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Substantial research effort has been devoted to understanding stream-dwelling salmonids' use of summer rearing and growth habitat, with a subset of studies focusing on foraging position selection and the energetic trade-offs of differential habitat use. To date, however, cost-benefit analyses for most foraging model studies have focused on small sampling areas such as individual habitat units. To address this knowledge gap, we applied a mechanistic foraging model to 22 stream reaches (100-400 m) from two watersheds within the Columbia River Basin. We found a strong, positive correlation ([R.sup.2] = 0.61, p < 0.001) between predicted carrying capacities and observed fish densities. Predicted proportion of suitable habitat was weakly correlated with observed fish density ([R.sup.2] = 0.18, p = 0.051), but the mean net rate of energy intake prediction in sampling reaches was not a significant predictor of observed fish biomass. Our results suggest spatial configuration of habitat, in addition to quantity and quality, is an important determinant of habitat use. Further, carrying capacity predicted by the model shows promise as a habitat metric. We also evaluated the feasibility of applying this data- intensive modeling approach in a large-scale monitoring program to examine habitat quality and quantity. Though the approach can be computationally expensive, we feel the model's ability to integrate physical habitat metrics (e.g., depth, velocity) with important biological considerations like food availability and temperature is a benefit that far outweighs associated costs. We feel this modeling approach has great potential as a tool to help understand habitat use in drift-feeding fishes. D'importants efforts de recherche ont ete voues a la comprehension de l'utilisation d'habitats estivaux d'alevinage et de croissance par les salmonides de cours d'eau, dont un sous-ensemble d'etudes s'etant axe sur la selection de la position d'approvisionnement et les compromis energetiques associes a l'utilisation differentielle d'habitats. Les analyses coutsavantages realisees a ce jour pour la plupart des etudes de modeles d'approvisionnement se sont toutefois attardees a de petites zones d'echantillonnage comme des unites d'habitat individuelles. Pour combler ce manque de connaissances, nous avons applique un modele d'approvisionnement mecaniste a 22 troncons de cours d'eau longs de 100 a 400 m dans deux bassins versants du bassin du fleuve Columbia. Nous avons constate une forte correlation positive ([R.sup.2] = 0,61, p < 0,001) entre les capacites de charge predites et les densites de poissons observees. La proportion predite d'habitats convenables etait faiblement correlee a la densite de poissons observee ([R.sup.2] = 0,18, p = 0,051), mais le taux net moyen d'apport energetique predit dans les troncons echantillonnes n'etait pas une variable explicative significative de la biomasse de poissons observee. Nos resultats donnent a penser que la configuration spatiale de l'habitat, combinee a sa quantite et sa qualite, est un important determinant de l'utilisation de cet habitat. En outre, la capacite de charge predite par le modele s'avere prometteuse comme parametre de l'habitat. Nous avons egalement evalue la faisabilite d'appliquer cette approche de modelisation riche en donnees dans le cadre d'un programme de surveillance a grande echelle visant a examiner la qualite et la quantite des habitats. Bien que cette approche puisse etre couteuse sur le plan computationnel, nous estimons que la capacite du modele a integrer des parametres physiques de l'habitat (p. ex. profondeur, velocite) et des considerations biologiques importantes comme la disponibilite de nourriture et la temperature constitue un avantage qui compense amplement les couts associes. Nous croyons que cette approche de modelisation a beaucoup de potentiel comme outil pour aider a comprendre l'utilisation de l'habitat chez les poissons qui se nourrissent a la derive. [Traduit par la Redaction], Introduction Conservation and recovery of many lotic fishes depend on successful management and restoration of their habitat. In the Columbia River Basin (CRB), for example, recovery efforts for listed salmon [...]

Biased perspectives of fisheries researchers may hinder scientific progress and effective management if limiting factors controlling productivity go unrecognized. We investigated whether river and lake researchers used different approaches when studying salmonid production and whether any differences were ecologically supported. We assessed 564 peer- reviewed papers published between 1966 and 2012 that studied salmonid production or surrogate variables (e.g., abundance, growth, biomass, population) and classified them into five major predictor variable categories: physical habitat, fertility (i.e., nutrients, bottom-up), biotic, temperature, and pollution. The review demonstrated that river researchers primarily analyzed physical habitat (65% of studies) and lake researchers primarily analyzed fertility (45%) and biotic (51%) variables. Nevertheless, understudied variables were often statistically significant predictors of production for lake and river systems and, combined with other evidence, suggests that unjustified a priori assumptions may dictate the choice of independent variables studied. Broader consideration of potential limiting factors on fish production, greater research effort on understudied genera, and increased publication in broadly scoped journals would likely promote integration between lentic and lotic perspectives and improve fisheries management. Les perspectives biaisees de chercheurs du domaine des peches pourraient faire entrave a des avancees scientifiques et a une gestion efficace, si cela devait se traduire par la non-reconnaissance de facteurs qui limitent la productivite. Nous avons verifie si les chercheurs travaillant en riviere, d'une part, et en lac, d'autre part, utilisent des approches differentes pour etudier la production de salmonides et si certaines differences sont appuyees par des considerations ecologiques. Nous avons examine 564 articles evalues par des pairs publies de 1966 a 2012 et portant sur la production de saumons ou des variables substitutives (p. ex. abondance, croissance, biomasse, population) et les avons classes selon cinq grandes categories de variables explicatives, soit celles reliees a l'habitat physique, a la fertilite (c.-a-d. nutriments, effet ascendant), au biote, a la temperature et a la pollution. Cet examen demontre que les chercheurs travaillant en riviere analysent principalement l'habitat physique (65% des etudes), alors que les chercheurs travaillant en lac analysent principalement des variables associees a la fertilite (45%) et au biote (51%). Cela etant, des variables sous-etudiees constituent souvent des variables explicatives statistiquement significatives de la production de systemes lacustres et fluviaux ce qui, combine a d'autres observations, semble indiquer que des hypotheses a priori non justifiees pourraient dicter le choix des variables independantes etudiees. Une plus grande prise en consideration de facteurs qui pourraient limiter la production de poissons, plus de recherche axee sur des genres sous-etudies et un nombre accru de publications dans des revues a grande portee favoriseraient probablement l'integration des perspectives lentique et lotique et amelioreraient la gestion des peches. [Traduit par la Redaction], Introduction One of the primary objectives in the study of freshwater ecosystems is to better understand controls on primary and secondary production, particularly the production of fish species of economic, [...]

Background: Ligamentum teres (LT) has traditionally been considered a vestigial or redundant structure in humans; however, based on new studies and the evolution of hip arthroscopy, the LT injury has been viewed as a source of hip pain. Therefore, LT reconstruction can be beneficial in some cases. Rabbits have been frequently used as a model for cranial cruciate ligament reconstruction but few studies are available for ligamentum teres reconstruction. Objective: To evaluate the semitendinosus tendon to replace ligamentum teres with the toggle technique, using rabbits as an experimental model. Methods: Twenty-six female Norfolk rabbits with approximately 3 months of age were divided into two equal groups after excision of ligamentum teres (LT) from the right hip joint: G1—no reconstruction of LT and capsulorrhaphy; G2—double— bundle reconstruction of the LT using semitendinosus tendon autograft. In both groups, the LT was removed from the right hip joint. In G2 the autograft was harvested from the left hind limb of the same rabbit. The rabbits were evaluated clinically at different time intervals; before surgery (M1), 48 h (M2), 15 days (M3), 30 days (M4) and 90 days (M5) after surgery. Results: The rabbits supported their limbs on the ground in both the groups. As complications of the procedure, four hip joints showed subluxations in the radiographic evaluation of G1; three at M4 and one at M5. In G2; two luxations of hip joints at M3 and one subluxation at M4 were seen. On ultrasound, irregular articular surface was seen in 30.8% of the rabbits that had subluxation of hip joints. Gross evaluation identified tendon graft integrity in 76.92% of the rabbits. Histological analysis revealed graft adhesion to the bone in the early phase comprised of sharpey-like collagen fibers. Conclusion: The double-bundle reconstruction of the LT using autologous semitendinosus tendon associated with the toggle rod shows an early phase of tendon graft ligamentization at 90 days post-operatively in young rabbits, but biomechanical bias suffered by the tendon during gait must be considered. [ABSTRACT FROM AUTHOR]

Hydrologic, terrestrial, and biologic disturbances influence stream channel conditions that are important to the persistence of aquatic biota. Past studies of how disturbance events alter streams have focused on fires, floods, and debris torrents as the magnitude of these events make them easy to detect. This approach has led to a bias in understanding which disturbances are likely to affect stream conditions. To address this concern, we used stream habitat data to identify where a substantial change in stream conditions had occurred and then used photographs of the evaluated reach to determine the disturbance that potentially caused those changes. We evaluated conditions in over 2,000 stream reaches and found that nearly a quarter of them had seen a substantial change in at least one of the five stream channel characteristics (bank‐full width, wood frequency, median particle size, pool depth, and bank stability) in the two decades that these streams were monitored. Although many stream reaches were affected by charismatic disturbance events such as fires, floods, and mass wasting, the majority of the substantial changes we observed in channel conditions were related to small‐scale disturbances. Mechanisms such as beavers, tree fall, vegetative growth, grazing, and active restoration all played an important role in bringing about large changes in stream channel conditions. While the majority of the disturbances were natural, some channel changes remain tied to anthropogenic activities. Our results suggest that no single sampling approach can be used to evaluate how stream conditions respond to all disturbances as they vary in intensity, over space and time, and based on which stream attribute is measured. By better understanding the full range of possible disturbances, managers should be better able to use such events to improve outcomes for streams and aquatic biota. [ABSTRACT FROM AUTHOR]