Ichthyological research in the Sorocaba River basin, State of Sao Paulo, southeastern Brazil: trajectory of knowledge, advances, and future directions.

Ichthyological knowledge of the Sorocaba River basin dates to the 19th century, with initial surveys by Johann Natterer. These were followed by expeditions at the turn of the 20th century by researchers from the University of São Paulo's (USP) Zoology Museum, which resulted in the description of five new species. After a hiatus of nearly a century, research resumed in 1992. Here, we present a comprehensive review of 64 publications to assess the current state of knowledge on the basin's ichthyofauna. The most frequently studied topics were community ecology (34.4%), followed by species inventory (14%), population ecology (12.5%), and feeding ecology (7.8%). The reviewed articles documented 109 fish species, with the majority belonging to the order Characiformes and the family Aces-trorhamphidae. This total comprises 93 native and 16 non-native species. Despite a recent increase in publications, we identify critical knowledge gaps. We conclude that the basin has a well-known ichthyofauna, meaning that future efforts should prioritize research on diet, reproduction, and invasive species, while also incorporating emerging topics such as microplastic pollution and modern techniques, such as stable isotope analysis, to effectively guide conservation and management.