A short Trasmiera tributary of the Miera, rising near Entrambasaguas and joining the parent river above the estuary. Limestone-influenced spring-fed water — clearer and steadier than the typical spate-fed Cantabrian small river, with karst character through the middle reaches above Entrambasaguas. Wild brown trout only. Best fished from late April through June.
In Cantabria's shorter mountain and foothill trout rivers, fish make the most of spring olives and stoneflies in clear windows between freshets, then switch to evening caddis and small buzzers through the warmer months, with terrestrials becoming a key option in sheltered glides and under tree cover once summer settles in.
- Limestone

