PURTON PASSAGE SSSI (SEVERN ESTUARY) - Fish Fossils, Migrant Birds And A Graveyard for Boats
Updated: Jan 28, 2022
(Nearest post code - GL13 9HY)
Visited by Shep and Pumpkin
On Saturday 22nd May, our humans took us on a completely different adventure. We went to explore part of the Severn Estuary SSSI at Purton – a village on its south bank.
It is at this point that the estuary runs parallel to and is very close to the Gloucester and Sharpness canal - a canal built to avoid the dangerous meanders of the estuary. By building this canal, huge sea-faring ships were able to carry freight fifteen miles all the way up into Gloucester.
It was busy when we arrived and there were lots of humans milling around the car park. Numerous kayaks and small dinghies and their occupants bobbed about on the water whilst other humans sat and sunned themselves in the early afternoon sunshine.
We left the crowds behind, crossed over a swing bridge and walked along the tow path by the side of the canal.
The canal was lined with a diverse array of boats, yachts and barges – all of them boasting the comforts of home - window boxes, hanging baskets and bicycles included.
There was lots of activity on the tow path too. Pumpkin was intrigued as an angler cast his line far out into the water. He sat glued to the spot and watched transfixed as the float repeatedly bobbed up and down. He waited for something else to happen ........then he got bored and allowed us to walk on.
Our humans led us off the tow path and down to the mud flats. The water glistened and winked at us but between it and us there were many strange structures wedged into the mud.These turned out to be the remains of tens of ships deliberately beached in order to save the estuary banks from coastal erosion and to protect the canal. Over several decades, over 80 boats have been deliberately abandoned here, and many of these boats have amazing stories to tell. Two of the boats whose hulks are wedged into the mud were actually responsible for the accidental destruction of the Severn Railway Bridge the purpose of which was to allow the transport of coal from the Forest of Dean to the docks at Sharpness. The accident happened on a very foggy night on the 25th October 1960.
The boats were in various degrees of disrepair – some, though ram-packed full of fine, soft sediment looked completely intact. For others, the bare skeleton was left behind and in places just one timber remained to mark where a boat had once lain.
The tide was half out and the mud flats were soft, wet and sticky to our paws. I found it very hard to keep on all four paws so Pumpkin must have really struggled with his dodgy hip. It was very quiet by the water except for the shrill cries of gulls.
The mud is rich in invertebrates making it a very attractive stopping off point for many migrant birds and it is for this reason that the Severn Estuary is given the status of a ‘Special Protection Area. A huge variety of birds pass through here including shelduck, pochard, curlew and wigeon. Many birds come here in the winter and will return to their breeding grounds when the weather improves. These include two races of white fronted geese that look quite different to each other. One race breeds in Greenland and have orange bills whilst their Siberian cousins have bright orange legs and pink bills. The Severn estuary is a bird-watchers' paradise.
Purton passage is special for another reason. Encased within the rocks at Tites Point are numerous fossilised teeth and other remains of primitive jawless fish whose skeletons , like sharks and rays, were made of cartilage. However, unlike sharks their fins had wide bony bases which sets them on a different evolutionary line.
Two types of jawless fish live in the estuary today. Both are long, thin and eel like with permanently open jawless mouths equipped with vicious teeth. One of them, the lamprey, is a parasite which lives on the blood of live fish. The other hagfish is a scavenger feeding on dead carcasses and frequently encountered by shipwreck-exploring divers.
When provoked a hag fish will emit a jelly-like slime the strands of which are very strong, thin and flexible. They use these threads to wrap around their food and also, to clog up the gills of any potential predator !! The slime is light and strong and scientists are researching how to use it to make bullet proof vests and air-bags or even to repair damaged tendons in the human body.
As we walked along the banks of the estuary, the tide was coming in more quickly. The estuary is funnel shaped so it takes much less time for the tide to come in than for it to go out again, On a very high spring tide there wouldn’t be much distance between the canal and the estuary so no wonder the boats were used to protect the canal embankment.
We walked through tall willowy reed beds, last years’ dead growth alive with tiny birds calling to each other over our heads.
Our walk along the estuary was abruptly blocked by another vessel and a very large brick structure which was the remains of the piers supporting the old Severn Railway Bridge.
We returned to the towpath. There were still lots of people enjoying their walk. The anglers were packing up for the day. A mother mallard led her family of six fluffy brown and yellow ducklings into the open water. A cuckoo called from the woodland on the far side of the canal. Our paws were tired, and we looked forward to getting back in the car and heading for home.
We reached the swing bridge just as it had opened to allow the river craft to pass through. We watched the dinghies and boats go by.
The swing bridge closed and we headed for the car - tired but happy!