The pesqueiras are the most extraordinary cultural object in Arbo: V-shaped stone walls built right out into the current of the Miño, designed to funnel migrating fish into wooden boxes or conical nets at their narrowest point. There are dozens of them in the river around Arbo, some isolated, others arranged in long lines, all of them dating in their basic form from the Middle Ages.
In late winter and early spring they are used to catch the lamprey that runs up from the Atlantic to spawn — the fish that gave Arbo its festival and its kitchens. The best view is from the riverside footpath downstream of the village; an interpretive trail (the Sendeiro das Pesqueiras) explains the construction techniques and the fishing rights, which are still held by individual families and pass down through generations.