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We used biotelemetry and genetic stock identification to assess sea-to-sea survival and run composition of 1212 late-migrating adult steelhead (anadromous Oncorhynchus mykiss) through the Columbia River and Snake River migratory corridors. The late run was predominated by steelhead from Idaho's Clearwater and Salmon rivers that must pass eight large hydroelectric dams during both prespawn and postspawn migrations. In 2 years (2013 and 2014), prespawn survival to Snake River tributaries (>500 km) was 0.48-0.67 for the most abundant populations and was higher for females and 1-sea fish (i.e., fish that spend one winter at sea). Annual survival from Snake River tributary entry to postspawn kelt status was 0.14-0.17, with higher survival for females and those without hatchery fin clips. Kelt outmigration survival was 0.31-0.39 past four Snake River dams and 0.13-0.20 past all eight dams and was highest for smaller kelts. Full-cycle adult freshwater survival (sea-to- sea) including 16 dam passage events was 0.01-0.02. Younger steelhead and those without fin clips survived at the highest rates. This study uniquely partitioned mortality across prespawn, reproductive, and kelt life history stages and informs management strategies for this conservation-priority metapopulation. Nous avons utilise la biotelemetrie et l'identification genetique du stock pour evaluer la survie de l'ocean a l'ocean et la composition de la montaison de 1212 truites arc-en-ciel anadromes (Oncorhynchus mykiss) a migration tardive dans les corridors de migration du fleuve Columbia et de la riviere Snake. Des truites arc-en-ciel anadromes provenant des rivieres Clearwater et Salmon en Idaho etaient predominantes dans la migration tardive, ces truites devant franchir huit grands barrages hydroelectriques durant leurs migrations avant et apres le frai. En 2 ans (2013 et 2014), le taux de survie avant le frai jusqu'a des affluents de la Snake (>500 km) etait de 0,48-0,67 pour les populations les plus abondantes et etait plus eleve pour les femelles et les individus ayant ete dans l'ocean une fois. La survie annuelle de l'entree dans les affluents de la riviere Snake jusqu'a l'etat de charognard etait de 0,14-0,17, les taux les plus eleves etant observes pour les femelles et les individus sans marque d'ablation de nageoire en aleviniere. Les taux de survie des charognards durant la devalaison etaient de 0,31-0,39 apres quatre barrages sur la riviere Snake et de 0,13-0,20 apres tous les huit barrages, et ce taux etait le plus eleve pour les charognards plus petits. Le taux de survie en eau douce des adultes apres un cycle complet (ocean a ocean) comptant 16 franchissements de barrage etait de 0,01-0,02. Les truites arc-en-ciel anadromes plus jeunes et celles sans marque d'ablation de nageoire en aleviniere presentaient les taux de survie les plus eleves. L'etude distingue nettement la mortalite des stades pregenesique, reproducteur et de charognard du cycle biologique et fournit de l'information utile pour l'elaboration de strategies de gestion pour cette metapopulation dont la conservation est prioritaire. [Traduit par la Redaction], Introduction Preservation of genetic and life history diversity are becoming increasingly important objectives in fish conservation and management programs. In the United States, the Endangered Species Act has essentially codified [...]

National Standard 8 of the reauthorized Magnuson-Stevens Fisheries Management Act mandates that fisheries managers consider a community's dependence on fisheries when crafting regulations. This article compares findings regarding dependence on commercial and recreational fisheries from direct observations and interviews in 21 U.S. South Atlantic communities to findings from publicly available data sources such as the U.S. census. The comparisons revealed that, in over 80% of the 21 ports examined, data developed from direct observations and interviews and those developed from publicly available data sources yielded similar results. Where there were large discrepancies between the two sets of findings, in most cases, the ports were located in large metropolitan areas where fishing constituted a small proportion of the economy. These findings indicate that the use of publicly available data sources is an efficient way for fisheries managers and others to meet the mandate of National Standard 8 in a timely fashion, yet they also suggest that rapid ethnographic procedures can aid in characterizing fishing communities that differ in terms of size, rural vs. urban settings, gentrification, resilience, and other features that could assist fishery managers in evaluating the impacts of fishing regulations., National Standard 8 and South Atlantic Fisheries Based on field research in 21 South Atlantic coastal communities reaching from Wanchese, N.C., to Palm Beach Shores, Fla., this article compares data [...]

Fishways designed for salmonids often restrict passage by non-salmonids, and effective tools are needed both to identify passage problems for nontarget species and to inform remediation planning. In this case study, we used migration histories from 2170 radio-tagged adult Pacific lamprey (Entosphenus tridentatus) to identify locations of poor passage (bottlenecks) at a large, multifishway dam. Over 10 years, 49% of tagged lamprey that entered fishways failed to pass the dam. Models accounting for repeated attempts by individual lamprey indicated successful passage strongly depended on attempted passage route. Success also varied with time of fishway entry, water temperature, and lamprey body size. Most failed passage attempts terminated in lower fishway segments, but extensive seasonal shifts in bottleneck locations were detected. Ranking metrics helped prioritize bottlenecks and identified sites where structural or operational modifications should improve lamprey passage. Our integration of spatially intensive monitoring with novel analytical techniques was critical to understanding the complex relationships among fishway features, environmental variation, and lamprey behavior. The prioritization framework can be applied to a wide range of fish passage assessments. Les passes migratoires concues pour les salmonides restreignent souvent le passage d'autres poissons, et des outils efficaces sont necessaires pour cerner les problemes associes au passage d'especes non visees et eclairer la planification de mesures correctives. Dans la presente etude de cas, nous avons utilise les historiques de migration de 2170 lamproies du Pacifique (Entosphenus tridentatus) adultes munies de radio-emetteurs pour cerner les lieux de passage difficiles (goulots d'etranglement) a un important barrage comptant plusieurs passes. Sur une periode de 10 ans, 49% des lamproies munies d'emetteurs qui entraient dans ces passes ne reussissaient pas a remonter le barrage. Des modeles tenant compte de tentatives multiples par les memes lamproies ont indique que le succes du passage dependait fortement de la voie de passage employee. Le taux de succes variait egalement selon le moment de l'entree dans la passe, la temperature de l'eau et la taille du corps de la lamproie. La plupart des tentatives de passage infructueuses prenaient fin dans des sections avals des passes, mais d'importantes variations saisonnieres de l'emplacement des goulots d'etranglement ont ete decelees. Le classement des differents parametres a aide a etablir la priorite des goulets et a cerner les sites ou des modifications structurales ou operationnelles devraient ameliorer le passage des lamproies. L'integration d'une surveillance spatiale fine et de nouvelles techniques analytiques s'est averee essentielle a une meilleure comprehension des liens complexes entre les caracteristiques des passes a poissons, les variations des conditions du milieu et le comportement des lamproies. Le cadre d'etablissement de la priorite peut etre applique a un vaste eventail devaluations de passes a poissons. [Traduit par la Redaction], Introduction River systems worldwide have been fragmented by dams and other anthropogenic obstacles that restrict fish movements (Nilsson et al. 2005). A diverse array of fishways and other passage systems [...]

Increasing pinniped abundance in the Pacific Northwest has coincided with population declines of Pacific salmon (Oncorhynchus spp.) and steelhead trout (Oncorhynchus mykiss), and concentrated predation may affect the recovery of some threatened and endangered salmonid stocks. We used radiotelemetry to evaluate pinniped-caused injury effects on migration survival of 17 007 adult Columbia River Chinook salmon (Oncorhynchus tshawytscha) and steelhead trout. Injuries from pinnipeds were common (mean injury rate across 29 run-years = 36.5%) and were most common for spring Chinook salmon and steelhead trout. Injury was not consistently associated with adult survival to spawning tributaries, but some negative survival effects were detected. Pinniped-caused injury rates decreased as annual run sizes increased, indicating density-dependent or saturation effects. Within a run, large fish generally had a higher injury incidence than small fish, suggesting pinnipeds targeted large fish or more efficiently captured small fish. Seasonal, size- dependent, and density-dependent results imply that pinniped effects likely differ widely among salmonid populations within the Columbia River basin. A better understanding of these effects is needed to guide management and conservation strategies. L'augmentation d'abondance des pinnipedes dans le Nord-Ouest Pacifique coincide avec les declins demographiques des saumons du Pacifique (Oncorhynchus spp.) et de la truite arc-en-ciel anadrome (Oncorhynchus mykiss)etla concentration de la predation peut affecter le retablissement de quelques stocks de salmonides menaces et en peril. La radiotelemetrie nous a servi a evaluer les effets des blessures causees par les pinnipedes sur la survie durant la migration de 17 007 saumons chinook (Oncorhynchus tshawytscha) et truites arc-en-ciel anadromes adultes dans le fleuve Columbia. Les blessures dues aux pinnipedes sont communes (taux moyen de blessures dans 29 montaisons-annees = 36,5%) et sont plus abondantes chez les saumons chinook et truites arc-en-ciel anadromes de printemps. Il n'y a pas d'association constante entre les blessures et la survie des adultes jusqu'aux tributaires de fraie, mais on peut deceler des effets negatifs sur la survie. Les taux de blessures dues aux pinnipedes diminuent a mesure que la taille des montaisons annuelles augmente, ce qui indique des effets de densite dependance ou de saturation. Dans une montaison, les poissons plus grands ont generalement une incidence plus elevee de blessures que les poissons plus petits, ce qui laisse croire que les pinnipedes ciblent les poissons plus grands ou alors capturent plus efficacement les plus petits. Ces resultats saisonniers et dependants de la taille et de la densite amenent a croire que les effets des pinnipedes different vraisemblablement beaucoup d'une population de salmonides a une autre au sein du bassin versant du Columbia. Une meilleure comprehension de ces effets est requise pour orienter les strategies de gestion et de conservation. [Traduit par la Redaction], Introduction Members of the Order Pinnipedia evolved >20 million years ago, and their distributions have likely overlapped those of Pacific anadromous salmonids (Oncorhynchus spp.) for much of their existence. Many [...]

Abstract: The relationships among behavior, environment, and migration success in anadromous fishes are poorly understood. We monitored migration behavior at eight Columbia and Snake river dams for 18 286 adult [...]

Interdisciplinary science and environmental management involve bringing together data and expertise at multiple spatial scales. The most challenging part of merging scales is aligning the scale of inquiry with the research application. Through the Louisiana case study relating wetland loss and commercial fishing, we examine how the nature and strength of the relationship changes depending on the scale of investigation. Resulting management implications also vary because of tradeoffs in choosing the scale of inquiry. State-level fisheries managers may miss effects of wetland loss in fishing communities because they are looking at aggregate data. Scientific information must directly address the constituent scale, where managers can enact policy. The case study demonstrates why scalar considerations should be an explicit part of the planning process for both science and management. [ABSTRACT FROM AUTHOR]