Many exploited coastal species rely on estuarine nurseries, however, the importance of different estuaries and their contribution to exploited populations can vary. Identification of connectivity between source nurseries and exploited populations is important for effective habitat and fishery management. We present a case study which employs otolith chemistry to investigate source-sink population dynamics across broad spatial scales for an exploited migratory sciaenid, Mulloway (Argyrosomus japonicus). Specifically, we compared the otolith chemical fingerprints of juveniles in putative estuarine nurseries across south-eastern Australia with the sub-yearling chemical fingerprints of post-recruited fish in the exploited component of the stock. Multinomial Logistic Regression (MLR) suggested that two of the eight estuarine nurseries sampled were particularly important sources of Mulloway recruits, and there was strong evidence of stock mixing which exceeded that expected from historic tag-recapture studies. However, there was some uncertainty in the patterns resolved. Variation in otolith signatures between the known-source juveniles and post-recruit fish may be explained by inter-annual variability in these systems, caused by extensive flooding on the central and northern-NSW coast during the study period. These events contributed considerable extrinsic variation to the chemical composition, influencing the lack of overlap between otolith chemistry of putative nurseries and sub-yearling otolith chemistry of exploited fish. The approach presented highlights the importance of considering inter-annual variability when examining source-sink relationships in long-lived species, but the use of otolith fingerprints shows promise for evaluating these questions for both Mulloway and other exploited fish species.

许多被开发的沿海物种依赖河口苗圃，然而，不同河口的重要性及其对被开发种群的贡献可能会有所不同。确定源苗圃和开发种群之间的连通性对于有效的栖息地和渔业管理很重要。我们提出了一个案例研究，该研究利用耳石化学研究了一种被开发的迁徙 sciaenid，Mulloway（Argyrosomus japonicus）在广阔空间尺度上的源汇种群动态。）。具体来说，我们将澳大利亚东南部假定河口苗圃中幼鱼的耳石化学指纹与种群中被开发成分中的后招募鱼的一岁以下化学指纹进行了比较。多项 Logistic 回归 (MLR) 表明采样的 8 个河口苗圃中有两个是 Mulloway 新兵的特别重要来源，并且有强有力的证据表明种群混合超过了历史标签重新捕获研究的预期。但是，解决的模式存在一些不确定性。已知来源的幼鱼和捕捞后的鱼之间耳石特征的变化可以用这些系统的年际变化来解释，这是由研究期间新南威尔士州中部和北部海岸的大面积洪水引起的。这些事件对化学成分造成了相当大的外在变化，影响了推定育苗场的耳石化学与开发鱼类的亚年幼耳石化学之间缺乏重叠。提出的方法强调了在检查长寿物种的源汇关系时考虑年际变化的重要性，但耳石指纹的使用显示出评估穆洛韦和其他被开发鱼类物种的这些问题的前景。