bluuebunny/crossref_metadata_2025 huggingface dataset:
Claiming Competence: Biographical Work among Victim‐Advocates and Counselors
Authors: Kolb Kenneth H.
Published: February 2011

Advocates and counselors at agencies that assist victims of domestic violence and sexual assault argue that they are especially suited to help their clients develop safe and practical strategies to protect themselves from further abuse. Yet the backstage of these agencies can depict a reality of confusion, doubt, and sometimes fear—especially when clients’ cases do not go according to plan. Data collected from in‐depth interviews and participant observation over fourteen months show how advocates and counselors engaged in “biographical work” (Gubrium and Holstein 2000) to construct coherent and consistent narratives as competent service providers in the aftermath of their clients’ unanticipated outcomes. Calling on different discursive strategies accessible to them according to their position within the agency, both groups were able to interpret negative results as beyond their responsibility. However, the counselor's rhetoric of “professionalism” proved more effective in this regard compared with the advocates’ “empowerment.”
Comparisons in the epidemiology, diagnostic features and cure rate by transsphenoidal surgery between paediatric and adult-onset Cushing's disease
Authors: Storr H L , Alexandraki K I , Martin L , Isidori A M , Kaltsas G A , Monson J P , Besser G M , Matson M , Evanson J , Afshar F , Sabin I , Savage M O , Grossman A B
Published: February 2011

Objective

There are few published comparisons between paediatric and adult-onset Cushing's disease (CD). We compare the epidemiology, diagnostic features and cure rate by transsphenoidal surgery (TSS) in these groups.

Design

Retrospective review of patient databases in a single university hospital centre.

Patients

Totally, 41 paediatric (mean age 12.3±3.5 years; range 5.7–17.8) and 183 adult (mean age 40±13 years; range 18.0–95.0) patients with CD were investigated.

Results

Paediatric CD was characterised by male (63%) and adult CD by a female predominance (79%, P<0.0001). There were small but significant differences in clinical presentation. Biochemical features of CD were comparable except the serum cortisol increase during a CRH test: mean change (105%, n=39) in paediatric and (54%, n=123) in adult subjects (P<0.0001). Macroadenomas were more common in adult (15%, 28/183) than in paediatric (2%, 1/41, P=0.04) CD. Corticotroph microadenomas were more easily visualised by pituitary magnetic resonance imaging (MRI) in adult (76%, 50/66) compared with paediatric (55%, 21/38, P=0.045) CD with poorer concordance of imaging with surgical findings in children (P=0.058). The incidence of ACTH lateralisation by bilateral simultaneous inferior petrosal sinus sampling was comparable in paediatric (76%, 25/33) and adult (79%, 46/58; P=0.95) patients with good surgical concordance in both (82% paediatric and 79% adult). Cure rates by TSS were comparable, with a paediatric cure rate of 69%.

Conclusion

Several features of paediatric CD are distinct: increased frequency of prepubertal CD in males, the different clinical presentation, the decreased presence of macroadenomas and the frequent absence of radiological evidence of an adenoma on MRI.
Heifer nutrient intake during early- and mid-gestation programs adult offspring adiposity and mRNA expression of growth-related genes in adipose depots
Authors: Micke Gina C , Sullivan Tracy M , McMillen I Caroline , Gentili Sheridan , Perry Vivienne E A
Published: February 2011

Changes in maternal nutrient intake during gestation alterIGFreceptor abundance and leptin (LEP) mRNA expression in fetal adipose tissue. It is not known whether such changes persist into adult life and whether they are associated with an effect on phenotype. We investigated the effect of high (240%) and low (70%) levels of recommended daily crude protein intake for beef heifers during the first and second trimesters of gestation on singleton progeny (n=68): subcutaneous (SC) adipose tissue depth at rump (P8) and rib (RF) sites from 65 until 657 days of age; plasma leptin concentrations from birth until 657 days and expression ofIGF1andIGF2, their receptors (IGF1RandIGF2R) andLEPmRNA in perirenal (PR), omental (OM) and SC adipose tissue at 680 days of age. High-protein diets during the first trimester increasedLEPandIGF1mRNA in PR of males and females, respectively, compared with low-protein diets, and decreasedIGF1RmRNA in SC of all progeny but increased RF depth of males between 552 and 657 days. High-protein diets compared with low-protein diets during the second trimester increasedIGF1RmRNA in PR and OM of all progeny;LEPmRNA in PR of males; andIGF2andIGF2RmRNA in OM of all progeny. Conversely,LEPmRNA in OM andIGF2mRNA in PR of all progeny were decreased following exposure to high- compared with low-protein diets during the second trimester. Heifer diet during gestation has permanent sex- and depot-specific effects on the expression of adipogenic and adipocytokine genes and offspring adiposity.
Benzene Induces Cytotoxicity without Metabolic Activation
Authors: Nishikawa Takuro , Izumo Kimiko , Miyahara Emiko , Horiuchi Masahisa , Okamoto Yasuhiro , Kawano Yoshifumi , Takeuchi Toru
Published: February 2011

Benzene Induces Cytotoxicity without Metabolic Activation: Takuro Nishikawa, et al. Departments of Environmental Medicine and Pediatrics, Graduate School of Medical and Dental Sciences, Kagoshima University—

Objectives

Benzene has been consistently associated with hematological disorders, including acute myeloid leukemia and aplastic anemia, but the mechanisms causing these disorders are still unclear. Various metabolites of benzene lead to toxicity through the production of reactive oxygen species (ROS), the inhibition of topoisomerase and DNA damage. However, benzene itself is considered to have no mutagenic or cytotoxic activity. In this study, we investigated the effects of benzene itself on a human myeloid cell line with or without benzene metabolizing enzyme inhibitors.

Methods

A human myeloid cell line, HL‐60, was exposed to benzene with or without cytochrome P450 2E1 or myeloperoxidase inhibitor. Cytotoxicity was evaluated in terms of global DNA methylation levels, induction of apoptosis, and ROS production.

Results

Benzene did not change global DNA methylation levels. However, benzene itself increased the levels of apoptosis and ROS. This cytotoxicity did not change with the addition of benzene metabolizing enzyme inhibitors. Benzene itself increased the mRNA levels of oxidative stress‐related genes and transcription factors of activator protein‐1.

Conclusions

Benzene did not Influence global DNA methylation in HL‐60 cells, but had cytotoxic effects and changed gene expression levels. To elucidate the mechanisms of benzene toxicity, benzene itself as well as benzene metabolites must be investigated.
The “gray zone” in fine-needle aspiration cytology of the organized mammography screening. Cytohistological correlation
Authors: Bak Mihály , Konyár Éva , Schneider Ferenc , Bidlek Mária , Szabó Éva , Nyári Tibor , Gődény Mária , Kásler Miklós
Published: February 2011

The National Public Health Program has established the organized mammography screening in Hungary. The aim of this study was to conduct an audit of “gray zone” smears of the organized mammography screening in comparison with histopathological diagnoses. Methods: Cytology results were rated to C3 atypia probably benign and C4 suspicious of malignancy. Results: 1361 women had aspiration cytology performed from a total of 47,718 mammography non-negative lesions. 105 (7.8%) were diagnosed as C3, whereas 78 (5.7) as C4. Of the 105 patients with C3 diagnosis 61 (58%) patients underwent surgical biopsy. Histology proved malignancy in 20 (32.8%) cases, and benign lesion in 41 (67.2%) cases. All (100%) of the 78 patients with C4 diagnosis had open biopsies; 69 (88.4%) cases were histologically malignant and 9 (11.6%) cases were benign lesions. Conclusion: The auditing results of fine needle aspiration cytology of “gray zone” in organized mammography screening meet the proposed threshold values. Authors conclude that the “gray zone” category in breast cytology is useful and of value if used judiciously. Orv. Hetil., 2011, 152, 292–295.
Dobutamine stress cardiovascular magnetic resonance imaging in patients with peripheral artery disease
Authors: Kirschner Róbert , Pécsvárady Zsolt , Bedros J. Róbert , Tóth Levente , Kiss Krisztián , Simor Tamás
Published: February 2011

Patients with peripheral arterial disease often have coronary heart disease, as well. However, their assessment with classical noninvasive cardiology methods is often non-diagnostic or limited. The aim of this study was to analyze the feasibility and the risks of dobutamine stress cardiovascular MRI for cardiac evaluation of patients with peripheral arterial disease. 21 patients with peripheral artery disease (mean±SD age 64.3±7.7 years) were studied prospectively with dobutamine stress cardiovascular MRI. The protocol was completed by all of 21 patients. The target heart rate was attained in 95.2% of the studies. No serious adverse event occurred. The image quality scores (1-4) for all ventricular wall segments were high (median, interquartile range) (4 [4-4]). Five patients (23.8%) have inducible wall motion abnormality. Interobserver agreement was almost perfect for wall motion scores (κ = 0.87, p<0.0001). Dobutamine stress cardiovascular MRI is feasible with low risk for the cardiological assessment of patients with peripheral arterial disease. Orv. Hetil., 2011, 152, 285–291.
Comparison of Green and White Mesh Trammel Nets and Gill Nets to Assess the Fish Community in a Large River
Authors: Wanner Greg A. , Klumb Robert A. , Shuman Dane A. , Steffensen Kirk , Stukel Sam , Utrup Nicholas J.
Published: February 2011

Standardized monitoring programs in great rivers need to identify and minimize the bias in the estimates of fish population characteristics to enable fishery managers to make informed decisions. We compared the effectiveness of green and white mesh in drifted trammel and anchored gill nets in capturing fish in the Missouri River from downstream of Fort Randall Dam, South Dakota, to the mouth of the river near St. Louis, Missouri. Sampling occurred from March to November 2006 and from April to May 2007. Paired green and white trammel net drifts (N = 383) caught 28 fish species from 12 families. Pairs of anchored gill nets set overnight (N = 193) caught 24 fish species from 12 families. Chi-square tests indicated that for most species there were no significant differences in occurrence between mesh colors in both the trammel and gill nets. However, occurrence was significantly higher in white mesh nets for goldeye Hiodon alosoides and blue sucker Cycleptus elongatus in trammel nets and for river carpsucker Carpiodes carpio and walleye Sander vitreus in gill nets. Despite turbidities in the Missouri River that ranged over two orders of magnitude, analysis of covariance indicated that water clarity had no significant effect on capture rates between green and white meshes. The majority of the variance in mean catch per unit effort (CPUE) of these species in both gears was spatial or temporal. In general, CPUE and precision were either similar or higher for white nets, making it unnecessary to dye nets green, which saves time and money. Because turbidity did not significantly affect catch rates between green and white mesh nets, the variations in CPUE can more confidently be attributed to localized changes in the actual relative abundance throughout the Missouri River.
Effects of Redd Superimposition by Introduced Kokanee on the Spawning Success of Native Bull Trout
Authors: Weeber Matthew A. , Giannico Guillermo R. , Jacobs Steven E.
Published: February 2011

Intra- and interspecific competition for spawning space is a commonly observed interaction in salmonids that can result in progeny loss. This study examined the impacts of redd superimposition by kokanee Oncorhynchus nerka on the reproductive success of bull trout Salvelinus confluentus in the Deschutes River basin, Oregon. The activities of high-density spawning groups of kokanee were hypothesized to place the eggs and alevins of bull trout at risk of displacement and damage wherever the spawning habitats of these two species overlap. Bull trout egg pocket depths and kokanee scouring depths were measured. Fry emergence from redds, a proxy for bull trout reproductive success in the presence of kokanee, was compared between superimposed and undisturbed redds by using fry emergence traps. Our results indicate that groups of spawning kokanee did not scour the stream bed deeply enough to reach bull trout eggs. Data on bull trout fry emergence revealed that kokanee redd superimposition did not affect bull trout egg-to-fry survival rates.
Genetic Structure and Diversity among Brook Trout from Isle Royale, Lake Nipigon, and Three Minnesota Tributaries of Lake Superior
Authors: Stott Wendylee , Quinlan Henry R. , Gorman Owen T. , King Timothy L.
Published: February 2011

Brook trout Salvelinus fontinalis from Isle Royale, Michigan, three Minnesota tributaries of Lake Superior, and Lake Nipigon in Ontario were analyzed for genetic variation at 12 microsatellite DNA loci. Analysis of molecular variance, genetic distance measures, and cluster analysis were used to examine the diversity, gene flow, and relatedness among the samples. The diversity estimates for the samples from Isle Royale were similar to those for the samples collected from Minnesota tributaries of Lake Superior, and all estimates were lower than those reported in other studies of brook trout from eastern North America. Genetic differences were detected among the brook trout at Isle Royale, Lake Nipigon, and the Minnesota tributaries of Lake Superior. Further, the population in Tobin Harbor at the eastern end of Isle Royale was distinct from the populations from tributaries at the southwestern end of the island. The Minnesota tributary population formed a group that was genetically distinct from those from Isle Royale and Lake Nipigon. The Isle Royale population should be managed to preserve the genetic and phenotypic variation that distinguishes it from the other brook trout populations analyzed to date.
A Comparison of the Survival and Migratory Behavior of Hatchery-Reared and Naturally Reared Steelhead Smolts in the Alsea River and Estuary, Oregon, using Acoustic Telemetry
Authors: Johnson Steven L. , Power James Harry , Wilson Derek R. , Ray James
Published: February 2011

We tracked three groups of steelhead Oncorhynchus mykiss smolts implanted with acoustic transmitters to determine whether the degree of hatchery domestication or the juvenile rearing environment (hatchery raceway versus natural stream) influenced migration timing and survival in the Alsea River and estuary, Oregon. Two groups consisted of age-1 smolts reared in concrete raceways. One hatchery-reared group (traditional brood group) was derived from the traditional Alsea River broodstock initially developed in the 1950s. The second hatchery-reared group (new brood group) was derived from naturally reared Alsea River adult steelhead that were captured and spawned at the hatchery beginning in the winter of 2000–2001. The third group (naturally reared group) consisted of age-2 naturally reared smolts captured in a downstream migrant trap located in a tributary stream near the hatchery. We placed transmitters in 74 traditional brood smolts, 76 new brood smolts, and 72 naturally reared smolts. Thirty-one acoustic receivers were located throughout the Alsea River and estuary and in the ocean offshore of the river mouth to monitor smolt movement. We found no significant difference between groups in their survival to the head of tide or to the mouth of the estuary. Most smolts from all three groups were detected at the head of tide (87% of fish from the traditional brood group, 78% from the new brood group, and 84% from the naturally reared group). However, survival was poor in the lower estuary for all three groups; we estimated that only 37% of the traditional brood group, 45% of the new brood group, and 47% of the naturally reared group survived to the ocean. The timing of migration through the river was highly variable in all three groups, and we found no significant differences in the rate of downstream movement from the release site to the head of tide. Mean residence time within the estuary was similar for all groups, although smolts from the naturally reared group showed less variability in estuary residence time than hatchery-reared smolts.
Mandatory Catch and Release and Maximum Length Limits for Largemouth Bass in Minnesota: Is Exploitation Still a Relevant Concern?
Authors: Carlson Andrew J. , Isermann Daniel A.
Published: February 2011

We evaluated the response of Minnesota populations of largemouth bass Micropterus salmoides to implementation of 305-mm maximum total length (TL) limits (three lakes) and mandatory catch-and-release regulations (six lakes). Responses were compared with population trends observed in nine reference populations where largemouth bass harvest was regulated by prevailing statewide regulations. Increased harvest regulation generally improved largemouth bass size structure, but statistically significant improvements in size structure indices were detected in only a few individual lakes. Increased regulation of harvest did not appear to influence electrofishing catch per unit effort (CPUE; fish/h) of largemouth bass less than 381 mm TL. Electrofishing CPUE of fish greater than or equal to 381 mm TL (CPUE-381) generally improved after more stringent harvest regulations were in place, but improvements were only significant for two of the three lakes where a 305-mm maximum length limit was implemented. With the exception of one lake, increased harvest regulation did not appear to reduce largemouth bass growth rates. Improvements in size structure and CPUE-381 were rarely observed in reference lakes. Our results suggest that despite increases in voluntary catch and release of largemouth bass, angler exploitation is still an important factor regulating size structure in some Minnesota lakes, and more intensive harvest regulations can improve size structure in some populations.
Short- and Long-Term Evaluation of Passive Integrated Transponder and Visible Implant Elastomer Tag Performance in Muskellunge
Authors: Younk Jerry A. , Herwig Brian R. , Pittman Bruce J.
Published: February 2011

Fisheries professionals charged with managing muskellunge Esox masquinongy frequently seek population information that requires the ability to identify cohorts as well as individuals; hence, reliable tagging methods are needed. Our approach was to simultaneously assess multiple marking techniques on different life stages of muskellunge over short and long time scales. We evaluated the short-term detection of visible implant elastomer (VIE) and passive integrated transponder (PIT) tags in muskellunge fingerlings in experimental ponds. We compared survival (relative to that of control fish) and tag retention for two PIT tagging locations (the cheek and dorsal musculature) and one VIE location (the jaw). Overwinter survival did not differ between tagged and untagged fish (84–98%), but overwinter PIT tag retention was lower for the cheek (92%) than the dorsal musculature (100%). We also fin-clipped and VIE-tagged (jaw) 1,651 muskellunge fingerlings from 1997 to 2002 to evaluate long-term tag retention in a broodstock lake. In addition, 125 adult muskellunge were captured and PIT-tagged from 2003 to 2006. Muskellunge were sampled annually with trap nets and electrofishing during spring and fall. Only 2 VIE tags were detected in adults marked as fingerlings. The proportion of PIT-tagged adults recaptured ranged from 52% to 84% during the sampling period. Our results indicate that both VIE and PIT tags are viable short-term marks for muskellunge fingerlings, while PIT tags appear to be reliable long-term tags when implanted in the dorsal musculature of adults.
Factors Associated with Mortality of Walleyes and Saugers Caught in Live-Release Tournaments
Authors: Schramm Harold L. , Vondracek Bruce , French William E. , Gerard Patrick D.
Published: February 2011

We measured the initial mortality (fish judged nonreleasable at weigh-in), prerelease mortality (fish judged nonreleasable 1–2 h after weigh-in [which includes initial mortality]), and postrelease mortality (fish that died during a 5-d retention in net-pens) in 14 live-release tournaments for walleye Sander vitreus conducted in April–October 2006 and April–July 2007 in lakes and rivers in Michigan, Minnesota, North Dakota, South Dakota, and Wisconsin. Among the 14 events, initial mortality was 0–28%, prerelease mortality was 3–54%, and postrelease mortality was 0–100%; the mortality of reference fish (walleyes ≥31 cm long that were captured by electrofishing and held in net-pens with tournament-caught walleyes to measure postrelease mortality) was 0–97%. Mortality was generally low in events conducted when water temperatures were below 14°C but substantially higher in events when water temperatures were above 18°C. The mortality of reference fish suggests that capture by electrofishing and minimal handling when the water temperature exceeds 19°C results in high mortality of walleyes that is largely the result of the thermal conditions immediately after capture. Mortality was not related to the size of the tournaments (number of boats), the total number or weight of walleyes weighed in, or the mean number or weight of walleyes weighed in per boat. Mortality was positively related to the depth at which walleyes were caught and the live-well temperature and negatively related to the live-well dissolved oxygen concentration. Surface water temperature was the best predictor of mortality, and models were developed to predict the probability of prerelease and postrelease mortality of 10, 20, and 30% or less of tournament-caught walleyes due to water temperature.
Use of Portable Antennas to Estimate Abundance of PIT-Tagged Fish in Small Streams: Factors Affecting Detection Probability
Authors: O'Donnell Matthew J. , Horton Gregg E. , Letcher Benjamin H.
Published: February 2011

Portable passive integrated transponder (PIT) tag antenna systems can be valuable in providing reliable estimates of the abundance of tagged Atlantic salmon Salmo salar in small streams under a wide range of conditions. We developed and employed PIT tag antenna wand techniques in two controlled experiments and an additional case study to examine the factors that influenced our ability to estimate population size. We used Pollock's robust-design capture–mark–recapture model to obtain estimates of the probability of first detection (p), the probability of redetection (c), and abundance (N) in the two controlled experiments. First, we conducted an experiment in which tags were hidden in fixed locations. Although p and c varied among the three observers and among the three passes that each observer conducted, the estimates of N were identical to the true values and did not vary among observers. In the second experiment using free-swimming tagged fish, p and c varied among passes and time of day. Additionally, estimates of N varied between day and night and among age-classes but were within 10% of the true population size. In the case study, we used the Cormack–Jolly–Seber model to examine the variation in p, and we compared counts of tagged fish found with the antenna wand with counts collected via electrofishing. In that study, we found that although p varied for age-classes, sample dates, and time of day, antenna and electrofishing estimates of N were similar, indicating that population size can be reliably estimated via PIT tag antenna wands. However, factors such as the observer, time of day, age of fish, and stream discharge can influence the initial and subsequent detection probabilities.
Comparison of Channel Catfish Age Estimates and Resulting Population Demographics Using Two Common Structures
Authors: Colombo Robert E. , Phelps Quinton E. , Miller Candice M. , Garvey James E. , Heidinger Roy C. , Richards Nathaniel S.
Published: February 2011

Sagittal otoliths and the articulating process of the pectoral spine have both been validated as accurate techniques for estimating the age of channel catfish Ictalurus punctatus (≤age 4). However, there is limited information on the relative precision of estimates from these two structures. Thus, we analyzed the precision of age estimates derived from otoliths and the articulating process of the pectoral spine and compared the dynamic processes (recruitment, growth, and mortality) resulting from those estimates. Aging structures were removed from 110 channel catfish captured from the Wabash River (river kilometers 550–9.6) via day–time electrofishing. The age estimation methodologies were similar to those described in previous studies. Agreement between the ages derived from the two structures was high; the average percent error was 8.4%, the coefficient of variation was 11.4, and the slope of the age bias plots did not differ from 1, indicating similar age assignments between structures. The corresponding recruitment patterns, von Bertalanffy growth models, and mortality rates did not differ between the aging structures. We conclude that the articulating process of the pectoral spine provides age assignments similar to those of otoliths and that the dynamic processes do not differ between structures. Further, based on the results of this study, the articulating process of the pectoral spine provides a suitable alternative to otoliths and has the advantage that channel catfish do not have to be sacrificed.
Habitat Selection and Spawning Success of Walleyes in a Tributary to Owasco Lake, New York
Authors: Chalupnicki Marc A. , Johnson James H. , McKenna James E. , Dittman Dawn E.
Published: February 2011

Walleyes Sander vitreus are stocked into Owasco Lake, New York, to provide a sport fishery, but the population must be sustained by annual hatchery supplementation despite the presence of appropriate habitat. Therefore, we evaluated walleye spawning success in Dutch Hollow Brook, a tributary of Owasco Lake, to determine whether early survival limited recruitment. Spawning success during spring 2006 and 2007 was evaluated by estimating egg densities from samples collected in the lower 725 m of the stream. Environmental variables were also recorded to characterize the selected spawning habitat. Drift nets were set downstream of the spawning section to assess egg survival and larval drift. We estimated that 162,596 larvae hatched in 2006. For 2007, we estimated that 360,026 eggs were deposited, with a hatch of 127,500 larvae and hatching success of 35.4%. Egg density was significantly correlated to percent cover, substrate type, and depth : velocity ratio. Two sections had significantly higher egg deposition than other areas. Adult spawning walleyes selected shallow, slow habitats with some cover and gravel substrate in the accessible reaches of Dutch Hollow Brook. Our results show that walleyes found suitable spawning habitat in Dutch Hollow Brook and that egg and larval development does not appear to limit natural reproduction.
A Review of Bull Trout Habitat Associations and Exploratory Analyses of Patterns across the Interior Columbia River Basin
Authors: Al-Chokhachy Robert , Roper Brett B. , Bowerman Tracy , Budy Phaedra
Published: February 2011

An understanding of habitat relationships for bull trout Salvelinus confluentus remains an important component for identifying future restoration, management, and recovery efforts. We examined past efforts through a comprehensive synthesis of peer-reviewed articles evaluating bull trout habitat relationships, and we used field data within classification tree analysis (CTA) to improve our understanding of the consistency of bull trout habitat use patterns. We performed CTA using reach-level habitat data collected from currently occupied stream networks (i.e., those within the current distribution of bull trout) and unoccupied stream networks where hierarchical filters (i.e., area and temperature) were met and from occupied areas where temperature criteria were exceeded. Results from the literature review demonstrated consistent results at the microhabitat and channel unit scales; indicated the importance of slow-velocity, deeper habitats; and, together with observed diel shifts, highlighted the importance of complex habitat regardless of scale or season. At the reach scale, however, our results indicated substantially less consistency in bull trout habitat relationships. Including maximum stream temperature into the CTA did not result in changes to the overall structure of the CTA; results from the CTA indicated that bull trout were found in reaches with larger substrate, deeper pools, and more cover, but the specific criteria differed along a gradient of stream depth. Our results indicated (1) important gaps in our knowledge regarding the role of substrate size in juvenile bull trout habitat use, (2) the need for elucidation of habitat use patterns in downstream reaches, which may act as critical overwintering habitat or migratory corridors, and (3) the need to incorporate sampling efficiencies in future bull trout habitat evaluations.
Estimating the Size of Steelhead Runs by Tagging Juveniles and Monitoring Migrants
Authors: Boughton David A.
Published: February 2011

The number of individuals in a spawning run of anadromous fish can be estimated by tagging juveniles with passive integrated transponders during the freshwater phase and the subsequent monitoring of adult upstream migrants by use of instream tag readers. The method may enable monitoring of steelhead Oncorhynchus mykiss in systems where other methods are intractable. I developed a hierarchical capture–resighting model and applied it to simulated data to develop a relation between the number of marked juveniles and the precision of run size estimates. Precision is primarily controlled by the number of tagged spawners that ultimately return and are detected; only 30–90 tagged spawners are required to obtain relatively precise estimates of run size. For typical marine survival rates, 0.0033–0.0330, this translates to a tagging effort of between 3,400 and 45,000 juveniles/cohort. Estimates are robust to imperfect detection of tagged fish if at least two instream readers independently scan for tags. Reach sampling allows for estimation of run size in large stream systems. Based on my simulations, the number of reaches could be as low as 30–40 under scenarios of high marine survival. Computer code is provided for the estimator using the freely available statistical software R.
δ13C and δ15N Signatures in Muscle and Fin Tissues: Nonlethal Sampling Methods for Stable Isotope Analysis of Salmonids
Authors: Hanisch Justin R. , Tonn William M. , Paszkowski Cynthia A. , Scrimgeour Garry J.
Published: February 2011

Stable isotope analysis has emerged as an important tool in aquatic ecology. For fish, dorsal muscle from sacrificed individuals has traditionally been used in stable isotope studies; however, there are many instances when lethal sampling is undesirable. We evaluated the feasibility of using adipose and caudal fin clips as alternatives to muscle in stable isotope studies for five species of salmonids. Because fish size and water temperature can affect stable isotope ratios, we also determined whether fish length and sampling date affected the difference in isotope signatures between fins and muscle. Biopsied muscle plugs and fin clips were collected from rainbow trout Oncorhynchus mykiss, brook trout Salvelinus fontinalis, and lake trout S. namaycush as well as lake whitefish Coregonus clupeaformis and pygmy whitefish Prosopium coulterii and analyzed for stable isotopes of carbon and nitrogen. The isotope signatures of both adipose and caudal fins were significantly correlated (0.33 < R2 < 0.97) with those of dorsal muscle from the five salmonid species studied, and in some cases the signatures of fins did not differ from those of muscle. Fish length and sampling date occasionally had a small effect (0.042 < R2 < 0.49) on the relationship between the isotope signatures of fin and muscle. Although muscle biopsy provides a viable, nonlethal method of collecting muscle tissue from suitably sized fish, the strong relationships between the isotope signatures of fin and muscle demonstrate that fin clips should be considered good surrogates for muscle in stable isotope studies of salmonids.
Long-Term Evaluations of Length Limit Regulations for Northern Pike in Minnesota
Authors: Pierce Rodney B.
Published: February 2011

The effects of maximum, minimum, and slot length limits on the sizes and relative abundance of northern pike Esox lucius were evaluated in 22 Minnesota lakes. The regulations were implemented in 1989–1998 and lasted 9–15 years. As preregulation information was available back to the 1970s, the evaluation periods covered 21–37 years. Comparisons were made with reference populations from 47 ecologically similar lakes during the same extended period. Although the regulations did not achieve management objectives in every lake, the broader-scale, statewide finding was that they improved the size structure of northern pike populations but produced no consistent trends in relative abundance. The improvements were detected against the backdrop of reference populations that initially appeared to have similar sizes and relative abundances. Maximum length limits protecting fish over 20, 22, and 24 in produced significant long-term increases in the percentages of northern pike 24 in and longer and 30 in and longer compared with the reference populations. Lakes with 30-in minimum length limits had increased percentages of northern pike 20 in and longer, but the improvements did not carry over to fish 30 in and longer. A mix of slot length limits produced results that are more difficult to interpret but generally improved size structure. A metaanalysis incorporating all of the length regulations indicated that the changes in northern pike size structure in regulated lakes were very large for an ecological experiment. Length limits protected large northern pike, with the expectation that lower yields were an acceptable trade-off for producing larger fish for recreational fisheries. This study reveals the range and magnitude of responses we can reasonably expect from length limits as well as the substantial value of conserving large fish when the goal is improved population size structure.
Interactions between Walleyes and Smallmouth Bass in a Missouri River Reservoir with Consideration of the Influence of Temperature and Prey
Authors: Wuellner Melissa R. , Chipps Steven R. , Willis David W. , Adams Wells E.
Published: February 2011

Walleyes Sander vitreus are the most popular fish among South Dakota anglers, but smallmouth bass Micropterus dolomieu were introduced to provide new angling opportunities. Some walleye anglers have reported reductions in the quality of walleye fisheries since the introduction of smallmouth bass and attribute this to the consumption of young walleyes by smallmouth bass and competition for shared prey resources. We quantified the diets of walleyes and smallmouth bass in the lower reaches of Lake Sharpe (a Missouri River reservoir), calculated the diet overlap between the two predators, and determined whether they partitioned shared prey based on size. We also quantified walleye diets in the upper reach of the reservoir, which has a different prey base and allowed us to compare the growth rates of walleyes within Lake Sharpe. Age-0 gizzard shad Dorosoma cepedianum composed a substantial proportion of the diets of both predators, regardless of location, for most of the growing season; the patterns in shad vulnerability appeared to drive the observed patterns in diet overlap. Smallmouth bass appeared to consume a smaller size range of gizzard shad than did walleyes, which consumed a wide range. Smallmouth bass consumed Sander spp. in some months, but in very low quantities. Given that global climate change is expected to alter the population and community dynamics in Great Plains reservoirs, we also used a bioenergetics approach to predict the potential effects of limiting prey availability (specifically, the absence of gizzard shad and rainbow smelt Osmerus mordax) and increased water temperatures (as projected from global climate change models) on walleye and smallmouth bass growth. The models indicated that the absence of rainbow smelt from the diets of walleyes in upper Lake Sharpe would reduce growth but that the absence of gizzard shad would have a more marked negative effect on both predators at both locations. The models also indicated that higher water temperatures would have an even greater negative influence on walleye growth; however, smallmouth bass growth was predicted to increase with higher temperatures. Fisheries managers should consider strategies to enhance the prey base or mitigate the effects of increased water temperatures that may occur in the future as a result of global climate change. Such proactive actions may alleviate potential future competition between walleyes and smallmouth bass resulting from changes in the fish community.
Estimating the Spawning Escapement of Hatchery- and Natural-Origin Spring Chinook Salmon Using Redd and Carcass Data
Authors: Murdoch Andrew R. , Pearsons Todd N. , Maitland Travis W.
Published: February 2011

Redd abundance and the demographic characteristics of salmon carcasses are frequently used (in combination) to estimate the abundance and characteristics of populations of Pacific salmon Oncorhynchus spp. However, there is uncertainty about the quality of these estimates because they rely on untested assumptions. We evaluated the quality of spawning ground estimates of Wenatchee spring Chinook salmon O. tshawytscha by comparing the number and origin of fish migrating upstream of Tumwater Dam with estimates of (1) redd abundance and (2) spawner abundance partitioned by sex and origin. Redd counts were well correlated with the abundance of fish passing Tumwater Dam (r2 = 0.84) between 1999 and 2007, indicating that such counts are a suitable index of population abundance. However, between 2004 and 2007, when carcass data were used to partition escapement estimates, the abundance of hatchery spring Chinook salmon was underestimated (mean = 6%, range 0–19%) and that of naturally produced fish was overestimated (mean = 19%, range = 1–43%). In addition, male spring Chinook salmon were underestimated by 20% (range = 18–22%) and females were overestimated by 32% (range = 15–65%). These biases were related to size-related carcass recovery bias and differences in the sex ratio between fish of different origins. The length of male spring Chinook salmon was significant in explaining the variation in the probability of carcass recovery but that of females was not. The sex ratios of carcasses adjusted for recovery bias were not significantly different from that for the population measured at Tumwater Dam. Spawning escapement estimates based on uncorrected carcass data underestimated those based on corrected carcass data 13–39%. We conclude that data collected during spawning ground surveys can be used to estimate the abundance and composition by origin of the spawning population if the biases in carcass recovery data are corrected.
Rotenone Toxicity to Rainbow Trout and Several Mountain Stream Insects
Authors: Finlayson Brian , Somer William L. , Vinson Mark R.
Published: February 2011

The piscicide rotenone has been used for over 70 years to eradicate unwanted fish, but controversy exists regarding its impacts on nontarget organisms, particularly aquatic invertebrates. We evaluated the toxicity of synergized Nusyn-Noxfish and nonsynergized CFT Legumine rotenone formulations in 4- and 8-h exposures to rainbow trout Oncorhynchus mykiss and six species of mountain stream caddisflies, mayflies, and stoneflies. We then compared these results with historical treatment data and aquatic invertebrate collections surrounding rotenone treatments in the 1990s that were designed to restore Paiute cutthroat trout O. clarkii seleniris to the Silver King Creek basin in Alpine County, California. The toxicity of rotenone was greatest to the trout; the synergist piperonyl butoxide appeared to have no effect on the toxicity of rotenone to the trout but did increase the toxicity to the invertebrates. The mean 8-h concentrations (as rotenone) lethal to 50% of the rainbow trout were 5.3 μg/L for CFT Legumine and 6.2 μg/L for Nusyn-Noxfish; the mean values for invertebrates ranged from 34 to 174 μg/L for CFT Legumine and from 13 to 74 μg/L for Nusyn-Noxfish. These findings corresponded to that observed in Silver King Creek, where three annual treatments of 16–23 μg/L for 6–18 h were successful in extirpating rainbow trout hybrids but caused little change in aquatic insect assemblages. To lessen the impacts of rotenone treatment in mountain streams, project planners should (1) use the lowest rotenone concentration and duration needed to accomplish the treatment objective (we suggest 25–50 μg/L for <8 h) and (2) avoid using formulations containing the synergist piperonyl butoxide.
Size Selectivity in Marine Mammal Diets as a Guide to Evolutionarily Enlightened Fisheries Management
Authors: Etnier Michael A. , Fowler Charles W.
Published: February 2011

Commercial fisheries have a long history of nonsustainable harvests—not through deliberate mismanagement but through an inability to simultaneously account for the complexity of relevant factors, including the ecological and coevolutionary interactions within ecosystems. We argue that these factors (e.g., natural selection and coevolution) are among the structuring processes behind the patterns of predation exhibited by species such as marine mammals. As such, these patterns provide an indication of harvest practices that are sustainable in the long term—that is, normal for the systems and circumstances involved. Thus, patterns in selectivity exhibited by predators in their consumption of prey species meet the needs for evolutionarily enlightened guidance in management, long seen as missing in current practice. Our analysis of data characterizing the diets of 63 species of marine mammals indicates that the majority of prey consumed are 30 cm or less in length. This pattern is common to all marine mammal taxa and is apparently independent of the body size of predator species and largely independent of the body size range of prey species, many of which exceed 100 cm in maximum length. The size selectivity of commercial fisheries differs from that of marine mammals for all but the smallest prey species and is positively correlated with size. When possible, commercial fisheries tend to target individuals greater than 30 cm. The selective pressure this exerts on large-bodied prey species is abnormal in comparison with that of the natural predator–prey systems that have evolved to sustain consumption of individual prey items of 30 cm or less. To minimize the abnormal effects of selective pressure imposed by fishing, we argue that the targeted size composition of catches should be modified to more closely match the patterns exhibited by marine mammals as another example of the application of systemic management, a holistic alternative to conventional management.
Mass-Marking Reveals Emerging Self Regulation of the Chinook Salmon Population in Lake Huron
Authors: Johnson James E. , DeWitt Steven P. , Gonder David J. A.
Published: February 2011

All Chinook salmon Oncorhynchus tshawytscha stocked in Lake Huron during 2000–2003 were marked with oxytetracycline (OTC), fin clips, or a combination thereof to determine the relative contributions of natural reproduction and stocking to recruitment. Oxytetracycline administered in feed proved to be an effective, low-cost method of marking spring fingerling Chinook salmon. Vertebrae proved to be suitable tissue for OTC detection, meeting standards for accuracy and reproducibility. Vertebrae were not suitable as aging structures, perhaps due to the slow somatic growth of Lake Huron's Chinook salmon during this study. Based on lakewide recoveries from recreational and commercial fisheries, we estimated that nearly 80% of Chinook salmon from the marked year-classes were from natural reproduction. Wild-origin Chinook salmon constituted 96% of open-water samples from Georgian Bay; 82, 80, and 68% of those from the central, southern, and northern portions of the main basin; and 64% of those from the North Channel. The percentage of wild-origin Chinook salmon in some tributaries in the Ontario watershed of Lake Huron approached 100%. There was less variation in wild recruitment between years than between lake areas. This Chinook salmon population was introduced in the late 1960s and until recently had been widely viewed as hatchery dependent; our findings suggest otherwise. A self-sustaining predator population would represent a paradigm shift from an era when predation rates could be manipulated by adjusting salmonid stocking (i.e., 1968 to about 1995). These findings should help managers to critically review the effects of stocked Chinook salmon on Lake Huron's fisheries and ecosystem, including prey consumption demand, and to assess future needs for propagated Chinook salmon in Lake Huron.
Evaluation of Methods for Identifying Spawning Sites and Habitat Selection for Alosines
Authors: Harris Julianne E. , Hightower Joseph E.
Published: February 2011

Characterization of riverine spawning habitat is important for the management and restoration of anadromous alosines. We examined the relative effectiveness of oblique plankton tows and spawning pads for collecting the eggs of American shad Alosa sapidissima, hickory shad A. mediocris, and “river herring” (a collective term for alewife A. pseudoharengus and blueback herring A. aestivalis) in the Roanoke River, North Carolina. Relatively nonadhesive American shad eggs were only collected by plankton tows, whereas semiadhesive hickory shad and river herring eggs were collected by both methods. Compared with spawning pads, oblique plankton tows had higher probabilities of collecting eggs and led to the identification of longer spawning periods. In assumed spawning areas, twice-weekly plankton sampling for 15 min throughout the spawning season had a 95% or greater probability of collecting at least one egg for all alosines; however, the probabilities were lower in areas with more limited spawning. Comparisons of plankton tows, spawning pads, and two other methods of identifying spawning habitat (direct observation of spawning and examination of female histology) suggested differences in effectiveness and efficiency. Riverwide information on spawning sites and timing for all alosines is most efficiently obtained by plankton sampling. Spawning pads and direct observations of spawning are the best ways to determine microhabitat selectivity for appropriate species, especially when spawning sites have previously been identified. Histological examination can help determine primary spawning sites but is most useful when information on reproductive biology and spawning periodicity is also desired. The target species, riverine habitat conditions, and research goals should be considered when selecting methods with which to evaluate alosine spawning habitat.