bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

AbstractSpatial 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.