The fish weir at Lohercannan, in Tralee Bay near Blennerville, was identified not by excavation or fieldwork but from an aerial photograph, its V-shaped outline visible from above the water and mud in a way it could never be from ground level. That distinctive profile is the calling card of a particular kind of fish trap, one where the converging arms of the V funnel tidal fish towards a confined point, making capture a matter of patience and geometry rather than effort. The technique is ancient, found in estuaries across Ireland, but this example sits in circumstances that make it quietly unreachable: the surrounding area has since become impassable mud flats, meaning the structure has been recorded but never formally visited.

The site lies on the south side of the entrance to the Tralee Ship Canal, a waterway that connected Tralee to the sea and whose construction in the early nineteenth century reshaped this stretch of the bay considerably. Whether the weir predates that canal or was adapted around it is not known from what has been documented, and since the mud flats prevent any closer inspection, those questions remain open. The weir was logged during a survey of the area carried out in the mid-1990s, a period when aerial photography was increasingly being used to identify sites that conventional fieldwork could not reach or had simply passed over.