Movement and migration of freshwater fish for the purpose of feeding, dispersal, and spawning are essential life history components often linked to river flows. Understanding movement responses to abiotic stimuli such as river flows is crucial to inform effective management, especially considering that river regulation is contributing to global population declines. We examined the flow‐related movements of three species of lowland river fish endemic to eastern Australia (golden perch Macquaria ambigua, Murray cod Maccullochella peelii, and silver perch Bidyanus bidyanus) over an 18‐month period in a large anabranch system of the Murray River, south‐eastern Australia. The telemetry study encompassed periods of extreme low river discharge, moderate discharge rates within the normal regulated operating range for this system, and a large overbank flood event that created hypoxic blackwater conditions and led to significant fish kill events. Movement of all three species was strongly affected by discharge rates, and although the direction and magnitude of responses varied by species, river discharge in general had a significant positive effect on the scale of movement. All species initiated large‐scale directional movements in response to flooding, and some emigration occurred; however, hypoxia‐induced mortality ultimately killed a large proportion of the tagged fish. The results of the current study highlight the significant challenges of managing flow restoration in highly modified landscapes that are prone to hypoxic conditions. We reiterate the value of connectivity, especially where it enables fish to access suitable refuges during periods of poor water quality and subsequently recolonize when conditions improve.

中文翻译：

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缺氧条件中断了三种低地河鱼类的洪水响应运动：对改良景观中水流恢复的影响

淡水鱼以觅食，散布和产卵为目的的移动和迁移是生活史的重要组成部分，通常与河流的流量有关。了解对非生物刺激（例如河流流量）的运动响应对于有效管理至关重要，尤其是考虑到河流管制正在导致全球人口下降的情况下。我们研究了三种特有的低陆河鱼类到澳大利亚东部的与流动有关的运动（黄金鲈鱼Macquaria ambigua，墨累鳕鱼Maccullochellapeerii和银鲈Bidyanus bidyanus）在澳大利亚东南部默里河的大型分支系统中进行了18个月的研究。遥测研究包括极低的河流排泄期，在该系统正常调节运行范围内的中等排泄率以及造成过氧黑水条件并导致重大鱼类致死事件的大型河岸泛滥事件。这三种物种的迁移都受到流量的强烈影响，尽管响应的方向和幅度因物种而异，但总体而言，河流流量对迁移规模具有显着的积极影响。所有物种都响应洪水而开始了大规模的定向运动，并发生了一些移徙。然而，低氧引起的死亡率最终杀死了大部分带标签的鱼。当前研究的结果突出了在易于发生缺氧条件的高度修改景观中管理流量恢复的重大挑战。我们重申连通性的价值，尤其是在水质较差的时期使鱼类能够进入合适的避难所并在条件改善时重新定殖的地方。