These are not the kind of thing you stumble across on a walk; they require the right tide, the right angle, and a reason to be looking.

The structure was identified during a drone-based intertidal survey of Wexford Harbour and subsequently inspected on foot at low water. A fish weir, in its simplest form, is a fixed trap built into a tidal channel, designed so that fish swim in with the flood tide and become stranded or corralled as the water retreats. This particular example runs roughly northeast to southwest, with two converging lines of posts stretching about 34 metres in total. There are 14 posts in one line and 13 in the other, each slender, between seven and eight centimetres in diameter. Most are barely visible above the mud surface, though a few stand as tall as 1.2 metres. The geometry of the trap is telling: the two lines sit 4.4 metres apart at the shoreward end, narrow to 2.2 metres at the centre, and then splay outward to 5.8 metres on the seaward side, a funnel shape that would have guided fish inward. Between the posts, hazel rods are intertwined in places, the remains of woven panels that once formed the walls of the trap, some of which have now collapsed into the mud.

The best chance of seeing the posts is during a low spring tide, when the harbour's intertidal zone is exposed for a brief window. The hazel weaving, where it survives, is fragile and partially buried, but enough remains to give a clear sense of how the whole structure once functioned.