Bio Anorí, the biological expedition that documented fish diversity after the post-conflict in Antioquia, Colombia

The peace process in Colombia allowed biodiversity experts to visit unexplored regions in the tropical Andes mountains. The diversity of fish species and characteristics of the aquatic environments (creeks, streams, and river channels) in which they live were determined by means of the Bio Anorí expedition. During the expedition, we evidenced the presence of alluvial mining activity, and we contrasted the environmental characteristics of the sites without disturbances with those where there was mining activity. A total of 478 specimens were captured, representing 22 endemic species of the region. The dominant species (Brycon henni, Chaetostoma aff. brevilabiatum, Creagrutus affinis) were distributed in the three environments, while the less abundant species (e.g., Leptoancistrus or Characidium) were captured in a particular environment. The number of species captured in each aquatic environment was representative and adjusted to the values expected to be obtained. Stream environments harbored a higher diversity of fish. A representative species inventory was inferred; however, this analysis suggested that it is possible to capture more species in the aquatic environments evaluated. The composition of assemblages was similar among aquatic environments; although, differences were observed between creeks and rivers. Stream environments connected creeks and river assemblages. In terms of environmental characteristics, the evaluated streams and creeks were cold, more transparent, and highly oxygenated; the opposite occurred in the rivers, which were less oxygenated, more turbid, and warmer. Canonical correspondence analysis suggested that species composition was influenced by the physicochemical conditions of the water. This study provides information associated with fish distribution in a region of the Colombian Andes that was under an armed conflict for more than five decades. In addition, it allowed us to observe habitat transformations because of alluvial mining activity. Finally, it is essential to continue exploring remote areas to know their preservation status and apply conservation measures.