Iberian Straight-mouth Nase

• GeneralEndemic to Iberia; it scrapes algae off the stones with its mouth.
• Its lower lip is a sharp horny plate, almost a blade, adapted to scraping the algal biofilm from river cobbles.
• It makes migrations of tens of kilometres upstream to spawn over gravel, movements that are blocked by dams and weirs.
• It is an Iberian endemic: it lives only in the basins of the Tagus, the Douro, the Guadiana and a few smaller rivers of Portugal and Spain.
• It scrapes the algal biofilm off stones with a mouth whose lower lip is horny and sharp-edged, an adaptation it shares with the other Iberian nases.
• Its populations suffer from dams, which fragment the rivers and stop it running upstream to its spawning grounds, and from introduced species such as the wels catfish and the black bass.
• The Iberian freshwater fish fauna has an extremely high share of endemics, and this genus is a good example: each major basin has its own species of nase.

Skeleton type

Vertebrate - internal bony skeleton (fish)

Habitat and environment

Rivers and streams of the Tagus, Duero and Guadiana basins

Sources consulted: Wikipedia (es): Pseudochondrostoma polylepis

Best time: Spring, during the upstream spawning migrations

The pins mark the parks where its presence is documented.