bluuebunny/crossref_metadata_2025_split huggingface dataset:
Responses of Benthic Fishes and Giant Salamanders to Placement of Large Woody Debris in Small Pacific Northwest Streams
Authors: Roni Philip 
Published: June 2004

Abstract
The placement of large woody debris (LWD) to improve or restore habitat for fishes is a common practice in North American streams, and the responses of salmonids to this practice have frequently been examined. In contrast, little information exists on the effects of LWD placement on nonsalmonid fishes and amphibians. In this study, I examined the responses of giant salamanders Dicamptodon spp., juvenile lampreyss Entosphenus tridentatus and Lampetra spp., reticulate sculpins Cottus perplexus, and torrent sculpins C. rhotheus to artificially placed LWD by sampling 29 small streams with paired treatment and reference reaches. Densities and mean lengths of giant salamanders, reticulate sculpins, torrent sculpins, and lampreyss did not differ significantly between treatment and references reaches. I also examined whether the observed responses were correlated with differences in physical habitat between reference and treatment reaches. Lampreys densities (log10(treatment) − log10(reference)) and length of age-1 and older reticulate sculpins (log10(treatment) − log10(reference)) among streams were positively correlated with LWD within the wetted channel. Lampreys length was also positively correlated with differences in percentages of pool area. These results indicate that artificial LWD placement may benefit lampreys and age-1 and older reticulate sculpins (two species known to prefer pools) but have little effect on other nonsalmonid species.
Electroshock-Induced Injury and Mortality in the Spotfin Chub, a Threatened Minnow
Authors: Michael Holliman F. , Reynolds James B. , Kwak Thomas J. 
Published: June 2004

Abstract
The effects of AC and pulsed DC (PDC) electroshock on mortality and injury (vertebral damage and hemorrhage) of spotfin chub Cyprinella monacha, a threatened minnow, were evaluated in a laboratory experiment. Groups of 18-20 captive-reared fish were either designated as a control or exposed for 3 s to one of five electrical treatments (60-Hz AC at a peak-to-peak voltage gradient of 1.7, 2.5, or 3.3 V/cm or 60-Hz PDC at a peak voltage gradient of 2.5 or 5.0 V/cm). Immobilization, which renders fish susceptible to capture during electrofishing, was the predominant response evoked in the groups exposed to electroshock, with the exception of the 1.7-V/cm AC group. No injury was detected in any fish in the experiment. Mortality was 10% or less in groups exposed to AC, regardless of voltage gradient. There was no significant variation in mortality among the groups exposed to AC (P = 0.487-1.00). Mortality varied significantly in the groups exposed to 60-Hz PDC (2.5 V/cm (0%) versus 5.0 V/cm (25%); P = 0.047). Our results indicate that electroshocking with 60-Hz AC and 60-Hz PDC may be safe for capturing spotfin chub when voltage (thus, voltage gradient) is limited to the immobilization threshold and the exposure period to 3 s. However, AC should be used only in low-conductivity waters (e.g., &lt;80 μS/cm).
Evaluation of a Large-Mesh Panel to Reduce the Flatfish Bycatch in the Small-Mesh Bottom Trawls Used in the New England Silver Hake Fishery
Authors: Milliken Henry O. , DeAlteris Joseph T. 
Published: June 2004

Abstract
Fishermen must use small-mesh bottom trawls to capture certain species of fish that cannot be retained by standard groundfish mesh sizes. These fisheries are subject to bycatch limits when such trawls are used in areas where regulated species reside. Bycatch of regulated flatfish in the small-mesh bottom trawl fishery for silver hake Merluccius bilinearis in the northwestern Atlantic is a concern of management because silver hakes are captured in areas where juvenile regulated flatfish are common. An evaluation of flatfish and silver hake behaviors using low-light underwater cameras suggested that the two species could be separated within the mouth of a bottom trawl. Using the alternate tow method, four different large-mesh panels positioned in the lower belly of the trawl were separately evaluated. One of them proved to be effective in reducing flatfish bycatch while not reducing the catch of silver hakes; a large-mesh panel constructed of 40.6-cm (16-in) stretched mesh that was diamond shaped using orange-colored nylon twine 1.6 mm (0.06 in) in diameter in the lower belly resulted in a 73% reduction in flatfish catch with no effect on the catch of silver hakes.
Designing Tagging Programs for Pelagic Longline Fisheries: Trade-offs between the Number of Releases and Observer Coverage
Authors: Polacheck Tom , Hearn William 
Published: June 2004

Abstract
Tagging experiments are becoming increasingly important for providing an alternative to catch indices in large pelagic fisheries. The design of these experiments, in terms of the resources to devote to the number of releases versus recovery activity, has generally been ad hoc. We examined the relationship between the level of observer coverage and the variance in the estimates of annual exploitation rates from a tagging experiment in which the reporting rate is estimated from comparisons of tag returns from vessels with and without observers. The results indicate that the predicted precision will be a function of the level of observer coverage, the number of tags released, and the actual fishing exploitation rate. The results suggest that a direct tradeoff exists between the number of tags released and the level of observer coverage, such that a proportional increase in either one has similar effects on the predicted coefficient of variation. However, considering the assumptions (particularly multistage aspects of observer sampling and the need to estimate catches by age), higher observer coverage would be favored. In fact, substantial benefits in terms of ensuring accuracy and precision of the estimates would be gained from having 100% observer coverage. In any case, the results emphasize the importance of ensuring both adequate numbers of tag releases and robust estimation of reporting rates.
Evacuation of Passive Integrated Transponder (PIT) Tags from Northern Pikeminnow Consuming Tagged Juvenile Chinook Salmon
Authors: Petersen James H. , Barfoot Craig A. 
Published: June 2004

Abstract
Prey fish implanted with passive integrated transponder (PIT) tags can be used in predation studies if the timing of tag evacuation from the predators is understood. Laboratory experiments were conducted to determine how PIT tags in juvenile Chinook salmon Oncorhynchus tshawytscha that were consumed by northern pikeminnow Ptychocheilus oregonensis were evacuated in relation to various parameters. The rate of evacuation was directly related to temperature, while predator size and the number of prey consumed had less effect on the timing of tag evacuation. A power model was fitted to predict the proportion of tags expected to be evacuated at different intervals after ingestion. These results could be used in planning field or laboratory predation experiments with PIT-tagged prey fish.
Comparison of Three Underwater Antennas for Use in Radiotelemetry
Authors: Beeman John W. , Grant Cam , Haner Philip V. 
Published: June 2004

Abstract
The radiation patterns of three versions of underwater radiotelemetry antennas were measured to compare the relative reception ranges in the horizontal and vertical planes, which are important considerations when designing detection systems. The received signal strengths of an antenna made by stripping shielding from a section of coaxial cable (stripped coax) and by two versions of a dipole antenna were measured at several orientations relative to a dipole transmit antenna under controlled field conditions. The received signal strengths were greater when the transmit and receive antennas were parallel to each other than when they were perpendicular, indicating that a parallel orientation provides optimal detection range. The horizontal plane radiation pattern of the flexible, stripped coax antenna was similar to that of a rigid dipole antenna, but movement of underwater stripped coax antennas in field applications could affect the orientation of transmit and receive antennas in some applications, resulting in decreased range and variation in received signal strengths. Compared with a standard dipole, a dipole antenna armored by housing within a polyvinyl chloride fitting had a smaller radiation pattern in the horizontal plane but a larger radiation pattern in the vertical plane. Each of these types of underwater antenna can be useful, but detection ranges can be maximized by choosing an appropriate antenna after consideration of the location, relation between transmit and receive antenna orientations, radiation patterns, and overall antenna resiliency.
Population Dynamics of Channel Catfish in Brownlee Reservoir and the Snake River, Oregon
Authors: Shrader Terry M. , Moody Barron , Buckman Mary 
Published: June 2004

Abstract
To evaluate a perceived decrease in trophy channel catfish Ictalurus punctatus in Brownlee Reservoir and the Snake River, Oregon, we used gill nets in the reservoir and longlines and slat traps in the river to capture and tag channel catfish larger than 305 mm during 1995-1997. Angler recaptures of tagged fish demonstrated that some channel catfish moved up to 254.3 km upstream and 122.5 km downstream from their initial tagging locations and that 48% of the fish recovered in the reservoir had been tagged in the river and 21% of the fish recovered in the river had been tagged in the reservoir. Recruitment to the river and reservoir stocks between 1984 and 1992 was significantly correlated. Age structure of river and reservoir stocks did not differ significantly. Mean length at age of fish of ages 5-10 was not significantly different in 1996 or 1997, although equations describing growth of the two stocks were significantly different in 1996. Total instantaneous mortality of river and reservoir stocks did not differ significantly, but the angler exploitation rate for channel catfish was significantly higher in the river (0.315) than in the reservoir (0.062) in 1995. The similarity between the population parameters of the river and reservoir stocks suggests that these fish should be managed as one population.
A New Tool for Measuring Sediment Accumulation with Minimal Loss of Fines
Authors: Lachance Stephanie , Dubé Maryse 
Published: June 2004

Abstract
To measure the impact of culvert construction on brook trout Salvelinus fontinalis spawning beds, we collaborated with Bio-Innove, Inc., to develop a simple method for measuring the physical characteristics of streambeds and for quantifying the accumulation of fine sediment at spawning depth. We developed a modified version of the Wesche method that greatly limits fine-sediment loss at retrieval and the loss of the sediment collectors themselves. We found all 128 collectors after a 1–3-month period and all but 3 after 1 year in four experimental streams. The collectors are reusable and permit easy transfer of samples to the laboratory without any visible loss of fine sediment. The data collected allowed us to compare, by use of parametric statistics, the upstream and downstream sections from newly built culverts in terms of percent fines of different diameters, distance of sediment accumulation downstream, grading curves, and organic matter content of accumulated fine sediment.
Fish and Invertebrate Recolonization in a Missouri Prairie Stream after an Acute Pollution Event
Authors: Meade Richard 
Published: June 2004

Abstract
Recolonization of invertebrates and fish was monitored for 50 weeks and 241 weeks (4.6 years), respectively, after a chicken manure spill killed more than 18,000 fish and an undetermined number of invertebrates in 31.4 km of a prairie stream in west-central Missouri. I have characterized the postspill water quality in the affected portions of the stream to provide insight about the impacts of water quality on the rate of recolonization, determined the recolonization of invertebrate populations to provide insight into the return of a suitable food base for the fish population, and documented the chronology of fish recolonization in the affected portions of the stream to assist with a more appropriate determination of losses of recreational and economic values as a result of fish kills. Water quality had improved by week 15 postspill, but degraded water quality retarded recovery by invertebrates at one site for 50 weeks. Total and noninsect invertebrate abundance improved at some, but not all, sites by week 22 postspill. Abundance of most invertebrates had recovered by week 50, but the invertebrate community remained unstable. The total numbers of fish at two polluted sites and at a reference site were similar by week 33 postspill. However, sunfish Lepomis sp. 178 mm or larger and largemouth bass Micropterus salmoides 305 mm or larger remained relatively scarce in the polluted stream segment by week 241. The low numbers of large sport fish present at 241 weeks postspill have greatly diminished the attractiveness of Muddy Creek for angling. The value of a lost or degraded recreational fishery should be included with assessments of penalties to help deter future violations of water quality laws and recover losses that may affect a fishery for two or more years after a major fish kill.
The Effect of Light Intensity on Sockeye Salmon Fry Migratory Behavior and Predation by Cottids in the Cedar River, Washington
Authors: Tabor Roger A. , Brown Gayle S. , Luiting Victoria T. 
Published: June 2004

Abstract
We examined the relationship between light intensity, migratory behavior of sockeye salmon Oncorhynchus nerka fry, and predation by cottids Cottus spp. We tested the hypothesis that above-natural intensities of nighttime light would increase cottid predation of sockeye salmon fry. In circular tank experiments under controlled laboratory conditions, we tested the ability of cottids to prey on sockeye salmon fry under six different light intensities using minimal water circulation to separate the effect of the migratory behavior of fry from the ability of cottids to capture them. We found that cottids preyed most effectively in complete darkness, whereas the lowest predation occurred at the brightest light intensity. We next tested the predation ability of cottids at four light intensities in a pair of artificial streams to simulate more natural conditions. In experiments without cottids, the majority of fry passed quickly through the artificial streams under complete darkness, but as light intensity was increased, fewer fry emigrated and did so at a slower rate. With cottids present and increased light intensity, even fewer fry emigrated but they did so at a faster rate than did those in the stream without cottids. We determined that cottids probably consumed about 5% of the sockeye salmon fry under complete darkness and ate about 45% of the fry at the brightest light intensity tested. In experimental field trials, the shoreline abundance of fry and predation by cottids increased as light intensities increased. Using two small lights within an 8-m shoreline section on the Cedar River, Washington, we delayed as many as 550 sockeye salmon fry and observed predation of as many as 7.6 fry/cottid. At the end of the experiment, we turned the lights off and noted that the shoreline abundance of fry declined dramatically. At two locations on the Cedar River lit by city lights, the abundance of sockeye salmon fry and predation by cottids was substantially greater than at nearby sites with low light. Also, we demonstrated at one site that reducing light intensity substantially reduced predation on sockeye salmon fry. Overall, we conclude that increased light intensity appears to slow or stop out-migration of fry, making them more vulnerable to capture by predators such as cottids.
Injury and Mortality Induced by Four Hook Types on Bluegill and Pumpkinseed
Authors: Cooke Steven J. , Suski Cory D. , Barthel Brandon L. , Ostrand Kenneth G. , Tufts Bruce L. , Philipp David P. 
Published: June 2004

Abstract
Tackle manufacturers have responded to concerns regarding hooking injury and mortality by attempting to design and market hooks that are less damaging to fish (e.g., circle hooks). To date, studies investigating circle hooks have been primarily restricted to large marine species. We compared the injury and short-term (72-h) mortality of bluegills Lepomis macrochirus and pumpkinseeds L. gibbosus angled using number-6 circle hooks and three other conventional hook types (aberdeen, wide-gap, and baitholder) across three water temperatures (18, 22, and 26°C). Unlike other hook types, circle hooks were never lodged in the gullet, but they were frequently lodged in the eye. Some fish captured on conventional hooks were hooked deeply in the gullet, necessitating line cutting for release. Incidences of bleeding were low using all hook types, and when not lodged in the gullet, all hooks were generally easy to remove. Anatomical hooking locations differed among small (&lt;145-mm) and large (&gt;145-mm) bluegills for all hook types but not among pumpkinseeds. Hooking depth differed between small and large fish of both species captured on circle hooks; smaller fish were hooked more deeply. Mortality in both species was negligible at all water temperatures except for bluegills at 26°C (3% mortality). Bluegills that died were smaller than those that survived. Our results confirm the supposition that circle hooks are less susceptible to deeply hooking fish in the gullet. However, circle hooks permanently impaired vision of up to 22% of the fish, much more than for other hooks types. Although efficient at minimizing injury and mortality in marine fish, our study suggests that circle hooks perform similarly to more conventional hook types in fisheries for small sunfish.
Predicting the Occurrence and Success of Walleye Populations from Physical and Biological Features of Northern Wisconsin Lakes
Authors: Nate Nancy A. , Bozek Michael A. , Hansen Michael J. , Ramm Carl W. , Bremigan Mary T. , Hewett Steven W. 
Published: June 2004

Abstract
We developed a linear discriminant function (LDF) using surface area, mean depth, fetch, and three substrate descriptors to discriminate the presence and absence of walleyes Sander vitreus (formerly Stizostedion vitreum) in 120 northern Wisconsin lakes. The resulting LDF correctly classified 90% of walleye lakes and 85% of nonwalleye lakes. For model validation, the model classified 90% of walleye lakes and 93% of nonwalleye lakes in an independent set of 100 randomly selected lakes. In contrast, within walleye lakes, an LDF using the same variables correctly classified only 60% of 30 self-sustaining walleye lakes and 50% of 30 stocked walleye lakes. For model validation, the model classified 30% of self-sustaining walleye lakes and 73% of stocked walleye lakes in an independent set of 40 randomly selected lakes. To further assess the differences between walleye lakes with self-sustaining and stocked populations, the angler catch rates for largemouth bass Micropterus salmoides, smallmouth bass M. dolomieu, northern pike Esox lucius, and muskellunge E. masquinongy obtained from creel surveys during 1990-2001 were analyzed by means of a principal components analysis. The first principal component explained 29% of the variation and represented a linear contrast between the relative abundance of walleyes and muskellunge and the relative abundance of largemouth bass and northern pike. High largemouth bass and northern pike densities characterized lakes with stocked walleye populations, whereas high walleye and muskellunge densities characterized lakes with self-sustaining walleye populations. We conclude that physical features may be used to discriminate lakes where walleyes presently occur from lakes where walleyes do not presently occur, and that fish community differences exist between stocked and self-sustaining walleye populations in northern Wisconsin.
Using a Geographic Information System to Assess the Accuracy of Radio-Triangulation Techniques for Fish Telemetry
Authors: James Daniel A. , Erickson Jack W. , Barton Bruce A. 
Published: June 2004

Abstract
We evaluated the accuracy of several triangulation methods that produce quantified rather than inferred transmitter position data on the movements of brown trout Salmo trutta in an urbanized stream. Other telemetry studies have reported accuracies of 0.5-5 m based on visual observation of fish or detection of hidden transmitters from within streams. With our geographic information system (GIS) method, coordinate locations for each transmitter position were recorded without entering the water. A global positioning system (GPS) was used to record coordinate locations on the stream bank and compass bearings with signals of hidden transmitters in the stream. Signal locations were then triangulated to estimate the coordinates of transmitter locations. Location coordinates were placed onto a GIS coverage, and accuracy was determined by comparing the actual positions of hidden transmitters with the estimated positions. Three different triangulation methods produced slightly different accuracies. Our GIS method is less biased and supported by data and could provide a standard method for triangulation. Moreover, the GIS-based radio-triangulation approach enables tracking in the field without disturbing a tagged fish in its habitat or otherwise altering a fish's behavior due to human intervention.
Tag Location and Retention in Black Rockfish: Feasibility of Using PIT Tags in a Wild Marine Species
Authors: Parker Steven J. , Rankin Polly S. 
Published: June 2004

Abstract
Tag and recovery programs can provide valuable information on population size and exploitation rates in fishes. Passive integrated transponder (PIT) tags are ideal for use in such programs because they provide identification of individual fish and are invisible to anglers, circumventing problems with nonreporting of tags. Our objective was to determine whether PIT tags could be used successfully to tag black rockfish Sebastes melanops. We tested tag placement and tag retention using intramuscularly injected PIT tags (12 × 2.1 mm) in 227 black rockfish (25-47 cm); three tag placement sites located outside of the area normally filleted were evaluated. Tag retention for all tag sites was 100% after 49 weeks; however, two fish retained inoperative tags, which possibly sustained damage during the tagging procedure. The results indicated that the best tagging site is ventral and anterior to the origin of the pectoral fin. At this site, tag retention is excellent, risk of infection is low, tag movement is minimal, and little or no tissue damage results from the tagging procedure.
Influence of Fishway Placement on Fallback of Adult Salmon at the Bonneville Dam on the Columbia River
Authors: Reischel Tami S. , Bjornn Theodore C. 
Published: June 2004

Abstract
Using radiotelemetry, we observed and quantified the behavior of upstream migrating adult Chinook salmon Oncorhynchus tshawytscha and sockeye salmon O. nerka exiting the Bradford Island fishway at the Bonneville Dam on the Columbia River in 1997 and 1998. Nearly all of the fish that exited the fishway migrated upstream along the Bradford Island shoreline. Those fish that took the route nearest to the spillway were most likely to fall back over the spillway. From 14.5% to 21.3% of the fish tracked along the Bradford Island shore fell back over the spillway of the dam. The combined effects of spill, water temperature, and Secchi disk visibility were associated with route patterns and fallback behavior during each year. High spill was significantly and positively correlated with fallback behavior for Chinook salmon in 1998. Most of the fish we tracked that fell back reascended the fishway and migrated upstream (≥95% in 1997; ≥70% in 1998). We suggest that modifying the configuration of this fishway's exit would decrease the proportion of fish that fall back, perhaps reduce the risk of injury and fatigue, and improve the precision of counts of fish migrating upstream.