1. Setting ecologically based water-extraction rules requires an understanding of the relationships between hydrology and the completion of aquatic organism life cycles. Successful reproduction of riverine fishes has been linked to hydrological variation across diverse climatic regions. However, the reproductive ecology for many species in wet–dry tropical northern Australia is poorly understood, and consequently there is little knowledge on how temporal (seasonal) and spatial hydrological variation influences fish reproduction in this region.
2. This study aimed to quantify the hydrology-related reproductive ecologies of freshwater fish across the wet–dry seasonal cycle and between differing hydrological classes in a northern Australian river (Daly River, Northern Territory) subject to increasing interest in water extraction. Sampling of larval and juvenile fish was undertaken over 1 year at eight sites classified into perennial and intermittent flow types. Fish spawning phenologies were developed and spatial–temporal dynamics in larval fish assemblages were investigated using model-based multivariate and univariate analyses.
3. Spawning occurred in all hydrological seasons, with low-flow dry season periods identified as important for many fish taxa. For a different fish assemblage, spawning mostly occurred during high-flow wet season periods. Larval assemblages in the wet season were more diverse than in the dry and wet–dry seasons. Perennial sites maintained higher diversity than intermittent sites year-round; however, larvae were more abundant in intermittent sites for some taxa. Spatial and temporal differences in larval assemblages were largely explained by variation in the occurrence and relative abundance of three aseasonally spawning taxa (Craterocephalus spp., Melanotaenia spp. and Ambassis spp.) and the largely wet-period spawning of Terapontidae spp.
4. These results add to growing evidence of variation in spawning phenologies among fish species and the use of multiple hydrological phases for aseasonal reproduction. The diverse range of hydrological conditions used for spawning and rearing, and the differences between hydrological river classes among taxa, suggests that water-extraction and environmental flow rules should aim to maintain hydrological conditions catchment-wide during both low and high-flow periods to reduce the risk of impacting fish reproduction. In particular, the results suggest that if perennially flowing sites began to flow intermittently, such as through over-extraction of water or due to climate change, less diverse fish assemblages may result.
5. This study expands our understanding of the relationships between hydrology and the reproductive ecology of freshwater fish in wet–dry tropical climates and may inform future ecologically based approaches to setting water-extraction rules.

中文翻译：

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水文驱动澳大利亚干湿热带鱼产卵物候和幼虫组合多样性的变化

1. 制定基于生态的取水规则需要了解水文与水生生物生命周期完成之间的关系。河流鱼类的成功繁殖与不同气候区域的水文变化有关。然而，对澳大利亚北部干湿热带许多物种的生殖生态知之甚少，因此对时间（季节性）和空间水文变化如何影响该地区鱼类繁殖知之甚少。
2. 本研究旨在量化淡水鱼在整个干湿季节循环中以及澳大利亚北部河流（北领地戴利河）中不同水文类别之间与水文相关的生殖生态，这些河流对取水的兴趣日益增加。幼鱼和幼鱼的取样在 8 个地点进行了一年多的时间，分为多年生和间歇流类型。开发了鱼类产卵物候，并使用基于模型的多变量和单变量分析研究了幼鱼组合的时空动态。
3. 产卵发生在所有水文季节，低流量旱季时期被认为对许多鱼类分类群很重要。对于不同的鱼类组合，产卵主要发生在高流量雨季期间。雨季的幼虫组合比旱季和干湿季更多样化。常年站点全年保持比间歇站点更高的多样性；然而，在某些类群的间歇性地点，幼虫更为丰富。幼虫组合的时空差异在很大程度上是由于三种非季节性产卵类群（Craterocephalus spp.、Melanotaenia spp. 和Ambassis spp.）的发生和相对丰度的变化以及 Terapontidae的主要湿润期产卵所解释的 属
4. 这些结果增加了越来越多的证据表明鱼类产卵物候变化以及使用多个水文阶段进行季节性繁殖。用于产卵和养殖的各种水文条件以及不同分类群之间水文河流类别的差异表明，取水和环境流量规则应旨在在低流量和高流量期间保持流域范围内的水文条件，以减少影响鱼类繁殖的风险。特别是，结果表明，如果常年流动的地点开始间歇性地流动，例如由于过度抽取水或由于气候变化，可能会导致鱼类组合的多样性降低。
5. 这项研究扩大了我们对水文与干湿热带气候中淡水鱼生殖生态之间关系的理解，并可能为未来制定水提取规则的基于生态的方法提供信息。