Fish weirs, known in Irish as cora éisc, are fixed trapping structures, typically built from stone, timber, or wattle, arranged to funnel fish into an enclosure as the tide recedes or the current flows through. They required no nets and no boats, just a careful reading of water and a willingness to build in an unforgiving environment. The fact that one is recorded at Bellass is a reminder that this stretch of Mayo was, at some point, organised around the rhythms of fish rather than field.