Hydroelectric dams and their reservoirs have been suggested to affect freshwater biodiversity. Nevertheless, studies investigating the consequences of hydroelectric dams and reservoirs on macroinvertebrate richness have reached opposite conclusions. We performed a meta-analysis devised to elucidate the effects of hydropower, dams and reservoirs on macroinvertebrate richness while accounting for the potential role played by moderators such as biomes, impact types, study designs, sampling seasons and gears. We used a random/mixed-effects model, combined with robust variance estimation, to conduct the meta-analysis on 107 pairs of observations ( i . e ., impacted versus reference) extracted from 24 studies (more than one observation per study). Hydropower, dams and reservoirs did significantly impact (P = 0.04) macroinvertebrate richness in a clear, directional and statistically significant way, where macroinvertebrate richness in hydropower, dams and reservoirs impacted environments were significantly lower than in unimpacted environments. We also observed a large range of effect sizes, from very negative to very positive impacts of hydropower. We tried to account for the large variability in effect sizes using moderators, but none of the moderators included in the meta-analysis had statistically significant effects. This suggests that some other moderators (unavailable for the 24 studies) might be important ( e . g ., temperature, granulometry, wave disturbance and macrophytes) and that macroinvertebrate richness may be driven by local, smaller scale processes. As new studies become available, it would be interesting to keep enriching this meta-analysis, as well as collecting local habitat variables, to see if we could statistically strengthen and deepen the conclusions of this meta-analysis.

Wild animals have parasites that can compromise their physiological and/or behavioural performance. Yet, the extent to which parasite load is related to intraspecific variation in performance traits within wild populations remains relatively unexplored. We used pumpkinseed sunfish ( Lepomis gibbosus ) and their endoparasites as a model system to explore the effects of infection load on host aerobic metabolism and escape performance. Metabolic traits (standard and maximum metabolic rates, aerobic scope) and fast-start escape responses following a simulated aerial attack by a predator (responsiveness, response latency, and escape distance) were measured in fish from across a gradient of visible (i.e. trematodes causing black spot disease counted on fish surfaces) and non-visible (i.e. cestodes in fish abdominal cavity counted post-mortem) endoparasite infection. We found that a higher infection load of non-visible endoparasites was related to lower standard and maximum metabolic rates, but not aerobic scope in fish. Non-visible endoparasite infection load was also related to decreased responsiveness of the host to a simulated aerial attack. Visible endoparasites were not related to changes in metabolic traits nor fast-start escape responses. Our results suggest that infection with parasites that are inconspicuous to researchers can result in intraspecific variation in physiological and behavioral performance in wild populations, highlighting the need to more explicitly acknowledge and account for the role played by natural infections in studies of wild animal performance.

The transformation of a river into a reservoir and the subsequent occupation of the riverbed by a reservoir can impact freshwater ecosystems and their biodiversity. We used the National Lake Assessment (134 reservoirs) and the National Rivers and Streams Assessment (2062 rivers and streams) of the United States Environmental Protection Agency in order to develop empirical characterization factors (CFs; in Potentially Disappeared Fraction of species [PDF]) evaluating the impacts of reservoir occupation on macroinvertebrate richness (number of taxa) at the reservoir, ecoregion and country spatial scales, using a space-for-time substitution. We used analyses of variance, variation partitioning, and multiple regression analysis to explain the role of ecoregion (or regionalization; accounting for spatial variability) and other potentially influential variables (physical, chemical and human), on PDFs. At the United States scale, 28% of macroinvertebrate taxa disappeared during reservoir occupation and PDFs followed a longitudinal gradient across ecoregions, where PDFs were higher in the west. We also observed that high elevation, oligotrophic and large reservoirs had high PDF. This study provides the first empirical macroinvertebrate-based PDFs for reservoir occupation to be used as CFs by LCA practitioners. The results provide strong support for regionalization and a simple empirical model for LCA modelers.

Group living is widespread among animal species and yields both costs and benefits. Presence of conspecifics can restrict or enhance the expression of individual behavior, and the recent social environment is thought to affect behavioral responses in later contexts, even when individuals are alone. However, little is known about how social group size influences the expression of individual physiological traits, including metabolic rates. There is some evidence that shoaling can reduce fish metabolic rates but this variable may be affected by habitat conditions such as shelter availability via density-dependent processes. We investigated how social group size and shelter availability influence Eurasian minnow (Phoxinus phoxinus) metabolic rates estimated by respirometry. Respirometry trials were conducted on fish in isolation before and after they were housed for 3 weeks in a social treatment consisting in a specific group size (n = 4 or 8) and shelter availability (presence or absence of plant shelter in the experimental tank). Plant shelter was placed over respirometers for half of the duration of the respirometry trials, allowing estimation of minimum daytime and nighttime metabolic rates in both conditions (in the presence or absence of plant shelter). Standard metabolic rate (SMR), maximum metabolic rate (MMR), and aerobic scope were also estimated over the entire trial. Minimum daytime and nighttime metabolic rates estimated while in presence of plant shelter were lower than when estimated in absence of plant shelter, both before and after individuals were housed in their social treatment. After the social treatment, SMRs were higher for fish that were held in groups of 4 as compared with those of fish held in groups of 8, while MMR showed no difference. Plant shelter availability during the social treatments did not influence SMR or MMR. Our results suggest that social group size may directly influence energy demands of individuals, highlighting the importance of understanding the role of group size on variations in physiological traits associated with energy expenditure.

Background There is growing evidence of the potential negative consequences of altered flow regimes, in terms of magnitude, frequency, timing, duration or season pattern, on fluvial ecosystems and the fisheries they support. The scientific and policy communities have acknowledged the need for a better understanding of the effects of flow alteration on fish productivity. We conducted a systematic map to provide an overview of the existing literature base on the effects of flow-regime changes on direct outcomes of freshwater or estuarine fish productivity in temperate regions to inform stakeholders and policy makers. Methods To identify relevant articles for inclusion in this systematic map, we searched six bibliographic databases, 29 organizational websites, one search engine, and 297 reviews, and solicited grey literature through relevant sources. We screened articles at title and abstract, then by full-text using predefined inclusion criteria. Included studies were coded for key variables of interest, along with a very basic critical appraisal for internal validity (i.e., susceptibility to bias). The quantity and characteristics of the available evidence, knowledge gaps and subtopics with sufficient coverage for full systematic reviewing are reported in a narrative synthesis. The distribution and frequency of examined effects of flow-regime changes on fish productivity outcomes are presented in visual heatmaps. Review findings A total of 1368 studies from 1199 articles were included in the systematic map database and used to identify a number of interesting themes in the evidence base: (1) large evidence bases were found in temperate regions of United States of America (USA), Canada, and Australia; (2) most studies either used a temporal or spatial trend design i.e., lacking a 'true' before intervention time period, or no intervention control sites; (3) the most studied causes of altered flow regime were natural (e.g., floods, droughts, climate change), hydroelectric facilities (hydro), and dams with no hydro; and (4) there were clear clusters of studies evaluating effects of changes in magnitude and surrogate measures (e.g., velocity, water depth) on fish productivity outcomes, in particular abundance and diversity metrics. A number of potential knowledge gaps were identified: including geographic (Northern Africa, and possibly parts of Asia), causes of altered flow regime (restoration, land-use change, and water abstraction/extraction/diversion), interventions (flow duration, frequency, rate of change, or timing), outcomes (population viability) and specific intervention/cause/outcome groups (e.g., changes in flow magnitude due to hydro or natural causes and fish survival, performance, and reproduction). A few aspects in methodology were also identified across studies, primarily a lack of true comparators (e.g., temporal or spatial trend designs). Conclusions This map suggests subtopics warranting future evidence synthesis include, examinations into how changes in flow magnitude affects: (1) fish abundance for dams with no hydro causes; (2) fish abundance, diversity/richness, migration, and growth for hydro causes; and (3) fish abundance, diversity/richness, growth, community structure, recruitment, and migrating fish abundance for natural causes. More comprehensive evidence is needed to understand how: (1) fish productivity metrics are affected by changes in flow regime due to restoration, land-use change, and water withdrawal/diversion activities; (2) how fish productivity is affected by changes to components of flow regime other than magnitude (e.g. , flow duration, frequency); and (3) changes in flow magnitude due to hydro or natural causes affect fish survival, performance, and reproduction; and (4) changes in flow regime (all causes, all interventions) affect population viability.

Climate change is impacting many, if not all, forms of life. Increases in extreme temperature fluctuations and average temperatures can cause stress, particularly in aquatic sessile ectotherms such as freshwater mussels. However, some species seem to thrive more than others in face of temperature-related stressors. Thermal tolerance may for example explain invasive species success. It is also known that mitochondria can play a key role in setting an ectothermic species’ thermal tolerance. In this study, we aimed to characterize the mitochondrial thermo-tolerance in invasive and endemic freshwater mussels. With the use of high-resolution respirometry, we analyzed the mitochondrial respiration of two freshwater bivalve species exposed to a broad range of temperatures. We noticed that the invasive dreissenid Dreissena bugensis possessed a less thermo-tolerant mitochondrial metabolism than the endemic unionid Elliptio complanata. This lack of tolerance was linked with a more noticeable aerobic metabolic depression at elevated temperatures. This decrease in mitochondrial metabolic activity was also linked with an increase in leak oxygen consumption as well as a stable maintenance of the activity of cytochrome c oxidase in both species. These findings may be associated both with species’ life history characteristics, as D. bugensis is more adapted to unstable habitats, in which selection pressures for resistance adaptations are reduced. Our findings add to the growing body of literature characterizing the mitochondrial metabolism of many aquatic ectotherms in our changing world.

Additional file 6. ROSES Systematic map checklist.

Availability of shelter is an important component of habitat selection for animals as it can influence survival (protection against harsh physical conditions and predation) and growth (energy acquisition and expenditure). Few studies address the effect of shelter on metabolic expenditures associated with non-mechanical tasks (excluding station holding or movement). The main goal of this study was to investigate the influence of shelter use on metabolic traits of smallmouth bass (Micropterus dolomieu) from two populations (Kiamika River and Lake Long). Respirometry experiments on smallmouth bass were conducted to measure standard metabolic rate (SMR), resting metabolic rate (RMR), aerobic scope (AS), recovery time (RT) and excess post-exercise oxygen consumption (EPOC) in the presence or absence of shelter. The presence of shelter did not affect most metabolic traits, except for RMR, which was reduced in the presence of shelter for Lake Long fish. The results of this study also show that larger fish had lower SMR in the presence of shelter than when it was absent. When accounting for social hierarchy, there were no differences in most metabolic traits in dominant or subordinate fish in the presence or absence of shelter, except for RT, which was significantly lower in the presence of shelter for dominant fish. These results do not support the existence of an unequivocal relationship between individual metabolic traits and the presence of shelter. If physiological motives may influence the use of shelter, sheltering in itself might not have important consequences on energy expenditures required for non-mechanical tasks.

Whether it is for water supply, flood control or hydropower uses, the transformation of a river into a reservoir can impact freshwater ecosystems and their biodiversity. Using the National Lake Assessment (NLA; 148 reservoirs) and the National Rivers and Streams Assessment (NRSA; 2121 rivers and streams) of the United States Environmental Protection Agency (USEPA), we evaluated the impacts of river impoundment on macroinvertebrate biodiversity at three spatial scales (, reservoir, ecoregion and country scale). We used a space-for-time substitution approach to model the impact of impoundment (, we used rivers and streams as the before-impoundment conditions, and reservoirs as the after-impoundment conditions). We expressed the impact on biodiversity in terms of potentially disappeared fraction of species (PDF) to be used in the life cycle assessment (LCA) framework. To understand the role of regionalization, and some potentially influential variables, on changes in macroinvertebrate richness following impoundment in the United States, we used analyses of variance (ANOVAs) as well as variation partitioning, and developed empirical predictive models. Overall, 26% of macroinvertebrate taxa disappeared following impoundment in the United States, and PDFs followed a longitudinal gradient across ecoregions (, higher PDFs in the western part of the country, lower PDFs in the eastern part). We also observed that large and oligotrophic reservoirs, located in high elevation had high PDFs. This study provides the first empirical PDF values for macroinvertebrates to be used as characterization factors (CFs) by LCA practitioners. We also provide strong support for regionalization and a simple predictive model to be used by LCA modellers.

Alterations to temporal patterns of river flow regimes resulting from damming and flow regulation practices may have negative consequences for freshwater communities. However, little has been performed to develop a holistic approach to assess the effects of hydrologic alterations on fish communities across a wide range of rivers and between different regulation strategies. To address this, we used daily and hourly hydrologic data from gauges in 10 regulated and 14 unregulated Canadian rivers. Building on the Ecological Limits of Hydrologic Alteration concept, hydrologic alterations for many ecologically relevant flow indices were combined to obtain river‐specific hydrologic alteration scores. Extensive community surveys to estimate fish abundance, biomass, diversity indices and habitat guild representation provided data for the derivation of similar river‐specific biotic alteration scores relative to unregulated river conditions. Our results indicate that biological impairment consisting of significant biotic alteration relative to the means from unregulated rivers was directly related to increasing flow alteration scores, with the smallest fish and flow alteration scores observed in run‐of‐river systems and the greatest alteration scores under hydro‐peaking regimes. Our approach not only examined the relationship between river‐specific hydrologic alteration scores and the associated biotic responses, but also provided a more comprehensive assessment of the flow‐response alteration relationship between regulation practices, which may better inform future environmental flow management guidelines. Copyright © 2015 John Wiley & Sons, Ltd.

Community attributes result from processes operating at various spatial scales. The hierarchic organisation of rivers and the prevailing hypotheses about the variables that affect fish communities make lotic ecosystems particularly suitable to study processes taking place across spatial scales. The general goal of this study was to investigate how river flow regime and local habitat properties explain and predict fish community attributes in unregulated and regulated rivers. Our objectives were: (1) to identify the hydrological indices that best describe the flow regimes of river segments subjected to different regulation types (unregulated, run-of-the-river, storage, and peaking), and; (2) to estimate the relative importance of hydrological indices (river scale), and water depth, water velocity, and substrate composition (local scale) in explaining and predicting local fish community attributes (species richness, total density, and total biomass). We surveyed 880 sites (~300 m2) in 25 rivers (14 unregulated and 11 regulated) located in six physiographic regions of Canada. Based on a discriminant function analysis, nine hydrological indices were selected to represent river flow regime. Models of fish community attributes were developed using linear mixed-models (LMM) by nesting sites within rivers and regions. A few hydrological indices along with habitat properties predicted fish community attributes at the site scale (0.43< cross-validation \(R_{CV}^{2} < 0. 6 6\)). Specific hydrological indices and local habitat properties can be managed to preserve fish community attributes in regulated rivers. Combining variables associated with different scales in a LMM was a powerful and efficient way to model fish community attributes and produced reliable predictive models.

In this paper, we describe an empirical approach to model community structure using phylogenetic signals. That approach combines information about the species (i.e. traits and phylogeny) with information about the habitat (i.e. environmental conditions and spatial distribution of sampling sites) and their interactions to predict the species responses (e.g. the local densities). As an application, we use the approach to model fish densities in rivers. In the model, the different species and size classes were described using a functional trait, body length, and phylogenetic eigenvectors maps whereas the sites were described using water velocity, depth, substrate composition, macrophyte cover, degree‐days, total phosphorus, and spatial eigenvector maps. The model (estimated using a regularised Poisson‐family generalised linear modelling approach) fitted the data well (likelihood‐based R2adj = 0.512) and showed fair predictive power (likelihood‐based cross‐validation R2 = 0.283) to predict the density of fish pertaining to 48 species totalling 143 combinations of species and size classes in 15 unregulated Canadian rivers. Using the model as a baseline to estimate the effect of flow regulation on community composition, we found that, with few exceptions, the densities of most fish species were lower in regulated than in unregulated rivers. Phylogenetics have been proposed to study community structure, but this is, to our knowledge, the first time phylogenetic information is used explicitly for numerical habitat modelling. We expect that models of that type will be in increasing demand now that development projects are routinely assessed through impact studies.

Morphological differentiation may allow individuals to cope with prevailing environmental conditions. Morphological differentiation in fish characterized by sagittiform shape and ambush predator behaviour, such as northern pike (Esox lucius L., 1758), has rarely been addressed. Morphological differentiation was assessed in two rivers exhibiting contrasting flow regimes: a hydropeaking river characterized by large and frequent fluctuations in flow rates and an unregulated river. An increase in northern pike movement rate was observed in the hydropeaking river. Therefore, morphological features enhancing sustained and burst swimming, as well as manoeuvrability, were expected. Our objectives are to (i) compare morphology between the two rivers and (ii) assess morphological differentiation between sexes. Using geometric morphometrics, shape significantly diverged between rivers irrespective of sex and between sexes in the hydropeaking river. Individuals from the hydropeaking river had more elongated heads, deeper bodies and caudal peduncles, and longer dorsal fin insertions than individuals from the unregulated river. Caudal fin differences between rivers were not consistent between sexes. Morphological differentiation suggested a trade-off among adaptations for sustained and burst swimming, as well as manoeuvrability, to cope with variable flows in a hydropeaking river. Morphological differentiation may allow the exploitation of spatially and temporally variable environmental conditions, including those stemming from river flow regulation.

Despite the fact that humans have dramatically altered flows in many rivers, little is known about the consequences of such alterations on the sub-daily behavior of resident fish. Data on adult northern pike (Esox lucius L.) sub-daily movements were collected in two rivers of northeastern Ontario on a total of 40 individuals: the Mississagi River, a hydropeaking river subjected to extreme daily flow variations associated with hydroelectric operations and the Aubinadong River, an unregulated river used as a reference site. Using manual tracking by radio-telemetry, we found that northern pike movement is affected by flow, but that the direction of this relationship can differ among rivers, depending on the water temperature and on the flow regime in which fish were tracked. Moreover, fish in the Mississagi River utilized a restricted longitudinal river section in comparison to fish inhabiting the Aubinadong River. This study contributes to our understanding of how fish react to hydropeaking flows and how they behave under natural flow conditions, which is relevant to the management of regulated rivers.

Little is known about the effect of short‐term flow changes on the movement of northern pike ( Esox lucius L.). We conducted a comparative study in two rivers with different flow regimes (i.e. one regulated and one unregulated) to evaluate the extent to which adult northern pike movement is influenced by short‐term river flow conditions. Data on northern pike hourly movement were collected in northeastern Ontario on 40 individuals in the Mississagi River, a river subjected to extreme daily flow variations associated with hydro‐electric operations (i.e. hydropeaking), and the Aubinadong River, an unregulated river. Using manual tracking by radio‐telemetry, we found that northern pike moved at a higher rate in the river subjected to short‐term changes in river flow than in the unregulated river. Results also show that the relationship between movement of northern pike and flow can vary among rivers. In the Mississagi River, flow had a significant positive effect on northern pike activity, while the effect of flow in the Aubinadong River depended on water temperature. Moreover, fish in the Mississagi River utilized a restricted river section and travelled more laterally in comparison to fish inhabiting the Aubinadong River, where longer upstream‐downstream movements were more common. The present study contributes to our understanding of the effects of short‐term changes in flow on fish movement. This constitutes the first step towards assessing the effect of flow on fish habitat use, and eventually developing flow management strategies to mitigate impacts on fish. Copyright © 2016 John Wiley & Sons, Ltd.

Abstract Ecological processes are structured in space and there are important benefits in incorporating spatial information for the analysis of data sets obtained from field studies. Assessing the effect of different flow management practices on river ecosystems is an example where such an exercise is highly relevant. Human activities such as hydroelectric power production are known to modify the temporal variability in river flow. Flow management strategies may have a direct influence on fishes and may trigger complex cascades of interactions involving different features of the river ecosystem. In this study, we performed an assessment of the effect of different flow management practices on fish count density (no. fish/m2), biomass density (g/m2), and species richness. Data were collected in 941 sites located along 28 Canadian rivers. These rivers were either naturally flowing or had altered flows from one of three flow management strategies: run of the river dams, storage with gradual release, or storage with peak release. Each site (300 m2) was surveyed using paired snorkeling and electrofishing techniques; environmental variables (water depth and velocity, and substrate composition) were also measured. The study spanned a broad geographic range (3497 km, geodesic distance) and involved repeated local observations (16–50 sites/river), and was therefore inherently spatially organized. We used spatial modeling to obtain a baseline to estimate the effect of flow management strategies on fishes. Our results indicate that rivers downstream of flow peaking storage dams have, by far, the lowest fish densities (count and biomass) and species richness, whereas those downstream of gradual release storage dams had higher fish biomass density than the unregulated rivers.

The Great Lakes Fishery Commission sponsored a 2-day workshop that sought to enhance the ability of Great Lakes agencies to understand, predict, and ideally manage fisheries production in the face of changes in natural and anthropogenic forcings (e.g., climate, invasive species, and nutrients). The workshop brought together 18 marine and freshwater researchers with collective expertise in aquatic ecology, physical oceanography, limnology, climate modeling, and ecosystem modeling, and two individuals with fisheries management expertise. We report on the outcome of a writing exercise undertaken as part of this workshop that challenged each participant to identify three needs, which if addressed, could most improve the ability of Great Lakes agencies to manage their fisheries in the face of ecosystem change. Participant responses fell into two categories. The first identified gaps in ecological understanding, including how physical and biological processes can regulate early life growth and survival, how life-history strategies vary across species and within populations, and how anthropogenic stressors (e.g., nutrient runoff, climate change) can interact to influence fish populations. The second category pointed to the need for improved approaches to research (e.g., meta-analytic, comparative, spatial translation) and management (e.g., mechanistic management models, consideration of multi-stock management), and also identified the need for improved predictive models of the physical environment and associated ecosystem monitoring programs. While some progress has been made toward addressing these needs, we believe that a continued focus will be necessary to enable optimal fisheries management responses to forthcoming ecosystem change.

Summary Hydropower currently accounts for 63% of Canada's total electricity generation and is bound to increase with the energy demands of a growing population. With damming and flow regulation known as major threats to aquatic biodiversity and river and floodplain habitats, an improved understanding of the specific impacts of river regulation is needed for the proper management of these systems. Although interactions among river flow and thermal regimes have been described in the literature, their concurrent influence on fish guild responses has yet to be analysed for temperate rivers. Such an analysis may be used to identify the ecological traits linked with the flow and thermal variables reflecting river regulation. Extensive field surveys were conducted across 25 unregulated and regulated rivers to estimate fish species density and biomass. Fish guild models were developed to characterise morphologic, trophic, reproductive, habitat preferences and behavioural traits, as well as phylogenetic associations. To characterise ecologically relevant components of the flow and thermal regimes of rivers, we calculated indices based on the magnitude, frequency, duration, timing and rate of change in each driver. Model relationships between fish biomass and density estimates were then run using redundancy analyses (RDA) on each type of guild and dominant patterns of flow and thermal variability. Variables representing the magnitude of summer temperatures and intra‐annual flow variability were consistently selected as independent drivers of fish guild responses (>86% of RDA models), clearly showing the importance of integrating thermal regimes in current river hydro‐ecological studies. Fish guild density and biomass were significantly explained (R2Adj = 25–44%) and predicted (R2CV = 35–76%) by flow and thermal variables characterising regimes across unregulated and regulated rivers, whereas total fish density and biomass were not. Fish guild models based on trait–environmental relationships performed better than those based on phylogeny. Our results also showed that the models describing habitat and trophic guilds had the greatest explanatory power (R2Adj = 0.44 and R2Adj = 0.41 respectively). This study identified differences in guild trait–environment relationships across rivers and the guilds most susceptible to changes in flow and temperature conditions resulting from river regulation. In particular, more constant summer temperatures and lower flow variability favoured habitat and trophic guilds over morphologic, reproductive and behavioural guilds. Our results showed that maintaining particular aspects of the flow and thermal regime may be important for ensuring the presence of certain guilds in temperate rivers.

Rock riprapping revetment is a form of riverbank stabilization that is commonly used to protect road and bridge infrastructures from fluvial erosion. However, little is known about how these may affect habitat selection by riverine fish in streams impacted by multiple stressors stemming from agricultural activities. Nine streams in Southern Quebec (Canada) served as study sites, where fish surveys and habitats attributes were measured. Nested linear mixed-models using percent cover of rock, wetted stream width, water depth, and flow velocity as fixed effects, and spatio-temporal variables as random effects, were conducted to assess the ecological effects of rock riprapping revetment across agricultural streams. Results indicated that overall fish density was significantly explained by fixed effects (R-2 = 35.7% : Marginal) and by random effects (R-2 = 24.2) which lead to a model explaining 59.9% (R-2 : Conditional). Nested linear mixed-models was assessed by cross-validation (jackknife leave-one-out procedure) and showed an (RCV)-C-2 of 57%. An interaction between rock riprapping revetment and wetted stream width on fish densities was also observed (p-value = 0.0195). These findings suggest that the rock riprapping revetment zones had greater fish densities if water depths were maintained, as these zones contributed to stream habitat complexities, providing suitable fish habitats that were not available elsewhere in these streams. The knowledge gained here may further improve on existing riprap zone designs implemented by the Ministsre des Transports du Quebec (Quebec Ministry of Transportation).