An A Coruña sea-trout river falling east-to-west from the Sierra de Domaio through Abegondo to the Ría de Betanzos. The Mero is granite freestone water through the middle reaches around Cambre, with the lower river joining the parallel Mendo at Betanzos. Wild brown trout throughout; reo running into the lower river around Cambre and Betanzos from July onwards.
In Galicia's Atlantic trout rivers, resident browns feed through a spring build-up of olives and other up-wings into a long summer of caddis and small buzzers, with frequent spates and cool water keeping fish active; terrestrials from lush banks and meadows become important once levels settle and the banks green up.
- Granite

