Quantitative relationships between river discharge and hydraulic habitat availability for key taxa are important elements of environmental flow assessment. We used radiotelemetry to examine diel patterns of habitat use by tracking the locations of 17 juvenile Sooty grunter (Hephaestus fuliginosus) over a 10-day period during the late dry season in a river in the wet–dry tropics of northern Australia. Habitat use data were integrated with a hydrodynamic model to identify preferred hydraulic habitat and explore different river discharge scenarios to assess the potential effects of water abstraction on habitat availability. Sooty grunter exhibited a strong preference for shallow, fast flowing mesohabitat (riffles and runs). Hydraulic microhabitat preference was modelled using generalised additive mixed-effect models (GAMMs) and showed no significant difference in microhabitat selection between day and night. Habitat criteria developed from a combined day-night GAMM were defined as locations with velocities of 0.26–1.42 m s⁻¹ and depths <0.69 m. Hydrodynamic modelling of river discharge scenarios in the study reach showed that the area of preferred habitat was highest at 8 m³ s⁻¹, with large declines in habitat area under low flows (61% decline in habitat area at 0.5 m³ s⁻¹ compared to the discharge of 2.8 m³ s⁻¹ at the time of radio-tracking). While the study focusses on a single species, our findings demonstrate the broad applicability of radiotelemetry as a means of quantifying the diel hydraulic habitat requirements of riverine fish to support the objective determination of environmental flow regimes.

中文翻译：

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使用无线电遥测来量化热带河流鱼类的栖息地偏好和最低环境流量要求（Sooty grunter Hephaestus fuliginosus）

河流流量与关键分类群的水力栖息地可用性之间的定量关系是环境流量评估的重要元素。我们使用无线电遥测技术通过跟踪 17 只黑尾鹱（Hephaestus fuliginosus）的位置来检查栖息地使用的日间模式) 在澳大利亚北部干湿热带地区的一条河流中，在旱季晚期的 10 天内。栖息地使用数据与水动力模型相结合，以确定首选的水力栖息地，并探索不同的河流排放情景，以评估取水对栖息地可用性的潜在影响。Sooty grunter 表现出对浅层、快速流动的中生境（浅滩和小径）的强烈偏好。使用广义加性混合效应模型 (GAMM) 对水力微生境偏好进行建模，并且在白天和黑夜之间的微生境选择上没有显着差异。从组合的昼夜 GAMM 制定的栖息地标准被定义为速度为 0.26-1.42 ms ^{-1 的位置}和深度 <0.69 m。研究河段河流排放情景的水动力模型显示，首选栖息地面积在 8 m ³ s ^-1时最高，在低流量下栖息地面积大幅下降（栖息地面积在 0.5 m ³ s ^-1处下降 61%与无线电跟踪时2.8 m ³ s ^-1的放电相比）。虽然该研究侧重于单一物种，但我们的研究结果表明，无线电遥测作为一种量化河流鱼类水力栖息地要求的手段具有广泛的适用性，以支持客观确定环境流态。