Anchovies are species of ecological and economic importance that inhabit coastal waters, where they are very abundant. The objective of the study was, through high-frequency temporal sampling, to analyze the diversity, seasonal and diel distribution patterns of anchovies and their relationships with environmental variables. For 19 months, 24-h monthly cycles were carried out, taking samples every two hours. Permutational analysis of variance (PERMANOVA) and redundancy analysis (RDA) were used

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... r data analysis. Seven species were captured, of which, Anchoa mitchilli, Anchoa hepsetus, Anchoa lyolepis, Anchoa lamprotaenia and Cetengraulis edentulus are common in brackish waters; however, Anchoviella perfasciata and Engraulis eurystole rarely occur in these systems. For these species, no major threats are known; therefore, they are listed as 'Least Concern'. A seasonal succession shows pulses during the closed-mouth phase and during the late warm-rainy season. At diel level, A. mitchilli, C. edentulus and A. lamprotaenia showed a markedly nocturnal pattern. RDA correlations showed that salinity, day/night effect, inlet state and rainfall were the most important factors related to anchovy distribution. Segregation along a salinity gradient was observed, in which A. mitchilli was captured mainly at low salinities, while other species occurred mainly at intermediate to high salinities. High-frequency sampling allowed a better understanding of the species richness and abundance patterns of anchovies in the system.