Cormorants in the dead of winter

Nothing like a bleak water scene to remind one of winter. But the birds don't seem to mind. Here are two seagulls and two cormorants on the River Wear (pronounced 'weir', maybe because there is a weir there – actually more than one). In keeping with Spotting Animals, I have also seen salmon leaping up the weir, right here in the centre of Durham.

Cormorants on the weir of the River Wear, Durham

   In Japan cormorants are used to fish for ayu (Plecoglossus altivelis altivelis), a small (ca. 20 cm) freshwater member of the salmon family, using a leash and a ring. They put a ring around the bird's neck to keep it from thoroughly swallowing down any fish, and then pull the bird back to the boat with the leash so it can disgorge the fish. It is a favourite tourist activity to watch the night-time cormorant fishing in Uji and Arashiyama in Kyoto during the traditional ayu fishing season between mid-May and Mid-October.
   I don't know what the cormorants eat here, but in the line of 'invented traditions', maybe this is an area to expand the tourist trade, here in Durham and in London where cormorants frequent the River Thames (pronounded 'tems'). Just have to find the right fishermen fishing for the right fish and get the fishermen to 'tame' the cormorants to do their work for them.