 Finally, 109 species of fish species have been identified by the IMNA alone, with a clear dependence on altitude.The largest specimens, which are the principal targets of commercial and subsistence fishing - such as sábalo, barred surubim, and pacú - are restricted to the alluvial plains, below 700 m. Above just 1000 m, the fish diversity diminishes dramatically.In the northern area, colonial settlements originated in the highlands.