta) of 15 cm total length or greater obtained by snorkeling in stream pools with estimates obtained by depletion Electrofishing. We sampled 12 pools in each of two streams formed by large springs in the Salt River Valley of western Wyoming. Snorkeling counts provided a relatively accurate index of depletion Electrofishing estimates of abundance of cutthroat trout, but not brown trout. Linear regression analysis showed that snorkeling counts were significantly related to depletion Electrofishing estimates for both cutthroat trout (P < 0.001) and brown trout (P = 0.002), but the coefficient of determination for brown trout (r2 = 0.33) was low compared to cutthroat trout (r2 = 0.95). Frequencies of fish in three length classes observed by snorkeling and depletion Electrofishing were close to being significantly different for cutthroat trout (P = 0.066) and substantially different ...
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snorkeling as an alternative to depletion Electrofishing for estimating abundance and length class frequencies of trout in small streams
North American Journal of Fisheries Management, 1998Co-Authors: Scott A Mullner, Wayne A Hubert, Thomas A WescheAbstract:Abstract Trout counts and length-class frequencies determined by snorkeling were compared with estimates determined by Electrofishing in 25 reaches of small (≤11-m wetted width) streams of the Bighorn Mountains, Wyoming. The numbers of trout (brook trout Salvelinus fontinalis, rainbow trout Oncorhynchus mykiss, and cutthroat trout O. clarki) counted by snorkeling were highly correlated (r 2 = 0. 90–0.99) to depletion estimates of abundance determined by Electrofishing, averaging 65% of depletion estimates. Inclusion of instream cover and underwater visibility significantly improved predictions of all salmonid species combined in regression models that predicted depletion estimates by Electrofishing from snorkeling counts. Length frequencies obtained by snorkeling and Electrofishing were similar when frequencies of trout in three length-classes (0–100, 101–300, and >300 mm) were adjusted (observed length by snorkeling divided by 1.25) for underwater visual magnification. Snorkeling was an alternative to el...
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single pass Electrofishing predicts trout abundance in mountain streams with sparse habitat
North American Journal of Fisheries Management, 1998Co-Authors: Carter G Kruse, Wayne A Hubert, Frank J. RahelAbstract:Abstract Fish abundances in mountain streams are typically estimated over a reach with multiple-pass-removal Electrofishing techniques, but such estimates are time consuming and they potentially harm fish. Recent research has indicated that a single Electrofishing pass can provide an index of trout abundance in some streams, but applicable circumstances were not clarified. We sampled 30 stream reaches in northwestern Wyoming to determine if the number of trout captured with a single Electrofishing pass could be used to predict trout abundance as estimated by a multiple-pass-removal maximum-likelihood model. Stream width, depth, channel slope, instream cover, and substrate were also assessed to determine their possible influences on the relationship between the number of fish captured with a single pass and multiple-pass estimates. We found that trout samples from a single Electrofishing pass accurately indexed the abundance of trout in small mountain streams with little instream cover and low fish densiti...
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Single‐Pass Electrofishing Predicts Trout Abundance in Mountain Streams with Sparse Habitat
North American Journal of Fisheries Management, 1998Co-Authors: Carter G Kruse, Wayne A Hubert, Frank J. RahelAbstract:Abstract Fish abundances in mountain streams are typically estimated over a reach with multiple-pass-removal Electrofishing techniques, but such estimates are time consuming and they potentially harm fish. Recent research has indicated that a single Electrofishing pass can provide an index of trout abundance in some streams, but applicable circumstances were not clarified. We sampled 30 stream reaches in northwestern Wyoming to determine if the number of trout captured with a single Electrofishing pass could be used to predict trout abundance as estimated by a multiple-pass-removal maximum-likelihood model. Stream width, depth, channel slope, instream cover, and substrate were also assessed to determine their possible influences on the relationship between the number of fish captured with a single pass and multiple-pass estimates. We found that trout samples from a single Electrofishing pass accurately indexed the abundance of trout in small mountain streams with little instream cover and low fish densiti...