Rockpooling on St. Martins

Although St. Martins does not seem to have any rockpools, the beach that was nearest to us (called ‘Lawrences’) has a stretch of rocks lying on the sand that can be turned over at low tide, and so we did! A nice find was a small Sevenarmed Starfish Luidia ciliaris (these can grow up to half a meter across, although you will not find them that size in rockpools). We also found a Bootlace Worm Lineus longissimus, which is (probably) the longest animal on the planet. These nermertean worms secrete a powerful toxin in their mucus, but luckily for us it affects arthropods and not mammals. They are not very rare btw, I see them here in Flushing and Falmouth too. It was about 5 meters long (without stretching it), but they can grow ten times the size of this! In the second photo you can see it in its natural habitat, under a rock, with some photobombing crabs and worm pipefish. Another cool find was a juvenile Conger Eel Conger conger. Otherwise we found the usual suspects, lots of crabs and a bunch of fish, see for a small selection below.

Back on St. Martins, Isles of Scilly.

Last week we visited St. Martin, one of the Isles of Scilly again, the first week we were allowed to do so. As a result, the islands were very quiet (and the pub was still closed, aargh!). It was sunny, but the easterlies were still cold and there was even a bit of frost some nights. However, I managed to get a snorkel in almost every day, which was great. I brought all my gear (again stepping on the boat wearing my weight belt…) but only used the strobes the first day; these are still an ongoing frustration of mine! I tried out most beaches, especially enjoying Porth Morran, where the kelp met the seagrass. (The pics in the Gallery are click-able btw.)

Some sites were dominated by kelp Laminaria digitata with Common Sea Urchins Echinus esculentus munching away. Fish life was very limited; I saw Ballan- and Corkwing Wrasse and Thicklipped Mullet but not much else.

Common Sea Urchin Echinus esculentus

Other sites were more ‘beachy’ with white sand, small rocks covered in Snakelocks Anemones and Seaweeds and Seagrass. The visibility looked very promising but was quite bad some days unfortunately (especially compared to our visit last September, see here). All in all a great time was had and we hope to visit again next year!

Rockpooling in Flushing

The wind has picked up and will ruin any chances of getting good seaweed shots this week. Too bad, but what can you do? A bit of rockpooling I guess. I took my son out to our local beach in Flushing where the rocks gently slope into Penryn River. Although there are no ‘proper’ rockpools, low tide gives access to a mixture of maerl sand and rocks that can be turned over. It is silty and definitely not very pretty, but there is always something to find. It was an especially good weekend for finding fish, seeing Shannies, Tompot blennies, Rock gobies, Gunnels, Worm Pipefish, Shore Rocklings and a tiny Eel, as well as Sea Scorpion eggs. (One Shanny was quite big and proceeded to bite my son’s hand; he was very brave and we slowly put it back.)

Invertebrates were plentiful too. The main mollusc here is the Variegated Scallop Chlamys varia, which is attached underneath every single rock. We found our smallest Great Scallop Pecten maximus as well. We found some Sea lemons Archidoris pseudoargus and lots of Yellow-plumed Sea slugs Berthella plumula (which apparently can secrete sulphuric acid when disturbed…). A small selection of what we found below, all pics taken with an Iphone.

More Macro 2

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!

Rockpooling

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. Berthella plumulaFinally 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 good’uns

l have not made much progress sorting through recent seaweed pics but it is easy to post two recent photos that came out well. Above the Spiny starfish Marthasterias glacialis. This seastar can grow up to 70 cm across, but on the shore you generally do not find them much larger than 20 cm. It occurs from Northern Norway down to West Africa. Below a patch of Snakelocks anemones Anemonia viridis, probably originating via binary fission. The most common anemone in the rockpools here, around half are this tan colour, the other half is green with purple tips. No one knows why. (And interestingly, it is not the only anemone species that shows two colour variants, beadlets are red or green, plumose anemones white or orange). Although the water was 9C, with the sun on the white sand it looks pretty tropical to me, a clownfish would not have been out of place! (I took a photo of this same patch in March but that one was not nearly as good.)

Falmouth Rockpooling

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.

Rockpooling in Flushing

Some pics from today at Flushing Beach. Above, a pair of Green shore crabs Carcinus maenas, below two Furrowed crabs Xantho hydrophilus. (I probably should have gone for a whole crab series, as I saw several other common species…) Instead I took loads of random photos, of things that were 150 mm to things that were only 5 mm, with varying success. For instance of a Painted Topshell Calliostoma zizyphinum on the invasive Bryozoan Watersipora subatra. Also the underside of the urchin Psammechinus miliaris, showing its mouth (Aristotle’s Lantern). Photobombing top left is the commensal worm Flabelligera affinis (which I noticed as well the last time I took a version of this picture). Bit random but it was fun practicing. It actually is more difficult to take photos abovewater compared to underwater due to the glistening and the awkward position kneeling on wet gravel/rocks. Next time I might try a tripod (ideally remote flash would be used but I do not think I am going to invest in that). Btw, if you are on instagram, I also post pics as @an_bollenessor.

Macro Practice III

What friends predicted happened last Sunday morning: someone scrambled down the rocks to check if this figure lying motionless in a shallow pool was dead or alive. Luckily, I was feeling very alive indeed, watching a sizable Spiny starfish Marthasterias glacialis moving over the rocks using its hydraulic tube feet. A beautiful blue-grey colour, the surface of these animals are very richly textured. I am not sure exactly what is going on at the tips of the arms: the very end shows a red organ, potentially light sensing. It is surrounded by nodules, which might be the precursors of the centres of new plates covering its body, or something else. The tube feet at the tips are smaller and orange-tinged and I am again not sure whether they are just newly developing or having special sensory functions. I noticed the madreporite at the top of the animal: this sieve plate is involved in pumping the water in the body for hydraulic locomotion. It resembles a stony coral ‘madrepore’ colony, hence its name. In general, the seastar surface resembles a coral I think. The photos are nice, but I know I could do a lot better: next time!

More Macro

These photos are from a couple of weeks back; since the weather has been hideous most of the time I have not been out much since. More practice with the m.zuiko 60mm macro lens abovewater. Above a small Strawberry anemone. Below a small Cushion star Asterina gibbosa and my finger tip for size. Below that the hydroid Candelabrum cocksii and an Idotoea isopod species (there are several common Idotoea species but I have not paid much attention to them yet I must admit). Finally, the adorable Worm pipefish Nerophis lumbriciformis which is common and usually found in small groups under rocks (I have never seen them underwater as they are small, slow, well-camouflaged and probably hidden most of the time). Definitely will try to get some more portraits of these lovely fish!