Gammarids
A short, steep Liébana tributary of the Deva, joining the parent river at Ojedo (Cillorigo de Liébana). The Bullón is alpine in character: limestone-and-shale bedrock, plunge-pool-and-pocket structure, the kind of water you fish wading slowly with a short rod. Wild brown trout only. Smaller and faster-falling than the parent Deva, the Bullón colours quickly in heavy rain but clears within hours, so it works well as a follow-on river when the Deva is still off. Best fished from late May through July, when the high meadows above Pesaguero come into their own and the river has dropped back from the snowmelt freshet.
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