bluuebunny/crossref_metadata_2025 huggingface dataset:
Coexistence of bunching and meandering instability in simulated growth of 4H-SiC(0001) surface
Authors: Krzyżewski Filip , Załuska–Kotur Magdalena A.
Published: June 2014

Bunching and meandering instability of steps at the 4H-SiC(0001) surface is studied by the kinetic Monte Carlo simulation method. Change in the character of step instability is analyzed for different rates of particle jumps towards step. In the experiment effective value of jump rates can be controlled by impurities or other growth conditions. An anisotropy of jump barriers at the step influences the character of surface structure formed in the process of crystal growth. Depending on the growth parameters different surface patterns are found. We show phase diagrams of surface patterns as a function of temperature and crystal growth rate for two different choices of step kinetics anisotropy. Jump rates which effectively model high inverse Schwoebel barrier (ISB) at steps lead either to regular, four-multistep or bunched structure. For weak anisotropy at higher temperatures or for lower crystal growth rates meanders and mounds are formed, but on coming towards lower temperatures and higher rates, we observe bunch and meander coexistence. These results show that interplay between simple dynamical mechanisms induced by the asymmetry of the step kinetics and step movement assisted by the step edge diffusion are responsible for different types of surface morphology.
Nanospherical-lens lithographical Ag nanodisk arrays embedded in p-GaN for localized surface plasmon-enhanced blue light emitting diodes
Authors: Wei Tongbo , Wu Kui , Lan Ding , Sun Bo , Zhang Yonghui , Chen Yu , Huo Ziqiang , Hu Qiang , Wang Junxi , Zeng Yiping , Li Jinmin
Published: June 2014

Large-scale Ag nanodisks (NDs) arrays fabricated using nanospherical-lens lithography (NLL) are embedded in p-GaN layer of an InGaN/GaN light-emitting diode (LED) for generating localized surface plasmon (LSP) coupling with the radiating dipoles in the quantum-well (QWs). Based on the Ag NDs with the controlled surface coverage, LSP leads to the improved crystalline quality of regrowth p-GaN, increased photoluminescence (PL) intensity, reduced PL decay time, and enhanced output power of LED. Compared with the LED without Ag NDs, the optical output power at a current of 350 mA of the LSP-enhanced LEDs with Ag NDs having a distance of 20 and 35 nm to QWs is increased by 26.7% and 31.1%, respectively. The electrical characteristics and optical properties of LEDs with embedded Ag NPs are dependent on the distance of between Ag NPs and QWs region. The LED with Ag NDs array structure is also found to exhibit reduced emission divergence, compared to that without Ag NDs.
Local thermodynamic equilibrium in rapidly heated high energy density plasmas
Authors: Aslanyan V. , Tallents G. J.
Published: June 2014

Emission spectra and the dynamics of high energy density plasmas created by optical and Free Electron Lasers (FELs) depend on the populations of atomic levels. Calculations of plasma emission and ionization may be simplified by assuming Local Thermodynamic Equilibrium (LTE), where populations are given by the Saha-Boltzmann equation. LTE can be achieved at high densities when collisional processes are much more significant than radiative processes, but may not be valid if plasma conditions change rapidly. A collisional-radiative model has been used to calculate the times taken by carbon and iron plasmas to reach LTE at varying densities and heating rates. The effect of different energy deposition methods, as well as Ionization Potential Depression are explored. This work shows regimes in rapidly changing plasmas, such as those created by optical lasers and FELs, where the use of LTE is justified, because timescales for plasma changes are significantly longer than the times needed to achieve an LTE ionization balance.
Human Discrimination of Depth of Field in Stereoscopic and Nonstereoscopic Photographs
Authors: Zhang Tingting , Nefs Harold T , Heynderickx Ingrid
Published: June 2014

Depth of field (DOF) is defined as the distance range within which objects are perceived as sharp. Previous research has focused on blur discrimination in artificial stimuli and natural photographs. The discrimination of DOF, however, has received less attention. Since DOF introduces blur which is related to distance in depth, many levels of blur are simultaneously present. As a consequence, it is unclear whether discrimination thresholds for blur are appropriate for predicting discrimination thresholds for DOF. We therefore measured discrimination thresholds for DOF using a two-alternative forced-choice task. Ten participants were asked to observe two images and to select the one with the larger DOF. We manipulated the scale of the scene—that is, the actual depth in the scene. We conducted the experiment under stereoscopic and nonstereoscopic viewing conditions. We found that the threshold for a large DOF (39.1 mm) was higher than for a small DOF (10.1 mm), and the thresholds decreased when scale of scene increased. We also found that there was no significant difference between stereoscopic and nonstereoscopic conditions. We compared our results with thresholds predicted from the literature. We concluded that using blur discrimination thresholds to discriminate DOF may lead to erroneous conclusions because the depth in the scene significantly affects people's DOF discrimination ability.
What's in a Face? The Role of Depth Undulations in Three-Dimensional Depth-Inversion Illusions
Authors: Vlajnic Vanja M , Papathomas Thomas V , Keane Brian P , Zalokostas Anna , Silverstein Steven M
Published: June 2014

Upright hollow human faces produce among the strongest depth-inversion illusions (DIIs), but why? We considered the role of depth undulations by comparing four types of hollow objects: An ellipsoid, a human mask, and two symmetric ‘Martian’ masks, which wavered in depth like the human mask but which lacked face-like features. Illusion strength was quantified either as the critical viewing distance at which the 3-D percept switched between convex and concave (experiment 1) or as the proportion of time (‘predominance’) that observers experienced DII from a fixed intermediate viewing distance (experiment 2). Critical distances were smallest—and hence the illusion was strongest—for the upright human mask; the remaining objects produced undifferentiated critical distance values. The predominance results were more fine-grained: illusions were experienced most often for the upright human mask, least often for the hollow ellipsoid, and to an intermediate extent for the Martian and upside-down human masks. These results suggest: (1) an upside-down human mask and a surface with nonface features undulating in depth are equivalent for the purposes of generating DIIs; (2) depth undulations contribute to DII; and (3) such undulations are most effective when structured into an upright human face.
An Appropriate Use of IMap Produces Correct Statistical Results: A Reply to McManus (2013) “IMap and IMap2 Produce Erroneous Statistical Maps of Eye-Movement Differences”
Authors: Miellet Sébastien , Lao Junpeng , Caldara Roberto
Published: June 2014

McManus (2013, Perception, 42, 1075–1084) contends the validity of the statistical approach adopted in previous versions of iMap (namely, iMap and iMap2; Caldara & Miellet, 2011, Behavior Research Methods, 43, 864–878), casts doubts on earlier results obtained with the toolbox, and offers an altered version of the code. Here we dispute these claims and argue that while some of the arguments put forward are valid, McManus's conclusions are misleading, since they are based on a partial use of the toolbox. Moreover, we compared iMap with the alternative code offered by McManus and objectively demonstrate that McManus's approach is underpowered and flawed. iMap offers an appropriate and effective alternative to the commonly used regions of interest approach for statistical analyses of eye-movement data.
Release from Retroactive Retention Interference for Acoustic Duration
Authors: Ries Dennis T , Gadd Danielle , Smith Meghan
Published: June 2014

Listener retention of stimulus duration was studied. Measures of difference-limen-for-duration (DLD) between standard and comparison stimuli were obtained for intervals with and without intervening noise bursts, including an intervening condition with a lateralization cue. The DLD was significantly higher when intervening sounds were present, but a lateralization cue mitigated the interference, presumably by allowing attention to be more readily allocated to retention of the standard. General interference results are in keeping with those reported for pitch, loudness, and timbre retention, but not for retention of gap length. Release from interference with a lateralization cue is akin to that reported for pitch. Overall, the ramifications of retroactive interference on duration retention are more similar to those reported for pitch than for another temporal-based attribute—namely, gap length.
Face Animacy is Not All in the Eyes: Evidence from Contrast Chimeras
Authors: Balas Benjamin , Tonsager Christopher
Published: June 2014

Observers are capable of distinguishing real faces from artificial faces of various types (eg dolls, computer-generated faces) relatively easily. While a number of diagnostic cues are potentially available to observers to accomplish this task, the appearance of the eyes has been shown to be critically important. However, eye appearance appears to interact with other cues, like the appearance of the skin, in some settings. The ‘uncanny’ appearance of some artificial faces appears to result from multiple visual features and their departure from typical face norms, for example, and recent results investigating how real and artificial features are perceived in chimeric faces also suggest that observers use multiple cues to measure face animacy. Presently, we examined the cues that support real-artificial face discrimination by using contrast negation and so-called ‘contrast chimeras’ to selectively disrupt the appearance of the eyes and the remainder of the face pattern. First, we demonstrate that, like other aspects of face perception, perceived animacy is significantly impacted by contrast negation. Second, by selectively manipulating the contrast of the eyes relative to the rest of the face, we demonstrate that these face regions are of approximately equal use to observers for animacy discrimination.
Scalar implicatures in a signed language
Authors: Davidson Kathryn
Published: June 2014

This paper tests the calculation of scalar implicatures in American Sign Language (ASL) in one of the first experimental pragmatic studies in the manual/visual modality. Both native signers of ASL and native speakers of English participated in an automated Felicity Judgment Task to compare implicatures based on two traditional scales as well as “ad hoc” scales in their respective languages. Results show that native signers of ASL calculate scalar implicatures based on a prototypical scale  in ASL in the same pattern as native speakers of English, within the same experimental paradigm. There are similarly high rates of exact interpretations of numbers  in ASL as in English, despite the iconicity of the numerals in ASL. Finally, an ad hoc scale was tested showing fewer implicatures in English than on the conventionalized scales. In ASL, there was a trend toward increased implicatures on the ad hoc scale which made use of the unique ability of ASL to convey spatial information using the classifier system. Taken together, these results show that conventionalized scales in ASL have the same semantic/pragmatic scalar properties as in spoken languages, although in non-conventionalized scales the inclusion of additional information such as spatial location may affect pragmatic interpretation.
Non-native or native vocabulary in Mexican Sign Language
Authors: Hendriks Bernadet , Dufoe Shelley
Published: June 2014

This paper discusses lexicalized fingerspelling and initialization in Mexican Sign Language (LSM). It analyzes various phonological restructuring processes that take place when fingerspelled words become lexicalized and it argues that these lexicalized signs are part of the foreign/non-native lexicon of LSM, based on a model by Brentari and Padden (2001). As far as initialization, which is extremely common in LSM, is concerned, this article describes variation in the use of initialization by different signers of LSM, and the various lexical families based on initialization that exist in LSM. It also argues that, unlike lexicalized fingerspelling and unlike initialized signs in ASL, initialized signs are part of the core vocabulary of LSM, because they behave like native signs both phonologically and morphologically. To conclude, the morphological structure of initialized signs is discussed.
Temperature, Hatch Date, and Prey Availability Influence Age‐0 Yellow Perch Growth and Survival
Authors: Kaemingk Mark A. , Graeb Brian D. S. , Willis David W.
Published: June 2014

Throughout their range, Yellow Perch Perca flavescens are an important ecological and economic component of many fisheries, but they often exhibit highly variable recruitment. Much research effort has been devoted to better understanding the mechanisms responsible for these erratic recruitment patterns, yet few studies have examined this process at the detail necessary to reveal complex interactions that may exist across multiple early life stages. Our current understanding of the early life recruitment patterns of Yellow Perch suggests a strong abiotic component. Using existing information, we developed three working hypotheses to examine Yellow Perch recruitment at two larval stages (5–14 and 15–24 d old) and to further identify the overarching mechanisms (abiotic versus biotic) related to Yellow Perch recruitment in 332‐ha Pelican Lake, Nebraska, during 2004–2012. Larval Yellow Perch growth and mortality were largely regulated by hatching date, temperature, and zooplankton availability. The growth of young larval Yellow Perch (5–14 d old) was positively related to temperature and hatch date; that of old larval perch (15–24 d old) was positively related to water temperature and postlarval age‐0 (≤25 mm TL) Yellow Perch density but negatively related to the available preferred zooplankton biomass. Mortality was inversely related to total zooplankton biomass and water temperature. Our results describe a model with two potential Yellow Perch recruitment bottlenecks, one immediately posthatch that is regulated by hatch date and temperature and another during the older larval stage that is regulated by temperature and zooplankton.

Received October 25, 2013; accepted January 14, 2014
The Healing Performance: The Medical Clown as Compared to African! Kung and Azande Ritual Healers
Authors: Raviv Amnon
Published: June 2014

The medical clown, the dramatherapist, the traditional healer and the witchdoctor each conduct a dramatic, theatrical healing performance with the objective of healing the ill in their community. Their healing ability lies in their capacity of being intermediaries between different worlds, between chaos and order, and between the factors which caused and accelerated the illness and healing and mental powers. Each healer, using his own unique practice embodied in the perception of reality in their community, facilitates accessibility to healing powers to benefit those who are ill. The current article compares and analyzes the healing performances.
Population Changes after 14 Years of Harvest Closure on a Migratory Population of Bull Trout in Idaho
Authors: Erhardt John M. , Scarnecchia Dennis L.
Published: June 2014

Primary data (size and age structure, abundance) and derived data (growth, mortality, recruitment) were used to assess the status and trends of Bull Trout Salvelinus confluentus in the North Fork of the Clearwater River, Idaho, under a 14-year harvest closure. From 2000 (6 years after harvest closure) to 2008, an increase in the number of larger and older migratory Bull Trout occurred, as evidenced by the rightward shift in the cumulative length-frequency distribution, increases in mean total length and weight, and increases in age. The stability in growth rates over an 8-year interval indicated that the increases in size structure were age related (e.g., recruitment and mortality changes) rather than growth related. The abundance of migratory spawning adults also steadily increased over the period 1994–2008, as indicated by the increases in redd counts. A logistic model fitted to population estimates (not including unsampled portions of the drainage where migratory Bull Trout are known to exist) indicated that the rate of population growth as of 2005 was beginning to slow and that a carrying capacity of 5,215 total migratory adults will be asymptotically approached, surpassing the U.S. Fish and Wildlife Service's drainage-wide recovery goal of 5,000 total adults. The results from an age-structured population model (model 1) indicated a carrying capacity (5,716 migratory adults) similar to that of the logistic model. If the results under model 1 are achieved, the migratory adult population (including nonspawning adults) will surpass 5,000 adults in 2019. The results under a second model depicted a lower carrying capacity (3,592 fish). This analytical approach has promise for application in situations where harvest restrictions or the elimination of fishing are part of Bull Trout restoration programs.

Received August 8, 2013; accepted December 11, 2013
Reductions in Instream Wood in Streams near Roads in the Interior Columbia River Basin
Authors: Meredith Christy , Roper Brett , Archer Eric
Published: June 2014

Despite the success of recent management efforts to reduce streamside logging, instream wood recovery may be limited by the presence of near-stream roads. We investigated the relationships between the presence of near-stream roads and the frequency and volume of different size-classes of wood in streams in the interior Columbia River basin. We developed models to evaluate the average reduction in instream wood for streams near roads (<30 m or 30–60 m). We compared this with the changes in wood frequency and volume related to changes in environmental conditions such as precipitation, bank-full width, gradient, and forest cover as well as to changes in grazing-related management. In order to extrapolate our findings to the entire study area, we used a GIS approach to determine the distance to roads for randomly selected sites throughout the study area. Sites <30 m from a road had 65 (26%) fewer pieces of total wood, 33 (34%) fewer pieces of coarse wood, 31 (37%) fewer pieces of pool-forming wood, and 37 m3 (42%) less wood volume per kilometer than sites >60 m from a road. We also observed significant reductions at sites 30–60 m from a road, but these were about half those documented for sites <30 m. Changes in environmental conditions and grazing intensity had effects similar to those of being near a road. Based on our GIS analysis, approximately 29% of the sites in the study area are within 60 m of a road, and this percentage is even greater if unroaded catchments are excluded. Our results provide strong evidence that the presence of roads has significantly reduced habitat conditions for salmonids in the interior Columbia River basin and illustrate the need for road removal or relocation projects to increase wood in streams.

Received April 3, 2013; accepted December 12, 2013
Downstream Passage of Lake Sturgeon through a Hydroelectric Generating Station: Route Determination, Survival, and Fine-Scale Movements
Authors: McDougall C. A. , Anderson W. G. , Peake S. J.
Published: June 2014

Downstream passage of Lake Sturgeon Acipenser fulvescens through hydroelectric facilities is known to occur but is poorly understood. Acoustic telemetry was used to investigate downstream-passage routes, survival, and fine-scale movements at the Slave Falls Generating Station, located on the Winnipeg River, Manitoba. Downstream-passage rates were estimated at 2.9% (range = 0.0–4.4%) per year for Slave Falls Reservoir adults and 21.1% (range = 19.3–22.9%) per year for subadults tagged in the lowermost section of the reservoir. No juvenile passage was observed. Lake Sturgeon movements immediately upstream of the Slave Falls Generating Station main sluiceway gates were related to bathymetric features. Fish that approached via deepwater habitat tended to abandon their downstream trajectory movements before or upon reaching the top of a relatively shallow (∼10 m depth) bedrock saddle that occurs ∼45 m upstream of the main sluiceway gates. Based on acoustic telemetry (fine-scale tracking and presence–absence data) and supplemental information, such as trash rack spacing and spill conditions, 7 of 11 (64%) observed downstream-passage events were concluded to have occurred via bottom-draw regulating sluices located in the northeastern end of the powerhouse. At least 91% of the observed downstream-passage events were survived. Results suggest that protection initiatives at hydroelectric facilities could exploit the Lake Sturgeon's bottom-oriented nature, with bottom-draw sluice gates likely providing a feasible way to facilitate safe downstream passage.

Received June 28, 2013; accepted January 28, 2014
Laboratory Investigations on the Use of Strobe Lights and Bubble Curtains to Deter Dam Escapes of Age-0 Muskellunge
Authors: Stewart Heather A. , Wolter Max H. , Wahl David H.
Published: June 2014

The movement of Muskellunge Esox masquinongy over a dam to leave a reservoir is known as dam escape. It is common in Midwestern U.S. reservoirs and has been as high as 25% of the adult population. A variety of barrier and guidance systems have been used to control fish movement, but the success of such barriers has been mixed and appears to be very species dependent. We examined the effectiveness of a simple, relatively low-power and low-cost bubble curtain, strobe light, and bubble curtain with strobe light barriers to deter Muskellunge from escaping over spillways. In 15 replicate trials of each treatment type conducted in a simulated spillway, age-0 Muskellunge were more likely to escape during daytime trials (P < 0.01), but the three barrier combinations did not reduce rates of escape. Light and bubble curtain barriers will likely not be effective in reducing spillway escapes by Muskellunge.

Received September 18, 2013; accepted January 22, 2014
Movements of Striped Bass between the Exclusive Economic Zone and Massachusetts State Waters
Authors: Kneebone Jeff , Hoffman William S. , Dean Micah J. , Armstrong Michael P.
Published: June 2014

In recent years, commercial and recreational fishermen have reported large aggregations of adult Striped Bass Morone saxatilis occurring in the U.S. Exclusive Economic Zone (EEZ) adjacent to Massachusetts state waters. Directed fishing for Striped Bass within the EEZ has been prohibited since 1990, and there is overwhelming public perception that adult Striped Bass remain as seasonal residents of the EEZ and do not enter state waters, where they would become available to anglers. Passive acoustic telemetry was utilized to examine the extent to which adult Striped Bass move between the EEZ and Massachusetts state waters and to assess the relative conservation benefit provided by the EEZ fishery closure. From 2008 to 2011, 125 adult Striped Bass (68–110 cm TL) were tagged with acoustic transmitters on Stellwagen Bank within the EEZ and were monitored with an extensive array of fixed acoustic receivers deployed within Massachusetts state waters. Of these tagged individuals, 119 (95%) were detected for 1–56 d within state waters during a given year, and 96 (77%) were detected seasonally for up to 2 years after tagging. Sixty-five (55%) fish moved into state waters within 30 d after tagging (during July and August) and became accessible to the Massachusetts commercial fishery. The results of this study provide definitive evidence that a majority of the adult Striped Bass encountered annually on Stellwagen Bank (i.e., in the EEZ) exhibit movement into Massachusetts state waters as part of their normal migratory and feeding behaviors. If future research in other areas off the northeast U.S. coast likewise documents routine movements between federal and state waters, fishery managers will need to re-evaluate the efficacy of the EEZ closure as a tool for reducing fishing mortality.

Received October 22, 2013; accepted January 21, 2014
Loss of Genetic Integrity in Hatchery Steelhead Produced by Juvenile-Based Broodstock and Wild Integration: Conflicts in Production and Conservation Goals
Authors: Bingham Daniel M. , Kennedy Benjamen M. , Hanson Kyle C. , Smith Christian T.
Published: June 2014

We examined whether a supplementation program for steelhead Oncorhynchus mykiss in southwestern Washington could produce hatchery fish that contained genetic characteristics of the endemic population from which it was derived and simultaneously meet a production goal. Hatchery fish were produced for three consecutive years by using broodstock comprised of endemic juveniles that were caught in the wild and raised to maturity, and then the program transitioned to an integrated broodstock comprised of wild and hatchery adults that returned to spawn. Importantly, some auxiliary conservation-based husbandry protocols were attempted (i.e., pairwise mating between males and females) but not always completed due to insufficient broodstock and conflict between production and conservation goals. The hatchery met production goals in 6 of 9 years, but wild-type genetic integrity of hatchery fish was degraded every year. Specifically, we analyzed 10 microsatellites and observed a 60% reduction in the effective number of breeders in the hatchery (harmonic mean of hatchery, Nb = 45, compared with the wild, Nb = 111). Hatchery fish consequently displayed reduced genetic diversity and large temporal genetic divergence compared with wild counterparts. To ensure the benefit of conservation-based husbandry, spawning protocols should be based on scientific theory and be practical within the physical and biological constraints of the system. Finally, if conservation issues are considered to be the most important issue for hatchery propagation, then production goals may need to be forfeited.

Received November 8, 2013; accepted February 19, 2014
Quantification and Evaluation of Factors Influencing Largemouth Bass Predation of Stocked Advanced Fingerling Yellow Perch
Authors: Lundgren Seth A. , Schoenebeck Casey W. , Koupal Keith D. , Lorensen Jared A. , Huber Caleb G.
Published: June 2014

Over 2 years, we examined the survival of stocked advanced fingerling Yellow Perch Perca flavescens involving over 16 stocking events in eight lakes in Nebraska. The survival of stocked fish was estimated with respect to both handling mortality during stocking and predation by Largemouth Bass Micropterus salmoides. Handling mortality during stocking was found to be zero, while Largemouth Bass consumption of stocked Yellow Perch averaged 26.4%. Consumption was highest on the day of stocking (0.35 perch/bass stomach), with only minimal consumption (0.01 perch/stomach) occurring beyond 4 d. Largemouth Bass populations with small size structure (PSD < 29) were predictive of greater Yellow Perch mortality, suggesting that there is greater perch survival in lakes with bass populations of larger size structure.

Received November 26, 2013; accepted February 25, 2014
An Estimate of Postrelease Mortality of School-Size Bluefin Tuna in the U.S. Recreational Troll Fishery
Authors: Marcek Benjamin J. , Graves John E.
Published: June 2014

The recreational fishery for juvenile Bluefin Tuna Thunnus thynnus along the U.S. Atlantic coast has a large number of regulatory discards, but little information exists on the fate of released fish. We deployed 20 pop-up satellite archival tags programmed to release after 31 d to estimate the postrelease mortality of school-size (69–119 cm curved FL) Bluefin Tuna caught in the recreational troll fishery. All fish were captured using lures or lure–bait combinations rigged with standard “J” hooks. Nineteen of the 20 tags (95%) reported, and analysis of temperature, depth, and light data indicated that all 19 fish survived for the tagging period. Three tags released prematurely (after 6, 7, and 26 d), and we inferred that one individual was consumed by a shark after 12 d. However, all four of these fish displayed behavior indicative of survival until the tag either released or the fish was consumed. Although the power of this analysis is limited by the relatively small sample size, the observed postrelease mortality rate of 0% suggests that the recreational catch-and-release troll fishery for school-size Bluefin Tuna does not represent a significant source of fishing mortality.

Received September 24, 2013; accepted March 3, 2014
Fishing for Northern Pike in Minnesota: Comparing Anglers and Dark House Spearers
Authors: Schroeder Susan A. , Fulton David C.
Published: June 2014

In order to project fishing effort and demand of individuals targeting Northern Pike Esox lucius in Minnesota, it is important to understand the catch orientations, management preferences, and site choice preferences of those individuals. Northern Pike are specifically targeted by about 35% of the approximately 1.5 million licensed anglers in Minnesota and by approximately 14,000–15,000 dark house spearers. Dark house spearing is a traditional method of harvesting fish through the ice in winter. Mail surveys were distributed to three research strata: anglers targeting Northern Pike, dark house spearing license holders spearing Northern Pike, and dark house spearing license holders angling for Northern Pike. Dark house spearers, whether spearing or angling, reported a stronger orientation toward keeping Northern Pike than did anglers. Anglers reported a stronger orientation toward catching large Northern Pike than did dark house spearers when spearing or angling. Northern Pike regulations were the most important attribute affecting site choice for respondents in all three strata. Models for all strata indicated a preference for lakes without protected slot limits. However, protected slot limits had a stronger negative influence on lake preference for dark house spearing licensees (whether spearing or angling) than for anglers.

Received September 26, 2013; accepted March 19, 2014
Psychological and Drug Abuse Symptoms Associated with Nonmedical Use of Opioid Analgesics among Adolescents
Authors: Boyd Carol J. , Young Amy , McCabe Sean E.
Published: June 2014

Background

Approximately 18% of US adolescents engaged in prescription opioid abuse in 2013. However, this estimate may be misleading because it includes both medical misusers and nonmedical users, and there is evidence that these are 2 groups that differ relative to substance abuse and criminal risk. Thus, this study does not combine medical and nonmedical users; rather, it seeks to better understand the characteristics of nonmedical users.

Methods

This was a school-based, cross-sectional study that was conducted during 2009–2010 in southeastern Michigan with a sample of 2627 adolescents using a Web-based survey. Three mutually exclusive groups were created based on responses regarding medical and nonmedical use of opioid analgesics. Group 1 had never used an opioid analgesic, Group 2 used an opioid analgesic only as prescribed, and Group 3 nonmedically used an opioid analgesic. In addition, Group 3 was divided into 2 mutually exclusive subgroups (self-treaters and sensation-seekers) based on reasons for nonmedical use. A series of multinomial logistic regressions were conducted to determine if the groups differed on the presence of pain, psychological symptoms (e.g., affective disorder, conduct disorder, attention-deficit/hyperactivity disorder [ADHD]), and drug abuse.

Results

Sixty-five percent (65.0%) of the sample was white/Caucasian and 29.5% was African American. The average age was 14.8 years (SD = 1.9). Seventy percent (70.4%; n = 1850) reported no lifetime opioid use, 24.5% ( n = 644) were medical users, 3.5% ( n = 92) were nonmedical users who used for pain relief only, and 1.6% ( n = 41) were classified as nonmedical users for reasons other than for pain relief (e.g., to get high). Both medical users and nonmedical users reported more pain and substance abuse symptoms compared with never users. Those nonmedical users who used opioids for sensation-seeking motivations had greater odds of having psychological symptoms.

Conclusions

These data support the need to further consider subgroups of nonmedical users of opioid analgesics.
Effects of Stocking Density on Growth, Survival, and Stress Physiology of Pigfish
Authors: DiMaggio Matthew A , Ohs Cortney L , Broach Jason S , Sink Todd D
Published: June 2014

Stocking density is an important consideration in the intensive commercial production of fishes. Decreased growth and survival may result from overcrowding in the culture environment, while understocking may lead to inefficient use of resources. The Pigfish Orthopristis chrysoptera is a marine baitfish species with great potential for commercial production in the southeastern United States. To date, no studies have assessed the effect of culture density on Pigfish in recirculating aquaculture systems. Thus, we conducted two experiments to evaluate the effect of stocking density on Pigfish growth, survival, and stress physiology. The small-scale trial included three densities—0.1, 0.3, and 0.5 fish/L (0.94, 2.82, and 4.70 kg/m3)—evaluated over the course of a 65-d growth period. The large-scale experiment encompassed four lower stocking densities—0.05, 0.1, 0.2, and 0.4 fish/L (0.10, 0.19, 0.38, and 0.76 kg/m3)—investigated over a 50-d growth period. Growth, survival, specific growth rate, and feed conversion ratio were assessed for each treatment at the conclusion of the experiments. Additionally, plasma osmolality, chloride, cortisol, and glucose in Pigfish were evaluated at the completion of the large-scale experiment. Trends in growth and survival were similar among most of the Pigfish densities tested. However, 50-d survival was significantly lower in the 0.05-fish/L treatment (mean±SD = 14.8±6.4%) than in the 0.2-fish/L (37.6±11.6%) and 0.4-fish/L (41.9±9.3%) treatments. Specific growth rate estimates ranged from 2.02±0.31% to 4.38±0.59% (mean±SD) during both trials. Differences in primary and secondary stress responses among treatments were generally unclear. Densities of up to 0.5 fish/L (4.70 kg/m3) appear to be conducive to the culture of juvenile Pigfish. Further research is needed to examine stocking densities greater than those investigated in this study. Results of physiological analyses represent the first published data on stress physiology in Pigfish.
Impacts of Combined Salinity and Temperature Extremes on Different Strains and Species of Tilapia Inhabiting the Watershed of the Salton Sea
Authors: Lorenzi Varenka , Schlenk Daniel
Published: June 2014

Tilapia have relatively rapid osmoregulatory abilities, but the combined stress due to extreme temperature and salinity can negatively affect the survival of the fish. This study compared the tolerance of the California Mozambique Tilapia hybrid (Mozambique Tilapia Oreochromis mossambicus × Wami Tilapia O. urolepis; CA hybrid) from aquaculture and three species of tilapia that currently live in the Salton Sea area: Blue Tilapia O. aureus, Redbelly Tilapia Tilapia zillii, and CA hybrid collected from the sea. The CA hybrid tilapia (both cultured and feral) was the most resistant species across all treatments and could survive salinities up to 60 g/L (‰). The CA hybrid from aquaculture was the most tolerant to higher temperatures (33–38°C), while the one from the Salton Sea was the most tolerant to colder temperatures (11–16°C). In terms of salinity regimes, the aquaculture CA hybrid and Blue Tilapia survived better at 20‰, while the CA hybrid from the sea did best at 45‰. The different stocks of tilapia showed very different tolerances, and these results provide valuable information for the future management of the Salton Sea.
A Self-Contained, Controlled Hatchery System for Rearing Lake Whitefish Embryos for Experimental Aquaculture
Authors: Mitz Charles , Thome Christopher , Cybulski Mary Ellen , Laframboise Lisa , Somers Christopher M , Manzon Richard G , Wilson Joanna Y , Boreham Douglas R
Published: June 2014

A self-contained, small-scale research hatchery was constructed in a modified chromatography refrigerator equipped with a filtered and UV-sterilized water recirculation system. Lake Whitefish Coregonus clupeaformis embryos were raised in conventional upwelling hatching jars, in dishes with a continuous slow “drip feed,” and in a variety of static water incubation systems in petri dishes and multiwell plates. The optimal rearing density for petri dishes was found to be 50 embryos per dish, with weekly water changes. The highest survival in multiwell plates was seen in the 6- and 24-well sizes. Survival rates in most multiwell plates and petri dishes, as well as in the hatching jar incubators, were between 40% and 60%, which is in line with survival rates seen in commercial large-scale rearing. Overall, these techniques permitted the rearing of large numbers of whitefish in separate batches and under controlled conditions, while greatly reducing space requirements and material costs. Our system is well suited for research and other situations requiring the temperature-controlled rearing of embryos on a small scale.
Growth Performance of Largemouth Bass Fed Fish Meal Derived from Asian Carp
Authors: Bowzer John , Bergman Alexis , Trushenski Jesse
Published: June 2014

Feeds for carnivorous fish like Largemouth Bass Micropterus salmoides are commonly based on marine-origin fish meal, but this ingredient is costly. Fish meal derived from undesirable species, such as invasive Asian carp Hypophthalmichthys spp., is a promising alternative source of protein for carnivorous fish, but information regarding its biological value as a feed ingredient is limited. Accordingly, we evaluated the growth performance of juvenile Largemouth Bass (initial weight, 11.6±0.2 g [mean±SE]) reared for 8 weeks on practical diets (∼14.5% lipid, ∼42% digestible protein) containing different levels of menhaden fish meal (MFM), Asian carp meal (CFM), or a 50:50 blend of these ingredients such that 40% (40 MFM, 40 CFM) or 60% (60 MFM, 60 CFM, 60 Blend) of the estimated digestible protein content was derived from fish meal. Weight gain (329–388%), feed conversion ratio (0.78–0.97), and specific growth rate (2.65–2.88% body weight/d) were generally consistent among treatments. Although our results suggest that performance is greater among fish fed diets with greater fish meal inclusion, regardless of its origin, this trend was not supported by clear statistical evidence. Asian carp fish meal appears to be broadly equivalent to MFM in feeds for Largemouth Bass. Development of CFM as a feed ingredient may offer producers of Largemouth Bass and other carnivorous fishes some savings in feed cost and encourage the harvest of invasive Asian carp.
Effects of Graded Taurine Levels on Juvenile Cobia
Authors: Watson Aaron M , Barrows Frederic T , Place Allen R
Published: June 2014

Taurine, which has multiple important physiological roles in teleost fish and mammals, is an amino acid not found in alternative protein sources not derived from animals. Although taurine is found in fish-meal-based feeds, its high water solubility leads to lower taurine levels in reduction-process-based feeds, which marine carnivores such as Cobia Rachycentron canadum are adapted to in their natural diets. Graded taurine supplementation (0, 0.5, 1.5, and 5.0%) added to a traditional fish-meal-based formulation was examined in two growth trials with Cobia: one initiated with 10-g individuals and the second initiated with 120-g individuals. During the first trial, in which growth as weight gain ranged from 123 to 139 g per fish, there was an increase in dietary taurine and a decrease in the feed conversion ratio from 1.04 to 0.99. During the second trial, in which growth ranged from 227 to 313 g gained per fish, there was no significant difference in performance characteristics between dietary treatments. Messenger RNA transcript expression levels for two of the genes involved in taurine synthesis, cysteine dioxygenase (CDO) and cysteamine dioxygenase (ADO), as well as the membrane-bound taurine transporter, TauT, were also measured at the conclusion of the second trial. Increasing dietary taurine in a diet containing 34.5% fish meal did not result in significantly different growth or production characteristics in Cobia, but did result in significantly increased taurine levels in fillet, liver, and plasma.
The Cast Net: an Overlooked Sampling Gear
Authors: Stein William , Smith Patrick W. , Smith Galen
Published: June 2014

Sampling fishes and decapods in shallow, estuarine, marsh habitats is challenging because of depth variation, soft substrates that make standing difficult, and the presence of submersed aquatic vegetation. Though often overlooked, a cast net is an efficient gear type for sampling nekton in this environment. Complaints about the cast net are that it is difficult to deploy successfully and the results are not repeatable. We present a method of standardization of cast net deployment that reveals that most of the variation in area covered is among individual operators rather than within one individual. The 1.8 m cast net collected more species, more biomass, and faster swimming nekton than the throw trap. There was no statistical difference in the total number of animals collected or the total number of species between the gear types. We conclude that the cast net is a useful gear type for sampling nekton communities in estuarine habitats especially when there are differences in the spatial and temporal occurrences and relative abundances of many different organisms in an area with complex and varying habitats.

Received May 9, 2013; accepted November 6, 2013
Age, Growth, and Mortality of Yellowmouth Grouper from the Southeastern United States
Authors: Burton Michael L. , Potts Jennifer C. , Carr Daniel R.
Published: June 2014

The Yellowmouth Grouper Mycteroperca interstitialis is a member of the snapper–grouper complex that is managed by the South Atlantic Fishery Management Council. There is little published life history information—specifically age–growth parameters—for use in assessing the resource. We sampled Yellowmouth Grouper from the fisheries along the southeastern U.S. coast from 1980 to 2012 (n = 391), determining ages by counting opaque zones on sectioned sagittal otoliths. Opaque zones were annular, forming in May–August with a peak in May and June. Yellowmouth Grouper age ranged from 3 to 31 years, and the largest fish was 859 mm FL. Body size relationships were as follows: whole weight W (g) = (8.89×10−6)(FL, mm)3.07 (n = 339; r2 = 0.96); W (g) = (1.13×10−5)(TL, mm)3.01 (n = 165; r2 = 0.96); and TL (mm) = 10.09 + [1.05×(FL, mm)] (n = 162; r2 = 0.98). The von Bertalanffy growth equation for Yellowmouth Grouper was Lt (length at age t) = 755[1 − e−0.14(t + 1.42)] when the model included an adjustment for minimum size limits and was Lt = 772[1 − e−0.11(t + 4.18)] when the model was not adjusted. Natural mortality (M) estimated by Hewitt and Hoenig's (2005) longevity based method was 0.14. Age specific estimates of M were obtained with the Charnov et al. (2013) method. The selection of growth model (size limit adjusted versus unadjusted) had a marked effect on M for the earliest ages: M was 1.22 versus 0.43 for age 0; 0.72 versus 0.35 for age 1; 0.51 versus 0.29 for age 2; 0.40 versus 0.26 for age 3; 0.33 versus 0.23 for age 4; and 0.29 versus 0.21 for age 5. We believe that these life history parameter estimates are accurate for Yellowmouth Grouper in southeastern U.S. fisheries.

Received June 6, 2013; accepted November 12, 2013
Simulating Fish Movement Responses to and Potential Salinity Stress from Large Scale River Diversions
Authors: Rose Kenneth A. , Huang Haosheng , Justic Dubravko , Mutsert Kim
Published: June 2014

River diversions are a major but controversial management approach to restoring coastal wetlands and mitigating offshore oil spills in the northern Gulf of Mexico. One of the controversies concerns the potential displacement of and salinity stress on commercially and recreationally important fish species in response to the widespread and prolonged freshening of habitat. We developed a coupled hydrodynamics–fish movement model and applied it to the Caernarvon diversion located in the Breton Sound estuary, Louisiana. Hydrodynamics model output was used as input to the individual based fish movement model. The period of model simulation was from April 1 to July 1, 2010. We simulated three diversion scenarios: baseline, pulse, and oil spill mitigation. We first used field data from Bay Anchovy Anchoa mitchilli and showed that the model predicted downestuary shifts similar to those observed in field studies under large diversions. We then defined generic low and intermediate salinity fish species and simulated each under the three diversion scenarios. Compared with the baseline diversion scenario, more than 50% of the intermediate salinity individuals moved about 15 km farther downestuary under the pulse diversion scenario and moved more than 35 km under the oil spill mitigation diversion scenario. The effects of the diversions on the low salinity species were evidenced by individuals becoming more dispersed (i.e., spreading out downestuary) and more exposed to bursts of too high salinity. Our conclusions agreed with those from earlier field and modeling analyses that focused on average (rather than transitory) fish responses.

Received November 4, 2013; accepted November 7, 2013
Juvenile Steelhead Distribution, Migration, Feeding, and Growth in the Columbia River Estuary, Plume, and Coastal Waters
Authors: Daly Elizabeth A. , Scheurer Julie A. , Brodeur Richard D. , Weitkamp Laurie A. , Beckman Brian R. , Miller Jessica A.
Published: June 2014

Relative to extensive research on the freshwater stages of steelhead Oncorhynchus mykiss life history, little is known about the species' estuarine and early marine phases despite the decline of numerous populations, including several from the Columbia River. Comparisons of the distribution, diet, and growth of juvenile steelhead collected during surveys of the Columbia River estuary and coastal waters in May, June, and September 1998–2011 were analyzed for comparisons between fish caught in the estuary and ocean and between hatchery (marked) and putative wild (unmarked) fish. Almost all catches of juvenile steelhead in the ocean occurred during the May surveys (96%). Juvenile steelhead were consistently caught at the westernmost stations (>55 km from shore), indicating an offshore distribution. Based on otolith structure and chemistry, we determined that these juveniles had been in marine waters for an average of only 9.8 d (SD = 10.2). Some of the steelhead that had been in marine waters for 1–3 d were captured at the westernmost edge of survey transects, indicating rapid offshore migration. Estuary caught fish ate fewer prey types and consumed far less food than did ocean caught fish, which ate a variety of prey, including juvenile fishes, euphausiids, and crab megalopae. Estuary and ocean caught unmarked fish exhibited higher feeding intensities, fewer empty stomachs, and better condition than hatchery fish. Growth hormone levels (insulin like growth factor 1 [IGF 1]) in unmarked fish and hatchery fish varied annually, with unmarked fish having slightly higher overall values. In general, the FL, condition, stomach fullness, and IGF 1 of ocean caught steelhead increased with distance offshore. Unlike juveniles of other salmonid species, steelhead appeared to quickly migrate westward from coastal rivers and showed patterns of increased feeding and growth in offshore waters. An understanding of the estuarine and ocean ecology of steelhead smolts may assist in the management of threatened steelhead populations.

Received July 18, 2013; accepted November 21, 2013