Tag Archives: aphotomarine

scummy pools

Posted on by under eggs, molluscs, rock pooling, seaweeds, sponges, tunicates

For the first time in a while I had time to nip over to Castle Beach to do a little rock pooling. The tide wasn’t the best and the pools did not look to great either actually; this seemed to be due to a mix of some seaweed species dying off, and some not so great-looking species ones blooming: IMG_0317Lots of Wireweed, Ulva and very fine weeds (the latter are often very pretty under magnified and in water, but not so much as a blob on the rocks). What might be Desmarestia viridis (but don’t take my word for it): IMG_0319Still, there was plenty to see: Orange-clubbed sea slugs for instance and one very weird-looking creature I had never noticed before was clinging on in little groups on red seaweeds under overhangs, the annual sponge Sycon ciliatum:

IMG_0218The Breadcrumb sponge Halicondria panicea can be very nicely coloured: IMG_0240There were a lot of tunicates about. Colony-forming Morchellium argum for instance and this beauty, probably Ascidia mentula (determined by helpful folks at the ‘NE Atlantic Tunicata‘ facebook group): IMG_0276IMG_0279One colony-forming tunicate looked superficially like Botryllus but was much bigger and less pretty, it might be Aplidium nordmanni:IMG_0248 Quite a lot of Sting winkles Ocenebra erinacea were around as well:IMG_0288Finally, I spotted the orange/yellow egg masses of the Cornish sucker (or Shore clingfish) Lepadogaster lepadogaster (see here for an older post on them). However, I also found some that were greyish and had a speckled band, as well as a red dot between the eyes. Local expert David Fenwick told me these are from the Small-headed clingfish Apletodon dentatus, a species I have not yet seen the adults of (see his site for pictures): IMG_0314

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a most peculiar animal

Posted on by under rock pooling, worms

The rock around Falmouth is very soft in places, and when turning over large stones, sometimes they break and reveal interesting things (I have posted previously about the high density of worms in rocks). I recently had another rock crumbling on Castle Beach and I noticed something unusual-looking slipping away in its burrow. A Sipuncula (‘peanut worms’) or Echiura (‘spoon worms’) I thought, something not featured in any old guide anyway, so I browsed David Fenwick’s aphotomarine site where I quickly found the suspect: the Spoon worm Thalassema neptuni. The Echiura are recognised as a separate Phylum in most books, but recent research has revealed that they are not as special as they look: they are actually ‘ordinary’ Annelid worms (see this Open Access paper):

IMG_8621 The diversity of life within rocks is actually quite surprising. I have not taken a good look at all the types of worms yet, but this one stands out: a tiny Green leaf worm Eulalia viridis (looks like a sock puppet):

IMG_8643The boring bivalve Wrinkled rock borer Hiatella arctica (a juvenile):

IMG_8626And even a small Sea cucumber:

IMG_8636 Perhaps I should make a list of all the species living in the rock. Finally, on the rock surface, I sighted a small Sea hare Aplysia punctata for the first time in Cornwall:

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