New strandline discoveries

Monday’s walk along the beach produced some more interesting strandline finds to add to those found on my previous strandline expeditions.  The sea was nearly at high tide, so the strandline was shifting all the time, wet weed and shells changing position as the waves pushed forward and retreated.  Sunday had been an endless day of really strong gales, complete with Met Office weather warnings, and although I expected this to have stirred things up a lot, I was not expecting to find much at high tide, so it was interesting to see what there was.

Barrel Jellyfish, Aberdovey shoreline

The most anomalous find was a dead barrel jellyfish (Rhizostoma pulmo), a common enough sight in warm summer months, but the first I have ever seen in winter.  The barrel jellyfish is distinguished by a thick rubbery bell and “arms” rather than tentacles, which have a distinctive frill along their edges. This is a  small one, but they can reach up to 1m in diameter and are the largest of jellyfish to be found in UK waters.  They have a mild sting.   The Marine Conservation Society collects sightings of jellyfish (and turtles, crawfish and basking sharks) throughout the year, so if you see one it is worth going to the MCS’s sightings page and filling in their online form.  There’s a good jellyfish identification guide on the IWS website, from which the following is taken:

Barrel jellyfish details

I also found two new eggcases.  If you are new to eggcases, have a look at my post on the subject, where I go into some detail.  These were very unlike the nursehound case that I found on the beach that day, but very distinctive.  Using the Shark Trust’s identification guide, it was possible to narrow them down to a Thornback Ray (Raja clavata) and a Spotted Ray (Raja montagui).  My photos of the two cases are below, together with the Thornback Ray  relevant page from the Shark Trust’s identification guide.

A page from the Shark Trust’s identification guide, accompanied by photos of the two eggcases found today.

Common piddock (Pholas dactylus)

The bivalve shell I picked up and kept is neither unusual nor relevant to any conservation programmes, but it is simply very attractive, with a wonderful textured surface, and I had never seen one before.  It’s a common piddock (Pholas dactylus), one of four species of piddock found mainly in the south and wet of Britain, all white. They are specialist borers, using the ridges for drilling into hard substrates to create burrows.  They have feeding siphons which reach out from the burrow into the sea to collect nutrients, and in the case of the common piddock the siphons are bioluminescent and glow green in the dark.  Shells can be up to 12cm long, and this one is exactly 12cm long.

I picked up a piece of seaweed that was a deep pink when I found it, and it turned black when I left it to dry out.  It’s a new one on me so I looked it up:  clawed fork weed (Furcellaria lumbricalis).  It only has the pods at the ends, which are its reproductive structures, in winter.  It tolerates low saline conditions, so will grow even in estuary waters.

 

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