The cormorants were obviously getting some rich fishing in the highly aerated water below the barrage on the Afon Tawe where it flows into Swansea Bay - they regularily popped up with a fish in their beaks.
There were lots more cormorants sitting on the yellow floating markers.
I guess that fish would get a bit dis-orientated by the water coming over the barrage, and take a while to find the fish ladder over in the corner.
It was a mean looking stopper, no doubt caused by the sloping front of the barrage - not a place to be in a small boat !