Last Wednesday I went for a sneaky worktime dive across the Fal estuary on the Maerl beds between St Just in Roseland and St Mawes. Maerl is a slow growing, calcified type of seaweed (looks more like coral) which forms a unique and quite rare habitat, see these older posts. The water was 17°C so nice and comfortable and it was probably the shallowest dive I’ve ever done, no deeper than 3 meters. I took my new Canon G16 in a Fantasea housing and went all semi-pro by adjusting the white balance first (not that I had a go at any other settings…). I was really pleased with the results, a world of difference to the Canon D30. The beds are an expanse of maerl nodules with very little to break it up, no rocks, no sand, just the occasional old bottle and so it is hard to get any exciting angles. Still there is always something to see. In order: a baby Smallspotted catshark Scyliorhinus canicula, a Spiny starfish Marthasterias glacialis, a (breadcrumb?) sponge, a closed-up Snakelocks anemone Anemonia viridis (a rare sight), a Parasitic anemone Calliactis parasitica, a Fan worm Myxicola infundibulum, a Harbour crab Liocarcinus depurator, a Velvet swimming crab Necora puber and a very well-camouflaged Spider crab Maja squinado.
It has been a while since I last posted an aquarium update; I have been a bit busy and have not done much with the tank recently. I have not done any water changes, never use the skimmer but have had zero algae because I have kept the light level low. I have experimented a bit with various seaweeds but nothing thrived. The Chrysemenia was doing well growing on the Tunze pump but disappeared overnight. Kelp always does well when attached to the pump. The tank is still a bit bare so no ‘full tank shot’ but some inhabitants below. I collected some Parasitic anemones Calliactis parasitica attached to an empty shell figuring that a not so pretty species might be actually quite hardy. Turns out they just stayed a bit limp and I therefore returned them to the sea.The Tompot blenny is a real character, very alert and always hungry. If you stick your finger in the water he immediately comes and nips it. The small scallop remarkably survived over the summer (remarkably because there is almost nothing to filter from the water) but the hungry Tompot ate it in the end (like most other snails). As the snails were not going to last long anyway, I introduced two small Common starfish Asterias rubens and two small Spiny starfish Marthasterias glacialis. They are usually hidden but that makes it extra fun when you spot one. The Cushion star Asterina gibbosa of course remain unperturbed and are always on the prowl. I noticed a tiny offspring (<2 mm).
A new location for the second dive: Helford Passage between Falmouth and the Lizard Peninsula. This is a shallow, sheltered creek with a sandy bottom and eelgrass beds and can only be dived (well) at high tide. A good site to spot Thornback rays Raja clavata we heard and we were indeed lucky to find several of them. We entered the water at Grebe Beach next to Durgan:
Again, we spotted some cuttlefish, which are not very shy at all. What was very cool were Great scallops Pecten maximus lying around and swimming away for a bit by opening and closing the shell, I will try to film that next time. Many Turban top shells and some large heremit crabs with one or more Parasitic anemones Calliactic parasitica on top. The shells of smaller hermit crabs were covered in the hydroid Hydractinia echinata:
We got to about nine meters depth (near the buoy) and found a large concrete block. Scattered among it lay the remains of crabs and in a hole dug underneath the snout of a Conger eel poked out. As I had to get close for a better look, I stirred up too much sediment and so I do not have a good picture but I will definitely like to go back and have a better look! Interesting was an old crab pot covered in sea squirts (mainly Morchellium) which was swarming with Leach’s spider crabs Inachus phalangium. Normally they sit under a Snakelocks anemone but there were none attached to the pot, strange. Very common were large Peacock Worms Sabella pavonina and Fan worms Myxicola infundibulum: