Fish stranding in freshwater systems: Sources, consequences, and mitigation

Nagrodski, Alexander; Raby, Graham D.; Hasler, Caleb T.; Taylor, Mark K.; Cooke, Steven J.

doi:10.1016/j.jenvman.2012.03.007

Cited by 149 publications

(174 citation statements)

References 62 publications

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“…Other reviews have highlighted important knowledge gaps about how the magnitude, frequency, and timing of anthropogenic flow fluctuations downstream of reservoir-storage hydropower systems affect the growth, survival, and reproductive success of fish (Young et al 2011;Nagrodski et al 2012). These knowledge gaps are also relevant to rivers regulated by RoR hydropower, although we argue that the gaps are even larger.…”

Section: (2) Effects Of Anthropogenic Flow Fluctuationsmentioning

confidence: 85%

“…Data from an unregulated montane stream in the US Pacific Northwest show that natural fluctuations in stage rarely exceeded 5 cm·h −1 (Hunter 1992, cited in Bell et al 2008, while frequent declines in river stage of 80-90 cm over 10 min were reported downstream of a reservoir-storage dam in Norway (Hvidsten 1985). Fish stranding or isolation in side channels may in turn lead to negative effects on survival, biomass, density, or fitness, as reported in studies from reservoir-storage systems (Young et al 2011;Nagrodski et al 2012;Senay et al 2016). Given the limited research that has specifically sought to understand the consequences of anthropogenic flow fluctuations in RoR hydropower systems, large uncertainties remain about how their effects differ from those documented downstream of reservoir-storage systems where most peer-reviewed research has occurred.…”

Section: Pathway 3: Anthropogenic Flow Fluctuationsmentioning

confidence: 99%

“…Salmonid fry are likely to be the most vulnerable life history stage to the negative effects of anthropogenic flow fluctuations, as they have limited swimming capacities and inhabit low-velocity, shallow habitats that are highly susceptible to dewatering (Bell et al 2008;Korman et al 2011). Flow fluctuations during natural low-flow periods may also reduce the availability of salmonid rearing habitats as well as interfere with spawning of anadromous and resident salmonids downstream of powerhouses (Nagrodski et al 2012). Besides their timing, the frequency and magnitude of anthropogenic flow fluctuations from RoR operations have the potential to generate impacts to salmonids.…”

Section: Pathway 3: Anthropogenic Flow Fluctuationsmentioning

confidence: 99%

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Run-of-River hydropower and salmonids: potential effects and perspective on future research

Gibeau

Connors

Palen

2017

Can. J. Fish. Aquat. Sci.

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Abstract:The spatial footprint of individual run-of-river (RoR) hydropower facilities is smaller than reservoir-storage hydroelectric projects and their impacts to aquatic ecosystems are often assumed to be negligible. However, these effects are poorly understood, especially for salmonids whose freshwater habitat often overlaps with RoR hydropower potential. Flow regulation for RoR hydropower is unique in how it influences the seasonality and magnitude of flow diversion and because low-head dams can be overtopped at high flows. Based on a review of the primary literature, we identified three pathways of effects by which RoR hydropower may influence salmonids: reduction of flow, presence of low-head dams impounding rivers, and anthropogenic flow fluctuations. We synthesized empirical evidence of effects of RoR hydropower on river ecosystems from 31 papers, of which only 10 explicitly considered salmonids. We identified key research gaps including impacts of extended low-flow periods, anthropogenic flow fluctuations, and cumulative effects of multiple RoR projects. Filling these gaps is necessary to help manage and conserve salmonid populations in the face of the growing global demand for small-scale hydropower.Résumé : L'empreinte spatiale individuelle des centrales hydroélectriques au fil de l'eau est moindre que celle des centrales hydroélectriques avec réservoirs de retenue et, en conséquence, leurs impacts sur les écosystèmes aquatiques sont souvent jugés négligeables. Par contre, leurs effets écologiques sont peu connus, particulièrement pour les salmonidés dont l'habitat en eau douce coïncide souvent avec le potentiel hydroélectrique des centrales au fil de l'eau. La régulation des eaux par les centrales au fil de l'eau se distingue par son influence sur la saisonnalité et l'ampleur de la déviation des eaux, et parce que les barrages de basse-chute peuvent être submergés lors des crues. À la lumière d'un examen des sources documentaires primaires, nous avons cerné trois voies principales par lesquelles la production d'électricité des centrales au fil de l'eau peut influencer les salmonidés, soit la réduction des débits, la présence de barrages de basse-chute sur les rivières et des fluctuations d'origine humaine des débits. Nous avons produit une synthèse des résultats empiriques de 31 études portant sur les effets de la production d'hydroélectricité des centrales au fil de l'eau sur les écosystèmes lentiques, dont seulement dix s'intéressaient explicitement aux salmonidés. Nous avons cerné d'importantes lacunes dans les connaissances actuelles, dont l'impact de périodes prolongées de faible débit, des fluctuations d'origine humaine des débits et des effets cumulatifs de plusieurs centrales au fil de l'eau. Il est nécessaire de combler ces lacunes pour soutenir la gestion et la conservation durables des populations de salmonidés dans un contexte de demande mondiale croissante pour la production d'hydroélectricité à petite échelle.

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Section: (2) Effects Of Anthropogenic Flow Fluctuationsmentioning

confidence: 85%

Section: Pathway 3: Anthropogenic Flow Fluctuationsmentioning

confidence: 99%

Section: Pathway 3: Anthropogenic Flow Fluctuationsmentioning

confidence: 99%

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Run-of-River hydropower and salmonids: potential effects and perspective on future research

Gibeau

Connors

Palen

2017

Can. J. Fish. Aquat. Sci.

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“…Each point represents one study (n = 72) and color-coded by study approach (Before-After = 45, ReferenceExperimental = 19, Gradient = 5, BACI = 3) critical species life history stages (see Larson et al 2016). Furthermore, drawdown rate can affect responses; if water levels drop fast, less mobile taxa like bivalves (Werner and Rothhaupt 2008) or even small fish (Nagrodski et al 2012) can become stranded. Differences in frequency of drawdown (e.g.…”

Section: Quantify Multiple Characteristics Of Drawdowns (Eg Duratimentioning

confidence: 99%

Ecological impacts of winter water level drawdowns on lake littoral zones: a review

2017

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with r-selected life history strategies and with functional traits resistant to direct and indirect drawdown effects. Fish assemblages, though less directly affected by winter drawdowns (except where there is critically low dissolved oxygen), experience negative effects via indirect pathways like decreased food resources and spawning habitat. We identify eight general research gaps to guide future research that could improve our understanding about the complex effects of winter drawdowns on littoral zone ecology.

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“…In the Hardangerfjord region, hydroelectric power production has changed annual patterns of discharge in some rivers considerably, reducing available juvenile habitats. Furthermore, due to lower winter discharges after spawning in these rivers, redds may become isolated, resulting in massive egg mortality (Barlaup et al 1994;Grabowski & Isely 2007;Nagrodski et al 2012). In some rivers, the water inlet to the hydroelectric power station has been designed to maximize water intake without any attempts to allow descending fish to bypass.…”

Section: Major Population Threatsmentioning

confidence: 99%

A conservation plan for Atlantic salmon (Salmo salar) and anadromous brown trout (Salmo trutta) in a region with intensive industrial use of aquatic habitats, the Hardangerfjord, western Norway

Skaala

Johnsen²,

et al. 2013

Marine Biology Research

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Extensive use of aquatic habitats, mainly for hydropower and aquaculture, has a negative impact on anadromous salmonid populations of the Hardangerfjord region, western Norway. High infection levels of salmon lice, and high proportions of escaped farmed salmon in spawning rivers, appear to violate the goals in the 'Strategy for an Environmentally Sustainable Aquaculture Industry' set by the Norwegian government. An overview of the anadromous populations in the fjord, their status and the major threats are presented. A conservation plan with mitigation efforts consisting of seven steps is presented: (1) genetic assessment of Atlantic salmon and anadromous brown trout populations, (2) reducing gene flow from escapees, (3) reducing infection pressure from salmon lice, (4) conduct an assessment of the freshwater habitats for anadromous salmonids and then implement it in order to restore smolt production, (5) efforts to reduce risk of river pollution from agriculture and industry and minimize impacts from hydropower production, (6) when and where necessary and practical, plant out eyed eggs from the Norwegian Genebank to increase parr and smolt production, and finally, (7) monitor spawning populations and parr densities to evaluate potential effects of the mitigation efforts. Experience and knowledge gained through the plan will be useful for other regions with similar challenges. We call for an initiative to establish a national fund under democratic and public control, where funding can be obtained for projects which focus on mitigation efforts and conservation of salmonid populations.

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Fish stranding in freshwater systems: Sources, consequences, and mitigation

Cited by 149 publications

References 62 publications

Run-of-River hydropower and salmonids: potential effects and perspective on future research

Run-of-River hydropower and salmonids: potential effects and perspective on future research

Ecological impacts of winter water level drawdowns on lake littoral zones: a review

A conservation plan for Atlantic salmon (Salmo salar) and anadromous brown trout (Salmo trutta) in a region with intensive industrial use of aquatic habitats, the Hardangerfjord, western Norway

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