Effects of bed slope on the flow field of vertical slot fishways

Vertical slot fishways (VSFs) are the most efficient and least selective typology of technical fish passage, due to their ability to remain effective even when significant upstream and/or downstream water level fluctuations occur. Fishway construction costs can be reduced by increasing its bed slope, but this affects the flow field inside the pools, with higher head drops between the basins, as well as turbulence levels and flow velocities, which may affect fish passage. In light of this, a VSF was investigated by 3D numerical simulations to identify the possible effects of the bed slope (using values from 1.67% to 10%) on the flow field and subsequent implications for fish passage. A particular focus was devoted to cyprinind species, but the results can be extended to other species of similar swimming abilities and, therefore, be applicable to multispecies rivers. Flow velocity and turbulence values such as turbulent kinetic energy and Reynolds stresses were analysed from a fish passage perspective in relation to threshold values derived from previous studies. Pool areas where turbulence values are compatible with fish ability and behaviour were quantified. Maps of the location of fish‐friendly zones in the VSF pools were produced and can constitute a reference for practical applications in fishway design. The flow field generated with bed slopes lower than 6.67% is more compatible with fish swimming capabilities, because it exhibits a predominantly 2D behaviour and more suitable hydraulic conditions, whereas at higher slopes, turbulence levels in the pools increase.     

齐口裂腹鱼幼鱼在竖缝式鱼道模型中的上溯行为研究

为了解齐口裂腹鱼在鱼道中的上溯情况,在大比尺竖缝式鱼道物理模型中开展了以齐口裂腹鱼幼鱼为过鱼对象的过鱼试验研究。试验中对通过时间、通过率和上溯轨迹进行了记录,并运用Spearman秩相关分析对齐口裂腹鱼的上溯轨迹和池室结构的水力因子(流速、紊动能、总水力应变)进行了分析。研究发现,试验用鱼通过时间平均值为132.7s,多数鱼倾向于快速通过鱼道完成上溯。试验鱼道通过率为71.9%,过鱼效果良好。多数齐口裂腹鱼上溯过程中会避开高流速区、高紊动能区和高水力应变区,在池室内齐口裂腹鱼上溯轨迹主要分布于上述参数较低的右侧回流区和隔板背水面,竖缝断面处多数齐口裂腹鱼选择上述参数相对较低的隔板侧区域通过。研究结果可为相关竖缝式鱼道设计和实践提供参考。     

鱼道紊流特性研究进展

鱼道内的紊流特性对于鱼类能否顺利上溯洄游至关重要。为了解鱼道内的紊流状态,综述了丹尼尔式、竖缝式、组合式、涵洞式等鱼道内紊流流速、紊动能、紊流强度、雷诺剪切应力以及漩涡等紊流特性的研究进展,分析不同鱼道内紊流的分布规律及特点,指出鱼道中的紊流强度、紊动能等均会对鱼类对栖息地的选择以及鱼类通行造成较大的影响。此外,目前国内对鱼道内漩涡紊流特性的研究较少,建议对其深入研究,以改善鱼道内水力条件,保证鱼道有效运行。     

鱼道水力特性研究进展

综述竖缝式、池堰式和涵洞式、丹尼尔式及组合式鱼道水力特性的国内外研究进展;对比分析水流流态、流速场特征、流量与水深的关系、紊流特性及消能率等几方面对不同鱼道的水力特性的影响;得出了竖缝式鱼道中无量纲流量与相对水深之间呈线性关系的结论,列出了池堰式鱼道中流量与水深的关系式;指出鱼道中紊流的紊动能、紊流强度及紊流结构均会对鱼道水力特性、鱼类对栖息地的选择以及鱼类通行造成较大影响;展望鱼道未来研究重心会逐渐集中于鱼道内紊流特性及其数值模拟的研究,尤其是紊流结构的研究。此外,不同结构形式鱼道内水力条件对鱼类通行的影响及改善措施亦将成为未来研究热点之一。     

Design of a bilateral-symmetric multi-slot fishway and its comparison with vertical slot fishway in terms of hydraulic properties

Aiming at improving the hydraulic properties and enhancing the fish passage efficiency, this study proposes a novel bilateral-symmetric multi-slot fishway (BMSF) by combining the structural features of a double-sided vertical-slot fishway, multi-slot fishway and T-shape fishway. Eight BMSF cases are further designed by adjusting the slot width and the distance between the short baffle and the front end of the central wall, in order to achieve the relatively best hydrodynamic characteristics. The flow fields of two vertical-slot fishways and eight BMSF fishways are obtained by numerically solving the Reynolds-averaged Navier–Stokes equation, the volume-of-fluid equation and the k-ω-SST turbulence model. Numerical results manifest that the recommended BMSF-8 provides the smallest values in terms of the maximum time-averaged velocity magnitude (1.42 m s⁻¹), the maximum time-averaged turbulent kinetic energy (0.132 m² s⁻²), the maximum time-averaged Reynolds shear stress component (44 Pa), the spatial-mean time-averaged velocity magnitude (0.58 m s⁻¹), and the spatial-mean time-averaged turbulent kinetic energy (0.042 m² s⁻²) in the middle pool at Q = 1000 L/s. Even for the depth-mean time-averaged velocity magnitude at the slot and the volume percentages of some critical physical quantities, BMSF-8 is also superior to the other cases. To sum up, BMSF-8 leads to the relatively lowest flow velocity and turbulence, being more suitable for the passage of the whole fish community (especially for small-sized fishes with weaker swimming ability). In addition, the generalizability of the aforementioned superiority of BMSF-8 is displayed by providing the numerical results of four operating conditions (i.e., Q = 600, 800, 1000 and 1200 L/s).     

USING AN EXPERIMENTAL IN SITU FISHWAY TO PROVIDE KEY DESIGN CRITERIA FOR LATERAL FISH PASSAGE IN TROPICAL RIVERS: A CASE STUDY FROM THE MEKONG RIVER,CENTRAL LAO PDR

Fish passage through an experimental vertical‐slot fishway was assessed at a floodplain regulator on the Mekong River in Central Laos between April and July 2009. Experiments were conducted to investigate the influence of fishway floor slope (1v:15h or 1v:7.5h) on fish passage success with a view to developing a series of optimal design criteria for the construction of vertical‐slot fishways at other barriers to fish passage in the Lower Mekong Basin. A total of 14 661 fish from 73 species were captured during the experiments. Catches were dominated by riverine (white) (n = 51; 69% of total) and floodplain (black) species (n = 15; 20%) which represented 19 families in total. The work demonstrated that fish were actively attempting upstream passage from the Mekong River to an adjacent floodplain and displayed strong migratory behaviour during river level rises. Migratory activity was greatest during sharp rises in water level but reduced substantially when river level fell. Fish community composition varied greatly among the two fishway floor slopes and the control group. More fish species were collected from control samples, but the most fish and species were collected when the fishway was configured on a moderate hydraulic slope (1v:15h). A range of size classes were also collected from control and moderate‐slope groups, but steeper‐gradient catches were dominated by larger fish. This study demonstrated that vertical‐slot fishways could provide passage for a biodiverse fish community where fish move laterally onto floodplains. The construction of fishways which consider the local fish ecology and hydrology may therefore represent a valuable management tool to help restore important movement pathways for tropical freshwater fish. Copyright © 2011 John Wiley & Sons, Ltd.     

An assessment of the effectiveness of a vertical‐slot fishway for non‐salmonid fish at a tidal barrier on a large tropical/subtropical river

Fishways for salmon in temperate rivers have often been successful, but salmonid‐type fishways for non‐salmonid species in tropical and subtropical rivers have frequently failed. This study assessed the effectiveness of modifying a salmonid‐type pool‐and‐weir fishway into a vertical‐slot design on a tidal barrage on the subtropical Fitzroy River, in Queensland, north‐eastern Australia. In 38 paired samples of the top and bottom of the fishway, over 16 months, 29 fish species and over 23 000 fish were collected at a maximum rate of 3400 per day. This study shows much greater potential for success with a vertical‐slot fishway as relatively few fish negotiated the original pool‐and‐weir design. Common species using the vertical‐slot fishway included blue‐catfish (Arius graeffei [Ariidae]), bony herring (Nematalosa erebi [Clupeidae]), striped mullet (Mugil cephalus [Mugilidae]), barramundi (Lates calcarifer [Centropomidae]), and long‐finned eels (Anguilla reinhardtii [Anguillidae]). Freshwater shrimp (Macrobrachium australiense [Palaemonidae]), juvenile crabs (Varuna litterata [Grapsidae]) and long‐finned elvers did not ascend the full length of the fishway and specific fishways for these species are recommended. Fish between 25 and 640 mm in length ascended the fishway, although the passage of smaller size classes of immature fish was restricted and this may be important for the sustainability of these migratory populations. The barramundi (200–640 mm) which ascended the fishway were all immature fish. However, during a period of low river flows enlarging the width of the vertical‐slot from 0.15 to 0.45 m only encouraged a small number of larger fish (890 mm maximum length) to enter. The strong diel movement patterns of many species will need to be considered in future fishway design. Blue‐catfish could ascend the fishway in 2 h, but many fish remained in the fishway and this behaviour may cause crowding and a reduction in fishway capacity. Further work is needed to assess the proportion of fish finding the fishway entrance. However, the findings suggest that vertical‐slot fishways with lower water velocities and turbulence than salmonid fishways have great potential to pass the diverse migratory fish fauna of subtropical and tropical rivers. Copyright © 1999 John Wiley & Sons, Ltd.     

Migratory fishes of Brazil: Life history and fish passage needs

Many of the most important commercial and recreational species of the megadiverse Brazilian freshwater fishes migrate in rivers among essential habitats during all life stages. These movements, however, have been severely blocked by hundreds of hydroelectric dams and reservoirs and they will be even more obstructed due to hundreds of new developments. Fishways have been used in many countries to allow fish to pass around dams. Fishway construction is booming in Brazil, but poor understanding of migrations by Brazilian fishes has led legislators, scientists, and the public to several misconceptions about the rules of fishways in fisheries conservation. First, is a belief that fishways are only needed to facilitate upstream spawning migrations. Also, it has been suggested that upstream passage for Neotropical migrant fishes is not useful if there is no large free‐flowing stretch upstream of a dam that contains spawning habitat and has a large natural floodplain (nursery habitat). In this paper, we discuss that, in addition to providing passage for pre‐spawning migrants, upstream fishways also provide passage for other fish migrations (e.g. foraging), and that all up‐ and downstream migrations during life history need to be addressed at dams to conserve fish resources. We also argue that an upstream fishway is important even if the upstream reach does not have spawning or nursery habitats. In addition, we discuss the need for protection of downstream migrant fish, and the importance of fish behaviourists and engineers working together on fishway design and operation to solve fish passage issues. Copyright © 2008 John Wiley & Sons, Ltd.     

Modelling upstream fish passage in standard box culverts: Interplay between turbulence,fish kinematics,and energetics

Box culverts are common hydraulic structures along rivers and streams, in rural and urban water systems. The expertise in fish‐friendly culvert design is limited, sometimes leading to adverse impact on the catchment ecosystem or to uneconomical structures. Basic dimensional considerations highlight a number of key parameters relevant to any laboratory modelling of upstream fish passage, including the ratio of fish speed fluctuations to fluid velocity fluctuations, the ratios of fish dimensions to turbulent length scale, and the fish species. Alternately, the equation of conservation of momentum may be applied to an individual fish, yielding some deterministic estimate of instantaneous thrust and power expended during fish swimming, including the associated energy consumption. The rate of work required by the fish to deliver thrust is proportional to the cube of the local fluid velocity, and the model results demonstrate the key role of slow‐velocity regions in which fish will minimize their energy consumption when swimming upstream.     

组合隔板式鱼道水力特性数值模拟研究

鱼道是为鱼类提供洄游通道的一种重要的工程措施。基于Flow-3D采用标准RNG k-ε紊流模型和Tru-VOF追踪自由液面方法,对鱼道池室内流场进行三维紊流数值模拟,研究池室内水流流速、流态空间分布,分析鱼道的水力特性对目标鱼类洄游上溯的影响。结果表明:溢流堰与竖缝组合隔板式鱼道在设计流速v=0.75 m/s条件下,竖缝处平均流速为0.83 m/s,竖缝处流速分布范围为0.76~0.89 m/s;堰上流速为0.90~1.12 m/s,回流区流速分布范围为0.09~0.25 m/s,流速大小在鱼类的克流能力范围之内,但靠竖缝隔板处存在明显的主流贴壁现象。为此开展了池室优化方案设计,使鱼道池室流态满足鱼类上溯要求。     

Fishway passage and post‐passage mortality of up‐river migrating sockeye salmon in the Seton River,British Columbia

Adult sockeye salmon (Oncorhynchus nerka) were studied to assess the consequences of a dam and vertical‐slot fishway on mortality during their spawning migration in the Seton–Anderson watershed, British Columbia, Canada. Since previous research suggests fishway passage may be difficult, our main hypothesis was that the dam and fishway have post‐passage consequences that affect subsequent behaviour and survival. Eighty‐seven sockeye were caught at the top of the fishway, implanted with an acoustic telemetry transmitter, non‐lethally biopsied to obtain a small blood sample and released either upstream or downstream of the dam. Indices of physiological stress (i.e. plasma cortisol, glucose, lactate and ions) indicated that fish were not stressed or exhausted after capture from the fishway, and were not unduly stressed by transportation to release sites or net‐pen holding. Of 59 fish released downstream of the dam, 14% did not reach the dam tailrace. Overall passage efficiency at the fishway was 80%. Mortality in two lakes upstream of the dam was greater in fish released downstream of the dam (27%) compared to fish released upstream of the dam (7%; p = 0.04) suggesting that dam passage has consequences that reduce subsequent survival. Cumulative mortality of fish released downstream of the dam (n = 55) resulted in only 49% survival to spawning areas, compared to 93% of fish released upstream of the dam (n = 28). Survival was significantly lower for females (40%) than for males (71%; p = 0.03), a finding that has implications for conservation because spawning success of sockeye salmon populations is governed primarily by females. Copyright © 2010 John Wiley & Sons, Ltd.     

Numerical study of the effect of a V-shaped weir on turbulence characteristics and velocity in V-weir fishways

Fishways are used to allow fish to migrate around water infrastructure, whether movements are in the upstream or downstream direction. Hydrodynamic conditions within various fishways, including turbulence levels, are important for successful fish passage. A numerical hydrodynamic study was conducted for V-weir fishways, which assist species migrating upstream. The variables investigated included, fishway slopes of 4%, 7%, and 10%, relative spacing between weirs of 1.3, 2.6, and 4 (D/L, ratio of distance between weirs to pool width), and weir angles of 22.5°, 40°, and 60°. Turbulence characteristics, including turbulent kinetic energy (TKE), Reynolds shear stress (RSS), turbulent intensity (TI), turbulent dissipation (TD), as well as maximum water velocity, were examined by CFD (computational fluid dynamics) simulation using a re-normalized group or RNG turbulence model. The CFD was calibrated with flow measurements made in a physical model of the V-weir fishway in laboratory control experiments. Based on inferences from fish passage literature, the results showed that, in the range of parameters studied, a weir angle of 22.5^°, a slope of 10% and relative spacing between weirs of 1.3 and 2.6 were assessed as offering the best potential performance for several species and sizes of fish, while the latter has lower cost as it requires fewer weirs. The V-weir fishway may be adaptable for smaller fish.     

MULTISPECIES FISH PASSAGE BEHAVIOUR IN A VERTICAL SLOT FISHWAY ON THE RICHELIEU RIVER,QUEBEC, CANADA

A shift from target species to ecosystem restoration has generated interest in developing fishways that are capable of passing entire fish communities. Although a number of multispecies fishways now exist in North America, evaluations of these fishways are lacking. We used a passive integrated transponder antenna array to quantify passage success and passage duration of fish using a vertical slot fishway (85 m in length, 2.65 m elevation rise, 12 regular pools and 2 turning basins) at a low head dam on the Richelieu River in Quebec, Canada. Fourteen of the 18 tagged species re‐ascended the fishway, and passage efficiency was highly variable among species (range 25%–100%); however, it was >50% for five of the species well represented in this study (n > 10) (Atlantic salmon, channel catfish, smallmouth bass, walleye and white sucker). Passage duration was likewise highly variable both among and within species (e.g. 1.0–452.9 h for smallmouth bass, 2.4–237.5 h for shorthead redhorse). Although this fishway design was not uniformly successful in passing fish of all species, this study does reveal the species that have problems with ascent and provides an estimate on the time spent in the fishway that is an important component of passage delay. Such information could be used to inform future design refinements to facilitate passage of the entire assemblage with minimal delay. Copyright © 2012 John Wiley & Sons, Ltd.     

Hydraulic and turbulence structure of triangular labyrinth weir‐pool fishways

Detailed laboratory experiments were conducted to analyze and evaluate a new weir‐pool fishway design. The new design consisted of a series of one‐cycle, triangular labyrinth weirs that formed a weir‐pool fish passage. Hydraulic characteristics of flow over the proposed fishway were examined for three pool lengths and a wide range of discharges. It was found that the new design had superior discharge capacity over classical weir‐pool fishways in plunging flow regime. Spatial and point analyses of measured velocity data were carried out to understand turbulence structure and distribution of turbulent flow. The power dissipation per unit volume was calculated for different tests, and it varied nonlinearly with discharge. Based on the limiting criteria for energy dissipation rates of different fish species, the maximum operating discharge for different slopes was extracted for the proposed design. The model‐to‐prototype scaling analysis was performed based on the recommended scaling factor of three for prototype. It was found that the approach velocity of prototype increased by 12%, whereas the total discharge increased by more than five times. The contour plots of time‐averaged velocity indicated that the proposed fishways offered diversified flow fields without exceeding the maximum velocity above the standards recommended for weir‐pool fishways. To study the size, direction, and periodicity of turbulent eddies, magnitude of the most energetic eddy and dominant frequencies were extracted using power spectrum analysis. Quadrant analysis consistently showed that Reynolds shear stresses in ejection and sweep events became weaker as the pool length increased. The small region of strong ejection and sweep events evidenced a good resting place for fish migration, whereas the generated turbulence was large enough to attract fish species to use the passage.     

Performance of a Vertical‐Slot Fish Pass for the Sea Lamprey Petromyzon marinus L. and Habitat Recolonization

In 2011, a vertical‐slot fish pass was built at the Coimbra Açude‐Ponte dam (Mondego River, Portugal), approximately 45 km upstream from the river mouth. The performance of this infrastructure for sea lamprey passage was evaluated between 2011 and 2015 using several complementary methodologies, namely radio telemetry [conventional and electromyogram (EMG)], passive integrated transponder (PIT) telemetry and electrofishing surveys. During the study period, the electrofishing revealed a 29‐fold increase in the abundance of larval sea lamprey upstream of the fish pass. Of the 20 radio‐tagged individuals released downstream from the dam, 33% managed to find and successfully surpass the obstacle in less than 2 weeks, reaching the spawning areas located in the upstream stretch of the main river and in one important tributary. Fish pass efficiency was assessed with a PIT antenna installed in the last upstream pool and revealed a 31% efficiency, with differences between and within migratory seasons. Time of day and river flow significantly influenced the attraction efficiency of the fish pass, with lampreys negotiating it mainly during the night period and when discharge was below 50 m³ s^?1. Sea lampreys tagged with EMG transmitters took 3 h to negotiate the fish pass, during which high muscular effort was only registered during passage, or passage attempts, of the vertical slots. The use of complementary methodologies provided a comprehensive passage evaluation for sea lamprey, a species for which there is a considerable paucity of valuable data concerning behavioural, physiological and environmental influences on obstacle negotiation. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.     

Reducing Carryover Effects on the Migration and Spawning Success of Sockeye Salmon through a Management Experiment of Dam Flows

Effective dam management requires an understanding of the ecological impact of a facility and its operations on individual fish and fish populations. Traversing high flows downstream of dams is an energetically challenging activity that could influence survival and spawning success following passage. Carryover effects, however, are an underappreciated consequence of dam passage that have been overlooked by researchers and natural resource managers. We conducted a large‐scale management experiment to determine if the operation of dam attraction flows could be changed to reduce high sockeye salmon Oncorhynchus nerka mortality following passage and increase spawning success. We tested two flow conditions: (i) a baseline condition—currently used by managers—that released high attraction flows directly adjacent to the entrance to a vertical‐slot fishway and (ii) an alternative condition that released attraction flows 10 m away from the fishway entrance to reduce the flows fish swim through while approaching the passage structure. We tagged 637 sockeye salmon with telemetry tags to monitor dam passage, post‐passage survival to spawning grounds and spawning success under the two flow conditions. Validated fish counters at the exit of the fishway and on spawning grounds were used to generate population level estimates of survival to spawning grounds. Individuals exposed to baseline flow conditions spent two times longer recovering from dam passage and exhibited 10% higher mortality following passage than those exposed to alternative flows. Release of alternative flows for 10 days assisted approximately 550 fish (or 3% of total spawners) in reaching spawning grounds. Once on spawning grounds, female spawning success was strongly influenced by individual spawning characteristics (longevity and date of arrival on spawning grounds) and not dam flow condition. Our findings highlight a cost‐effective solution that decreases mortality following passage simply by altering the location of dam flow releases and not reductions in discharge. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.     

Effects of water velocity and turbulence on the behaviour of Iberian barbel (Luciobarbus bocagei,Steindachner 1864) in an experimental pool‐type fishway

The restoration of fish passage has been focused on anadromous fish species, whilst studies accommodating passage of coarse species have often been considered incidental, yet frequently these are the predominant group of species encountered in rivers. In addition, fishway designs depend greatly on the interplay between hydraulics and biomechanics, yet very little data are available on the responses to specific hydraulic settings for these species. This study aims to explore the effects of water velocity and turbulence on the behaviour of a cyprinid species ‐ the Iberian barbel Luciobarbus bocagei (Steindachner, 1864) ‐ particularly their upstream movements upon different discharges (38.5 to 77.0 L · s^?1), through an indoor full scale pool‐type fishway prototype. Larger adults had a higher passage success (mean = 79%) and took less time (mean ± SD (min): 5.7 ± 1.3) to negotiate the entire six pool fishway, when compared to small adults. Correlation analysis between hydraulic variables and fish transit time yielded different results. Correlations were found to be the highest between the horizontal component of Reynolds shear stress and fish transit time, particularly for smaller size‐individuals (r = ?0.45; p < 0.001), highlighting this variable as a key‐parameter which strongly determines the movements of Iberian barbel. The present study identified key factors on Iberian barbel movements that may have direct application to future fishway designs for this species and for other ‘weak’ swimmers. Copyright © 2010 John Wiley & Sons, Ltd.     

Bidirectional connectivity via fish ladders in a large Neotropical river

The conservation of migratory fish species worldwide has been threatened by the loss of longitudinal connectivity caused by dams intercepting large rivers. One environmental management strategy for reestablishing connectivity is providing passage through fish ladders. However, ladders in Neotropical rivers have been described as ascending one‐way routes. We analysed the movements of Prochilodus lineatus through a fish ladder at a large dam—Porto Primavera—in the heavily impounded Upper Paraná River, Brazil, to determine whether the ladder connected habitats downstream and upstream of the dam, in both directions. A total of 1,419 specimens of P. lineatus were PIT‐tagged above and below the dam, and continuously monitored for 4 years. We documented bidirectional movements of P. lineatus through the fish ladder. Many individuals repeated these movements annually; one individual as many as six times. It was estimated that the cumulative probability that P. lineatus would return from downstream after descending through the ladder was 0.38, 0.50, and 0.56 in 1, 2, and 3 years, respectively. Correspondingly, return probabilities from upstream were 0.15, 0.22, and 0.26 in 1–3 years, respectively. Although return probabilities from upstream were roughly half, our results suggest the Porto Primavera fish ladder contributes to habitat connectivity, bidirectional passage, and preservation of P. lineatus. These results deviate from the perception that fishways are ineffective in Neotropical rivers. We suggest that fishways can restore the bidirectional connectivity denied to some Neotropical species, and until the services of dams are no longer needed, environmental management through fish ladders could continue to be considered as an integral part of broader conservation strategy designed to preserve native fauna.     

竖缝式鱼道水力特性与鱼类运动特性相关性分析

竖缝式鱼道(Vertical Slot Fishway,VSF)作为一种协助上溯性鱼类恢复其洄游通道的生态补偿措施,受到广泛关注。其过鱼效果与VSF的水力特性和鱼类的游泳运动能力密切相关。因而,良好的VSF设计应保证池室内的水力特性与过鱼对象的游泳运动能力相适宜。本文选取上溯性鱼类鳙鱼和草鱼为研究对象,将VSF池室内水力因子空间分布与鱼类运动轨迹相叠加,定量分析了鳙鱼和草鱼在上溯过程中的运动特性、水力偏好以及鱼类运动轨迹与特定水力因子的相关程度。试验结果表明:在流量为0.135 m3/s的VSF池室内,两种鱼喜好在紊动能为0.02~0.035 m2/s2、流速为0.16~0.4 m/s、紊动耗散率为0.02~0.04 m2/s3、应变率为2~3.5 s-1的范围内运动。鳙鱼和草鱼在不同水力区域内的上溯时间与紊动能、流速相关性较大;水流流速矢量体现鱼的趋流特性,决定了鱼的上溯方向,而对于局部空间内鱼的游泳运动行为,紊动能可能是影响更直接的水力因子。