Understanding the relationships between hydrodynamics and the spawning activities of small pelagic fishes is crucial for understanding their recruitment dynamics and for fisheries management. Here, we clarify the effects of marine environmental factors and the associated hydrodynamic processes on the spawning activities of the Japanese anchovy Engraulis japonicus in the coastal Yellow Sea using data from in situ ichthyoplankton surveys (7 recent years), a hydrodynamic model and satellite remote sensing. We confirmed the peak spawning period (May and June) and primary spawning location (Haizhou Bay). We defined the ‘spawning temperature optima’ hypothesis to identify the optimal spawning temperature (13.0–18.0°C) for the Japanese anchovy based on egg occurrence and abundance. We detected fortnightly variation in spawning behaviour, which peaked after the spring tide. Anchovy eggs showed evident aggregation in the nearshore upwelling area during May and June, while strong upwelling in July may cause a negative spawning-site choice in upwelling zone. These findings clarify the effects of hydrodynamics on the spawning behaviour of the Japanese anchovy in the coastal Yellow Sea.

中文翻译：

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黄海沿岸日本鳀鱼的产卵策略：选择与动态

了解水动力与小型远洋鱼类产卵活动之间的关系对于了解它们的补充动态和渔业管理至关重要。在这里，我们阐明了海洋环境因素和相关的水动力过程对日本凤尾鱼Engraulis japonicus产卵活动的影响使用原位浮游鱼调查（最近 7 年）、水动力模型和卫星遥感的数据在黄海沿岸。我们确定了产卵高峰期（5 月和 6 月）和主要产卵地点（海州湾）。我们定义了“最佳产卵温度”假设，以根据卵发生率和丰度确定日本凤尾鱼的最佳产卵温度（13.0–18.0°C）。我们每两周检测到产卵行为的变化，在大潮之后达到顶峰。鳀鱼卵在5-6月在近岸上升流区聚集明显，而7月强上升流可能导致上升流区产卵地点选择不利。这些发现阐明了流体动力学对黄海沿岸日本凤尾鱼产卵行为的影响。