Fermoy’s Blackwater has had a weir for over 800 years, ever since the Cistercian monks built their abbey Sancta Maria de Castro Dei (Our Lady of the Camp of God) somewhere on what is now Ashe Quay. In 1791, centuries after the abbey was lost to history, the Scottish businessman John Anderson bought the old abbey lands and founded the modern town. To power the industrial base of his fledgeling town, Anderson built the modern weir, shaping the Blackwater, sculpting its flow and channelling its power down through the sluice gates and down to Mill Island. Anderson understood that salmon have travelled upstream along the Blackwater to spawn since time began. The centrepiece of Anderson’s weir is a tiered fish pass to the west of the bridge, a series of rectangular limestone pools designed to create at its base a turmoil in the water, to attract salmon and to draw them up the steps and further along their journey home to spawn.