Snakelocks Anemones Anemonia viridis

I have been snorkelling a few times in recent days and it has been generally fantastic. The pools are probably at their peak now when it comes to seaweeds, I hope it lasts a little while longer (in June it will most definitely be over, see this old post, actually, they are in decline in May already). It is the plan to get in the water again this week to take some more seaweed photos, but in the meantime some photos on one of the more common anemone species: the Snakelocks anemone Anemonia viridis. There are two colour morphs: the greys and the purple-tipped greens. In Falmouth, they seem equally common, no matter if it is high on the shore or subtidally. I recently learned that in Scotland there are almost only greys, perhaps in the Med there are mainly the other type and it has something to do with temperature tolerance, if you know please let me know in the comments! I really like thuis species, in fact, the very first blog post back in 2013 consisted of a photo of these anemones in my aquarium. I have two of these in my aquarium at the moment, they are very easy to keep. This might be because in addition to being voracious predators, they are also capable of living on sunlight, as they harbour photosynthesizing algae. In any case they grow rapidly (and very occasionally split into two).I took these photos in very shallow water. When scuba diving you can commonly observe the commensal Leach’s spider crab Inachus phalangum sitting under the anemones (see here in the aquarium and here in the wild). (In Dorset there is a beautiful little prawn that lives as a commensal, and in the Mediterranean there is a goby that is associated with this species.) Only very occasionally do Snakelocks attempt to retract their tentacles (see here); tentacles can be quite long and slender or more stout (see here), probably a response to the strength of the currents. I have tweaked some of the photos a tiny bit (but not the nicest one on top for instance). Below two photos taken on different days of the same three anemones with different light conditions and different camera settings (most importantly probably the white balance, which I use to tone down the reds caused by the seaweeds).

diving in the Helford Passage

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:IMG_0333

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:IMG_0343

IMG_0341

IMG_0376We 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:IMG_0342

IMG_0346

Snorkelling at Silver Steps Part I

High time for a snorkel, and few better places in the area than ‘Silver Steps’, between Castle Beach and Pendennis Point in Falmouth. I took my little Lumix camera (goes up to 10 meters deep, no optical zoom) with me to take some sub-standard pics (all other photos on the blog are taken with my iPhone). This site is a mix of rocks covered in kelp and gravel and even the remains of two U-Boats (they are no longer recognisable as such though, see here for more specifics on these and other wrecks off Falmouth). There is always something to see: schools of Smelt chased by Sand eels, hovering Two-spotted gobies, Corkwing and Ballan wrasse, Spiny starfish and loads of seaweeds. In fact, there was so much to see that I have divided the pictures over two posts. First a photo of the site and some of the U-Boat wreckage:P1040041

P1040031We were in for a nice surprise: a good-sized John Dory Zeus faber at around seven meters depth. I have posted a very nice picture from my first and only dive in Cornwall courtesy of Charlotte Sams, but here a short, jittery video as well:

Anyway, a perhaps even nicer find were Leopard-spotted gobies Thorogobius ephippiatus. Some sources make it seem like this is a rare species only ever encountered by divers, but it is actually not uncommon and we saw them at two meters down (the tide was low though). It is a shy species that lives under ledges, burying between the rock and the gravel. The picture is crap but also proof I am not lying. The next picture is of a Tompot blenny Parablennius gattorugine peeking from a crack in the rocks. Large snakelocks anemones are everywhere on the kelp, and although a month ago I saw none, many of them again housed commensal Leach’s spider crabs Inachus phalangium. (These anemones and crabs do well in the aquarium btw, see here.) It would be interesting to know if these crabs arrive from deeper waters or just grow up really fast.

P1040024

P1040039

P1040012

 

aquarium update: snails

Time for an update. The five Snakelocks anemones have settled and are doing very well (I have fed them some defrosted shrimps which they quickly devour). The Leach’s spider crab was sitting happily under one of the anemones until it decided to move behind a piece of slate and now does not show itself much anymore. Perhaps this has to do with a prawn I introduced, although I have not seen any scuffles. I have to see what I’ll do about this. If it is really shy then I perhaps have to choose between keeping it or introducing fish. In any case I have seen it munching on some algae and a dead Cushion star and it seems to do OK.

IMG_6422

The main problem I have is the dreaded return of algae…There is quite a diversity of them: fuzzy green ones, darker green blotches, slimy purple ones, brown diatoms and more. All interesting organisms surely but I do not want them to take over the tank! I have used food sparingly and used the skimmer most nights, but now have also removed my daylight lamp, to leave a single actinic lamp (see this post about lighting). I still have to get used to this new look, but less light must surely help. Most interestingly, I have enlisted the help of 80 or so grazing snails. Mainly the Common periwinkle Littorina littorea and the Flat top shell Gibbula umbilicalis but also some other species, including two very small Painted top shells Calliostoma zizyphimum. I never had many snails in my aquarium, as they were always eaten by Shannies, but hopefully they will survive this time. I will dunk in a lot more snails, and keep an eye out which species does best. A Flat top shell (picture taken using my olloclip macrolens for the iPhone):

IMG_6468

One returning encrusting red algae is actually a seaweed, with new ‘leaves’ growing from the round crusts. I suspect it is Devil’s tongue weed Grateloupia turuturu. I have been scraping it off the glass, except from the corners where the scraper is of no use, but will let the rest sit and see how it grows:

IMG_6431

I also noticed that Sea lettuce Ulva has started to grow from the slate. The aquarium does not look that nice yet, but with the new animals there is plenty to watch in any case!

new inhabitants

Last weekend I went for a bit of snorkeling off Pendennis Point to catch some new inhabitants of my tank: some Snakelocks anemones and a Leach’s spider crab (just one for a start). Although it was overcast and late, it was nice to be in the water. I was lucky to straight away find a diving knife, this helped me to cut of some kelp housing snakelocks. I took a perforated plastic Lidl bag with me in the water to serve as a net for the crab, low tech but it worked fine. The tricky thing was to get the snakelocks from the kelp afterwards (I did not want a load of rotting kelp pieces in the tank):

IMG_6148

With some finicking I could get the anemones off the kelp and on the rocks or gravel. The Leach’s spider crab (decorated with small pieces of red seaweed) quickly hid behind a rock. However, after two days it was accustomed to its new surroundings and found a place underneath one of the anemones right in the front of the tank:

IMG_6216

snorkeling at pendennis point

The sun was shining this weekend and the sea water is currently at its warmest so we went out for a bit of snorkeling off Pendennis Point in Falmouth. My experience with the iPhone waterproof case was not that good, so I took my Panasonic Lumix (DMC-FT10) along (which is not too great either!). The seaweeds are dying off mostly; the kelp is covered by bryozoans and hydroids to the point that they are completely fuzzy:

P1030862

I mentioned in the previous post that the Spiny starfish Marthasterias glacialis was common in rock pools; bigger ones can be found when snorkeling:

P1030845

Big Snakelocks anemones Anemonia viridis were everywhere and perhaps half of them had a little Leach’s spider crab Inachus phalangium associated with them. Wikipedia tells me that these crabs eat the anemones’ leftover food and also their mucus:

P1030869

This hour of snorkeling gave me some inspiration for a new aquarium set-up: less seaweeds (specifically less dying seaweeds clogging up the filter and releasing nutrients) and more rocks. On top of these a couple of big snakelocks with spider crabs and some Two-spotted gobies Gobiusculus flavescens. The latter are very common and pretty. I will have to catch them underwater with a net though, which will probably be difficult…

first dive in Cornwall

A couple of weeks ago I went for a bit of a spur of the moment after-work dive with colleague Andrew (like me a quite unexperienced diver) and his friend Charlotte Sams. Charlie is an experienced diver and natural history photographer, who has her own blog: Charlottesamsphotography, which you should check out. We dove in Falmouth off Pendennis point. The water was not very clear (maybe 5-6 meters visibility) but the temperature was quite nice. We saw (amongst others) Sand eels (do not know which of the two species), Pollack Pollachius pollachius, Dragonets Callionymus lyra, Two-spotted gobies Gobiusculus flavescens, a Tompot blenny Parablennius pararugine, very large Ballan wrasse Labrus bergylta and a beautiful little John dory Zeus faber:

4595847792

We also saw some very large Common starfish Asteria rubens and also a nice Spiny starfish Marthasteria glacialis. We dove only to about 5-7 meters, which meant we could stay in quite long, over an hour. At seven meters, the bottom was a sandy expanse, interspersed with mounts of Laminaria Kelp covered in hydroids. In-between the kelp were other seaweeds, such as Red rags Dilsea carnosa but I was more focused on the animals during the dive. In shallower water were enormous bundles of Wireweed Sargassum muticum (also known as japweed but that is not very pc…) and the very long slimy Mermaid’s tresses or Bootlace weed Chorda filum. Snakelocks anemones were very common, and we managed to also see Leach’s spider crab Inachus phalangium, which lives associated with these anemones. All in all a fantastic experience, and I hope to find the time to go diving very soon again!