Quantifying fish dispersal and identifying its general predictors is key for understanding temporal patterns in population dynamics, emigration and immigration, meta-community dynamics, many ecological processes and predicting recovery time or population responses to environmental changes. This is the first comprehensive quantitative meta-analysis of heterogeneous freshwater fish movement, aiming to determine mobile and stationary shares of fish communities, their dispersal distances and key predictors of dispersal patterns. By reviewing and analysing 160 empirical data sets from 71 studies covering 62 fishes in streams, it goes beyond previous studies of salmonids’ heterogeneous movement. Based on fitted leptokurtic dispersal kernels, the movement distances of (i) a stationary component (σstat) and (ii) a mobile component (σmob) as well as the (iii) share of each component (p) were calculated. The median movement distance of the stationary and mobile component of a fish population was 36.4 and 361.7 m, respectively. The share of the stationary individuals was high (median = 66.6%), but unrelated to movement distance. Single and multiple linear regressions as well as mixed-effects models revealed movement distances positively related to fish length, aspect ratio of the caudal fin, stream size and duration of the study. Furthermore, movement distance differed between taxonomic families. The quantitative parameters of heterogeneous fish movement provided are prerequisite to estimate time lags in fish response to river rehabilitation, temporal patterns in species dispersal, and minimum effective size of potential founder populations for species conservation and stock recovery based on minimum numbers of specimen to disperse.

Patterns and predictors of fish dispersal in rivers

State of the environment report

We quantified movements of brook trout Salvelinus fontinalis and brown trout Salmo trutta in a complex riverscape characterized by a large, open-canopy main stem and a small, closed-canopy tributary in eastern West Virginia, USA. Our objectives were to quantify the overall rate of trout movement and relate movement behaviors to variation in streamflow, water temperature, and access to coldwater refugia. The study area experienced extremely high seasonal, yearly, and among-stream variability in water temperature and flow. The relative mobility of brook trout within the upper Shavers Fork watershed varied significantly depending on whether individuals resided within the larger main stem or the smaller tributary. The movement rate of trout inhabiting the main stem during summer months (50 m/d) was an order of magnitude higher than that of tributary fish (2 m/d). Movement rates of main-stem-resident brook trout during summer were correlated with the maximum water temperature experienced by the fish a...

Brook Trout Movement in Response to Temperature, Flow, and Thermal Refugia within a Complex Appalachian Riverscape

Telemetry is an increasingly common tool for studying the ecology of wild fish, with great potential to provide valuable information for management and conservation. For researchers to conduct a robust telemetry study, many essential considerations exist related to selecting the appropriate tag type, fish capture and tagging methods, tracking protocol, data processing and analyses, and interpretation of findings. For telemetry-derived knowledge to be relevant to managers and policy makers, the research approach must consider management information needs for decision-making, while end users require an understanding of telemetry technology (capabilities and limitations), its application to fisheries research and monitoring (study design), and proper interpretation of results and conclusions (considering the potential for biases and proper recognition of associated uncertainties). To help bridge this gap, we provide a set of considerations and a checklist for researchers to guide them in conducting reliable and management-relevant telemetry studies, and for managers to evaluate the reliability and relevance of telemetry studies so as to better integrate findings into management plans. These considerations include implicit assumptions, technical limitations, ethical and biological realities, analytical merits, and the relevance of study findings to decision-making processes.

Conducting and interpreting fish telemetry studies: considerations for researchers and resource managers

Empirical relationships between stream flow and ecological responses (flow–ecology relationships) are essential for establishing environmental flows and evaluating tradeoffs between instream values and out-of-stream uses. Establishing the shape of flow–ecology relationships (i.e. slope, linearity versus nonlinearity) is particularly important to avoid crossing ecological thresholds in water management.
This review focuses on ecological responses to discharge at low summer flows when out-of-stream water demand is often highest, and identifying ecological contexts where nonlinearities are most likely. Most physical attributes (temperature, dissolved oxygen, available habitat) and ecological responses (energy flow, fish survival, recruitment, community structure) show at least some evidence of nonlinear relationships with flow, although assumptions of linearity may be reasonable across limited discharge ranges which may include low flows.
Nonlinearities are most likely in systems that are near existing thresholds (e.g. cold-water transitional fish communities that are close to upper thermal tolerances). The probability of nonlinearities is likely to increase under future landuse and climate change scenarios, particularly in combination with other stressors, such as eutrophication, which may greatly accelerate temperature-related decline in dissolved oxygen under climate warming.
Managers need to anticipate changes in flow–ecology relationships and develop management systems that are robust to change. Field programmes to establish the slope and linearity of local flow–ecology relationships are essential for regional management, but developing generalisable flow–ecology relationships that are transferrable to regions with limited resources also needs to be a priority.
Generalised relationships can be generated through meta-analysis of empirical flow–ecology relationships, and may prove especially useful if they can capture how environmental and ecological context (channel size and morphology, landuse, flow regime, antecedent conditions, habitat or taxonomic guild) affect flow–ecology relationships. For instance, linking empirical data from flow–ecology relationships to available habitat predicted by physical habitat simulation models (e.g. PHABSIM) may provide a better mechanistic basis for modelling ecological responses, while providing much needed validation for habitat simulation approaches. This would also help bridge the gap between emerging holistic environmental flow modelling approaches and more traditional habitat simulation methods.

Developing flow-ecology relationships: implications of nonlinear biological responses for water management.

Management of the effects of water quality and flow on fisheries requires an understanding of the factors that control fish movements. We used radiotelemetry to monitor the movements of adult brown trout Salmo trutta in a New Zealand river over 11 months (September 2004 to August 2006) and linked those movements to the changes in flow and water temperature. Individual fish moved up to 41 km during the study. However, most fish moved less than 1 km. All of the trout that showed little movement throughout the summer were living in relatively deep pools that presumably provided cover. The rates of movement declined steadily over the spring–summer period, as flow decreased and water temperature increased. The percentage of fish moving was positively related to the average daily flow during the interval between tracking occasions and negatively related to the average daily water temperature, less than 20% of the tagged fish moving once temperatures were above 19°C. A severe, 50-year flood occurred in ...

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Movement and mortality of adult brown trout in the Motupiko River, New Zealand: effects of water temperature, flow, and flooding.

We compared a process-based invertebrate drift and drift-feeding net rate of energy intake (NREI) model and a traditional hydraulic-habitat model (using the RHYHABSIM [River Hydraulics and Habitat Simulation] software program) for predicting the flow requirements of 52-cm Brown Trout Salmo trutta in a New Zealand river. Brown Trout abundance predicted by the NREI model for the constant drift concentration–flow scenarios were asymptotic or linear, depending on drift concentration, increasing through the mean annual low flow (MALF; 17 m3/s). However, drift concentration increased with flow, consistent with passive entrainment. The predicted fish abundance–flow relationship based on flow-varying drift concentration increased logistically, and more steeply, with flow through the MALF and beyond. Predictions for the relationship between weighted useable area (WUA) and flow were made for three sets of drift-feeding habitat suitability criteria (HSC) developed on three midsized and one large New Zealand ...

Can Weighted Useable Area Predict Flow Requirements of Drift-Feeding Salmonids? Comparison with a Net Rate of Energy Intake Model Incorporating Drift–Flow Processes

1 Cawthron Institute 98 Halifax Street East Private Bag 2 NELSON 2 Tasman District Council 189 Queen Street Private Bag 4 RICHMOND A technical report presenting results of the Tasman District Council’s “State of the Environment” Surface Water Quality Monitoring Programme from 1999 to April 2004 incorporating monitoring data collected by National Water Quality Network from 1989 to 2003 and other data. Along with physical and chemical indicators, results from macroinvertebrate and periphyton indicators are presented. The report highlights freshwater quality issues and outlines what Tasman District Council is doing to help improve water quality where it is found to be poor.

State of surface water quality in tasman district

We investigated the potential of dual-frequency identification sonar (DIDSON) deployed from a drifting cataraft for estimating abundance in rivers of Brown Trout Salmo trutta larger than 20 cm. We compared triplicate trout density estimates made by DIDSON with drift-diving density estimates in three reaches of a clear-water river in New Zealand. DIDSON density estimates were much lower (∼22% of drift-dive estimates, range = 7–33%) and less precise than drift-dive estimates (DIDSON CV = 0.13–0.47; drift diving CV = 0.15–0.17). Variation in detecting fish in the DIDSON field survey contributed substantially more (95%) to DIDSON count variability than did fish detection in the image files. Highest precision with DIDSON was achieved in the reach with the least shallow habitat and most uniform channel. Fewer person-hours were required to undertake the field component of DIDSON surveys than the drift dives (5 versus 8.3 h), but the substantial time spent on image review (3.3 h) made DIDSON surveys 34% m...

Joe Hay

Papers

Movement and mortality of adult brown trout in the Motupiko River, New Zealand: effects of water temperature, flow, and flooding.

Can Weighted Useable Area Predict Flow Requirements of Drift-Feeding Salmonids? Comparison with a Net Rate of Energy Intake Model Incorporating Drift–Flow Processes

State of surface water quality in tasman district

Estimating Trout Abundance with Cataraft-Mounted Dual-Frequency Identification Sonar: a Comparison with Drift Diving