bluuebunny/crossref_metadata_2025 huggingface dataset:
ACaenorhabditis elegansRNA-Directed RNA Polymerase in Sperm Development and Endogenous RNA Interference
Authors: Gent Jonathan I , Schvarzstein Mara , Villeneuve Anne M , Gu Sam Guoping , Jantsch Verena , Fire Andrew Z , Baudrimont Antoine
Published: October 2009

Short interfering RNAs (siRNAs) are a class of regulatory effectors that enforce gene silencing through formation of RNA duplexes. Although progress has been made in identifying the capabilities of siRNAs in silencing foreign RNA and transposable elements, siRNA functions in endogenous gene regulation have remained mysterious. In certain organisms, siRNA biosynthesis involves novel enzymes that act as RNA-directed RNA polymerases (RdRPs). Here we analyze the function of a Caenorhabditis elegans RdRP, RRF-3, during spermatogenesis. We found that loss of RRF-3 function resulted in pleiotropic defects in sperm development and that sperm defects led to embryonic lethality. Notably, sperm nuclei in mutants of either rrf-3 or another component of the siRNA pathway, eri-1, were frequently surrounded by ectopic microtubule structures, with spindle abnormalities in a subset of the resulting embryos. Through high-throughput small RNA sequencing, we identified a population of cellular mRNAs from spermatogenic cells that appear to serve as templates for antisense siRNA synthesis. This set of genes includes the majority of genes known to have enriched expression during spermatogenesis, as well as many genes not previously known to be expressed during spermatogenesis. In a subset of these genes, we found that RRF-3 was required for effective siRNA accumulation. These and other data suggest a working model in which a major role of the RRF-3/ERI pathway is to generate siRNAs that set patterns of gene expression through feedback repression of a set of critical targets during spermatogenesis.
Pediatric Burn Injuries Treated in US Emergency Departments Between 1990 and 2006
Authors: D'Souza Anjali L. , Nelson Nicolas G. , McKenzie Lara B.
Published: October 2009

OBJECTIVE: The goal was to examine comprehensively the patterns and trends of burn-related injuries in children, adolescents, and young adults treated in US emergency departments between 1990 and 2006.

METHODS: Through use of the National Electronic Injury Surveillance System database, cases of nonfatal burn-related injuries were selected by using diagnosis codes for burns (scalds, thermal, chemical, radiation, electrical, and not specified). Sample weights were used to calculate national estimates. US Census Bureau data were used to calculate injury rates per 10000 individuals ≤20 years of age. Computation of relative risks with 95% confidence intervals was performed.

RESULTS: An estimated 2054563 patients ≤20 years of age were treated in US emergency departments for burn-related injuries, with an average of 120856 cases per year. Boys constituted 58.6% of case subjects. Children <6 years of age sustained the majority of injuries (57.7%), and more than one half of all injuries (59.5%) resulted from thermal burns. The body parts injured most frequently were the hand/finger (36.0%), followed by the head/face (21.1%). Of the 1542913 cases for which locale was recorded, 91.7% occurred at home. The rate of burn-related injuries per 10000 children decreased 31% over the 17-year time period.

CONCLUSIONS: Burn-related injuries are a serious problem for individuals ≤20 years of age and are potentially preventable. Children <6 years of age consistently sustained a disproportionately large number of injuries during the study period. Increased efforts are needed to improve burn-prevention strategies that target households with young children.
Recombinant Human Hyaluronidase-Enabled Subcutaneous Pediatric Rehydration
Authors: Allen Coburn H. , Etzwiler Lisa S. , Miller Melissa K. , Maher George , Mace Sharon , Hostetler Mark A. , Smith Sharon R. , Reinhardt Neil , Hahn Barry , Harb George ,   for the INcreased Flow Utilizing Subcutaneously-Enabled-(INFUSE) Pediatric Rehydration Study Collaborative Research Group
Published: October 2009

OBJECTIVES: The Increased Flow Utilizing Subcutaneously-Enabled (INFUSE)-Pediatric Rehydration Study was designed to assess efficacy, safety, and clinical utility of recombinant human hyaluronidase (rHuPH20)-facilitated subcutaneous rehydration in children 2 months to 10 years of age.

METHODS: Patients with mild/moderate dehydration requiring parenteral treatment in US emergency departments were eligible for this phase IV, multicenter, single-arm study. They received subcutaneous injection of 1 mL rHuPH20 (150 U), followed by subcutaneous infusion of 20 mL/kg isotonic fluid over the first hour. Subcutaneous rehydration was continued as needed for up to 72 hours. Rehydration was deemed successful if it was attributed by the investigator primarily to subcutaneous fluid infusion and the child was discharged without requiring an alternative method of rehydration.

RESULTS: Efficacy was evaluated in 51 patients (mean age: 1.9 years; mean weight: 11.2 kg). Initial subcutaneous catheter placement was achieved with 1 attempt for 46/51 (90.2%) of patients. Rehydration was successful for 43/51 (84.3%) of patients. Five patients (9.8%) were hospitalized but deemed to be rehydrated primarily through subcutaneous therapy, for a total of 48/51 (94.1%) of patients. No treatment-related systemic adverse events were reported, but 1 serious adverse event occurred (cellulitis at infusion site). Investigators found the procedure easy to perform for 96% of patients (49/51 patients), and 90% of parents (43/48 parents) were satisfied or very satisfied.

CONCLUSIONS: rHuPH20-facilitated subcutaneous hydration seems to be safe and effective for young children with mild/moderate dehydration. Subcutaneous access is achieved easily, and the procedure is well accepted by clinicians and parents.
Recommendations for Screening, Monitoring, and Referral of Pediatric Chronic Hepatitis B
Authors: Haber Barbara A. , Block Joan M. , Jonas Maureen M. , Karpen Saul J. , London W. Thomas , McMahon Brian J. , Murray Karen F. , Narkewicz Michael R. , Rosenthal Philip , Schwarz Kathleen B.
Published: October 2009

Most children with chronic hepatitis B virus infection (persistent hepatitis B surface antigen–positive for >6 months) are asymptomatic and do not generally require treatment. These children are, however, at increased risk for severe complications later in life, including advanced liver disease and liver cancer. On November 11, 2008, the Hepatitis B Foundation, a nonprofit research and disease advocacy organization, convened a panel of nationally recognized North American pediatric liver specialists to consider and recommend an approach for the screening, monitoring, initial management, and referral of children with chronic hepatitis B. The panel developed recommendations to provide guidance to practitioners on determining what additional tests to conduct, how often to monitor on the basis of test results, and when to refer to a pediatric liver specialist to build a partnership between the practitioner and liver specialist to enhance the success of management of children with this lifelong infection.
Young Driver Education Programs That Build Resilience Have Potential to Reduce Road Crashes
Authors: Senserrick Teresa , Ivers Rebecca , Boufous Soufiane , Chen Huei-Yang , Norton Robyn , Stevenson Mark , van Beurden Eric , Zask Avigdor
Published: October 2009

OBJECTIVE: The research aimed to explore associations between participation in 2 education programs for school-based learner drivers and subsequent road traffic offenses and crashes among a large cohort of newly licensed drivers.

METHODS: DRIVE is a prospective cohort study of 20822 first-year drivers aged 17 to 24 in New South Wales (NSW), Australia. Participants completed a detailed questionnaire and consented to data linkage in 2003–2004. Questionnaire items included year of participation in 2 specific education programs: a 1-day workshop-only program focusing on driving risks (“driver-focused”) and a whole-of-community program also including a 1-day workshop but also longer term follow-up activities and a broader focus on reducing risk-taking and building resilience (“resilience-focused”). Survey data were subsequently linked to police-reported crash and offense data for 1996–2005. Poisson regression models that adjusted for multiple confounders were created to explore offenses and crashes as a driver (dichotomized as 0 vs ≥1) after program participation.

RESULTS: Offenses did not differ between groups; however, whereas the driver-focused program was not associated with reduced crash risk, the resilience-focused program was associated with a 44% reduced relative risk for crash (0.56 [95% confidence interval: 0.34–0.93]).

CONCLUSIONS: The large effect size observed and complementary findings from a comparable randomized, controlled trial in the United States suggest programs that focus more generally on reducing risks and building resilience have the potential to reduce crashes. A large, representative, randomized, controlled trial is urgently needed to confirm road safety benefits and ensure evidence-based spending and practitioner recommendations in this field.
Optimizing Copper Sulfate Treatments for Fungus Control on Channel Catfish Eggs
Authors: Straus David L. , Mitchell Andrew J. , Carter Ray R. , Steeby James A.
Published: October 2009

This range-finding study determined the optimum concentration of copper sulfate (CuSO4) for fungus control on eggs of channel catfish Ictalurus punctatus. The study consisted of five CuSO4 concentrations (2.5, 5, 10, 20, and 40 mg/L) and an untreated control in a flow-through system. A single spawn was used for each replication (N = 4). Eggs were treated daily until the embryos reached the eyed stage. When hatching was complete for all viable eggs, fry were counted to determine the percent survival in each treatment. Fungal growth was severe in the untreated controls; survival of hatched fry in the control group was approximately 2%. The optimum CuSO4 treatment, as determined by percent survival of hatched fry, was 10 mg/L daily (69% survival); survival for this treatment group was significantly different from that for the controls. Very little fungus was present in treatments receiving 10-mg/L CuSO4 or higher except in one replication that had approximately 40% unfertilized eggs. The average survival rates in the 0-, 2.5-, 5-, 10-, 20-, and 40-mg/L CuSO4 treatments were 2, 34, 50, 69, 59, and 51%, respectively.
Evaluation of Sodium Carbonate Peroxyhydrate as a Potential Catfish Egg Disinfectant
Authors: Small Brian C.
Published: October 2009

Two experiments were conducted to evaluate the efficacy of sodium carbonate peroxyhydrate (SCP) in improving the hatching success of channel catfish Ictalurus punctatus when used as a prophylactic chemotherapeutant during egg incubation. In the first experiment, the efficacy of SCP was evaluated in 379-L aluminum incubation troughs similar to those used in commercial hatcheries. Egg masses treated daily with 254 mg of SCP/L of water had significantly higher mean hatching success than untreated controls, and a pathogen-inhibiting effect was also evident (i.e., no gross infection was observed on the treated egg masses). In the second experiment, the hatching success of egg masses treated daily with 254 mg/L was compared with that of egg masses treated daily with hydrogen peroxide (70 mg/L). The effects of both treatments on the pH, dissolved oxygen, and hydrogen peroxide concentrations in the trough were also examined. Both SCP and hydrogen peroxide significantly improved hatching success. Unlike in the treatment with hydrogen peroxide, water pH increased during the treatment with SCP; however, no negative effects on hatching success were observed. The results of this research suggest that SCP acts similarly to hydrogen peroxide in improving channel catfish hatching success and warrants further research to determine whether it could be a practical and effective alternative for managing catfish egg infections in commercial hatcheries.
Assessment of Cellular and Functional Biomarkers in Bivalves Exposed to Ecologically Relevant Abiotic Stressors
Authors: Joyner-Matos Joanna , Andrzejewski Jenessa , Briggs Laura , Baker Shirley M. , Downs Craig A. , Julian David
Published: October 2009

An understanding of the complex effects of the environment on biomarkers of bivalve health is essential for aquaculturists to successfully select field culture sites and monitor bivalve health in these sites and in hatcheries. We tested several whole-organism (functional) and cellular-level biomarkers as indicators of health of the cultured, stress-tolerant northern quahog (hard clam) Mercenaria mercenaria. We performed single- and dual-stressor experiments that were consistent with available water quality data from a clam culture area on the Gulf coast of Florida. Clams from the culture area were exposed over a 14-d period to low O2 (hypoxia), elevated temperature, hyposalinity, and a combination of elevated temperature and hyposalinity. There was no clear relationship between the functional and cellular-level biomarkers, with most of the treatment effects being detected at the whole-organism level but not the cellular level. Survival and burial ability were significantly affected by elevated temperature and by the combination of elevated temperature and hyposalinity. Glycogen content decreased over the experiment duration and did not differ significantly among treatments. There were no significant changes in expression patterns of eight stress proteins or in the levels of oxidatively damaged RNA. The results highlight the importance of investigating the effects of multiple stressors in short-term, controlled laboratory conditions and suggest that such cellular-level biomarker assays should be paired with functional biomarkers to better understand the responses of highly stress-tolerant species.
Relationships Between Shoreline Development and Nest Site Selection by Black Crappie and Largemouth Bass
Authors: Reed Jeffrey R. , Pereira Donald L.
Published: October 2009

To evaluate potential effects of lakeshore development on nest site selection, we compared locations of black crappie Pomoxis nigromaculatus and largemouth bass Micropterus salmoides nests in three Minnesota lakes with available habitat in the littoral and riparian zones and the presence or absence of developed shoreline. We used binomial logistic regression to determine how the frequency of nest sites varied among lakes and with the presence or absence of five habitat variables. Black crappies in all three lakes were more likely to nest adjacent to undeveloped shoreline. Black crappies were also more likely to nest in stands of emergent vegetation, particularly hardstem bulrush Scirpus acutus. Largemouth bass were more likely to nest near undeveloped shoreline but were less dependent on hardstem bulrush. Shoreline development has the potential to alter nest site selection by largemouth bass and, particularly, by black crappies.
Graphical Evaluation of Fishery Status Using a Likelihood Inference Approach
Authors: Jiao Yan , Reid Kevin , Nudds Tom , Smith Eric
Published: October 2009

We present a graphical method that uses a statistical likelihood approach to summarize evidence and risk in fishery status evaluation. The graphical method is based on the surplus production model and shows the fishery status as regions and colors on graphs. Two fishery status graphs are used: one is based on the comparison between observed catch and catch at the fishing mortality level corresponding to maximum sustainable yield; the other one is based on the comparison between observed catch and catch at the surplus production level. The graphical statistical likelihood approach quantifies the strength of evidence in supporting different hypotheses of fishing status as regions in the status graphs. A simulated hypothetical fishery is given as an example. Results are graphically presented to show the exploitation status of the fishery, and they compare favorably with those from a composite risk assessment method. This graphical statistical likelihood approach may improve the communication of knowledge and evidence among scientists, fishery stakeholders, and management agencies and may provide a better understanding of current fishery status.
Returns of Hatchery Steelhead with Different Fin Clips and Coded Wire Tag Lengths
Authors: Bumgarner Joseph D. , Schuck Mark L. , Blankenship H. Lee
Published: October 2009

Left ventral (LV) fin clips have routinely been used in the Columbia River basin to visually identify the presence of a coded wire tag (CWT) in steelhead Oncorhynchus mykiss. Managers and researchers alike have expressed concern that the ventral fin clip may negatively affect survival. Adult returns from summer steelhead smolts released from Lyons Ferry Hatchery (LFH), Washington State, between 1996 and 1999 having combinations of adipose (AD) and LV fin clips and 1.1- or 1.6-mm-long CWTs were compared. The CWT loss rate calculated from release to adult recovery was 1.9% and the LV fin clip regeneration rate was 2.4%; neither of these rates influenced our recovery results. We found slight, nonsignificant differences in return rates between fish with AD fin clips and those with both AD and LV fin clips (ADLV) and between fish with 1.1-mm CWTs and those with 1.6-mm CWTs. Overall, fish with ADLV fin clips had LFH return rates that were 5% greater than those of fish with AD-only clips, and fish with 1.6-mm CWTs had LFH return rates that were 6% higher than those of fish with 1.1-mm CWTs. Increased straying because of the 1.6-mm CWT length was not evident, although there was likely sampling bias at other hatcheries or traps that did not conduct electronic CWT scans of fish that lacked LV clips. Two variables that may have influenced our results were examined, but neither was determined to be a factor in our results. Our study results suggest that a ventral fin clip or longer CWT does not impair adult returns (survival) of hatchery summer steelhead. Unfortunately, study limitations reduced our statistical power to definitively conclude that there was no significant difference in survival, and additional study may be necessary. However, our study provides sufficient information for fishery managers to consider use of the LV clip on hatchery steelhead as a visual cue for CWT recovery when electronic scanning of fish will be inconsistently used or is unavailable. Also, we suggest the use of 1.6-mm CWTs if electronic detection is to be the primary recovery method as it does not appear to affect survival in hatchery steelhead. We strongly caution managers to ensure that 100% electronic scanning of fish occurs throughout the region before foregoing standard LV fin clip marks on steelhead that contain CWTs.
In-Season Forecasting of Coho Salmon Marine Survival via Coded Wire Tag Recoveries
Authors: Holt Kendra R. , Cox Sean P. , Sawada Joel
Published: October 2009

Calculation of in-season marine survival rate forecasts for coho salmon Oncorhynchus kisutch can provide valuable support for in-season harvest management decisions because annual variability in marine survival accounts for a large proportion of total recruitment variability. We present a new forecasting model that utilizes coded wire tag (CWT) recovery information from early occurring fisheries to provide in-season marine survival forecasts that are timely enough to inform harvest management decisions for subsequent fisheries. We evaluate performance of the CWT model by using retrospective analyses on four coho salmon indicator stocks from northern British Columbia, Canada. For each stock, model selection analysis was used to identify which of three time-varying fishery catchability models used within the CWT model maximized forecasting performance. A Bayesian approach to parameter estimation was then applied to the best CWT model to generate probabilistic forecasts of marine survival rate for six consecutive weeks of in-season forecasting in each year. Although forecasted posterior distributions were wide in some cases, the posterior mode tracked marine survival relatively well in comparison with postseason marine survival estimates based on recoveries from all fisheries and the spawning grounds. Average percent forecast biases based on posterior modes were −1, −4, 19, and 57% for the four indicator stocks in the final week of forecasting. The lower tails of the posterior distributions were well defined, which is most relevant to identifying years of conservation concern due to extremely low marine survival. We conclude that timely in-season recovery and analysis of CWT information could improve the level of information available to inform in-season harvest management decisions.
Equilibrium Analyses of a Population's Response to Recovery Activities: A Case Study with Atlantic Salmon
Authors: Gibson A. Jamie F. , Jones Ross A. , Bowlby Heather D.
Published: October 2009

Recovery planning for populations in decline requires a thorough understanding of how life history characteristics, environmental conditions, and human activities interact to determine how abundance changes through time. In a detailed case study of the declining population of Atlantic salmon Salmo salar in the Tobique River, New Brunswick, we demonstrate an equilibrium modeling approach to analyzing the dynamics of the population so as to identify stressors and predict the population-level response to potential recovery actions. Parameter values for the equilibrium analysis were obtained by fitting a life history model to population-specific data, including annual estimates of juvenile density and egg deposition as well as the number and age composition of emigrating smolts. Two unique aspects of the statistical analysis—standardization of the electrofishing data using a generalized linear model and scaling of the juvenile density estimates to total abundance using a catchability coefficient—significantly improved model fits and resulted in parameter estimates that were biologically realistic. The subsequent equilibrium analysis was used to evaluate how population size was expected to change in response to recovery actions focused on fish passage, marine survival, and freshwater production. Recovery actions focused only on freshwater habitat or fish passage were not sufficient to produce an equilibrium population size greater than zero; however, either factor could limit the effectiveness of other recovery actions if not included in the recovery plan. The case study highlights the complex dynamics that can limit population growth, illustrates the need to consider the full life cycle of a species as part of the recovery planning process, and shows that responses to multiple threats may be required to bring about recovery.
Survival of Discarded Sublegal Atlantic Cod in the Northwest Atlantic Demersal Longline Fishery
Authors: Milliken Henry O. , Farrington Marianne , Rudolph Tom , Sanderson Melissa
Published: October 2009

The survival of sublegal Atlantic cod Gadus morhua discarded in the U.S. Northwest Atlantic demersal longline fishery was examined for the effects that handling technique, sea surface temperature, and capture depth have on it. Longline-caught Atlantic cod were either removed from the hook by hand (unsnubbed) or by allowing the hydraulic hauler to pull the fish against the parallel steel cylinders placed vertically on the gunwale, causing the hook to pull through the jaw (snubbed). Jigged-caught fish served as an indicator of mortality occurring because of the experimental design in the survival experiments. Once caught, live fish were placed in underwater cages, and short-term survival was assessed after holding the fish for 3 d (approximately 72 h). Survival was analyzed with respect to three water depths and four sea surface temperature (SST) strata. Atlantic cod survival in these strata ranged from 31% to 100%. Depth and SST affected survival more than the dehooking technique; survival was higher in shallow depths and at lower temperatures. Unsnubbed fish had higher survival rates than snubbed fish.
Effect of Thiamine Status on Probability of Lake Ontario Chinook Salmon Spawning in the Upper or Lower Sections of Salmon River, New York
Authors: Ketola H. George , Johnson James H. , Rinchard Jacques , Verdoliva Francis J. , Penney Mary E. , Greulich Andreas W. , Lloyd Russell C.
Published: October 2009

Consumption of thiaminase-containing forage fishes reduces egg and muscle thiamine content and impairs the spawning migration of Cayuga Lake (New York) rainbow trout Oncorhynchus mykiss. Because some Chinook salmon O. tshawytscha from Lake Ontario have been shown to produce eggs low in thiamine, we examined the relationship between the migration of Chinook salmon and the thiamine content of their eggs spawned in the lower and upper sections of the Salmon River, a major tributary to Lake Ontario, in 2003–2006. Eggs from the upper section of the river were collected from 79 salmon returning to the state hatchery 25 river kilometers from the mouth. Eggs from 25 salmon in the lower section were collected from redds or females angled on redds approximately 1–3 km from the mouth. For all years combined, we found the mean thiamine concentration in eggs spawned in the lower section to be significantly lower than that for eggs spawned in the upper section; however, the annual differences in thiamine content of eggs between the upper and lower sections were significant only in 2003 and 2006. Binary logistic regression showed that the odds of spawning in the upper section was increased by 96% (95% confidence interval, 21–217%) for every nanomole of increase in the thiamine content of eggs. Therefore, the migratory achievement of Chinook salmon was significantly dependent on their thiamine status.
Recovery Potential Assessment for Lake Sturgeon in Canadian Designatable Units
Authors: Vélez-Espino Luis A. , Koops Marten A.
Published: October 2009

Significant declines in the abundance of lake sturgeon Acipenser fulvescens across most of its North American range have led to abundances less than 10% of estimated minimum sustainable population sizes and, in some locations, less than 1% of historic abundances. These precipitous declines in abundance have resulted in most lake sturgeon populations being considered a conservation concern and have prompted management actions toward recovery. Here we present modeling in support of a recovery potential assessment, using stage-structured matrix models and population viability analysis to quantitatively assess allowable harm, recovery efforts, probabilities of recovery, and recovery time frames. From this assessment, we conclude that lake sturgeon populations are most sensitive to harm on adult survival and that some designatable units are highly sensitive to any level of harm. However, the scope for recovering lake sturgeon by improving adult survival is limited; instead, larger proportional increases in population growth rates can be achieved by focusing recovery efforts on age-0 and juvenile survival. Finally, based on a recovery target of 1,188 spawning females/year for each discrete population and current abundances from 1% to 10% of this target, long-term projections indicate recovery time frames ranging from 20 to over 100 years, depending on the recovery actions implemented.
Landscape-Level Sampling for Status Review of Great Basin Redband Trout
Authors: Dambacher Jeffrey M. , Jones Kim K. , Larsen David P.
Published: October 2009

In response to a petition to list Great Basin redband trout (subspecies of rainbow trout Oncorhynchus mykiss) as threatened or endangered, the U.S. Fish and Wildlife Service conducted a status review in 1998. To support that review, we conducted a survey of the abundances of redband trout in each of six subbasins of the Great Basin that included the states of Oregon, California, and Nevada. We used a generalized random-tessellation stratified algorithm to select a target sample size of 35 sites/subbasin. Out of a target number of 210 sites, 185 were visited by three-person crews that surveyed stream habitat and estimated the abundance of fish populations in sample reaches with lengths that were nearly 20 times the respective channel widths. A minimal sampling intensity was based on previously encountered levels of between-site variance in estimates of redband trout abundance. The total population estimate of age-1 and older (age-1+) redband trout in the Great Basin was 971,313 fish, with a 95% confidence interval equaling ±15% of the mean estimate; 95% confidence limits ranged from 15% to 31% for population estimates in individual subbasins. Age-1+ fish abundance in terms of numerical density showed no significant differences between any subbasins. However, there were significant differences in terms of biomass: Catlow Valley subbasin biomass was significantly higher than the Great Basin mean, whereas Goose Lake subbasin biomass was significantly lower than the basinwide mean. These comparisons were supported by like differences in average weight. Analysis of stream habitat characteristics and fish abundance revealed no relationships that were generally consistent throughout the Great Basin, although spatial patterns were evident within some stream systems where sampling intensity was sufficiently high.
Evaluation of an Electric Gradient to Deter Seal Predation on Salmon Caught in Gill-Net Test Fisheries
Authors: Forrest Keith W. , Cave Jim D. , Michielsens Catherine G. J. , Haulena Martin , Smith David V.
Published: October 2009

An electric deterrent system was tested as an effective and safe method of deterring predation by Pacific harbor seals Phoca vitulina richardsi on sockeye salmon Oncorhynchus nerka and pink salmon Oncorhynchus gorbuscha caught in a Fraser River gill-net test fishery. Seals were deterred from foraging in a test fishing gill net in the Fraser River by using a pulsed, low-voltage DC electric gradient. Salmon catch per unit effort (CPUE) was significantly greater for the treated (electric) section of the gill net than for the nontreated section (marginal mean CPUE = 4.0/1,000 m · min versus 1.0/1,000 m · min), and there was no overlap in the 95% confidence intervals for the two treatments. There were no apparent injuries to any animals during the study. This previously undocumented nonlethal technology demonstrates the potential to reduce pinniped predation on salmon, with meaningful implications for fisheries management agencies that rely on gill-net test fisheries in freshwater rivers frequented by pinnipeds.
Evaluating the Effectiveness of Grassbed Treatments as Habitat for Juvenile Black Bass in a Drawdown Reservoir
Authors: Ratcliff Donald R. , Wurtsbaugh Wayne A. , Zustak Joseph
Published: October 2009

Many reservoirs in arid regions experience highly variable water levels caused by seasonal inflow fluctuations and designated outflow requirements. At Shasta Lake, California, managers plant cereal-grain grassbeds on exposed drawdown shorelines to increase juvenile fish habitat, localize productivity, and increase invertebrate fish prey. To determine the efficacy of these plantings, the abundance of juvenile black basses Micropterus spp. (20–55 mm standard length) and the amount of periphyton and macroinvertebrate prey were compared among three treatment types: (1) planted grassbeds of cereal barley Hordeum vulgare; (2) artificial rope grassbeds, which eliminated physical deterioration and nutrient release; and (3) nonplanted control sites with predominately sand and gravel substrates. In comparison with control areas, juvenile black bass abundance averaged 54 times higher in planted grassbeds and 230 times higher in artificial grassbeds. Periphyton (chlorophyll a) and benthic invertebrate biomass did not differ significantly between planted grassbeds and control sites. In artificial grassbeds, periphyton was more than two times the control levels, and benthic invertebrate biomass was more than 12 times the control levels. We conclude that the long-term availability of physical structure, rather than nutrient release associated with decomposition of grassbed materials, drives use and effectiveness of grassbed treatments. Future management decisions in drawdown reservoirs should emphasize increasing long-term availability and integrity of physical habitat for juvenile fishes in the littoral zone.
Detection Distances of Selected Radio and Acoustic Tags in Minnesota Lakes and Rivers
Authors: Shroyer Steven M. , Logsdon Dale E.
Published: October 2009

In freshwater, the optimal choice between radiotelemetry or acoustic telemetry has often been unclear because the combined effects of tag power, conductivity, tag depth, and antenna type on radio tag detection distances have not been quantified. To enable more informed decisions regarding the best telemetry methods to use at particular study sites, we measured maximum detection distances of an acoustic tag and two different 48–49-MHz radio tags over a wide range of conductivities, depths, and acoustic conditions in Minnesota lakes and rivers. Radio tag detection distances increased with increasing tag power, decreased with increasing conductivity, and generally decreased with increasing depth. Detection distances measured with a Yagi antenna were typically about double those measured with a loop antenna. Maximum detection distances of the radio tags were predicted by the equation logeR = 13.69 − 0.005771·C − 0.006575·D + 0.1044·P + 0.7275·A − 0.001302·C·D − 0.00008208·C·P (where R = maximum detection distance, m; C = surface conductivity, μS/cm, at ambient temperature; D = tag depth, m; P = tag output power, dB relative to 1 mW; and A = antenna type [1 = Yagi, 0 = loop]). Acoustic detection distances were less variable overall than radio detection distances but still differed substantially between and within water bodies. We saw no consistent relationship between acoustic detection distance and tag depth, but detection distance was negatively affected by ambient noise. Our model indicates that a 48–49-MHz radio tag can be detected with a boat-mounted Yagi antenna at a depth of 50 m or more if conductivity is low enough, but the maximum detection depth decreases drastically as conductivity increases. The equation above can be used to predict whether detection distances of radio tags similar to the ones we tested will be adequate for a particular study.
Survival of Striped Bass Entrained into the Cooling Systems of Two Hudson River Power Stations
Authors: Young John R. , Dey William P. , Jinks Steven M. , Mosier David T.
Published: October 2009

Data from entrainment survival sampling programs conducted in 1979, 1980, and 1988 at the Indian Point generating stations and in 1977, 1978, and 1980 at the Roseton generating station, both located on the tidal Hudson River estuary, were reanalyzed using a series of failure time models to estimate the survival of entrained striped bass Morone saxatilis based on sampling stress, mechanical entrainment stress, and thermal stress. The model with the lowest Akaike information criterion value was the most complex model examined, with year- and station-specific parameters for both sampling and entrainment. However, the lowest Bayesian information criterion was achieved with a model that had year- and station-specific sampling parameters but only station-specific entrainment parameters. The models indicated that survival was positively related to fish length and salinity and negatively related to discharge temperatures above 30°C. Parameter uncertainty was addressed via a bootstrap resampling procedure to estimate parameters for the station-specific model, and the results were applied to entrainment abundance data from each facility from 1983 to 1987. The distribution of the estimated mean annual entrainment survival after 1 d for Indian Point had modes at 0.48, 0.60, 0.70, and 0.81. For Roseton, the distribution of mean annual entrainment survival was normal, with a mean of 0.41 and a variance of 0.0028. Survival differences between the two stations were due to inherent differences in entrainment stresses, as indicated by differences in the parameters for the model as well as differences in the length of entrained striped bass, discharge temperature, and salinity.
Hierarchical Modeling of Late‐Summer Weight and Summer Abundance of Juvenile Coho Salmon across a Stream Network
Authors: Ebersole Joseph L. , Colvin Michael E. , Wigington Parker J. , Leibowitz Scott G. , Baker Joan P. , Church M. Robbins , Compton Jana E. , Cairns Michael A.
Published: October 2009

Spatial variation in stream habitat quality can lead to network‐level patterns in the survival and growth of juvenile coho salmon Oncorhynchus kisutch that provide important insights into the factors influencing the freshwater population dynamics of this species. Our objectives were to quantify the relationships among summer habitat conditions, coho salmon density, and coho salmon parr abundance and weight across an extensive stream network over 3 years. We used hierarchical linear models to assess the factors influencing coho salmon weight and abundance at the levels of individual fish (fork length and parasite burden), habitat unit (surface area, cover, and density), reach (temperature and density) and stream (total nitrogen, soluble reactive phosphorus, and discharge). Habitat‐unit‐level surface area and stream‐level minimum discharge were important predictors of both the abundance and weight of coho salmon parr. An area × discharge interaction term was also important in models of weight and reflected network‐level patterns of the highest abundances and highest parr condition in the middle portions of the basin. In these locations, streamflow, habitat area, and temperature were moderate compared with the warmer, higher‐discharge downstream reaches and cooler, lower‐discharge (or even intermittent) upstream reaches. We conclude that in the study basin coho salmon parr weight was limited by habitat unit density and minimum summer discharge in the headwaters and abundance was limited primarily by space (pool area) in the headwaters and warm summer temperatures in the lower portions of the basin.
Fish Diversity and Abundance in Relation to Interannual and Lake‐Specific Variation in Abiotic Characteristics of Floodplain Lakes of the Lower Kaskaskia River, Illinois
Authors: Shoup Daniel E. , Wahl David H.
Published: October 2009

The importance of floodplain lakes to tropical river systems is well established, but little is known about the function of these habitats in temperate river systems. We examined fish diversity, abundance, and reproduction within six oxbow lakes of the Kaskaskia River, Illinois, over 5 years and their relationship to 11 abiotic environmental variables. The lakes were hydrologically dynamic within and among years, varying in the time connected with the main stem (0‐22 weeks/year) and the frequency of low (<0.3‐m) water (0‐23 weeks/year). Differences were found both among years and lakes. All measured limnological variables (dissolved oxygen, Secchi disk depth, conductivity, and temperature) varied temporally, but only conductivity and Secchi disk depth varied among lakes. Fish species differed among lakes and between adjacent lotic habitats, and species‐specific abundance varied among years, seasons, and lakes. This variation was related to several environmental variables. Diversity was positively related to the distance between the oxbow lake and the river but not to any variables that had interannual variation. Seine catch per unit effort (CPUE) was negatively related to mean water level and Secchi disk depth. Total electrofishing CPUE was not related to any variables; however, that of bluegills Lepomis macrochirus was positively related to maximum depth and that of warmouths L. gulosus was positively related to vegetated area. Across all lakes, evidence of reproduction was found for five species and was negatively related to the mean water level and frequency of low water and positively related to flood periodicity. The oxbow lakes have the potential to contribute to the fish community of the main river by providing spawning and nursery habitat for several fish species as well as helping maintain several less abundant main‐stem species. However, when considering management options to maintain or restore these ecosystem functions, interannual variation in environmental variables, particularly those related to flood periodicity, should be considered.
Hearing Sensitivity of the Walleye Pollock
Authors: Mann David A. , Wilson Christopher D. , Song Jiakun , Popper Arthur N.
Published: October 2009

The hearing abilities of three age‐groups (which correspond to size‐classes) of walleye pollock Theragra chalcogramma were determined from auditory evoked potentials. Walleye pollock had the best hearing sensitivity from 100 to 200 Hz, with thresholds around 75 dB re: 1 μPa. Hearing sensitivity decreased with increasing frequency up to 450 Hz. There was no significant difference in hearing sensitivity between the age‐groups, although there was a significant interaction between frequency and age as well as a trend in which the older fish had slightly lower mean thresholds. At the same time, there was a substantial increase in the size of the saccular otolith and associated sensory epithelia of the inner ear, suggesting that a large increase in ear size does not lead to a large change in hearing sensitivity. In addition, there was an effect of water temperature on the hearing thresholds at 350 Hz, whereby each degree of temperature (°C) increase resulted in an 8.3‐dB decrease in hearing threshold. The results suggest that the hearing thresholds of walleye pollock are generally similar to those of other gadid fishes. This knowledge can be used to evaluate the potential impact, in terms of behavioral responses or physiological effects, that various human‐generated sounds (e.g., seismic survey and underwater radiated vessel noise) may have on this species.
Interspecific Resource Competition between the Invasive Round Goby and Three Native Species: Logperch, Slimy Sculpin, and Spoonhead Sculpin
Authors: Bergstrom Margot A. , Mensinger Allen F.
Published: October 2009

The invasive round goby Apollonia melanostomus (formerly Neogobius melanostomus) has negatively affected benthic fish communities throughout the Great Lakes. In this study, we compared the sensory physiology and behavior of three native species—slimy sculpin Cottus cognatus, spoonhead sculpin C. ricei, and logperch Percina caprodes—with those of the round goby to determine the mechanisms that allow the round goby to dominate native fish. The reaction and strike distances of the four species were examined during predator‐prey trials using natural amphipod prey Gammarus spp. under varying light intensities (0‐130 lx) to compare input from the mechanosensory lateral line and visual systems. Trials in the dark (0 lx) indicated that the sculpins and the round goby had similar lateral line sensitivity. However, all three native species had a significant advantage in reaction and strike distance over the round goby at higher light intensities. Interspecific resource competition was assessed by pairing a round goby with a native fish in an artificial stream. Round gobies gained significantly more weight than the native fishes during all trials. Slimy sculpins were able to maintain their weight in the presence of the round goby; however, spoonhead sculpins and logperch lost a significant amount of weight during the trials. These experiments indicate that although the round goby does not possess an inherent sensory advantage, it can dominate resources and outcompete native fish. Thus, round gobies may pose risks for a wide variety of native benthic fishes.
Migration Characteristics of Hatchery and Natural Spring Chinook Salmon Smolts from the Grande Ronde River Basin, Oregon, to Lower Granite Dam on the Snake River
Authors: Monzyk Fred R. , Jonasson Brian C. , Hoffnagle Timothy L. , Keniry Patrick J. , Carmichael Richard W. , Cleary Peter J.
Published: October 2009

Smolts of spring Chinook salmon Oncorhynchus tshawytscha experience substantial mortality while migrating through free‐flowing reaches of the Snake River basin before reaching Lower Granite Dam, the first dam encountered in the Columbia‐Snake river hydrosystem. We investigated the patterns of travel time and survival of hatchery and natural smolts fitted with passive integrated transponder (PIT) tags through specific reaches of the migration corridor during the 2000‐2006 migration years for two populations originating in the Grande Ronde River basin (Lostine River and Catherine Creek). For both populations, median travel times for natural smolts were significantly longer in the upper reaches of the migration corridor but shorter in the lower reaches than for their hatchery counterparts. Also, among both hatchery and natural smolts, smaller individuals spent more time in the upper reaches, presumably feeding to attain a larger size before continuing their migration. Within populations, both hatchery and natural smolts showed similar patterns of survival through the reaches of the migration corridor above Lower Granite Dam. Size‐selective mortality was evident for hatchery and natural smolts from both populations, especially in the upper reaches, larger individuals experiencing higher survival. The Catherine Creek population experienced the majority of natural and hatchery smolt mortality (32.8‐65.8%) in a relatively short (91‐km), low‐gradient reach immediately below the summer rearing habitat. In contrast, the Lostine River natural and hatchery smolts experienced lower mortality (3.6‐46.1%) in a 174‐km reach below the summer rearing habitat. The results of this study demonstrate the dynamic nature of survival and migration rate among spring Chinook salmon smolts during their initial seaward migration from tributaries.
Shifts in the Trophic Ecology of Brook Trout Resulting from Interactions with Yellow Perch: An Intraguild Predator‐Prey Interaction
Authors: Browne David R. , Rasmussen Joseph B.
Published: October 2009

In size‐structured populations, predator‐prey interactions may be preceded by a phase of resource competition earlier in ontogeny, with potential consequences for population dynamics and resource management. We hypothesized that brook trout Salvelinus fontinalis and yellow perch Perca flavescens would compete for shared resources and interact as predator and prey. We used stable isotopes and stomach content analysis to compare the trophic ecology of brook trout in lakes with and without yellow perch. Percent littoral resource use by brook trout differed between perch and nonperch systems, ranging from approximately 50% to 100% in nonperch lakes compared with 10‐70% in perch lakes. Nonpiscivorous‐sized brook trout (fork length [FL] < 25 cm) showed a significant ontogenetic diet shift toward greater pelagic resource use during growth from 15 to 25 cm in sympatry with yellow perch. Nonpiscivorous‐sized brook trout in nonperch lakes consumed a mixture of zoobenthos, zooplankton, and littoral prey fish. In contrast, in lakes containing yellow perch, nonpiscivorous‐sized brook trout fed primarily on pelagic prey. Brook trout shifted to piscivory at a FL of approximately 25 cm in both perch and nonperch systems. Isotopic results and stomach content analysis indicated that yellow perch were the primary prey of piscivorous‐sized brook trout (FL > 25 cm) in perch lakes, occurring in 66‐100% of the brook trout sampled and accounting for over 97% of the diet by weight. Overall, the presence of yellow perch resulted in a shift in the energetic basis for brook trout production from primarily littoral to primarily pelagic. The shift in brook trout food web position was associated with a decline in brook trout catch per unit effort. We conclude that brook trout and yellow perch interact as intraguild predator and prey and that the interaction is dominated by yellow perch.