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Beginning in the 1980s, return rates of Atlantic salmon (Salmo salar) to the Penobscot River, Maine, USA, declined and have persisted at low levels. This downturn coincided with similar declines in North American and European Atlantic salmon stocks and with changes in the Northwest Atlantic ecosystem. Previous studies investigated whether early marine growth explained the declines, but results varied, with decreased growth associated with declines in European stocks but not North American stocks. In this study, we evaluate whether growth over the entire marine stage is related to Atlantic salmon marine survival. We constructed a growth time series from scales of returned Penobscot River Atlantic salmon spanning periods of varying marine survival. We used analysis of variance (ANOVA) and post hoc tests to quantify seasonal growth increment differences and principal component analysis to characterize variability among the suite of growth increments. We observed reduced growth during the second winter and second marine year starting in the 1990s, with compensatory seasonal growth relationships. These results indicate that diminished growth during late marine stages is associated with low return rates in this population. A partir des annees 1980, les taux de retour de saumons atlantiques (Salmo salar) dans le fleuve Penobscot (Maine, Etats-Unis) ont baisse pour ensuite demeurer faibles. Ce declin coincide avec des declins semblables des stocks nord-americains et europeens de saumons atlantiques et avec des changements dans l'ecosysteme de l'Atlantique Nord-Ouest. Des etudes anterieures ont tente d'etablir si la croissance en mer expliquait ces baisses, avec des resultats mitiges, dont une diminution de la croissance associee a des declins dans les stocks europeens, mais non dans les stocks nord-americains. Nous avons evalue s'il existe une relation entre la croissance durant l'ensemble de la phase marine et le taux de survie en mer du saumon atlantique. Nous avons constitue une serie chronologique de croissance a partir d'ecailles de saumons atlantiques de retour dans le fleuve Penobscot couvrant des periodes caracterisees par differents taux de survie en mer. Nous avons utilise l'analyse de variance et des tests post hocs pour quantifier la variation des increments de croissance saisonniers et l'analyse en composantes principales pour caracteriser la variabilite au sein de la serie d'increments de croissance. Nous relevons une croissance reduite durant le deuxieme hiver et la deuxieme annee en mer a partir des annees 1990, marquee par des relations de croissance saisonniere compensatoire. Ces resultats indiquent qu'une croissance reduite durant la phase marine est associee a de faibles taux de retour dans cette population. [Traduit par la Redaction], Introduction Over recent decades, declines in Atlantic salmon (Salmo salar) populations in both North America and Europe have been associated with large-scale ecosystem changes in the North Atlantic Ocean (Beaugrand [...]

The first marine circulus is the scale feature associated with marine entry and has been used to support research evaluating the relationships between size, growth, and survival for Atlantic salmon. Ambiguity in growth rates and circulus deposition during the transition from freshwater to the marine environment leads to difficulty in the correct identification of the first marine circulus. In this study, scale growth occurring after the last freshwater annulus (plus-growth) was characterized for Atlantic salmon smolts migrating out of the Narraguagus River in Maine. Plus-growth was present in over 95% of scales from smolts leaving the river and represented on average 12.2% of total freshwater growth. These findings suggest plus-growth presents a significant source of error in growth analyses, if ignored, and the characterization of this scale feature helps to inform accurate identification of marine entry for future studies. Run day was a driver of plus-growth, suggesting extended freshwater residency provides opportunity for growth prior to smolt emigration. The negative association between fork length and plus-growth suggests smaller smolts that delay migration are demonstrating compensatory growth. Cumulative air temperature was positively associated with plus-growth, suggesting warming spring temperatures driven by climate change may influence size at marine entry for smolts. [ABSTRACT FROM AUTHOR]

Fish scale microchemistry can be used to make life‐history inferences, although ecological studies examining scale composition are relatively rare. Salmon scales have an external layer of calcium phosphate hydroxyl apatite (HAP). The structure, hardness, and calcium content of this layer have been shown to vary within and between species. This variation may lead to misinterpretation of trace element profiles. This study uses backscatter scanning electron microscopy with electron dispersive spectrometry to compare scales from salmon populations and to present a more detailed analysis of scale HAP than was previously available. Our findings extend the range of salmon populations for which HAP Ca is available and confirm previous findings that the HAP Ca is relatively invariable within this species. [ABSTRACT FROM AUTHOR]

Dams challenge Atlantic salmon (Salmo salar) conservation, while hatcheries are a common but poorly evaluated recovery tool. We developed a spatially explicit smolt survival model for the Penobscot River, Maine, USA, population. By partitioning survival through dams (with flow dependency), free-flowing river reaches, and the estuary (with dam dependency), the model quantified how these factors influenced the number of fish entering the ocean. Given historical impounded conditions, 74%-22% of hatchery smolts released entered the ocean annually from 1970 to 2012. Of 19.7 million smolts stocked, 7.7 million entered the ocean (39%). Survival was most variable at dams (range 95% to 63%), followed by in-river (range 98% to 70%) and estuary (range 88% to 82%). Overall, lower-river stocking sites resulted in significantly higher numbers at ocean entry because of fewer dam encounters and shorter migrations. Higher flows also resulted in reduced losses. By reconstructing these freshwater and estuary dynamics, the model provides a more accurate estimate of ocean recruitment annually and can be used for scenario planning of future stocking locations relative to predicted flows while being adaptable to new survival rates. Les barrages constituent un defi pour la conservation du saumon atlantique (Salmo salar), et les alevinieres sont un outil de retablissement repandu, bien que mal evalue. Nous avons developpe un modele de survie des saumoneaux spatialement explicite pour la population du fleuve Penobscot (Maine, Etats-Unis). En partitionnant la survie a travers les barrages (dependant du debit), les troncons a ecoulement libre du fleuve et l'estuaire (dependant des barrages), le modele quantifie l'influence de ces facteurs sur le nombre de poissons entrant dans l'ocean. Etant donne les conditions de retenue historiques, de 74 % a 22 % des saumoneaux d'elevage relaches dans le fleuve sont entres dans l'ocean annuellement de 1970 a 2012. Sur 19,7 millions de saumoneaux d'elevage relaches, 7,7 millions sont entres dans l'ocean (39 %). La survie est la plus variable aux barrages (de 95 % a 63 %), suivis des troncons du fleuve (de 98 % a 70%) et de l'estuaire (de 88 % a 82%). Globalement, les lieux d'ensemencement situes plus bas dans le fleuve se traduisent par des nombres significativement plus grands de saumoneaux entrant dans l'ocean en raison du moins grand nombre de barrages rencontres et des migrations plus courtes. Des debits plus eleves se traduisent egalement par des pertes moins grandes. En reconstituant ces dynamiques en eau douce et dans l'estuaire, le modele fournit une estimation plus exacte du recrutement oceanique annuel et peut etre utilise pour la planification de scenarios de lieux d'ensemencement futurs en fonction des debits prevus, tout en pouvant s'adapter a de nouveaux taux de survie. [Traduit par la Redaction], Introduction Dams impact riverine ecosystem function by interrupting natural physical, chemical, and biological gradients. These impacts increase in systems with multiple dams in a concept called 'serial discontinuity' (Ward and [...]

Objectives for recovery of alosines commonly involve improving fish passage at dams during migration. However, a quantitative basis for dam passage performance standards is largely absent. We describe development of a stochastic life-history-based simulation model for American shad, Alosa sapidissima, to estimate effects of dam passage and migratory delay on abundance, spatial distribution of spawning adults, and demographic structuring in space and time. We used the Penobscot River, Maine, USA, as a case study to examine sensitivity of modeled population metrics and probability of achieving specific management goals to inputs. Spawner abundance and percentage of repeat spawners were most sensitive to survival and migration delay at dams, marine survival, and temperature cues for migratory events. Recovery objectives related to abundance and spatial distribution of spawners were achievable under multiple scenarios, but high rates of upstream and downstream passage were necessary. The simulation indicated trade-offs between upstream and downstream passage efficacy whereby increased downstream passage was required to maintain or increase population abundance in conjunction with increased upstream passage. This model provides a quantitative support tool for managers to inform ecologically based decisions about a suite of management scenarios to facilitate recovery and sustainability of diadromous fish populations. Les objectifs concernant le retablissement d'alosines comprennent souvent l'amelioration du passage de poissons aux barrages durant la migration. Il y a toutefois quasi absence de fondement quantitatif pour l'etablissement de normes de performance de passage de barrages. Nous decrivons l'elaboration d'un modele de simulation stochastique base sur le cycle biologique pour l'alose savoureuse, Alosa sapidissima, afin d'estimer les effets du passage de barrages et le retard de la migration sur l'abondance, la repartition spatiale d'adultes geniteurs et la structuration demographique dans l'espace et le temps. Nous utilisons l'exemple du fleuve Penobscot (Maine, Etats-Unis) comme etude de cas pour examiner la sensibilite aux intrants de parametres demographiques modelises et la probabilite d'atteinte d'objectifs de gestion precis. L'abondance des geniteurs et le pourcentage de geniteurs a reproductions anterieures sont les parametres les plus sensibles a la survie et au retard de la migration aux barrages, a la survie en mer et aux signaux de temperature pour les evenements migratoires. Les objectifs de retablissement associes a l'abondance et a la repartition spatiale des geniteurs sont atteignables pour differents scenarios, mais des frequences elevees de passages en amont et en aval sont necessaires. La simulation indique des compromis entre l'efficacite des passages en amont et en aval, une augmentation des passages en aval etant necessaire pour maintenir ou accroitre l'abondance de la population, de concert avec de plus nombreux passages en amont. Ce modele fournit un outil de soutien quantitatif aux gestionnaires pour eclairer des decisions basees sur l'ecologie concernant un ensemble de scenarios de gestion visant a faciliter le retablissement et la perennite des populations de poissons diadromes. [Traduit par la Redaction], Introduction The American shad, Alosa sapidissima, is an anadromous fish that spawns in the main-stem of coastal rivers on the Atlantic coastal drainage of North America from the St. Johns [...]

As more diverse students enter the field of addiction counseling, educators and researchers are challenged to explore more inclusive teaching methods for better academic outcomes. In this study, outcomes from an experimental group using cooperative learning methods for a course in addiction counseling were compared to outcomes from the same course taught with traditional lecture. Measures of learning perception, cooperation, and factual learning did not reveal significant differences. While cooperative learning presents an opportunity for innovation, teacher skill and acumen may weigh more heavily as predictors of effective learning outcomes. (Contains 4 tables.)

Assuring learning outcomes that result in expert alcohol and drug dependency counseling is a continuous challenge for educators. Working systemically to craft a solid vision for the future, the Hazelden Foundation developed a graduate school for the sole purpose of educating highly skilled clinicians. Key ingredients included building a school--rather than a program, establishing a center of excellence model, and creating a curriculum that afforded high performance outcomes. (Contains 2 figures.)

Fisheries targeting mixtures of populations risk the overutilization of minor stock constituents unless harvests are monitored and managed. We evaluated stock composition and exploitation of Atlantic salmon (Salmo salar) in a subsistence fishery in coastal Labrador, Canada, using genetic mixture analysis and individual assignment with a microsatellite baseline (15 loci, 11829 individuals, 12 regional groups) encompassing the species' western Atlantic range. Bayesian and maximum likelihood mixture analyses of fishery samples over 6 years (2006-2011; 1772 individuals) indicate contributions of adjacent stocks of 96%-97%. Estimates of fishery-associated exploitation were highest for Labrador salmon (4.2%-10.6% per year) and generally < 1% for other regions. Individual assignment of fishery samples indicated nonlocal contributions to the fishery (e.g., Quebec, Newfoundland) were rare and primarily in southern Labrador, consistent with migration pathways utilizing the Strait of Belle Isle. This work illustrates how genetic analysis of mixed stock Atlantic salmon fisheries in the Northwest Atlantic using this new baseline can disentangle exploitation and reveal complex migratory behaviours. En l'absence de surveillance et de gestion des prises, les peches qui ciblent des melanges de populations posent un risque de surutilisation de stocks mineurs. Nous avons evalue la composition et l'exploitation des stocks de saumons atlantiques (Salmo salar) dans une peche de subsistance sur la cote du Labrador (Canada) par l'analyse des melanges genetiques et l'affectation d'individus a la lumiere de donnees microsatellitaires de reference (15 microsatellites, 11829 individus, 12 groupes regionaux) couvrant l'aire de reparation de l'espece dans la partie ouest de l'ocean Atlantique. Les analyses bayesiennes et de maximum de vraisemblance de melanges d'echantillons tires de cette peche sur une periode de 6 ans (2006-2011, 1772 individus) indiquent que les stocks adjacents constituent de 96% a 97% de cette peche. Les estimations de l'exploitation associee a cette peche etaient les plus elevees pour le saumon du Labrador (de 4, 2% a 10, 6% par annee) et generalement < 1% pour le saumon d'autres regions. L'affection des individus des echantillons de la peche indiquait que les contributions non locales a cette peche (p. ex. de Quebec ou Terre-Neuve) etaient rares et principalement limitees au sud du Labrador, ce qui concorde avec les voies de migration passant par le detroit de Belle-Isle. L'etude illustre comment l'analyse genetique de peches au saumon atlantique de stocks melanges dans le nord-ouest de l'Atlantique a la lumiere de la nouvelle base de donnees de reference peut permettre de discriminer l'exploitation des differents stocks et reveler des comportements migratoirescomplexes. [Traduit par la Redaction], Introduction Mixed stock fisheries target admixtures of populations, presenting both challenges and benefits for fisheries management and conservation (Chase 2003; Schindler et al. 2010; Utter and Ryman 1993). As stock [...]

Billions of hatchery salmon smolts are released annually in an attempt to mitigate anthropogenic impacts on freshwater habitats, often with limited success. Mortality of wild and hatchery fish is high during downstream and early ocean migration. To understand changes that occur during migration, we examined physiological and endocrine changes in Atlantic salmon (Salmo salar) smolts during hatchery rearing, downstream migration, and early ocean entry in two successive years. Gill [Na.sup.+]/[K.sup.+]-ATPase activity increased in the hatchery during spring, increased further after river release, and was slightly lower after recapture in the ocean. Plasma growth hormone levels increased in the hatchery, were higher in the river, and increased further in the ocean. Plasma IGF-I remained relatively constant in the hatchery, increased in the river, then decreased in the ocean. Plasma thyroid hormones were variable in the hatchery, but increased in both river- and ocean-captured smolts. Naturally reared fish had lower condition factor, gill NKA activity, and plasma thyroxine than hatchery fish in the river but were similar in the ocean. This novel data set provides a vital first step in understanding the role and norms of endocrine function in smolts and the metrics of successful marine entry. Si des milliards de saumoneaux issus d'ecloseries sont relaches annuellement afin d'attenuer les impacts de l'activite humaine sur les habitats d'eau douce, l'efficacite de ces efforts est souvent limitee. La mortalite des poissons sauvages et provenant d'ecloseries est elevee durant l'avalaison et le debut de la migration en mer. Pour mieux comprendre les changements qui s'operent durant la migration, nous avons examine les changements physiologiques et endocriniens chez des saumoneaux de saumon atlantique (Salmo salar) durant l'alevinage en ecloserie, l'avalaison et le passage en mer pendant deux annees consecutives. L'activite de l'ATPase [Na.sup.+]/[K.sup.+] branchiale a augmente au printemps en ecloserie, puis apres la liberation en riviere et avait legerement diminue apres la recapture en mer. Les teneurs de l'hormone de croissance plasmatique ont augmente en ecloserie, puis davantage en riviere ainsi qu'en mer. L'IGF-I plasmatique est demeure relativement inchange en ecloserie, a augmente en riviere, pour ensuite diminuer en mer. Les teneurs en hormones thyroidiennes plasmatiques etaient variables en ecloserie, mais avaient augmente chez les saumoneaux captures tant en riviere qu'en mer. Si, en riviere, les poissons issus de l'alevinage naturel presentaient des coefficients d'embonpoint, une activite de la NKA branchiale et des teneurs en thyroxine plasmatique plus faibles que ceux des poissons issus d'ecloseries, ces valeurs etaient semblables pour les deux groupes de poissons une fois en mer. Ce nouvel ensemble de donnees constitue un premier pas critique vers la comprehension du role et des normes de la fonction endocrine chez les saumoneaux, ainsi que vers la caracterisation des parametres associes a un passage en mer reussi. [Traduit par la Redaction], Introduction As part of their normal life history, Atlantic salmon migrate as juveniles from freshwater to seawater. Atlantic salmon undergo a transformation that is adaptive for life in the ocean, [...]

Adaptive multimedia streaming aims at adjusting the transmitted content based on the available bandwidth such as losses that often severely affect the end-user perceived quality are minimized and consequently the transmission quality increases. Current solutions affect equally the whole viewing area of the multimedia frames, despite research showing that there are regions on which the viewers are more interested in than on others. This paper presents a novel region of interest-based adaptive scheme (ROIAS) for multimedia streaming that when performing transmission-related quality adjustments, selectively affects the quality of those regions of the image the viewers are the least interested in. As the quality of the regions the viewers are the most interested in will not change (or will involve little change), the proposed scheme provides higher overall end-user perceived quality than any of the existing adaptive solutions. Index Terms--Content adaptation, multimedia streaming, region of interest, user perceived quality.