After half a year of strobe troubles (probably a mix of different faults, making it difficult to troubleshoot), I seem to finally have a working set-up again. Although the stalked jellyfish season passed me by, I am now raring to go. I went in today and yesterday and although I did not manage to spot any nudibranchs, there is always something to see. For instance, the White Tortoiseshell Limpet Tectura virginea above, which is very common on coralline algae. Below, the chiton Callochiton septemvalvis (stuck to the same rock as a week earlier), a tiny gastropod, probably Rissoa parva, a Cushion Star Asterina gibbosa, the Sea Ghurkin (a sea cucumber) Pawsonia saxicola and a baby squat lobster (<1 cm). There is currently a large influx of Crystal Jellies, which are not jellyfish but the medusa stage of hydrozoa. It probably is Aequorea vitrina. I have seen several being eaten by Snakelock anemones (slightly too large to take a good photo of with a macrolens). Below a detail. Finally, another, very different-looking, hydrozoan (I have to have a look at the biology of these things some time). It is Candelabrum cocksii, a species which was originally described based on specimens collected from this very beach. (I have posted a photo of this species before, but they look very blobby abovewater). The second pic is for scale. Hopefully a dive sometime soon!
I have not been in the water recently but went good oldfashioned rockpooling instead a week ago. No ‘lifers’ but there is always something interesting to see. For instance, my first albino cushion star (Asterina gibbosa). This small species (these individuals are only a little over a centimetre) is incredibly common here. Btw, I must confess this shot was staged, I placed these seastars together. Below, a Candy-striped flatworm (Prostheceraeus vittatus), also about a centimetre. Next, the Yellow-plumed or Side-gilled seaslug (Berthella plumula). Another common species but it is difficult to get a decent photo of this blob! This mollusc has an internal shell and, interestingly, glands that secrete sulphuric acid when it is attacked. You can see a little slug right beside it, maybe a juvenile Sea Lemon. Finally a photo that I had wanted to take for a while: can you spot the crabs? One of the most common invertebrates here is the Furrowed Crab or Montagu’s Crab Xantho incisus. Xantho species are known as Pebble Crabs which is the name I prefer; although highly variable in colouration they are very good at blending in amongst the pebbles! How many can you spot? There might be a stray Risso’s Crab Xantho pilipes in there as well, as they are quite similar (except for a fringe of hairs on the legs and carapace) and also common here. High time to have a look again underwater as well.
Some photos from Last Sunday at Castle Beach in Falmouth. Above, the periwinkle Littorina littorea, which aggregrates in great numbers on the upper shore. Below, three echinoderm cousins: a Cushion star Asterina gibbosa and a little Sea cucumber Pawsonia saxicola with a Brittle star in the background. It was the first time I saw this beautiful colour variant of the Risso’s or Furrowed crab Risso pilipes. More common is the very similar Montagu’s crab Risso hydrophilus, there are usually 5-10 individuals under a single rock. The small ones especially come in a range of colours that make them excellently camouflaged against the pebbles. Next a juvenile Shanny Lipophrys pholis, a detail of a Corkwing wrasse (I could pick it up, that is how low the tide was) and a shot of the beach, showing the versatility of the mzuiko 60mm lens.
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).
I usually head down straight to the lowest reaches of the shore when rock pooling, but when there is a neap tide and a lot of inshore wind as there was this weekend, you have to make do with turning rocks higher up the shore. Although biodiversity is lower, there are some species that are only found there (see for instance this recent post) and so it is actually nice to have a look there for a change. The very first rock turned over actually had a couple of interesting inhabitants underneath it. Another lifer, the tiny gastropod mollusc Onoba semicostata (surrounded by a couple of even tinier Rissoa parva), very quickly identified by members from the British Marine Mollusca facebook group:
The same rock had a number of the tiny (< 1 cm) Cushion star species Asterina phylactica on it as well. It is prettier than the common Cushion star Asterina gibbosa (one of my favourite aquarium species), but perhaps a bit too small to be an option for the tank.
One other beautiful species, the colonial tunicate Botryllus schlosseri, this is a nice blue/purple one:
I have started a youtube ‘An Bollenessor’ account to be able to embed some of my short iPhone videos here*. First my favourite the Cushion star Asterina gibbosa. My aquarium is more or less empty at the moment, but I still have five of these around. A short movie made with my olloclip macrolens showing how these little starfish move about using their tube feet:
I went out snorkeling yesterday in the mouth of the Helford river (in the rain). A very beautiful spot, I’ll post some pictures of it when I am back and it is sunny. It was high tide and the visibility was bad so I had to dive five meters or so to have a closer look at the Seagrass. I did not see that much but I did spot a Sand star Astropecten irregularis for the very first time. A very beautiful starfish with purple tips and very long tube feet. I took it home and placed it in the aquarium, after which it did what it does best: digging itself in:
*= I use Microsoft Moviemaker to upload files, so had to use my Microsoft account in addition to my Google account, a bit of a hassle. Anyway, it should be easier next time now everything has been set up. For the next videos I will make sure to clean the glass. I probably also should buy a gorillapod to keep my phone still.
OK, part two of my list of fun and easy species to keep in an unchilled native marine aquarium (see here for numbers 10-6). I will later post about species to avoid, and of course also about easy seaweeds to keep.
5: juvenile crabs
Crabs are active and interesting to watch, however, in a community tank they should not be too large as they can be quite destructive as well. Juvenile Shore crabs Carcinus maenas are an option, or a variety of crab species that stay small, such as Pirimela denticulata (I am not too sure what species the above pictured crab is, but it is still doing well four months after collecting it).
4: Squat Lobster Galathea squamifera
Squat lobsters Galathea squamifera can be a bit shy but are entertaining to watch as they scuttle about. Very common under rocks in silty areas.
3: Snakelocks Anemone Anemonia viridis
Very pretty and common anemones that are easy to keep. Beadlet anemones Actinia equina and Strawberry anemones Actinia fragacea survived in my aquarium as well but they seemed to shrink a bit over time rather than grow and these species can retract their tentacles which looks less nice. I did not specifically feed my anemones by dropping artemia or food pellets on them. The photosynthetic capabilities of Snakelocks anemones due to their algal symbionts probably makes it easier for them to thrive when food is relatively scarce. Beware for the tentacles of larger individuals though, as they can sting!
2: Common prawn Palaemon serratus
Prawns* have been a rage in tropical freshwater aquariums for years but people forget that there are very pretty ones right in our seas. I must admit I have not got round to checking rostrum (the ‘nose’) structures to differentiate between several closely related Palaemon species, but I think I have the Common prawn. They are always foraging and flock to any new object in the aquarium to check for edible bits. If the pumps are switched off they will swim and compete with the fish for food.
* or shrimp, these two names can mean different things in different English-speaking countries. In other languages ,like my native language Dutch, we only have a single word (garnaal) for these critters
1: Cushion star Asterina gibbosa
My numbers 2, 3 and 4 could have been number 1 as well, but I ended up picking the very common Cushion Star. Although grey and just an inch in size, these quintessential rock pool inhabitants are active, hardy and just plain cool!
Time for an update on the tank. Switching to two lamps instead of one looks good but has not brought the iridescence of the Bushy rainbow wrack back. I could not resist putting a new specimen in. Iridescence is defined as the property of certain surfaces to appear to change color as the angle of view or the angle of illumination changes. Left: viewed from below, right: viewed from above.
I noticed that the underside of the rock the weed was attached to harbored a nice little strawberry worm, but before I could photograph it, the large rock goby gulped it down. It is noticeable that the fish have full bellies after putting in a new piece of seaweed, which is no surprise as there is so much growing on and in it.I have seen the very cute amphipod Caprella acanthifera which looks like a tiny, marine cross between a praying mantis and a caterpillar, but since they did not come not near the glass I could not get a good shot. I have seen one Cushion star Asterina Phylactica as well, which looks nicer than the light grey Asterina gibbosa I have. I also noticed a couple of Cerithiopsis tubercularis (3-4 mm):
The tank is completely full of snakelocks anemones, hundreds maybe:
In the foreground an Idiotea isopod; there are many of these sitting on seaweed branches and occasionally swimming around, although most of them will probably be eaten by now. Finally, three seaweeds have started to grow from the pump outlets. Dudresnay’s whorled weed, a fine purple weed and a broadleaved red seaweed. I have placed adult plants of the latter species (30 cm or so) in my aquarium before, but these were quickly eaten. It is either a type of laver or dulse, but I am not sure. It has also settled on the glass, but seldomly grows ‘leaves’ on there. Growing in the water current protects the weeds from predation from shrimps, let’s see how big they can grow!
I found our favourite aquarium inhabitant Squatty the Squat lobster dead this week, which was genuinely sad! (We had a false alarm a month back finding some legs in one corner and its carapace in another but it turned out that that was just moulting.) This is the only Common squat lobster Galathea squamifera individual I have seen when rock pooling and it did very well in the aquarium for half a year. It was quite shy, although it could wave its arms fiercely at any prawn of blenny passing by. It was also quite clumsy, often falling over backwards when attempting to scale a rock. Two close-ups:
An unceremonious end: Cushion stars Asterina gibbosa and a Common prawn Palaemon serratus recycling Squatty: