A preferred current changes with age
For a young nase, a calm stretch can make a difference.
Explore: The same river, different ways of living →Read here and view sources
The Douro nase, Pseudochondrostoma duriense, is native to the Iberian Peninsula. Santa Maria da Feira’s municipal profile describes adults in strong-current river sections and juveniles preferring slower water and fine substrates. It also mentions upstream movements before reproduction. The Cavez record from 2016–2017 confirms the species in that survey; it does not describe the sampled fish’s ages or behaviour.
There is a clue in the mouth: the lower lip is straight and has a well-developed horny edge. The body may show small dark spots. These features complement the habitat story; they do not replace careful identification.
The municipal source places upstream migrations between March and June and gives an approximate lifespan of six years. Upstream means towards the source. The calendar and lifespan describe the species in general, without dating a movement or determining the age of fish sampled in the Tâmega.
Source and context
Municipality of Santa Maria da Feira — Northern Boga, fauna catalogue
Accessed:
Editorial summary; the date of consultation is not the date of the facts.