Wednesday, 5 February 2014

Honeycomb reefs of St Austell Bay

This winter has been unbelievable - Massive gales and high tides have been battering Cornwall's coast relentlessly since Christmas.  This weekend saw some of the highest tides of the winter and It looked like the Shoresearch Rockpool ramble leaders training day would be a total washout!
Fortunately on Sunday morning we woke to the first sunny day of the year (more or less) and we had a cracking time down on the shore at Spit beach near Par!
It was great to have such a good turnout of lovely people all keen to learn and to gain the skills needed to share their enthusiasm with the public.A total of 22 volunteers took part and they traveled from all over the county, from Polzeath, Fowey, Looe, St Agnes, the Roseland and we also had sevenlocals who are members of the Friends of Par beach. After a couple of slideshows held in Gott hall we walked down (though the floods) to the beach which is right next to Par Docks.

Happy shoresearchers! 

It was really exciting to see how alive and diverse the shore is here so close to the docks - I had heard reports but it was great to see for first hand the beautiful colonies of Honeycomb Worm - Sabellaria alveolata that cover a large area of the mid shore. these worms grow in colonies and they construct their concrete like tubes using sand. The sand they need is very specific and this rare Biodiversity Action Plan species is only found in a handful of locations around the country. The only other place in Cornwall where this species is found is along the coast between Millook and Bude on Cornwall's far north coast.

GPS proof that these rare colonies exist! 

Honeycomb worm colony closeup, Matt Slater
The beach at Spit is made up mainly of quartz sand and gravel, and mica which are waste products from the china clay processing that has been carried out for centuries in this area. It was interesting to see that the tubes were made up mainly of tiny fragments of quartz (plus some shell sand). Perhaps this is the reason why this rare species is found in this one location alone on the south coast of Cornwall?

The shore is very unusual with very few mussels and a large covering of pepper dulse Osmundia pinnatifida over the rocks.
Pepper dulse carpeting rocks, Matt Slater 

Volcano barnacles - Balanus perforatus are very common on this site.
Volcano barnacles Balanus perforatus, Matt Slater
Cystoseira tamariscifolia Rainbow wrack (photo Matt Slater )
 and in the pools we found small rainbow wracks growing as well as the beautiful false eyelash seaweed, sausage weed and young plants of Sargassum muticum.

Snakelocks anemone Photo by Margaret Gardner

There were countless hermit crabs Pagurus bernhardus, daisy anemones, snakelocks, strawberries and beadlet anemones.
We also found a young sea hare - Aplysisa punctata, and a sheep sea slug Aeolida papillosa.

It was great to see large numbers of freshly laid dog whelk eggs! and so many signs of the coming spring on such a beautiful day (amongst such heavy storms!) Including a small spotted sea hare Aplysia punctata.
Sea Hare

Thanks to all who came along and I hope to see you at the next surveys!



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