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Pacific salmon Oncorhynchus spp. hatcheries in British Columbia (BC) have been the major activity of the Salmonid Enhancement Program since 1977. However, the present diminished abundance of Pacific salmon and loss of fisheries in BC called for a review of hatchery effectiveness. The Pacific Salmon Foundation conducted a review resulting in 15 reports publicly available on the Pacific Salmon Foundation marine science website. The review includes evaluations of effectiveness of hatchery production, evidence of interactions with natural salmon populations (including rebuilding natural populations with hatchery‐produced salmon), and future opportunities via genomics. Beyond the estimation of juvenile production and contribution to catches and spawning escapements, the ability to assess effectiveness was limited. The assessments of interactions provided a few examples of positive outcomes, but most were negative. The lack of comparative assessments in purely wild populations seriously limits interpretations of hatchery–wild interactions. Future evaluations of the hatchery effectiveness require more quantitative and integrated assessments of hatchery and wild salmon, open data sharing for public review or research, and related studies could benefit from application of new genomic technologies. This paper presents recommendations to address these needs and calls for regularized reviews of the Salmonid Enhancement Program and its net value to sustainability of BC's Pacific salmon. [ABSTRACT FROM AUTHOR]

Aquatic systems are warming and exceeding upper thermal limits (UTLs) for many fish species, yet understanding how they inform resilience to climate change is challenging. Using Pacific salmon (Oncorhynchus spp.) as a model, we conducted a systematic review involving 168 papers investigating UTL in five species. We found considerable variation in UTL among species, within species and across life stages; largely attributed to methodological approaches (e.g. CTmax/UILT, Aerobic/Cardiac Scope, Thermal Migration Barriers, Rearing Mortality, Thermal Preference/Avoidance). Given that each method has strengths and weaknesses owing to logistics, time scale and ecological realism, we offer a new framework for assessing vulnerability to warming that stresses the importance of considering UTL metrics in the context of intended use (i.e. the development of management guidelines, projections of future persistence and survival) and what aspect (physiological or behavioural) of thermal response a metric investigates. Comparing studies with identical UTL approaches revealed that within species, UTL was higher for populations historically encountering higher temperatures—suggesting local thermal adaptation. Within populations, UTL differed across the lifecycle, being highest in fry and lowest in embryo and migrating adults, but this was not universal. For spawning Pacific salmon, UTL has not been assessed and few studies have examined estuarine and marine stages. Ultimately, this data gap limits the life‐history thermal perspectives that can be drawn and may indicate a broader gap for all fishes, given that Pacific salmon are among the most well‐studied species. Our framework illustrates the inherent and methodological inconsistencies in UTL and offers a guide for how thermal limits can best be used to assess the warming tolerance and vulnerability of fishes. [ABSTRACT FROM AUTHOR]

Dam removal is often proposed for restoration of anadromous salmonid populations, which are in serious decline in California. However, the benefits of dam removal vary due to differences in affected populations and potential for environmental impacts. Here, we develop an assessment method to examine the relationship between dam removal and salmonid conservation, focusing on dams that act as complete migration barriers. Specifically, we (1) review the effects of dams on anadromous salmonids, (2) describe factors specific to dam removal in California, (3) propose a method to evaluate dam removal effects on salmonids, (4) apply this method to evaluate 24 dams, and (5) discuss potential effects of removing four dams on the Klamath River. Our flexible rating system can rapidly assess the likely effects of dam removal, as a first step in the prioritization of multiple dam removals. We rated eight dams proposed for removal and compared them with another 16 dams, which are not candidates for removal. Twelve of the 24 dams evaluated had scores that indicated at least a moderate benefit to salmonids following removal. In particular, scores indicated that removal of the four dams on the Klamath River is warranted for salmonid conservation. Ultimately, all dams will be abandoned, removed, or rebuilt even if the timespan is hundreds of years. Thus, periodic evaluation of the environmental benefits of dam removal is needed using criteria such as those presented in this paper. [ABSTRACT FROM AUTHOR]

Abstract: This paper describes an attempt in 2008 to establish an aerial census of adult chum salmon using a small radio-controlled (RC) helicopter. The Moheji River, located in southern Hokkaido, was chosen because all the salmon in a stretch of the river between a weir and the estuary are seine-netted every morning for artificial propagation. Aerial photographs of the river were taken from a RC helicopter equipped with a digital single-lens reflex camera and polarized filter. To quantify salmon density within the census area, the number of salmon per aerial photograph was counted using image-processing software. Salmon could be clearly identified in photographs taken from an altitude of ∼30m. Salmon numbers estimated by aerial census and seine-netting were significantly related. The results indicate that a small RC helicopter can be used to generate adult salmon abundance data in Japanese rivers. [Copyright &y& Elsevier]

This paper studies the formation of the large dark patterns, known as parr marks, that form on the Amago trout as it grows from the early larval stages to adulthood. The Amago trout, known as Oncorhynchus masou ishikawa, exhibits stripes during the early stages of development that in turn evolve (through reorientation and peak insertion) to form zigzag spot patterns as the fish grows to adulthood. By considering a standard representation of the Turing model for biological self-organization via interacting and diffusing morphogens, we illustrate that a diffusively driven instability can generate transient patterns consistent with those experimentally observed during the process of parr-mark formation in the early development of the Amago trout. Surface evolution is modeled through an experimentally driven growth function. Our studies conclude that the surface evolution profile, the surface geometry, and the curvature are key factors that play a pivotal role in reaction-diffusion systems in a study motivated by observations of Amago trout parr-mark pattern formation. [ABSTRACT FROM AUTHOR]

Our paper describes case of lerneosis in rainbow trout (Oncorhynchus mykiss). Lerneosis is disease of fish caused by Lernaea cyprinacea. This species is a cosmopolitan ectoparasite, worldwide distributed. Invasion by L. cyprinacea were rare described in Poland. This parasite is highly adapted to a parasitic life. The life cycle of L. cyprinacea is composed of nine stages. After mating males (mature stage) subsequently die and mated females attach to the body surfaces of host fish and then passing trough the skin to the muscles. Infections of this parasite can cause localized inflammation and ulceration at the area of attachment and are entrance of secondary bacterial and fungal infections. Massive invasion in fish can cause serious economic problems. [ABSTRACT FROM AUTHOR]

Photoperiod enhancement of growth is becoming an area of increasing interest as a means of enhancing rainbow trout production efficiency in commercial practice. This paper examines the possible implications of shortening periods of constant light (LL) exposure on rainbow trout growth during autumn–spring grow-out under ambient water temperatures in freshwater to portion size. Triplicate groups of juvenile all-female rainbow trout were permanently exposed to LL in October, November, December or January. Growth was monitored and compared with those maintained under a simulated natural photoperiod (SNP) until the following May. Permanent exposure to LL (all treatments) resulted in significantly greater weight gain of rainbow trout than those under SNP. Furthermore, greatest growth was achieved when fish were left permanently exposed to LL from October. These findings suggest there may be implications for fish farmers if the period of photoperiod exposure is reduced, or timing of application is not considered with regards to ambient water temperatures. [ABSTRACT FROM AUTHOR]

Institutions are the mechanisms that integrate the human and ecological spheres. This paper discusses the institutional challenge of integrating salmon (Oncorhynchus spp.) ecosystems and human systems in ways that effectively promote resilience. Salmon recovery in the Columbia River Basin demonstrates the challenge. Despite the comprehensive scope of Basin salmon management, it has a number of problems that illustrate the difficulties of designing institutions for ecosystem and human system resilience. The critical elements of salmon ecosystem management are incentives and transaction costs, and these comprise a large piece of missing institutional infrastructure. Once the focus is placed on incentives and costs, a number of different management strategies emerge as options for salmon ecosystems, including refugia, property rights to ecosystem goods and services, co-management, and markets in ecosystem services. [ABSTRACT FROM AUTHOR]

Large portions of anadromous salmonid habitat in the western United States has been lost because of dams and other blockages. This loss has the potential to affect salmonid evolution through natural selection if the loss is biased, affecting certain types of habitat differentially, and if phenotypic traits correlated with those habitat types are heritable. Habitat loss can also affect salmonid evolution indirectly, by reducing genetic variation and changing its distribution within and among populations. In this paper, we compare the characteristics of lost habitats with currently accessible habitats and review the heritability of traits which show correlations with habitat/environmental gradients. We find that although there is some regional variation, inaccessible habitats tend to be higher in elevation, wetter and both warmer in the summer and colder in the winter than habitats currently available to anadromous salmonids. We present several case studies that demonstrate either a change in phenotypic or life history expression or an apparent reduction in genetic variation associated with habitat blockages. These results suggest that loss of habitat will alter evolutionary trajectories in salmonid populations and Evolutionarily Significant Units. Changes in both selective regime and standing genetic diversity might affect the ability of these taxa to respond to subsequent environmental perturbations. Both natural and anthropogenic and should be considered seriously in developing management and conservation strategies. [ABSTRACT FROM AUTHOR]

There is no consensus between morphological and molecular data concerning the relationships within the Pacific basin salmon and trout clade Oncorhynchus. In this paper we add another source of characters to the discussion. Phylogenetic analysis of 39 behavioral and life history traits produced one tree structured (O. clarki (0. mykiss (0. masou (0. kisutch (0. tshawytscha (0. nerka (0. keta, O. gorbuscha))))))). This topology is congruent with the phylogeny based upon Bayesian analysis of all available nuclear and mitochondrial gene sequences, with the exception of two nodes: behavior supports the morphological data in breaking the sister-group relationship between O. mykiss and O. clarki, and between O. kisutch and O. tshawytscha. The behavioral traits agreed with molecular rather than morphological data in placing O. keta as the sister-group of O. gorbuscha. The behavioral traits also resolve the molecular-based ambiguity concerning the placement of O. masou, placing it as sister to the rest of the Pacific basin salmon. Behavioral plus morphological data placed Salmo, not Salvelinus, as more closely related to Oncorhynchus, but that placement was only weakly supported and awaits collection of missing data from enigmatic species such as the lake trout, Salvelinus namaycush. Overall, the phenotypic characters helped resolve ambiguities that may have been created by molecular introgression, while the molecular traits helped resolve ambiguities introduced by phenotypic homoplasy. It seems reasonable therefore, that systematists can best respond to the escalating biodiversity crisis by forming research groups to gather behavioral and ecological information while specimens are being collected for morphological and molecular analysis. [ABSTRACT FROM AUTHOR]

Acoustic tag systems have been used for many years to study the behavior of fish in specific areas of interest. In particular tag systems are being used successfully to study the behavior of downstream migrating salmon smolts (Oncorhynchus spp.) as they approach hydro-electric dams. While field studies have demonstrated the potential for acoustic tag systems, little has been done to quantify their performance. This paper develops a method for predicting the accuracy of the “position estimates” provided by acoustic tag systems. General expressions are developed that can be applied to any particular deployment of a tag system which lead onto a method for the direct calculation of the “position error” as a function of hydrophone geometry, standard deviation of the signal arrival times, and the inaccuracies in the assumed sound velocities. This method is independent of the algorithm used to determine the position solution. Using the methods of analysis developed here some specific examples are presented that provide general guidelines that should be followed to achieve good performance when deploying an acoustic tag system. [Copyright &y& Elsevier]

Abstract This paper describes DNA sequence variation within and among four populations of chinook salmon (Oncorhynchus tshawytscha) at the transferrin, somatolactin and p53 genes. Patterns of variation among salmon species at the transferrin gene have been hypothesized to be shaped by positive natural selection for new alleles because the rate of nonsynonymous substitution is significantly greater than the rate of synonymous substitution. The twin goals of this study were to determine if the history of selection among salmon species at the transferrin gene is also reflected in patterns of intraspecific variation in chinook salmon, and to look for evidence of local adaptation at the transferrin gene by comparing patterns of nonsynonymous and synonymous variation among chinook salmon populations. The analyses presented here show that unlike patterns of variation between species, there is no evidence of greater differentiation among chinook salmon populations at nonsynonymous compared to synonymous sites. There is also no evidence of a reduction of within-species variation due to the hitchhiking effect at the transferrin gene, although in some populations nonsynonymous and synonymous derived mutations are both at higher frequencies than expected under a simple neutral model. Population size weighted selection coefficients (4Ns) that are consistent with both the inter and intraspecific data range from ~10 to ~235, and imply that between 1 and 40% of new nonsynonymous mutations at the transferrin gene have been beneficial. [ABSTRACT FROM AUTHOR]

Growth dynamics of rainbow trout (Oncorhynchus mykiss), superior to other salmonids species, led to the exploitation of this species in the most countries of the world. The individuals of this species, depend on many factors, like environment, nutrition and genetics. In this study, authors have followed over 540 days, the evolution of body mass and average daily gain at the specimens of rainbow trout from Fiad-Telcisor salmonids complex, Bistrita-Nasaud county, from the larval stage and up to the stage of trout for consumption with an average weight of 250 gr. These studies are necessary to prepare a strategy on fisheries production planning, depending on market demand of these products and eliminating additional costs due to over production. Fish and fish products always represented a staple food in human nutrition. The aquatic resources of continental and oceanic natural waters, have permanently assured the humanity's food needs, but today, on the conditions of the demographic boom, may be destroyed the ecosystems balance, on the strenght of irrational exploitation of their (Svennevig & co., 2000). For this reason, specialists' attention bound for aquaculture, field of the last years a real progress (Goldburg & Naylor, 2005). On this economic stage, a fierce commercial competition and significantly reduction of the market price, involving development and alignment a new concept of strategy, to decrease the production price. For this, aquaculture producers focus their efforts to obtain high yields at a high quality level and in conditions of maximum efficiency. A common situation on the fish market in Romania, is to sell products. Lack of strategy on the relationship between production capacity of fish farms and marketing opportunities of these products, lead to the accumulation of hardly marketable stocks which involving additional financial burden (Popescu, 2009). To avoid such situations, are requested market studies and research on the possibilities to obtain rhytmic and constant productions. They involve serious knowledge about factors which influence the physiology of fish growth (Cocan & co., 2009). In Romania, but also in many other countries around the world, salmonid species predominantly found in farms are rainbow trouts (Oncorhynchus mykiss). It is successfully exploited, due to its plasticity and resistance to changes in environmental conditions and diseases, and due to efficient conversion of feed (Cocan, 2008). There have been numerous studies on the factors that influence the growth of rainbow trout, including: growth density, environmental conditions, water quality, the rate of removal of water or operating system adopted (North & co., 2006; Roque d'Orbcastel & co., 2009; Sørensen & co., 2005; Matthews & co., 1997; Clark, 2003). Leatherland (1993), has conducted studies on interaction between plasma growth hormone, thyroid hormones and cortisol concentrations in rainbow trout, depending on the density of growth (150 kg/m³, respectively 60 kg/m³). The results demonstrated that to a high density, the growth rate drops significantly, due to high concentration of cortisol, but also due to restricted diet because of the high density. Because are poikilotherms, trouts shows changes of behavior and some physiological parameters according to season (Gallardo, 1997). Temperature is one of the abiotic factors with a major influence on the development of metabolic processes. Farming system adopted are also greatly influence on the growth dynamics of rainbow trout, each showing the advantages and disadvantages. Recirculating systems (RAS) providing optimal growth conditions, medial parameters being monitored continuously (Sirakov & Ivancheva, 2008), but inefficient water filtration systems can affect meat quality (Rønsholdt & McLean, 1999), or may give rise to health problems (Svobodova & co., 2005). Classical breeding systems are often at risk of contamination by polluted waters (Moogonei & co., 2010), and environmental conditions can not be controlled. In this study, authors have monitored the growth dynamics, body mass evolution and average daily growth of rainbow trout (Oncorhynchus mykiss), from Fiad-Telci or salmond complex. [ABSTRACT FROM AUTHOR]