Going up?

Haverfordwest, the county town of Pembrokeshire, has never been my favourite destination for a shopping trip but there were a few things I needed there today.
It's an old trading port and market town with a ruined priory and a castle and plenty of history but destruction and reconstruction in the 60s ripped the soul out of the place. It's had more than its share of unemployment and poverty and now a brand new retail park on the edge of town has left the centre occupied mainly by charity shops and discount stores.

Business thrived on the river in former times despite being a few miles from the sea but the arrival of the railway put paid to waterborne commerce. The waterway silted up leaving the quays and warehouses abandoned or given over to other uses. There are no ships or even boats moored here now and the river is simply something that flows through. But the fish still follow their old courses: Atlantic salmon, lampreys, eels and sea trout (sewin in Welsh, a great delicacy) all head back to their native spawning grounds when the urge to procreate comes over them. Hatched upriver, they spend their adult life in the sea but return to breed in the sheltered reaches of rivers like this Western Cleddau. So what you see here is a fish pass, or ladder, constructed to enable them to ascend the weir and continue their journey upstream. Most of these fish will die after spawning but the young fry will travel down again on their route from fresh water to salt, as ever they did and will continue to do.

This is my submission for this week's challenge UP.