The Hair Curler Seaslug (Spurilla neapolitana) is a southern species that was first discovered in Cornwall by @charlotte.cumming last year. It has quickly established itself as one of the most common species found here in Falmouth. As always I was a little bit late to the party spotting this nudibranch but lately they have become hard to miss! This species feeds on anemones using their radular teeth and can easily be found at the base of Snakelocks anemones. The stinging cells of their prey are neatly incorporated into their own curly cerata. I found baby slugs as well and this species is clearly here to stay. What will this explosion of new predators mean for the anemones? Will Snakelocks populations collapse before antipredation mutations appear? Or perhaps it is not such a problem for them, we will find out!
Apologies for the title, but this is what this post is about: snorkelling in one meter of water taking soft focus images. Low depth of field (DoF) results from a large (or wide) aperture (somewhat confusingly, to make the aperture larger you need to select a lower f-number on your camera). A wider aperture results in more light hitting the sensor, so it is something you’d do when taking photos under low light, but it can also be used for creative effects, as it results in only a thin slice of the image being in focus. This leaves cluttered backgrounds and foregrounds blurred out which makes for a more pleasing aesthetic effect. I used this technique for the photos above and below of a European Cowrie (Trivia monacha) (M43: f4, 1/160s, ISO100). Of course there is a trade-off: most of the subject is out of focus, so it is not a setting you would use for an ID shot that needs as much detail as possible. The golden rule is to keep the eye(s) in focus – something that worked slightly better in the second pic. Strangely, this snail has two pupils in its right eye! I have indicated the slice that is in focus in the second photo with a red line; the shell is 10-15mm in length.
While I was taking photo after photo of this snail, I was approached by several small Tompot Blennies. This species (as well as Common Blennies, but not so much Montagu’s Blennies) is very curious which is great for a photographer (although sometimes they come too close and you have to keep moving back). I used the same settings as above for the smallest individual (not longer than 4 cm). I noticed for the first time the blue spots on the dorsal fin (see first pic). I did not get THE photo but it was good practice. Finally, a close-up of a baby Topknot; although the aperture was smaller this time, the mouth is still not in focus. Sorry for all the photography talk if you are not into that, but at least I hope you enjoyed the pictures!
It is jellyfish season again and the Blue Jellyfish (Cyanea lamarckii) is probably the commonest species in Cornwall. Supposedly they sting but I have never noticed. Rather than taking a ‘true’ photo with an exposed background, I usually opt to not expose the background and light up the jellyfish with strobes. As these jellyfish are quite small (the ones I see are 5-12 cm in diameter; they can grow larger though) this is hard with the jelly up against the mini-dome (using a 8mm fisheye lens). The Microsoft Photo app let’s me get rid of the backscatter in the background but this does not always work as it tends to remove tentacles as well. (I cannot really see it on my computer screen but did notice on my phone: the bottom two pics have the background replaced but the top one hasn’t and so is a bit less clean.) Anyway, these animals are beautiful and quite otherworldly!
I realised I had not posted (much) about this year’s rockpool snorkels so I am taking the opportunity to post a ‘picdump’ with a whole array of tiny species. These photos were taken with a macrolens, and for most a wetlens was used for even greater magnification. Above the White Tortoiseshell Limpet Tectura virginea, a tiny species living on calcified red seaweed. I have added species names to the photos below.
The rain has been hammering down and I am in accute underwater withdrawal… Just a bit of the ole bloggin then! These are some pictures from April, when the phytoplankton had not kicked in and the water was still quite blue. Out of curiousity I swam out to the marker buoys off Castle Beach in Falmouth to see if there was anything interesting growing on them. There was! Lots of mussels, including on the chain going down to the bottom (10ish meters deep). I took my fisheye lens and after much adjusting of strobes (holding the housing sideways for portrait mode, and also up, meaning that the lower strobe needed to be pulled back) I got the nice shot above. Mussels are not a favourite of underwaterphotographers (this is an understatement!) but they are beautiful upclose, the white mantle contrasting with the blueish black shell.
A few days later I returned with my probe lens, as i thought this would offer an original perspective. It was a tricky thing to do as this lens lets in very little light. The difference between foreground and background seems slightly off as well! These photos show that the mussels were crawling with the tubedwelling amphipod Jassa marmorata, a prominent fouling species. I planned to return to try again a few days later, but the chains had been replaced by ‘fresh’ ones, bad luck! I will go back to have a look at them as soon as the weather allows it.
P.S. there are two older posts tagged with ‘buoys‘.
Above some pics of a recent, impromptu snorkel in the Helford; a catshark, a cuttlefish and a greater pipefish which I could snap with the fisheye lens while battling a raging tidal current. I have dived a lot recently, did my PADI advanced open water (to make it easier to participate in some deeper diving in the future ), finally dived Porthkerris, bought a fancy new wetlens and stepped up my iNaturalist game. I took some good photos as well, but for many of these I reckon I could replace them with an even better version. For this reason, and also because there will be plenty of rainy days at the end of the year to blog instead of dive, I will probably remain a bit quiet here for now, add to the collection of photos, and update the blog a lot more later! (P.S. I do post from time to time on instagram: @an_bollenessor.)
The sun is shining (most days) and the water has warmed up, so ideal conditions for a bit of snorkeling. I have been out at my usual spot in Falmouth (rockpools and kelp forest) and my local beach in Flushing (seagrass) (and yes, I really count myself lucky every time that l live here!). The last couple of times I have brought my son along, as he is now old enough (nine). He is a nature freak just like his dad, actually probably more so! I need to get him fins and a weight belt soon, but he has been doing fine in the water already.
The photos above and below illustrate the state of the rock pools at the moment: quite brownish with the Sargassum and Himanthalia growing everywhere. The red, pink and purple species have largely disappeared (apart from Harpoon weed) and there is quite a bit of green Ulva growing. The water teems with juvenile pollack in the rock pools and schools of sand eels a bit further out. Diving over sandy patches, you can see the latter species shooting out of the sand en masse. It is crazy how such a silvery pelagic fish can also burrow in the sand. I guess it does take its toll, as there are quite some dead ones to be seen too.
The Flushing snorkel site is very different, no (deep) rockpools, only a little bit of kelp but with a very healthy patch of seagrass. No catsharks or thornback rays when we went in, just the odd small sea bass. There are many small Snakelocks anemones on the seagrass. I used to think that it was mostly the purple form that did this but I now noticed that most were the green variety, so the morphs do not seem to differ in this respect after all. One anemone had ‘caught’ a crystal jellyfish (an Aequorea medusa). Not sure if it was in the process of being digested or just ‘stuck’.
I have played around with my new INON strobe, which works a lot better than my old strobe. I have ordered a second one for Wide Angle photos too….(as you can see there is quite some backscatter in the pic of the Shore Crab above). I will need to get back to some shore diving to make optimal use of two strobes, as I am too lousy a freediver to get the lighting and exposure right in one breath!
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!
Photography during my last snorkel was a bit frustrating as I could not get my strobes to work. Luckily I was saved by a subject that did not require any extra light: beautiful translucent crystal jellies slowly pulsating near the surface. Crystal jellyfish are not true jellyfish (these belong in the Class Scyphozoa), but hydromedusae (Class Hydrozoa) which have a polyp stage in their lifecycle that bud of these sexual medusae. They are difficult to identify to species level so I keep it to Aequorea sp. I saw a few, around 10 cm in diameter, and had fun diving under them and get them in front of the afternoon sun.
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.)
Wrack Siphon Weed Vertebrata lanosa
Bladder Wrack Fucus vesiculosus
After the wracks, the rocks were dominated by Brown Tuning Fork Weed Bifurcaria bifurcata (with Osmundea, Chondrus, Ceramium and other species mixed in).
Very common on top of the Bifurcaria was either Colpomenia or Leathesia; I should know the difference but I cannot figure it out (even after squeezing between fingers)!
After the Bifurcaria zone dense Himanthalia elongata stands.
Very tall Sargassum muticum.
Very tall Gongolaria baccata.
The tall Brown seaweeds, Himanthalia, Sargassum and Gongolaria, were interspersed with seagrass beds, with Ulva, Saccharina and some Asparagopsis inbetween.
Seagrass
Huge masses of Sugar Kelp Saccharina latissima.
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!
Seagrass, showing the extensive root- and rhizome systems that are so good at storing carbon (in addition, the seagrass beds store carbon by trapping floating particles).
A Spiny Starfish Marthasterias glacialis.
A tiny Macropdia crab covered in seaweed, not done justice without a strobe!
