miniature species

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:

IMG_8352The 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.

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One other beautiful species, the colonial tunicate Botryllus schlosseri, this is a nice blue/purple one:

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tank update

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.

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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):

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The tank is completely full of snakelocks anemones, hundreds maybe:

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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!

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