sentences:  The fish species are affected by the high number of reservoirs in the region.Among the threatened species in the rivers stand out the European eel, the iberian barbel, the "Squalius alburnoides", the "Cobitis calderoni" and, potentially, the "Chondrostoma lemmingii".Conversely the set of invasive species of fish includes pike, black bullhead catfish, pumpkinseed, zander, common bleak and black-bass.