The Aspe valley sits in western Béarn where limestone keeps the water clear and the mountains feel close enough to touch. The Gave d'Aspe joins the Gave d'Ossau at Oloron to form the main Gave, but on its own it's a proper wild-trout river — cold, limestone-buffered, selective in the way limestone water always is. Wild brown trout and a useful run of grayling share the middle and lower reaches; the upper valley thins out into classical mountain water where the fish are smaller but willing. Match the olive in spring, work caddis through summer, and fish the evening rise properly when the hatches come off. Limestone springs maintain summer flow better than most Pyrenean rivers, which extends the prime window. The AAPPMA manages multiple no-kill reaches — check the current arrêté because the boundaries shift year on year.

• Limestone