Behaviour of two small pelagic and demersal fish species in diverse hydraulic environments

Increased hydraulic diversity could be a means to promote fish diversity in rivers, but little is known of the behaviour of fish in hydraulic environments. This study concerns the behaviour of two species of small native Australian freshwater fish in variable hydraulic environments and ecological habit, with regard for (a) whether the apparent differences in swimming ability are reflected in the behaviour of the species and (b) the influence of changing hydraulic conditions on their patterns of use. An artificial channel was constructed with three levels of discharge, and fish were allowed to swim freely for 3 h without human interference. Their movements and habitat choices reflected their swimming ability and ecological habit, in that the stronger swimming, pelagic common galaxias (Galaxias maculatus) spent most time cruising in the open channel, preferring the turbulent inflow, and the demersal flat‐headed gudgeon (Philypnodon grandiceps) remained in the shelter of boulders. In effect, the galaxias changed their behaviour with changes in hydraulic conditions, while the gudgeons continued to use their preferred habitat. This study, therefore, provides support for the use of hydraulic diversity as a tool to foster fish diversity. Copyright © 2010 John Wiley & Sons, Ltd.     

台阶式溢洪道相对流速和相对消能水头的关系

流速和消能水头是重要的水力参数,但在台阶式溢洪道中尚无系统研究成果。将台阶式溢洪道流速、消能水头与对应光滑溢洪道流速、消能水头对比,引入相对流速、相对消能水头的概念。通过对0.5,1.0,2.0 m 3种不同台阶高度,38.66°坡度的台阶式溢洪道进行试验研究,探讨了流速、消能水头,相对流速、相对消能水头之间的关系。结果表明:非均匀流流态下流速、消能水头呈曲线关系,不便分析应用;相对流速和相对消能水头表现出良好线性关系,相关系数0.973 7~0.995 9,证实了引入相对流速、相对消能水头的必要性。     

鱼类下行过坝相关工程措施综述

为保护洄游性鱼类,各国在修建大坝和堤堰的同时,根据工程的特点及鱼类保护的需求修建了各种类型的过鱼设施。首先简要介绍了鱼类下行过坝的一些途径,如:溢洪道、水轮机、鱼道、集运鱼系统、船闸等。其次,详细介绍了国外目前关于鱼类下行研究的一些新技术,如:水表面集鱼技术、全水深集鱼技术、下行旁路、集运鱼系统、鱼类友好型水轮机以及相关辅助技术等。最后针对我国的下行过鱼工程需求,指出应广泛借鉴国外先进经验,特别关注国外集鱼导鱼技术,加强我国鱼类下行过程的基础研究,以期实现我国鱼类下行过坝技术的突破。     

进出水口双向流动结构流速分布与脉动规律研究

抽水蓄能电站水道系统侧式进出水口因内部分流隔墩等导致流动复杂,其内部双向流动规律尚不清晰。本文以某实际工程进出水口为基础建立典型进出水口试验装置,利用先进的流速量测仪器进行试验研究。基于粒子图像测速技术（PIV）量测结果,揭示了侧式进出水口内部双向流动规律,出流工况,中孔扩散段内形成明显的主流且位于孔口中部,扩散段及调整段顶部形成低流速区,边孔扩散段内主流不明显;进流工况,中孔及边孔调整段顶部存在低流速区,水流汇入扩散段后流速分布趋于均匀。基于声学多普勒测速技术（ADV）量测结果,揭示了拦污栅断面脉动流速规律,出流工况,其脉动流速很大,流速脉动值可达到时均值的1.8倍,有别于脉动值较小的一般规律;进流工况,其脉动流速较小,符合脉动值绕时均值上下波动的一般规律。研究成果将为优化进出水口体型参数和分析引起拦污栅振动破坏提供理论依据。     

Swimming behaviour and ascent paths of brook trout in a corrugated culvert

Culverts may restrict fish movements under some hydraulic conditions such as shallow flow depths or high velocities. Although swimming capacity imposes limits to passage performance, behaviour also plays an important role in the ability of fish to overcome velocity barriers. Corrugated metal culverts are characterized by unsteady flow and existence of low‐velocity zones, which can improve passage success. Here, we describe swimming behaviour and ascent paths of 148 wild brook trout in a 1.5‐m section of a corrugated metal culvert located in Raquette Stream, Québec, Canada. Five passage trials were conducted in mid‐August, corresponding to specific mean cross‐sectional flow velocities ranging from 0.30 to 0.63 m/s. Fish were individually introduced to the culvert and their movements recorded with a camera located above the water. Lateral and longitudinal positions were recorded at a rate of 3 Hz in order to identify ascent paths. These positions were related to the distribution of flow depths and velocities in the culvert. Brook trout selected flow velocities from 0.2 to 0.5 m/s during their ascents, which corresponded to the available flow velocities in the culvert at the low‐flow conditions. This however resulted in the use of low‐velocity zones at higher flows, mainly located along the walls of the culvert. Some fish also used the corrugations for sheltering, although the behaviour was marginal and did not occur at the highest flow condition. This study improves knowledge on fish behaviour during culvert ascents, which is an important aspect for developing reliable and accurate estimates of fish passage ability.     

Poor Performance of a Retrofitted Downstream Bypass Revealed by the Analysis of Approaching Behaviour in Combination with a Trapping System

The implementation of fish downstream migration bypass systems is still a major challenge, and there is interest in validating the adequacy of different configurations of bypass devices. In the Amblève River (Belgium), a mobile 3.3‐m height dam feeds two principal Francis and one Francis micro‐turbine and is equipped with a modern vertical slot fish pass and a downstream bypass. The aim of this study was to test the bypass attraction and efficiency (i.e. percentage of fish that approach the entrance and use the bypass) for Atlantic salmon smolts. During three consecutive years, a total of 1346 smolts were equipped with a radio frequency identification tag and released from March to May upstream of the dam of Lorcé. The entrance of the downstream migration bypass was equipped with a radio frequency identification antenna in order to detect the smolts approaching. In 2014, a capture cage was also placed downstream the bypass to evaluate its efficiency. The mean percentage of detected smolts at the entrance varied from 26.2 to 39.7%. In 2014, 16.5% of the released smolts entered the bypass and were finally caught in the cage, representing 39% of the smolts detected at the entrance. More than 98% of the detections occurred during night (mainly between 9 pm and 3 am ). The searching delay near the bypass entrance varied from less than 5 min to more than 5 days (median 4.3 min). Visual observation indicated a behavioural reluctance before entering the bypass, with a shift from positive to negative rheotaxy. Our results underline the difficulty to install retrofitted bypass system on old existing hydropower plants. Copyright © 2016 John Wiley & Sons, Ltd.     

Optimum fish passage and guidance designs are based in the hydrogeomorphology of natural rivers

Understanding hydrodynamic cues used by outmigrating juvenile salmon (emigrants) to guide fine‐scale swim path selection is critical to successful fish guidance and passage at man‐made structures. We show how these cues can be inferred from channel features and complex flow fields of natural rivers through which emigrants pass. We then describe a new cue, ‘total hydraulic strain’, integrating properties of flow acceleration and turbulence through the spatial gradients in velocity to create a single flow field distortion metric amenable to the analysis of fish movement at the scale of large man‐made structures. We explain how total hydraulic strain, together with the magnitude of velocity, provide sufficient information for any fish to distinguish between the two categories of channel features with their mechanosensory system. We demonstrate that total hydraulic strain, velocity magnitude and hydrostatic pressure can be integrated into rule‐sets (the Strain–Velocity–Pressure (SVP) Hypothesis) to explain emigrant swim path selection near dams. To confirm the reasonableness of the SVP Hypothesis, we describe how its separate elements can be detected by different components of the fish mechanosensory system. We evaluate the SVP Hypothesis by (1) using it to explain the traces made by acoustically tagged emigrants overlaid on coincident total hydraulic strain and velocity magnitude fields, (2) using it to explain different passage efficiencies of competing bypass designs and (3) testing it via stepwise discriminant analysis to infer the relationship between hydrodynamic pattern and emigrant orientation. We conclude the SVP Hypothesis is a reasonable and useful approximation of the strategy used by emigrants to select their swim path through complex flow fields sufficient to serve as the basis of guidance and bypass system design. Published in 2008 by John Wiley & Sons, Ltd.     

水电开发对鱼类资源的影响及其保护措施

水电开发造成了河流环境结构和水文情势的改变,对河流水生生态系统形成了破坏。水电开发对鱼类资源的影响主要表现为阻隔了鱼类洄游通道以及对鱼类多样性、鱼类栖息地、下泄水水温、气体过饱和的影响。针对这些影响,提出采用修建过鱼设施、建设鱼类增殖站、建立鱼类种质资源保护区、下泄生态流量、分层取水等保护措施,以维持鱼类资源的多样性。水电开发应采取综合措施解决水生生态问题,特别是流域梯级开发更应注重对整个流域生态系统结构进行统筹规划,保护河流生态系统的完整性。     

龙开口水电站坝上坝下鱼类群落结构变化趋势

2016年3月至2017年4月在龙开口水电站库区和坝下江段开展鱼类资源调查,库区6个采样点,坝下3个采样点,共采集到鱼类4目9科32属42种。坝上坝下鱼类主要类群较为一致,但是坝下鱼类资源更为丰富,其鱼类群落多样性指数2.751和丰富度指数5.322均高于坝上。但是与建坝前相比,库区鱼类群落结构由流水型鱼类向水库型演变,坝下鱼类总种类锐减12种。总之,同建坝前相比,龙开口坝上坝下处于鱼类群落演变期,其中坝下资源呈萎缩状态,本次调查中坝下江段尚未采集到的四川裂腹鱼、中华金沙鳅、前臀鮡、安氏高原鳅等具有保护价值的特有鱼类。     

乌弄龙水电站升鱼机设备布置与设计

目前我国升鱼机的设计和研究还没有相应的规程规范,对乌弄龙水电站升鱼机金属结构设备的选型、布置及设计的思路和方法进行介绍,重点阐述了诱捕鱼系统和运输过坝系统设备布置、运行流程、设计参数及结构特点。目前设备安装调试已完成并投入运行,运行效果好。     

大坝异常性态定性评判的原理及实例分析

大坝异常性态的定性评判，是从大坝原型监测量中总结出一些变化规律，诸如突变性、趋势性、合理性、相关性、相似性、对称性等，用以对大坝的运行性态进行安全评判。本文概率其基本原理，结合国内外几座大坝实例，进行具体分析研究。     

PIV相关法中错误速度矢量的识别与评价

在PIV相关法中,分析结果中存在一些错误矢量。计算分析表明,搜索域的相关系数分布图中出现“多峰状态”是出现错误速度矢量的根本原因。由此,通过确定最佳相关域的范围来识别错误矢量的方法,用综合评价系数对这种方法进行评价,用这种方法对水泵水轮机内部流动的矢量图进行处理,效果较好。     

跌坎下游流场的时均流速分布和脉动特性

本文采用颗粒示踪的方法试验研究了跌坎下游主流重新接触床面流区的时均流速分布，流速的脉动强度及各点脉动流速的概率密度分布。试验结果表明，跌坎下游水流分离，具有稳定的漩涡发展，漩涡产生的频率约为每２秒３次。重新接触点离跌坎的距离约在３￣６倍坎高之间。在主流重新接触床面的流区，紊动剪切应力最大，在量测的流区，脉动流速的概率密度接近正态分布。     

Flow structures and hydrodynamics of unsteady cavitating flows around hydrofoil at various angles of attack

This paper investigates the unsteady structures and the hydrodynamics of cavitating flows. Experimental results are presented for a Clark-Y hydrofoil fixed at ?= 0?, 5? and 8?, for various cavitation numbers, from subcavitating flow to supercavitation. The high-speed video camera and the particle image velocimetry(PIV) are applied to observe the transient flow structures. Statistics of the cavity lengths, the velocity and vorticity distributions, as well as the turbulent intensities are presented to quantify the unsteady process. Meanwhile, the dynamic measurement system is used to record the dynamic characteristics. The experimental results show that the flow structures and the hydrodynamics of the cavitation vary considerably with various combinations of angles of attack and cavitation numbers. Under various conditions, the cavitation can be generally grouped as the inception cavitation, the sheet cavitation, the cloud cavitation and the supercavitation. The cloud cavitation exhibits noticeable unsteady characteristics. Experimental evidence indicates that the hydrodynamics are clearly affected by the cavitating flow structures, the amplitude of the load fluctuation is much higher in the cloud cavitating cases.     

Hydropower Development,Riverine Connectivity,and Non‐sport Fish Species: criteria for Hydraulic Design of Fishways

Hydropower barriers are among the most conspicuous anthropogenic alterations to natural riverine connectivity, resulting in species‐specific effects linked to dispersal abilities, especially swimming performance. They may present a particular problem for small‐bodied ‘non‐sport fish’, such as those that characterize the freshwater communities of temperate regions in the Southern Hemisphere. Recent studies have suggested that nature‐like fishways could ensure passage of diverse fish assemblages through hydropower barriers. Through experiments performed in a swim tunnel, we present, for the first time, fishway design criteria for two non‐sport species endemic to Chile, a country experiencing rapid hydropower development. In`cremental velocity tests showed that Cheirodon galusdae and juveniles of Basilichthys microlepidotus were capable of very similar standardized critical swimming speeds of 69.7 and 69.6 cm s^?1, respectively. When expressed in units of body lengths, C. galusdae was capable of very high critical speeds of 16.2 bl s^?1, whereas for B. microlepidotus, this was 7.6 bl s^?1. However, fixed velocity tests revealed that the swimming endurance of the latter species was slightly higher. Dimensionless analysis showed a clear relationship between fatigue time and fish Froude number, similar to that already described for subcarangiforms. Based on these results, we present fishway design curves indicating a transition from sustained to prolonged swimming at a fishway length of 15 m. Our results show that the swimming capacity of these species is well‐suited to the mean flow velocity field described for nature‐like fishways. However, more work is required to understand the effects of turbulence on the passage of non‐sport species. Copyright © 2016 John Wiley & Sons, Ltd.     

Effects of Contaminants on Toxicity of the Lampricides TFM and Bayer 73 to Three Species of Fish

Waters in the Great Lakes basin contain more than 400 contaminant chemicals that potentially affect fishery resources, commerce, and human inhabitants. We determined in the laboratory the effects of selected contaminants on the toxicity of the widely used lampricides TFM (3-trifluoromethyl-4-nitrophenol) and Bayer 73 (2′,5-dichloro-4′-nitrosalicylanilide) to three species of fish—rainbow trout (Salmo gairdneri), white sucker (Catostomus commersoni), and fathead minnow (Pimephales promelas). The fish were exposed to paired mixtures of lampricides and selected contaminants in standardized, acute static toxicity tests to determine the resulting type of response—less than additive, additive, or greater than additive (synergistic). As expected, the toxicities of combinations of lampricides with organic pesticides, metal, industrial or municipal pollutants, and tannic acid were mostly additive. However, the toxicity of a combination of TFM, Delnav, and malathion was synergistic, and extremely small quantities of each chemical became lethal when mixed. The concentration that produced 50% mortality was 1.64 mg/L for TFM alone but only 0.041 mg/L for TFM with the pesticides. Toxicities of the pesticides in the combination also increased commensurately. The triple combination of chemicals produced extraordinary synergism and effectively demonstrated the hazards that may result if certain chemical combinations occur in the aquatic environment. However, synergism is not the only kind of toxic action that produces hazards to aquatic organisms. All three types of toxic action are of concern because toxic units produced by contaminant chemicals add to the toxic units of applied management chemicals. Since the toxicity of the majority of chemical combinations is simply additive, this cumulative toxic action contributes more total units to aquatic environments than the extreme actions of less than additive and synergism. The toxicity of the lampricide TFM, as well as other management chemicals, is reinforced by the presence of any contaminant that contributes additional units of toxicity. Therefore, all types of cumulative toxic action should be of concern to people and agencies involved with protecting the environment.     

泰晤土河口水温和水化学特性对鱼类的影响研究

根据1915～2005年的长系列数据，对泰晤士河口水温和水化学特性对鱼类的影响进行了评价。结果表明，20世纪60年代之前河口上中游水温持续上升，此后下游水温开始上升而上中游水温下降，河口地区的温度变化模式受电厂热排水影响。水温与鱼类平均数量和水体溶解氧呈负相关，其Spearman相关系数分别为-0.468和-0.607（P〈0.05）。BOD、氨氮和溶解氧与鱼类消失和重现存在对应关系，说明污染是影响鱼类长期变化的一个主要因素。气候变化也可能通过径流和潮汐的改变对鱼类产生影响。由于河口环境复杂以及各因子间的协同作用，泰晤士河口生态改善的影响因子还有待进一步深入研究。     

Relative Effects of Water Temperature and Water Chemistry on the Fish of the Thames Tideway

1 IntroductionThe Tidal Thames is a well mixed estuary stretching some140 km from Teddington to the North Sea , which provideshabitats for both resident and migrant fish species . With tidalwater enteringfromthe ocean and fresh water flowingfromtheland ,t…     

泰晤士河口水温和水化学特性对鱼类的影响研究

根据1915~2005年的长系列数据,对泰晤士河口水温和水化学特性对鱼类的影响进行了评价。结果表明,20世纪60年代之前河口上中游水温持续上升,此后下游水温开始上升而上中游水温下降,河口地区的温度变化模式受电厂热排水影响。水温与鱼类平均数量和水体溶解氧呈负相关,其Spearman相关系数分别为-0.468和-0.607(p<0.05)。BOD、氨氮和溶解氧与鱼类消失和重现存在对应关系,说明污染是影响鱼类长期变化的一个主要因素。气候变化也可能通过径流和潮汐的改变对鱼类产生影响。由于河口环境复杂以及各因子间的协同作用,泰晤士河口生态改善的影响因子还有待进一步深入研究。