Category Archives: molluscs

Violet Sea Snail

Posted on by under beach combing, molluscs

An hour of beach combing today at Praa Sands, chosen because it is a reasonably long beach facing the prevailing wind that day. A fair amount of Goose Barnacles smattered among the rocks. On the strand line, bits of seaweed and lots of plastic rope fragments from fishing boats (which were duly picked up). Not expecting anything spectacular, my eye was caught by a tiny bit of violet, which proved to be a Violet Sea Snail! We had only found a Janthina janthina once before in our ten years in Cornwall but that was an empty shell whereas this still had its bubble raft. Janthina floats at the surface on the open ocean under this raft and therefore is part of the ‘neuston’ (or ‘pleuston’). It is a predator of other such purple ocean surface dwellers such as By-The-Wind Sailors Velella velella, and the Portuguese Man o’ War, Physalia physalis. It was tiny, the shell measuring only a centimeter or so. There were many By-The-Wind Sailors too, and these were just as small or smaller (usually they are 4-8 centimeters or so). I did not use a flash (looks to artificial), keeping ISO at 200 and f/7.1 I had to go down to 1/30s for shutter speed which was doable leaning on the beach. The protoconch is nice and sharp when you zoom in.

Macro Musings

Posted on by under Macro, molluscs

Foul weather in Cornwall at the moment (it is November, so no surprise there!). Not tempted to go in the water but still wanted to take photos, so I spent some time on the foreshore of my village Flushing looking at Flat Periwinkles (Littorina obtusata). This species is very common, and the only snail that actively crawls about above the waterline. The trouble with macro photography is that with a small aperture, the depth of field is large and everything is in focus, but this includes the usually cluttered background that takes away from the subject. With a large aperture, it is possible to get an aesthetically pleasing, soft focus bokeh background, but the depth of field is much smaller, and too much of the subject is blurry (see the pic on the right). I tried my hand at focus stacking, in which the camera takes a bunch of photos each with a different part of the subject in focus, and then merges them so the depth of field is greater (whilst still having the out-of-focus background). This proved too difficult with a handheld camera (especially on my knees in seaweed). I therefore reverted to ‘normal’ manual photography and it was fun to practice. However, I did not manage to improve on my best Flat Periwinkle photo I took when I first got my Olympus….

Miscellaneous Macro

Posted on by under bryozoans, echinoderms, Macro, molluscs, tunicates, worms

I have not posted a lot this year; in part just because I have not been out as much as I hoped I would, and in part because I had some technical difficulties (I had to sent back a malfunctioning strobe and am also having snoot troubles). As a result I have not gone scuba diving and did not see much of the rock pools either. I managed to take some macro shots over summer though that are worth a quick post. Above a Cushion Star Asterina gibbosa on a colony of the star ascidian Botryllus schlosseri. Below one of my favourite little molluscs, the beautifully patterned White tortoiseshell limpet Tectura virginea. Another tiny mollusc, is the Needle Whelk Bittium reticulatum. The Variegated Scallop Chlamys varia is also common (under rocks) and can be nicely patterned when they are small. Finally some other tiny critters: the Flatworm Leptoplana tremellaris (I like their beady little eyes) and the Bryozoan Disporella hispida.

new strobe

Posted on by under echinoderms, eggs, Macro, molluscs, nudibranchs

Long time no post! Due to a combination of not-so-good weather and work I have not been in the water much the last few months. I attempted some seaweed photography but most times the viz was bad; the one time the conditions were great, somehow all my photos turned out to be a bit meh and I could not be bothered to post them. (For some older shots on seaweed diversity see here, and many older posts as well.) Anyhow, my exciting news is that I finally bought a new strobe (an INON D-200 for those who are interested) because my old Sea&Sea strobes just proved to be too temperamental. Something I should have done a long time ago, but the thrifty Dutchman in me just never pulled the trigger. I have now taken it out twice this weekend and it works like a charm! Now I just need to practice, as it is actually still very hard to go from an OK photo to a truly good pic. Above a shot of a baby urchin Psammechinus miliaris. The true stars of the weekend however were nudibranchs.

A very special find (shown to me by fellow rockpool photography enthusiasts Martin and Greg) were two Goby egg-eating seaslugs Calma gobioophaga. This tiny species can only be found on the goby eggs it eats. With such a ‘niche niche’ and with very good camouflage it is no wonder that reports of this species are rare. A fun fact: its protein-rich diet means it does not have to poo and it therefore does not have an anus…The rock with the eggs and nudis was very shallow and so it was a challenge to get the port of the camera housing under water. Luckily Greg assisted with pointing out the nudi and holding my strobe in place. Freshly hatched goby fry could be seen hovering above the eggs (the fact that a predator was munching through their brothers and sisters might have triggered some of the hatching). The cerata (the fleshy lobes on the nudi’s back) seem to have two goby eyes in them to make them better blend in!

Finally, two other nudibranch species, neither very colourful. Both are predators of anemones: first the largish Grey sea slug Aeolidia papillosa and second the smaller species Aeolidiella alderi. Both adequate shots but I need to practice to make them truly good. I will probably buy a second INON strobe so I can practice wide angle shots as well when diving. I hope to go out a lot more during summer and will make sure to post here about my finds and progress!

Macro

Posted on by under cnidarians, Macro, molluscs

The weather has been horrible lately, with three storms coming in straight after each other. On the upside this means that there is good potential for beachcombing, but alas, the one beach on the North Coast we checked was as clean as a whistle, just sand! So here are some photos from a few weeks back when the weather was good better. On top a Spotted Kaleidoscope Jellyfish (Haliclystus octoradiatus), about 15 mm across, on some Irish Moss seaweed. Please see this site for more information on these beauties; there are several species in our rockpools, but you have to develop a bit of an eye for them! Some other pics below: Blue-rayed Limpets (Patella pellucida) on kelp and a Thicklipped Dogwhelk (Tritia incrassata (when I was young Nassarius incrassatus…). Still need a lot of practice with the strobe, these shots I was very happy with, but most were way off the mark somehow. Looking forward to spring!

Candelabrum cocksii

Posted on by under Hydrozoa, Macro, molluscs

It was a nice day and a good low tide last Wednesday and so I decided to go for a snorkel; I was glad I did! Last year, I had been trying to take photos of this weird little animal, Candelabrum cocksii, but failed miserably, this time it worked. It is a hydrozoan that was first described in Victorian times on the exact beach I always go snorkelling here in Falmouth. It is tiny (see last pic) and lives underneath rocks, so it goes mostly unnoticed (and therefore does not have a common name). To take this photo, I had to do some ‘underwater rockpooling’, turning over a rock to find them. I am not sure what the deal is with these guys; I know the white bulbous structures at the bottom are reproductive structures, and the reddish bit at the top is for feeding (this bit can be stretched out quite a lot). It is colonial just like the Portuguese Man O’War. Please correct me if I am wrong hydrozoan experts! Shout out to David Fenwick and his ID site aphotomarine.com, which I highly recommend.

Other notable finds were stalked jellyfish Calvadosia cruxmelitensis and my very first Wentletrap (which is a Dutch word: wenteltrap=spiral staircase) Epitonium clathrus. As I had my macrolens on the camera I could not shoot any general impressions but the pools started to look beautiful again. The big Wireweed and Thong weed plants were all gone (new ones emerging) and the red seaweeds (Sphaerococcus, Plocamium, Chylocladia) were already quite big.

It was great to be back in the water today and it is my New Year’s resolution to spend a lot more time underwater than I did in 2021! Who knows I will even learn how to use strobes. A happy 2022 to all blog readers!

Rockpooling in Flushing

Posted on by under anemones, echinoderms, eggs, iPhone, molluscs, rock pooling

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.

  • Gunnel (or Butterfish)
  • Shanny (a big one!)
  • Rock Goby
  • Variegated Scallops
  • Sea Scorpion eggs
  • Shanny and Shore Rockling
  • Spotted Cowrie
  • Worm Pipefish (male carrying eggs)
  • Red-Speckled Anemone
  • Sea Lemon
  • baby scallop
  • Berthella plumula
  • Spiny Starfish and Cushion Starfish

Necklace Shell

Posted on by under beach combing, iPhone, molluscs

A quick post as it has been a while…..Last Sunday we went on a walk on sunny Carne Beach on the Roseland Peninsula. The primary aim was to get some fresh air, the second to find some dahlia anemones to bring home to the aquarium (we succeeded in that) and the third to do a bit of beach combing. Nothing much washed up, but we did find a number of live Necklace Shells (Euspira catena). These gastropods hunt bivalves in and on the sand; if you see shell valves with a neat little hole in them, you know they were victims of this predator. They are name after their necklace-shaped, sandy egg capsules (see here).

This one is about as big as they get. Their cousins in the North-East of the Pacific Ocean (Euspira lewisii) are something else though, take a look at this!

More Macro 2

Posted on by under crustaceans, echinoderms, molluscs

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

Posted on by under crustaceans, echinoderms, molluscs, rock pooling, worms

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.