From July 2003 to June 2004, the physiographic characteristics of the ichthyofauna of the estuary of Saco da Fazenda were studied in four defined areas representative of the estuary. A total of 4502 individuals were captured, with 42 species, 35 genera, and 21 families. Engraulidae were the most abundant fish, and Cetengraulis edentulus dominated the captures. The species of occasional occurrence prevailed in the samplings and were represented mainly by juvenile individuals. The highest abundances occurred during the months of summer and autumn, in contrast with high biomasses in the spring and autumn; area IV contributed the largest captures. The richness indexes, diversity, and equitability presented similar flotation patterns, with high values in spring and summer. The Jaccard index revealed a greater similarity in the composition of the ichthyofauna in areas II and IV, while the lowest happened between I and IV, which is probably due to the different sizes of these areas.
This paper clearly shows the relevance of this estuary, albeit strongly impacted, for recruitment of small fish mainly during summer and autumn months.