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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, [...]

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]

Evaluating the effectiveness of instream structures for increasing trout populations is complicated by a paucity of long-term studies. We report on a study spanning 23 years to assess the effect of installing log weirs on stream habitat and trout abundance. Structures were installed in a randomly selected half of a 500 m study reach in six small Colorado, USA, mountain streams in 1988, and habitat and trout abundance and biomass were measured annually from 1987 to 1994. When five of the streams were resampled in 2009, none of the 53 logs had moved, and all but one were functioning properly. Pool volume remained more than three times higher in treatment sections than in adjacent controls, and mean depth was also greater. Adult trout abundance increased rapidly after structures were installed and remained 53% higher in treatment sections than in controls 21 years later. Effects on juvenile trout abundance were not detected, probably because fry recruitment is strongly influenced by effects of snowmelt runoff, which vary annually among basins. This evaluation shows that instream structures placed in small, stable channels can function for more than two decades when properly installed and can cause long-lasting increases in trout abundance when habitat is limiting. L'evaluation de l'efficacite des structures ajoutees dans un cours d'eau pour augmenter les populations de poissons est compliquee par l'absence d'etudes a long terme. Nous presentons une recherche sur 23 annees qui mesure l'effet de l'addition de digues en billes de bois sur l'habitat du cours d'eau et l'abondance des truites. Les structures ont ete installees dans la moitie (choisie au hasard) de sections d'etude de 500 m dans six petits cours d'eau de montagne du Colorado en 1988 et des mesures de l'habitat, de meme que de l'abondance et de la biomasse des truites, ont ete faites chaque annee de 1987 a 1994. Quand cinq des cours d'eau ont ete re-echantillonnes en 2009, aucune des 53 billes de bois ne s'etait deplacee et toutes, sauf une, fonctionnaient adequatement. Le volume des fosses etait encore trois fois plus important dans les sections modifiees que dans les sections temoins adjacentes et la profondeur moyenne etait aussi plus grande. L'abondance des truites adultes a augmente rapidement apres l'installation des structures et elle etait encore 53 % plus elevee que dans les sections temoins 21 ans plus tard. Aucun effet n'a pu etre decele chez les jeunes truites, probablement parce que le recrutement des alevins est fortement influence par les effets du ruissellement de la fonte des neiges qui varie chaque annee d'un bassin a un autre. Notre evaluation montre que les structures placees dans de petits chenaux stables peuvent fonctionner pendant plus de deux decennies lorsqu'elles sont bien installees et qu'elles peuvent produire des augmentations persistantes de l'abondance des truites lorsque l'habitat constitue un facteur limitant [Traduit par la Redaction], Introduction Management of stream salmonids often involves manipulation of habitat, under the assumption that increasing physical habitat will increase fish populations (Hunt 1994; Fausch et al. 1995; Whiteway et al. [...]

The endothelial cell (EC)-derived tissue inhibitor of metalloproteinase-2 (TIMP-2) and pericyte-derived TIMP-3 are shown to coregulate human capillary tube stabilization following EC-pericyte interactions through a combined ability to block EC tube morphogenesis and regression in three-dimensional collagen matrices. EC-pericyte interactions strongly induce TIMP-3 expression by pericytes, whereas ECs produce TIMP-2 in EC-pericyte cocultures. Using small interfering RNA technology, the suppression of EC TIMP-2 and pericyte TIMP-3 expression leads to capillary tube regression in these cocultures in a matrix metalloproteinase-1 (MMP-1)-, MMP-10-, and ADAM-15 (a disintegrin and metalloproteinase-15)-dependent manner. Furthermore, we show that EC tube morphogenesis (lumen formation and invasion) is primarily controlled by the TIMP-2 and -3 target membrane type (MT) 1 MMP. Additional targets of these inhibitors include MT2-MMP and ADAM-15, which also regulate EC invasion. Mutagenesis experiments reveal that TIMP-3 requires its proteinase inhibitory function to induce tube stabilization. Overall, these data reveal a novel role for both TIMP-2 and -3 in the pericyte-induced stabilization of newly formed vascular networks that are predisposed to undergo regression and reveal specific molecular targets of the inhibitors regulating these events.