Fish Passage Research Articles

Conditional probabilistic encounter-impact model for fish-turbine interactions

Knowledge gaps exist in the collective effort to quantify risks and impacts of fish-turbine interactions. Empirical data and modeling studies have characterized stages of fish approach and pass through hydrokinetic turbines, but there has not been a comprehensive model that quantifies conditional occurrence probabilities of fish approaching and then interacting with a turbine in sequential steps. When calculating conditional probabilities, the probability of each step occurring is, in part, dependent on the occurrence of the previous step in the sequence. We combined acoustic data measurements and when data limited, published probabilities to estimate conditional probabilities of tidal turbine impacts on marine animals. The encounter-impact probability model includes approach, entrainment, and impact phases. The approach phase includes probabilities of entry into a spatial domain and zone of influence, followed by entrainment to the device. Each model component of an encounter includes probabilities of active or passive avoidance. Impacts are defined as fish collisions with a device, blade strikes by a rotating blade, and/or a collision followed by a blade strike. Probabilities are estimated using acoustic data from surveys in Admiralty Inlet, WA USA for Pacific herring (Clupea pallasii) encountering an axial or cross-flow turbine during day or night. Conditional probabilities are additive or multiplicative depending if events are cumulative or sequential. Impact probabilities for collisions and blade strikes are estimated individually and then combined to estimate the probability of overall impacts. Probabilities of occurrence for each model component range from 0.0000242 to 0.40. Impact probabilities for collision followed by a blade strike was lowest with estimates ranging from 0.0000242 to 0.0678. Impact probabilities for blade strike had the highest probabilities ranging from 0.000261 to 0.40. Overall impact probabilities had wide variability from 0.00110 to 0.689. Maximum probabilities occurred in each model component and overall impact probabilities for a cross-flow turbine at night with no active or passive avoidance. Estimates were lowest when probabilities were conditional on sequential events, and when active and passive avoidance was applied for an axial-flow turbine during the day. As expected, conditional probabilities were typically lower than equivalent model component and overall probabilities published in the literature. The encounter-impact conditional probability model can be applied to any marine animal in any environment for any hydrokinetic device. Estimating impact probabilities for Pacific herring in Admiralty Inlet for two device types illustrates utilization of existing data and simultaneously identifies data gaps needed to fully calculate empirical-based probabilities for any specific site-species scenario. As additional monitoring data are collected, accuracy of impact risks due to encounters of marine animals with hydrokinetic devices will increase and be confidently used in establishing regulatory policy.

FishSeg: 3D Fish Tracking Using Mask R-CNN in Large Ethohydraulic Flumes

To study the fish behavioral response to up- and downstream fish passage structures, live-fish tests are conducted in large flumes in various laboratories around the world. The use of multiple fisheye cameras to cover the full width and length of a flume, low color contrast between fish and flume bottom and non-uniform illumination leading to fish shadows, air bubbles wrongly identified as fish as well as fish being partially hidden behind each other are the main challenges for video-based fish tracking. This study improves an existing open-source fish tracking code to better address these issues by using a modified Mask Regional-Convolutional Neural Network (Mask R-CNN) as a tracking method. The developed workflow, FishSeg, consists of four parts: (1) stereo camera calibration, (2) background subtraction, (3) multi-fish tracking using Mask R-CNN, and (4) 3D conversion to flume coordinates. The Mask R-CNN model was trained and validated with datasets manually annotated from background subtracted videos from the live-fish tests. Brown trout and European eel were selected as target fish species to evaluate the performance of FishSeg with different types of body shapes and sizes. Comparison with the previous method illustrates that the tracks generated by FishSeg are about three times more continuous with higher accuracy. Furthermore, the code runs more stable since fish shadows and air bubbles are not misidentified as fish. The trout and eel models produced from FishSeg have mean Average Precisions (mAPs) of 0.837 and 0.876, respectively. Comparisons of mAPs with other R-CNN-based models show the reliability of FishSeg with a small training dataset. FishSeg is a ready-to-use open-source code for tracking any fish species with similar body shapes as trout and eel, and further fish shapes can be added with moderate effort. The generated fish tracks allow researchers to analyze the fish behavior in detail, even in large experimental facilities.

Assessment of migration conditions for fish swimming through a semi-natural fish pass on the Nidzica River in Bronocice

Assessment of migration conditions for fish swimming through a semi-natural fish pass on the Nidzica River in Bronocice

Benefits from recreational catch improvements may hinge on fish consumption safety: Evidence from the Cape Fear River, North Carolina

Stock declines in the Cape Fear River in southeastern North Carolina have prompted management actions to improve the ability of migratory fish species to reach suitable spawning habitat. Understanding the benefits of improvements to migratory fish passage will help policy makers make informed decisions regarding potential net gains from modifying existing locks and dams that inhibit upstream access by migratory species. A survey of licenced recreational anglers employing stated preference valuation methods was used to assess angler preferences and willingness to pay for improvements in fishing quality. Results from a contingent valuation exercise suggest that efforts to improve fish passage will generate economic benefits, with a majority of anglers willing to donate to a fund dedicated to improving the ability of migratory fish species to reach spawning habitat. Lower bound estimates of average willingness to donate range from approximately US $18.00 to US $21.00 per year, illustrating a viable source of revenue from donations by licenced anglers. Results from a discrete choice experiment suggest that recreational anglers have strong preferences for avoiding fish consumption advisories and catching more fish and are willing to incur higher travel costs for higher quality fishing trips, providing more evidence of benefits to recreational anglers from improving fish passage. However, anglers’ strong aversion to fish consumption advisories suggests that the economic benefits of improved catch quality will be significantly diminished if fish are not considered safe to eat.

Individual variation in the habitat selection of upstream migrating fish near a barrier

BackgroundMigration is a vital element of the life cycle of many freshwater fish species but is increasingly hampered globally by riverine barriers. Fish passes are a common approach to enable migration past barriers but are often ineffective. More knowledge is required on fish behaviour as they approach barriers such as habitat preferences.MethodsWe evaluate the habitat selection of two upstream migrating fish species, barbel Barbus barbus and grayling Thymallus thymallus, at a hydropower plant in southern Germany, considering individual variation and population trends. Fish were tracked via fine-scale 2D acoustic telemetry in 2018 during their spawning migration. Step selection functions were used to evaluate selection of hydraulic parameters by the fish for a time step of 20 s. Exploratory models were built via model selection for each individual fish, to evaluate the extent of individual variation in model structure. A population model was developed for each species by averaging coefficients from individual models to describe general trends. The extent of individual variation was determined and confidence intervals for the population model coefficients were calculated.ResultsFish varied greatly in individual model structure though common terms were apparent in both species, such as depth, flow velocity, the angular difference between fish and velocity, and the logarithm of the step length. Final population models for barbel included several parameters describing habitat selection and displacement. Barbel selected for faster flows, deeper water, and higher spatial velocity gradients. In addition, they selected to move more with the flow than against. Interactions were also present between habitat parameters, suggesting selection is context dependent. Barbel movement speed also changed with depth, flow velocity and spatial velocity gradient. With grayling, terms often had contrasting effects among individuals and thus general trends could not be distinguished for most terms.ConclusionOur findings demonstrate habitat selection by upstream migrating fish approaching a fish pass and differences in individual selection which may have an impact on barrier management. Step selection functions are a promising approach and can provide useful insight into habitat selection and movement by migrating freshwater fish in an altered river system.

Evaluation of a Prefabricated Fish Passage Design for Great Plains Fishes

Connectivity is critical for stream fish persistence, and fish passage structures are a useful conservation tool to reconnect fragmented systems. The design of fish passage structures is a tradeoff between the area available for construction, slope, and costs associated with the structure. The Longrie–Fecteau fish passage structure was designed to be modular, adjustable to barrier-specific needs, and to have a low slope (2%) to pass small-bodied fishes. We evaluated fish passage through this structure in Fountain Creek, Colorado, USA, via a PIT tag mark–recapture study. We documented four native Great Plains fish species successfully ascending the passage structure, with most passage occurring at night. We estimated a 3% probability of a released fish entering the structure, then 89% and 99% passage to the midpoint and exit of the 123 m structure, respectively. Low entrance efficiency was due to low recapture probability of small-bodied study organisms in a relatively large system, and the low percentage of space of the entryway on this barrier (<3% of the length of the barrier). Fish that entered the structure ascended quickly, with median time for successful ascent of 19 min, and minimum time of 6 min. The Longrie–Fecteau fish passage structure is a conservation tool that may broaden the adoption of fish passage structures for small-bodied fishes due to its modularity and low slope.

Design, construction, and preliminary hydraulic evaluation of a model rock ramp fishway

AbstractObjectiveNew fish passage structures are frequently designed using information gained from existing structures, particularly those that have been shown to allow passage of the target species. However, this process rarely involves a preinstallation design and testing phase. Developing an apparatus that allows rapid and relatively low‐cost testing of potential fish passage structure designs prior to field installations could reduce the reliance on a “build it, monitor it, does it work?” approach.MethodsTo meet this need, we developed an indoor research flume at Colorado State University’s Foothills Fisheries Laboratory that housed a full‐scale experimental rock ramp fishway.ResultThe slope of the flume can be adjusted (0–10%) and integrates a set of four PIT tag antennas to allow fine‐resolution tracking of fish movements in the fishway. The flume can deliver variable flows (up to 0.082 m3/s) of 9–25°C water. Lessons learned during the design, construction, and initial operation of the flume are presented here.ConclusionThe basic system could be adapted for similar studies in other regions and provides a robust and flexible infrastructure that could be modified for other evaluations of instream structures in lotic systems.

Restoration of a fish-attracting flow field downstream of a dam based on the swimming ability of endemic fishes: A case study in the upper Yangtze River basin

The construction of fish passage facilities can mitigate the negative effects of dams and other water engineering construction on river connectivity and have a significant positive effect on the conservation of local fish diversity. To attract target fishes into fish passage facilities effectively, the optimal flow velocity range to attract fish must be determined. Three local endemic species of the Mishi Reservoir were considered as the protection targets. However, their swimming abilities remain unclear. Therefore, the induced swimming speed (Uind), critical swimming speed (Ucrit) and burst swimming speed (Uburst) of three fish species were tested. Based on these results, we identified the optimal flow velocity to attract fish, which falls within the range of 0.15–0.51 m/s. A validated three-dimensional hydrodynamic model was used to simulate different schemes. By comparing the flow field simulation results of different schemes, we obtained the optimal measure to restore the flow field, namely, a multiple engineering measure combining increased the fish attraction flow in the fish collection pond and the construction of a spur dike. This study offers a solution for the specific case and enhances the database of swimming characteristics of endemic fish in the upstream reaches of the Yangtze River. It also provides a valuable reference for designing fish-attracting flows and potential measures for restoring flow fields in similar future projects.

An Experimental Study of Fish Movement with Turbulent Kinetic Energy along the Pools of A Vertical Slot Fish Pass

Bangladesh is a land of river which is situated in the delta of the Ganges-Brahmaputra-Meghna (GBM) Rivers which are three of the largest rivers of the world. These rivers provide an arterial transportation network for fish movement. Fish migration depends on flow characteristic and surrounding flood plain connected to rivers. In recent time for flood control in monsoon and water storage in lean period a lot of structure has been built along and across the river [77]. As a result the natural sequence of flooding in floodplain of Bangladesh, food chain and life cycle of natural fish and other aquatic species has become under sever threat [64]. In this research an experimental approach has been carried out to understand the turbulence structures of the flow inside a laboratory flume with different local fish species. The structural set up consists of an adverse slope of 6% followed by a mild slope of 3.4%. The adverse slope is 2.54 m in length and the mild slope is 4.45 m in length. Total nine sets of experiments have been conducted. For each set of experiments, data points were distributed on a 10 cm (in the longitudinal direction) x 10 cm (in the transverse direction) grid at 0.6 hydraulic depth and 10 cm (in the longitudinal direction) x 20 cm (in the transverse direction) grid at 0.4 and 0.8 hydraulic depth. In this experimental setup turbulent kinetic energy and fish movement in all four pools will be observed. This experimental study consists of three types of fish species; Rui (Labeo rohita), Catla (Giberlion catla) and Mrigel (Cirrhinus mrigala) of fry size (1-2 cm body length), fingerline size (7-10 cm) and juvenile size (10-20 cm) have been selected for studying. The flow from slot travels through the center of the pool to the next slot with two recirculation region on either side of the jet. At the pool opening the flow appear almost in the form of a shooting jet. There are similarities with turbulence characteristics in each case. Fishes have avoided high turbulent kinetic energy area in the contour map. The comparison shoes the area with low turbulent kinetic energy was most suitable for fishes to pass the pools or taking rest inside the pools. The results may be useful insight on the turbulence characteristics of flow in the vertical slot fish pass and can be used to study fishes characteristic and also for guidance in the design of fish pass in the future.

Movement and behavioral states of common carp (Cyprinus carpio) in response to a behavioral deterrent in a navigational lock

BackgroundFreshwater ecosystems are some of the most affected by biological invasions due, in part, to the introduction of invasive carp worldwide. Where carp have become established, management programs often seek to limit further range expansion into new areas by reducing their movement through interconnected rivers and waterways. Lock and dams are important locations for non-physical deterrents, such as carbon dioxide (CO2), to reduce unwanted fish passage without disrupting human use. The purpose of this study was to evaluate the behavioral responses of common carp (Cyprinus carpio) to non-physical deterrents within a navigation structure on the Fox River, Wisconsin. Acoustic telemetry combined with hidden Markov models (HMMs) was used to analyze variation in carp responses to treatments. Outcomes may inform CO2 effectiveness at preventing invasive carp movement through movement pinch-points.MethodsCarbon dioxide (CO2) was recently registered as a pesticide in the United States for use as a deterrent to invasive carp movement. As a part of a multi-component study to test a large-scale CO2 delivery system within a navigation lock, we characterized the influence of elevated CO2 and forced water circulation in the lock chamber on carp movements and behavior. Through time-to-event analyses, we described the responses of acoustic-tagged carp to experimental treatments including (1) CO2 injection in water with forced water circulation, (2) forced water circulation without CO2 and (3) no forced water circulation or CO2. We then used hidden Markov models (HMMs) to define fine-scale carp movement and evaluate the relationships between carp behavioral states and CO2 concentration, forced water circulation, and temperature.ResultsForced water circulation with and without CO2 injection were effective at expelling carp from the lock chamber relative to null treatments where no stimulus was applied. A portion of carp exposed to forced water circulation with CO2 transitioned from an exploratory to an encamped behavioral state with shorter step-lengths and a unimodal distribution in turning angles, resulting in some carp remaining in the lock chamber. Whereas carp exposed to forced water circulation only remained primarily in an exploratory behavioral state, resulting in all carp exiting the lock chamber.ConclusionOur findings illustrate the potential of forced water circulation, alone, as a non-physical deterrent and the efficacy of CO2 injection with forced water circulation in expelling carp from a navigation lock. Results demonstrate how acoustic telemetry and HMMs in an experimental context can describe fish behavior and inform management strategies.

Response of Upstream Behavior and Hydrodynamic Factors of Anguilla Japonica in a Combined Bulkhead Fishway under Tidal Conditions

Frequent changes in the tide levels in estuaries cause constant changes in the hydraulics of fish passage systems, with important effects on successful fish passage and swimming behavior. In most cases, Japanese eels often have low passage rates in engineered fishways because of their special habits. In this study, we established a 1:4 scaled-down weir-hole combination bulkhead fishway, studied the effects of different tidal differences and water depths on the passage rates and swimming behavior of yellow-phase Japanese eels, and analyzed the response of the Japanese eels to the hydraulic factors by superimposing their swimming trajectories and the flow field simulation results. We found that the passage rate of the eels decreased from 68.18% to 50.00% and 45.45% under extreme high tide differences and extreme low tide differences, respectively. The eels tended to use the low-velocity area to climb up the wall, and when crossing the mainstream, the yellow-phase Japanese eels preferred the area with a flow velocity of 0.1~0.36 m/s and a turbulent kinetic energy range of 0.001~0.007 m2/s2. Their upstream swimming speed was maintained at a range of 0.1~0.3 m/s.

Verification of Hydraulic Parameters of Nature-like Fish Pass

Verification of Hydraulic Parameters of Nature-like Fish Pass

The Effect of Rectifier Baffles on the Flow Regime of 180° Turning Pools in Vertical Slot Fishways

To imitate the constraints of topographic conditions, turning pools with different angles, such as 90° and 180°, are set in fish passage arrangements. If the mainstream in the turning pool is close to the wall and the recirculation zone is too large, it will have an adverse effect on fish migration. Taking the 180° turning pool as an example, five types of arrangements without and with additional rectifier baffles are proposed to optimize the body shape of the turning pool. A three-dimensional numerical simulation method is used to compare and analyze the different arrangement schemes. The results show that adding rectifier baffles can adjust the flow structure in the 180° turning pool. The arrangement adding rectifier baffles at the two three-equidistant points of the 180° turning pool and tilting 15° inward outperforms others in this study. This arrangement can center the mainstream, reduce turbulent kinetic energy, significantly decrease the flow velocity along the course, downscale the recirculation zone, and decrease the overall flow velocity.

Distribution and straying of minijack Chinook Salmon released from a captive broodstock hatchery program

AbstractObjectiveProduction of Chinook Salmon Oncorhynchus tshawytscha in hatcheries can unintentionally produce large numbers of age‐1 males, termed "minijacks," which pose ecological and genetic risks to target and nontarget populations. We evaluated the postrelease distribution of minijacks produced in a hatchery captive broodstock program targeting the White River in the Columbia River basin between 2010 and 2015.MethodsFish were passive integrated transponder (PIT)‐tagged in the hatchery (n = 218,555), and databases were searched to determine movement behavior and final detections on fixed PIT tag antenna arrays during the year in which they were released.ResultTwo main movement behaviors were detected: (1) residuals, which moved solely within the subbasin of release; and (2) migrants, which moved downstream into the Columbia River and then reascended the Columbia River in the year of release. Minijacks that reascended fish ladders in the Columbia River were most often detected at Rock Island and Bonneville dams, the nearest and furthest detection locations downstream of the Wenatchee River. Minijacks were last detected in all locations where spring Chinook Salmon spawn in the Wenatchee River subbasin (seven tributaries and one main‐stem area) and also in the Entiat River (an adjacent watershed); minijacks in eight of the nine locations were considered strays. Estimates of minijacks that strayed outside of the White River were between 61% and 100% annually and were influenced by release location. Minijacks were also more abundant than males of all older ages in some of the tributaries during some years. In addition, they were detected in these tributaries during periods when anadromous adults migrate into spawning areas and when spring Chinook Salmon spawn.ConclusionThe large amount of minijack production and the spatial and temporal overlap could pose genetic and ecological risks to both target and nontarget populations and particularly high straying poses risks to the maintenance of between‐population genetic variability.

Ice processes in culverts with two fish passage designs: a case study in southern Quebec

According to Department of Fisheries and Oceans Canada, culverts and other stream crossings must be designed to ensure fish passage. The effects of ice processes on these fish passage designs have never been assessed. This study is the first to document ice processes on two different types of fish passage designs (streambed simulation and baffle). The results of a 2 year field monitoring campaign showed that the culvert simulating the streambed retains a natural ice regime, i.e., both freeze-up and break-up occurred concurrently with the rest of the stream, while multiple supercooling events were recorded under a thin ice cover. As for the culvert with baffles, it was observed that the ice cover formed earlier and stayed longer in the culvert, which can create a barrier for fish transiting through them.

If you build it, will they pass? A systematic evaluation of fish passage efficiency for three large-bodied warm-water fishes

Fish passages are constructed to facilitate movement around barriers, but few are quantitatively evaluated for non-salmonids. We quantified the efficiency of a selective, nature-like fish passage for three native fishes, Colorado pikeminnow ( Ptychocheilus lucius), flannelmouth sucker ( Catostomus latipinnis), and razorback sucker ( Xyrauchen texanus), in the San Juan River, NM, USA, by estimating the probabilities of completing three navigational phases and associated delay times. We compared passage efficiency in years when fish were captured in a trap and manually moved upstream to years when the trap was removed in the spring. All species were less efficient at navigating the attraction and exit phases compared with the ascent phase. Operating the passage without the trap generally increased passage success and shortened delay times. The mean probability of passage and delay time among species when the trap was removed ranged from 34%–55% and 5–21 days, respectively. Our results suggest species- and phase-specific variation in passage efficiency and highlight the need for evaluations to aid future passage design and operation for a greater diversity of fish.

Measures to safeguard and restore river connectivity

Freshwater connectivity and the associated flow regime are critical components of the health of freshwater ecosystems. When freshwater ecosystems are fragmented, the movements and flows of species, nutrients, sediments, and water are altered, changing the natural dynamics of freshwater ecosystems. The consequences of these changes include declines and loss of freshwater species populations and freshwater ecosystems, and alterations in the delivery of certain ecosystem services, such as fisheries, buffering of flood events, healthy deltas, recreational and cultural values, and others. Measures exist that can maintain and restore connectivity or mitigate against its loss in the face of constructed barriers or other habitat alterations. These measures include system-scale planning for energy and water resources that includes options for limiting loss of freshwater connectivity; putting in place protections for keeping critically important freshwater habitats connected; mitigating impacts on freshwater ecosystems via barrier design, fish passage, or implementation of environmental flows; and restoring freshwaters via barrier removal and reconnection of rivers, wetlands, and floodplains and via active management of groundwater recharge. We present case studies of measures applied in Europe, Asia, Africa, and the Americas and reflect on the next generation of innovation needed to further enhance and advance the implementation of restoration and protection and the mitigation of freshwater connectivity impacts.

Modelling dynamic fish-waterfall interactions with digital image field data: From rescaling to weir removal for migratory freshwater fish

Major declines in river connectivity due to human infrastructure increase river fragmentation. Acting as barriers, weirs impair or disrupt the ecological process of fish migrations. Economic or cultural interests may prevent the removal of such barriers, the common approach being the use of standard guidelines to retrofit a fish passage system. In this study, we explore a novel approach of rescaling the dimensions of a weir in height and reach of the waterfall to match the swimming and leaping capacities of the fish. Hydraulic and hydrological scenarios at seasonal and multi-annual scales are considered quantitatively. The novel technique is based on field data obtained from digital image techniques. The fish-hydraulics interaction is addressed by means of a calibrated and validated biophysical model. A sensitivity analysis explored the degrees of weir downscaling to removal across a range of population viability objectives. The results show that it is possible to reach the efficiency goal of maintaining viable biological populations of barbels and, at the same time, retain the weir infrastructure for human water uses. Biophysical modelling of field image data and infrastructure rescaling proved to be successful quantitative tools to inform management decisions.

Assessment of the Attractiveness and Passage Efficiency of Different Fish Passage Solutions at a Hydropower Plant by Combining Fine Scale 2D-Telemetry and Hydraulic Numerical Modelling

Mitigation measures for downstream-migrating Atlantic salmon smolts (Salmo salar L.) are commonly insufficiently attractive to enable safe entrance and passage with no delay. Combining 2D telemetry with hydrodynamic modelling has been shown to be a good tool to better understand the influence of hydrodynamic factors on the migration route choice of fishes. In this study, we investigated the smolt downstream migration at a hydropower plant in Belgium that offers five migration routes, including two Archimedes screws and one nature-like fishway. At the hydropower plant, the Archimedes screws were the most used migration routes, due to higher discharges and more important water depths at their entrance. The weir and the canal intake were less used by the smolts. The nature-like fishway turned out to be less used, with 23% of the smolts. Its associated crossing time was significantly longer, probably due to shallow water depths and high flow velocities. The nature-like fishway had the potential to become a good migration route for salmon smolts after improvements to increase attractiveness and passage efficiency. Moreover, the Archimedes screws were not detrimental to the smolts and did not cause any significant delays to the crossing time.

Conventional pool fish pass project for small threshold

Fish migrate alongside the river in search of food, suitable hiding places and spawning grounds during the various seasons and periods of their lives. Damming a river with a weir or other artificial dam disrupts these normal life processes or even makes them impossible. The main way to overcome this problem is to build fish passes. Passes are facilities that allow fish and other aquatic organisms to migrate up and down the river through barriers such as thresholds, dams and weirs. Conventional solutions of fish pass construction have the most significant number of studies both in the literature as well as in engineering practice. Therefore, their design methodology is widely available. It considers, first of all, hydraulic and granulometric parameters, conditions of particular structure elements locations, but also properties of migrating fish species. This study covers the concept of restoration of a dam on the Radomka river with a conventional pool fish pass. The pool fish pass will be located along the river bank, allowing the migration of fish identified in the study area. Additionally, it was developed a concept of bed material mixture, consisting of clastic material in the form of sand with addition of a coarser gravel-stone fraction.