The present study describes the larval and juvenile fish fauna of an estuary and its adjacent coastal area (Mondego estuary, Northwest coast of Portugal) and evaluates their function as nurseries for marine fish. For this, larvae and juveniles were sampled in both systems. The temporal and spatial patterns of the ichthyoplankton community were described for each system and related to the influence of environmental factors. Additionally, the recruitment pattern was evaluated based on the composition of juveniles. Results show a seasonal variation of larval density and community structure between and within systems, indicating a degree of segregation according to their ecological functional classification. Temperature was the most important environmental factor structuring the communities. The juvenile recruitment patterns observed show a different nursery function of the estuary and coastal area for early life stages of different species, reinforcing the need to integrate larval and juvenile stages to better understand fish life cycles and the connectivity between systems.

本研究描述了河口及其邻近沿海地区（葡萄牙西北海岸的蒙德戈河口）的幼鱼和幼鱼群，并评估了它们作为海水鱼苗圃的功能。为此，在两个系统中都对幼虫和幼虫进行了采样。描述了每个系统的浮游鱼类群落的时空格局，并与环境因素的影响有关。此外，还根据少年的组成评估了招募模式。结果显示系统之间和系统内的幼虫密度和群落结构的季节性变化，表明根据其生态功能分类的隔离程度。温度是构成群落的最重要的环境因素。