Calvadosia cruxmelitensis | An Bollenessor

It was a nice day and a good low tide last Wednesday and so I decided to go for a snorkel; I was glad I did! Last year, I had been trying to take photos of this weird little animal, Candelabrum cocksii, but failed miserably, this time it worked. It is a hydrozoan that was first described in Victorian times on the exact beach I always go snorkelling here in Falmouth. It is tiny (see last pic) and lives underneath rocks, so it goes mostly unnoticed (and therefore does not have a common name). To take this photo, I had to do some ‘underwater rockpooling’, turning over a rock to find them. I am not sure what the deal is with these guys; I know the white bulbous structures at the bottom are reproductive structures, and the reddish bit at the top is for feeding (this bit can be stretched out quite a lot). It is colonial just like the Portuguese Man O’War. Please correct me if I am wrong hydrozoan experts! Shout out to David Fenwick and his ID site aphotomarine.com, which I highly recommend.

Other notable finds were stalked jellyfish Calvadosia cruxmelitensis and my very first Wentletrap (which is a Dutch word: wenteltrap=spiral staircase) Epitonium clathrus. As I had my macrolens on the camera I could not shoot any general impressions but the pools started to look beautiful again. The big Wireweed and Thong weed plants were all gone (new ones emerging) and the red seaweeds (Sphaerococcus, Plocamium, Chylocladia) were already quite big.

It was great to be back in the water today and it is my New Year’s resolution to spend a lot more time underwater than I did in 2021! Who knows I will even learn how to use strobes. A happy 2022 to all blog readers!

I now am the proud owner of a nauticam CMC wetlens. It arrived too late for my first encounter with a nudibranch this year, however, it came just in time for a proliferation of stalked jellyfish. These tiny (around one centimeter), sessile relatives of jellyfish are not very well-known, but seem to be getting more popular, see for some other recent finds the other local blogs Cornish Rock Pools and The Marine Enthusiast. To find them, you need to carefully scan seaweeds in rock pools (they are not very picky when it comes to which species they attach themselves to). The key resource for UK (European even) rock poolers is David Fenwick’s Stauromedusae website. Above, the most common species, the Spotted kaleidoscope jellyfish Haliclystus octoradiatus, recognizable by the primary tentacles or anchors (the white ‘balls’ inbetween the tentacles). Below, St. John’s stalked jellyfish Calvadosia cruxmelitensis, with a zoomed out photo and finger nail to give an idea of scale. Finally, two not so good photos of a third species Calvadosia campanulata taken above-water as these were located just below the surface. One more species can be found on mainland Cornwall (the Goblet stalked jellyfish Craterolophus convolvulus) and one on the Scillies (the Horned stalked jellyfish Lucernaria quadricornis, but who knows this species is also present on the mainland). So some more searching to do!