Estimating species’ potential distribution is one of the main objectives of macroecology, especially when sampling biases can affect knowledge on how environmental variables affect species distribution. Ecological niche models estimate species’ environmental niches from different variables and their occurrences. Using the presence‐only data from eight Amazonian fish species, which inhabit rivers and

Identifying the spatial patterns of fish diversity in streams is basic for the conservation and management of stream fishes. The “upstream–downstream” patterns in the taxonomic α‐diversity of stream fishes have been widely surveyed. However, the longitudinal patterns in the functional diversity and β‐diversity of stream fishes have been given less attention. In this study, we surveyed fishes along

Lake sturgeon (Acipenser fulvescens) have been negatively impacted by barriers to migration, pollution and overharvest. Biological data such as the timing of spawning activity and larval drift have provided a better understanding of larval production success or failure on a site‐specific basis. However, many river systems that serve as reproductive locations for remnant lake sturgeon populations remain

Stable isotope ratios of nitrogen (δ15N) have been used to estimate trophic position (TP) of organisms due to the predictable enrichment of nitrogen‐15 in consumer tissues relative to their diet. We explored estimates of trophic position using liver and muscle δ15N and stomach content analysis in a broad size range of Arapaima sp. from Amazonian floodplain lakes. Estimates of TP based on liver δ15N

Climate change will increase the temperature of rivers and will lead to more extreme events, such as floods. Temperature increases and floods will likely alter the phenology of freshwater species differently and have the potential to significantly disturb prey–predator interactions. In spring, an increase in temperature triggers an increase in primary production and controls the timing of the emergence

The conservation, management and monitoring of aquatic resources should benefit from understanding their spatial structuring. In this paper, we used the reference condition approach (RCA) to test if the variability in biotic communities, riverine fish assemblages in the present case, is better controlled with a spatial delineation based on ecoregions or by grouping rivers with local catchment characteristics

Volitional dispersal is a ubiquitous strategy characteristic of species across major faunal groups. Dispersal during the juvenile life stage is of interest because early performance can be critical for determining future success (survival/reproduction). For salmonids, dispersal can influence local density, competition, individual growth and survival, though drivers of dispersal at meso‐scales are rarely

Clear Lake Hitch is an imperilled minnow endemic to Clear Lake, Lake County, California, United States listed as threatened under the California Endangered Species Act (ESA) and a candidate for listing under the United States ESA. It exhibits a potamodromous life cycle whereby adults, which reach up to 6 + years in age and over 350 mm in length, migrate into Clear Lake's ephemeral tributaries briefly

Adaptations that maximise food intake are dependent on food and/or habitat types. However, there have been few studies on the ability of floodplain primary freshwater fish to rapidly change their morphology, especially the internal one, to maximise utilisation efficiency of food resources in response to environmental fluctuations during their life history. We investigated morphological changes of an

Predicting the potential effects of changes in climate on freshwater species requires an understanding of the relationships between physiological traits and environmental conditions among populations. While water temperature is a primary factor regulating metabolic rates in freshwater ectotherms, how metabolic rates vary across the species range is unclear. In addition, photoperiod has also been hypothesised

Between global climate change and anthropogenic water needs, freshwater systems are becoming more intermittent, stressing organisms adapted to perennial waters. Drought‐induced intermittency concentrates aquatic organisms into drying pools. These pools represent refugia from desiccation but apply other stressors, such as extreme temperatures and increased competition for dwindling resources. In the

Swimming performance is a key feature that mediates fitness and survival in many fish species. Using a swim tunnel respirometer, we compared prolonged swimming performance and energy use for two competing species: an endangered, endemic toothcarp (Aphanius iberus) and a worldwide invasive mosquitofish (Gambusia holbrooki). Critical (Ucrit) and optimal swimming speeds, standard and maximal metabolic

One of the main impacts on aquatic environments is the alteration of flow regime, usually caused by dam construction. This impact changes the dynamics and functioning of the environment. We aimed to evaluate changes in the composition of functional traits of fish assemblages from 29 reservoirs of different chronological ages. We assessed if there were any alterations in trophic state of these reservoirs

The process of urbanisation is increasing the frequency and magnitude of fluctuations in the availability of food resources for fish. In this study, we investigated whether the diet and prey selected by the guppy Poecilia reticulata reflect the different levels of urbanisation using the total area of impervious surface soil as the metric. Rural streams (low percentage of urbanisation—LPU) and urban

River infrastructures such as weirs, hydropower stations or water reservoirs represent obstructions to migration for diadromous fish. Knowledge of accurate behaviour of fish in front of such structures is required to protect migrants from hazardous areas, guide them towards safe passage or adapt structure to improve the escapement. We developed and made available a method to process acoustic telemetry

Comparing multiple fitness components and potential movement of wild hybrids with their parental species is necessary to fully understand the consequences of human‐mediated introgression, but studies tracking both parental species and their hybrids at the individual‐level are limited. Here, we compared growth, survival and movement of sympatric introduced brook trout (BT: Salvelinus fontinalis) and

Pugnose minnow (Opsopoeodus emiliae) is a small, reclusive species that is widespread in North America, but is one of the rarest fishes in Canada, found in less than 12 known localities in southwestern Ontario. In contrast to most pugnose minnow populations across the global range, Canadian populations are primarily found in turbid systems, potentially indicating persistence in suboptimal conditions

We studied daily spawning periodicity of a nest‐building species, bluehead chub (Nocomis leptocephalus), and a nest associate, yellowfin shiner (Notropis lutipinnis), in three streams in the upper Piedmont region of South Carolina, USA. Field observations were conducted for 89 consecutive days in 2016 by recording the number of active nests and environmental variables. A total of 71 nests were located

Dam removals allow fish to access habitats that may provide ecological benefits and risks, but the extent of fish movements through former dam sites has not been thoroughly evaluated for many species. We installed stationary PIT antennas in 2016 and 2017 to evaluate movements and survival of brook trout Salvelinus fontinalis in the West Branch of the Wolf River (WBWR) in central Wisconsin following

Anthropogenic increases to turbidity (suspended particulates) in the water column can alter the underwater visual environment, resulting in disruptions to visual signals in fishes exposed to these conditions. However, dissimilar turbidity types (e.g. sedimentary or algal particles) are expected to influence the visual environment in different ways as they exhibit differing physical characteristics

Unravelling the effect of climate variability on species biology has been one of the main goals of ecological studies. Environmental factors such as river discharge and temperature have being proposed as triggers of reproductive cycle in fish. In temperate climates, fish reproduction is affected mainly by temperature, while is influenced by flood pulses in large tropical rivers. We evaluated the influence

Understanding the spatial ecology of juvenile freshwater fish beyond summer months is an essential component of their life history puzzle. To this end, declines in the natural populations of sympatric Muskellunge (Esox masquinongy) and Northern Pike (Esox lucius) in the upper St. Lawrence River prompted study of spatiotemporal patterns and habitat requirements associated with earlier life stages of

Understanding biodiversity and community composition is a prerequisite to sustainable exploitation and conservation of fisheries. We assessed the spatial and seasonal patterns of fish community composition and biodiversity in seasonal no‐take riverine sanctuaries in Bangladesh, which aim to conserve the anadromous hilsa shad (Tenualosa spp. and Hilsa keele). Fish samples were collected during monsoon

Individual variability in dispersal strategies, where some individuals disperse and others remain resident, is a common phenomenon across many species. Despite its important ecological consequences, the mechanisms and individual consequences of dispersal remain poorly understood. Here, riverine Northern pike (Esox lucius) juveniles (age 0+ (young‐of‐the‐year) and 1+ years) were used to investigate

We employed the trophic upsurge hypothesis as an analytical framework to describe the response of Neotropical fish communities to terrestrial inundation associated with river damming. Data were collected for the impact assessment of the Peixe Angical Dam, Tocantins River, Brazil. Monthly surveys were conducted at nine sites (seven upstream, two downstream) from 15 months before to 20 months after dam

The catadromous life cycle of the European eel encompasses a spawning migration to the Sargasso Sea. Prior to their migration, eels develop a silver coloration being referred to as “silver eels.” Due to the dramatic European eel recruitment decline, it is crucial to quantify silver eel escapement to evaluate the success of measures taken under Eel Management Plans (Regulation EC (1100/2007)). Thus

The establishment of national parks are an important and often‐used tool to protect biodiversity. However, when considering freshwater ecosystems, many of these areas in Brazil are habitat mosaics in which a small part of the ecosystem is protected and strongly influenced by the surrounding environment. By assessing the fish fauna and their diversity patterns in five national parks (NPs) within the

Alternative life‐history tactics of masu salmon Oncorhynchus masou are well documented. Subsequent to the freshwater parr stage (age ≥ 1 + years), an anadromous form migrates to the sea after smolting, while a resident form matures without seaward migration. In addition to this typical migratory dimorphism, anecdotal reports based on field observations have indicated that some underyearling masu salmon

Smolt lengths are increasingly recognised as an important determinant of salmonid marine survival rates. Overwintering growth rates could thus strongly influence adult return rates. In Atlantic salmon Salmo salar, most overwintering studies focus on rivers in harsh climates with minimal growth, yet in more southerly rivers, overwintering growth rates can be relatively high. Here, the factors influencing

Differences in reproductive strategies of male and female fishes are presumably accompanied by differences in nutrient allocation and predicted to lead to divergence in body composition between the sexes. We compared patterns of variation in fatty acid profiles of lipids extracted from ova, liver, muscle and visceral fat between mature male and female walleye (Sander vitreus) sampled from two wild

Body shape variation should play a central role in determining the feeding ability of a fish species. We tested whether variations in feeding resource use of sympatric and closely related fish species could be explained by differences in ecologically relevant metrics, such as body morphology, trophic apparatus or combinations thereof. Fish were sampled at 14 sampling sites from Pelotas River and tributaries

There is concern that expanding beaver (Castor fiber) populations will negatively impact the important economic, recreational and ecological resources of Atlantic salmon (Salmo salar) and sea trout (Salmo trutta) populations in Europe. We studied how beaver dams influenced habitat, food resources, growth and movement of juvenile Atlantic salmon and trout on three paired beaver‐dammed and beaver‐free

Experimental predation studies were conducted to evaluate and compare the predation threats of 10 species of native and non‐native fishes on larvae of Pacific Lamprey, Entosphenus tridentatus, and Western Brook Lamprey, Lampetra richardsoni. The relative predatory threats were examined over four sets of binary factors, including the following: (a) short (2‐day) or long (7‐day) duration, (b) presence/absence

We investigated whether isotopic niche partitioning could mediate the coexistence between native (Hoplias sp. B) and non‐native (Hoplias mbigua) trahira in a Neotropical floodplain. We hypothesised that during the dry season both species inhabit isolated sites (i.e. lakes) and thus rely on distinct food resources to sustain their coexistence. We found evidence of trophic segregation among native and

Growth of fish is an important contributor to individual fitness as well as fish production. Explaining and predicting growth variation across populations is thus important from fundamental and applied perspectives, which requires knowledge about the ecological factors involved in shaping growth. To that end, we estimated environment‐dependent von Bertalanffy growth models for 13 gravel pit lake populations

Bayesian inference was used to estimate the main population parameters (sex ratio, L50, LWR and somatic growth) and to evaluate sexual dimorphism and growth patterns (isometric/allometric and monophasic/biphasic growth) of Astyanax paranae of the Upper Paraná River. This study brings three statistical differentials: (a) the reparametrisation of the logistic model as a function of L50; (b) the reparameterisations

Multiyear drought is projected to increase in frequency and duration in arid and semiarid regions across the world, threatening native species and ecosystem function. The effects of multiyear drought are often exacerbated by human water use, which manifest in reduced lake elevation, reduced stream discharge, and disruption in hydrologic connectivity for aquatic species. Here, we demonstrate that drought‐driven

Many species of salmonids have been stocked into waters outside of their native range. The invasiveness and impact of these species on native species varies depending on their biological traits, and on environmental conditions, such as climate. In Japan, rainbow trout and brown trout, both listed in 100 of the world's worst invasive alien species by the International Union for Conservation of Nature

The consequences of over‐exploitation may seriously impair the integrity and functioning of ecosystems. When loss of species is accompanied by the loss of ecological processes, the effects are no longer just taxonomic and may affect the stability of the environments. Ornamental fishing is one of the main economic activities of the middle Negro River. Such activity is directed to a small number of species

Trout and charr, members of the salmonid family, have high conservation value but are also susceptible to anthropogenic threats in part due to the specificity of their habitat requirements. Understanding historical and future threats facing these species is necessary to promote their recovery. Of freshwater trout and charr in the Canadian Rocky Mountain region, westslope cutthroat trout (Oncorhynchus

Understanding resident fish population responses to restored connectivity would enhance decision‐making on dam removal and fish passage. Since evaluations of river connectivity changes on resident trout populations are limited in the Great Lakes region of North America, we compared abundance, survival and growth of resident brook trout and brown trout between sets of Michigan streams where populations

Inter‐basin water transfers create new pathways between previously disjunct systems and communities. If fish movement occurs, it can lead to invasion or altered regional connectivity patterns, which could induce biotic/genetic homogenisation or synchronisation. Understanding ecological factors promoting movement is critical for predicting potential impacts during project planning, to assess ongoing

Proliferative kidney disease (PKD) is an emerging parasitic disease that affects wild and farmed salmonid fishes worldwide. Currently, it is widespread in Europe with records in many countries. This study assessed the status of PKD in the river Wulka, a small Austrian river, which was known to host a vital brown trout population despite having high water temperatures. Contrary to the initial hypothesis

Understanding juvenile salmonid habitat requirements is critical for their effective management, but little is known about these requirements in lowland rivers, which include important but unique salmonid habitats. We compared the relative influence of in‐stream Ranunculus cover, water depth, prey abundance, distance upstream and two previously unexplored factors (water velocity heterogeneity and site

Food availability and thermal regimes can largely govern growth opportunities in fishes. In temperate regions, streams can exhibit summer temperatures that exceed the optima for coolwater‐adapted species relative to the amount of available food, and therefore, spring and fall may confer better growing conditions, especially for larger size classes. We examined the relationship between growth, consumption

Understanding how changes in stream temperature affect survival and growth of coldwater fishes, including brown trout (Salmo trutta) and rainbow trout (Oncorhynchus mykiss), is important for conserving coldwater stream fisheries in a changing climate. However, some contemporary stream temperature models assume spatially uniform (i.e. unrealistic) air–stream temperature relationships or demand hydrometeorological

We reviewed 199 published data sets (21 species) to assess the relative frequency of various density‐dependent processes in salmonids. We examined studies for the presence or absence of density‐dependence: in growth, mortality, fecundity and recruitment. Based on data from all studies pooled 71% showed density‐dependence in growth, 23% found density‐dependence in mortality, 2% detected density‐dependence

Historical data are widely used in river ecology to define reference conditions or to investigate the evolution of aquatic systems. Most studies rely on printed documents from the 19th century, thus missing pre-industrial states and human impacts. This article discusses historical sources that can be used to reconstruct the development of riverine fish communities from the Late Middle Ages until the

Threespine stickleback (Gasterosteus aculeatus) populations that have evolved pelvic girdle reduction are most commonly found in lakes with low dissolved ion concentration, a lack of piscivorous fishes, and abundant macroinvertebrate predators. Researchers have speculated that macroinvertebrates have a propensity to consume prey with pelvic spines. If this is true, perhaps macroinvertebrates use the

Emigration is a widespread phenomenon among fish species in seasonal habitats, but little is known about the factors which trigger this behaviour. In controlled experiments using Tilapia guineensis, a species widely occurring in the seasonal floodplains of West Africa, density of fish played a significant role in triggering fish migration, whereas a lack of food available caused an increase in exploratory