Three main groupings of weirs, one with eight v-shaped bays, stretch around Swansea bay, from Blackpill in the southwest around to the Black Rock at the entrance to the River Neath in the northeast. The majority of the weirs have stone foundation walls 1-2m wide which would have supported wattles fences. Small roundwood posts line the inner face. Each wall is generally between 120m and 170m in length. A very large, single fish traps, NPRN 90542 to the east of Swansea harbour mouth, may have had walls up to 2000m in length, but is now largely subsumed by Swansea Docks. The apex of the angles varies between 70 and 100 degrees. At the apex, the wall becomes progressively more parallel to one another and the wooden posts continue beyond the walls to form a gradually narrowing 'snout' traceable for up to 20m. There are also two isolated groups comprising a small numbers, also v-shape in a plan form, but of wooden stakes with no stone foundations.

Event and Historical Information:
The Royal Commission on Sea Fisheries of 1863 described the weirs as 'about 6 feet high... composed of stakes driven into the sand, and wattled to constitute a fence. At the junction of the arms near low water mark, was a closely woven conical basket, with its entrance facing the inner side of the weir'.

Sources include:
Davidson, A (ed), 2002, The Coastal Archaeology of Wales, pg101
Matheson 1929, Wales and the Sea Fisheries, National Museum of Wales pg63

Maritime Officer, RCAHMW, April 2011