Blue Jellyfish

Posted on July 18, 2026 by An Bollenessor under cnidarians, fisheye, jellies, photography, wide angle

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!

Early Spring Macro

Posted on March 29, 2026 by An Bollenessor under crustaceans, eggs, fish, Flushing, Macro, molluscs, mzuiko60mm, nudibranchs, rock pooling, seaweeds, shells, snorkeling, worms

High time for a quick update. Spring has not started in earnest yet and so the number of days in the water have been limited. As is usual, I have practiced taking pics of Flat Periwinkles (Littorina obtusata or L. fabialis) on a bank of the Penryn River. Below that another set of pics taken in Flushing and Falmouth when it was too windy and choppy to get in the water. These were all taken with my cygnustech diffuser which give the pictures a quite distinctive, slightly subdued look.

I did go in the water a few days in a row when the weather and tides allowed it, which was great. I think one time I stayed in for three hours – my core temperature took some time to recover! No special finds and only a few good pics as my strobe placement had become quite rusty but here are the best and/or the most interesting ones. (Species names in the photo captions.) Bring on proper spring weather and flat seas!

Rainbow Seaslug

Posted on January 11, 2026 by An Bollenessor under molluscs, nudibranchs, snorkeling

Because it was only a few degrees I had opted for rockpooling instead of snorkeling, but as this was my chance, I left the overturned rock to walk back to the carch, ange into my wetsuit and run back. By gently lowering the rock in a pool I was able to take underwater photos. (Some people manage to submerge their camera only when they are out in waders but that approach just does not work for me.) Seaslugs are fairly slow but small (this one was maybe 15 mm) so it is not easy to photograph them. I always go through many aperture/ISO/shutterspeed/strobe output combinations before shots become acceptable. One way of shooting nudis is to use a very small aperture to get as much of the animal in focus, another is to use a larger aperture to only have (parts of) the head in focus, leaving behind the often cluttered background. I am still figuring out what works best for me!

A Gray Seaslug

Posted on March 18, 2025 by An Bollenessor under Macro, molluscs, nudibranchs, snorkeling

There have been a few finds lately at my local spot in Falmouth (and in other places in Cornwall) of the fantastically coloured Rainbow Slug Babakina anadoni. I have tried in vain so far to find it, but I did manage to find another species of Seaslug last Friday: Aeolidia filomenae. It is the opposite of the Rainbow Slug; large, not small, drab, not extravagant, and common instead of rare. More of an understated beauty I guess, and still a nice find! This species feeds on anemones (mainly Beadlet Anemones but also Snakelocks Anemones) rather than the Candelabrum hydroids the Rainbow Slug prefers. I am not very good at spottting nudibranchs so the plan is to keep looking this spring and find more species!

macro macro macro

Posted on November 18, 2024 by An Bollenessor under Macro, mzuiko60mm, shells, snorkeling

There was little wind last Saturday and a superlow tide so time for some rockpool macro! Above, a Purple Topshell *Calliostoma zizyphinum*; common ~~but~~ and pretty. I liked the background which was achieved using a relatively shallow depth of field (f/8). I took my time exploring a small patch (core body temperature slowly decreasing) as this is the only way to find creatures that are smaller than topshells. I spotted a St. John’s Stalked Jellyfish *Calvadosia cruxmelitensis* and took the same shallow depth of field approach (f/5.6).

Lastly a pretty little mollusc: the White Tortoiseshell Limpet *Tectura virginea*. (It is only about half a centimetre long, so I had to use my CMC-1 wetlens for extra magnification.) This species is found on calcified red seaweeds on which it grazes. Their colouration is amazing (I especially like that the growing edge of the shell looks very different). Similar-sized Blue-rayed Limpets (see this recent post) are much more often photographed than this species – what can I say, Tortoiseshell Limpets are the hipster’s choice!

Rockpool Macro

Posted on November 3, 2024 by An Bollenessor under Macro, snorkeling

Easterlies (bad viz) and low tides meant some macro photography in the rockpools this Saturday. The water is getting chillier but staying in for two hours is still possible. I returned to a subject I tried my hand at before: the tube feet of a Green Sea Urchin (Psammechinus miliaris). The 60mm macro + cmc-1 wetlens plus some cheeky cropping gets me close, although I always want to get even closer! I was happier with the results than the previous times, so I posted it on instagram (@an_bollenessor). Below a more zoomed out view of the underside of the urchin, yours truly in the water, a common brittlestar, a small brittlestar, a pheasant shell, a tiny nermertean worm which might be this (thanks David Fenwick!) and a detail of a redspeckled anemone.

A Late October Snorkel

Posted on October 21, 2024 by An Bollenessor under cnidarians, crustaceans, molluscs, mzuiko60mm, photography, shells, snorkeling, tunicates

I have a lot more pics from this year to put on the blog but those have to wait, as I want to post some photos from last Saturday first, when there was little wind, a low tide and some sun! The viz was not great as expected, so I brought the macrolens and went in search for some small critters. No special finds, but I was very happy with my shots of a common little mollusc the European Cowrie (*Trivia monacha*). Most people will be familiar with this species as beach finds of empty shells, but not know how it looks like when it is alive, when its mantle covers most of the shell, it shows its striped tail at the back and a siphon and cute little eyes at the front. I used a shallow depth of field (f/4) to get rid of the ugly cluttered background, which worked well if I may say so myself (I need to try this technique more often!).

Many other critters were found too and I took shots of a selection. First, a Sea Spider, all legs and crawling away. A tiny mat of colonial tunicate that looked like a persian rug on drugs. A quick shot of the ubiquitous (if you know where to look – on kelp fronds) blue-rayed Limpets and a stalked jellyfish. Finally, I spent a lot of time taking shallow-depth-of-field AND slow shutter-speed photos of a scorpion spider crab in a snakelocks anemone to get some sort of ‘artistic’ shot. It did not really work, but it was fun nonetheless and I will have a go at it again. After almost 2,5 hours in the water I stumbled back to the car to get changed – an afternoon well-spent!

A weird little hydroid

Posted on March 14, 2024 by An Bollenessor under cnidarians, hydroids, Hydrozoa, Macro

This is a weird little hydroid and so only has a Latin name to go by: Candelabrum cocksii. It was first described by Cocks in his ‘Contributions to the fauna of Falmouth’ in the 1850s and it is quite common locally. I find them mostly as pictured here, but sometimes I see them with their foot extended, going from a centimetre to 8 centimetres or so in length. This allows them to rove over the rock surface in search of tiny (crustacean) prey. Their mouth is located at the end of the trunk which is covered in ‘capitate’ tentacles (see the pic below for anatomical labels). The white spheres are gonophores used for reproduction. It should be possible in summer when these hermaphrodites reproduce to see dedicated clasper tentacles holding the embryos, that would be cool (to me at least!). Btw, I remembered I posted about this species not even that long ago! See here and also see this link and this link from fellow enthusiasts across the pond who likewise have been fascinated by Candelabrum.

Sea Hares

Posted on July 6, 2023 by An Bollenessor under molluscs

The Sea Hares (Aplysia punctata) are still out in force. They are great characters, with faces like Star Wars extras, crawling over seaweeds and each other. Here another batch of pictures!

Tiny critters under rocks

Posted on July 1, 2023 by An Bollenessor under anemones, bryozoans, chitons, cnidarians, crustaceans, echinoderms, fish, Macro, molluscs, mzuiko60mm, rock pooling, snorkeling

When the viz is bad, I take my macrolens (sometimes with the Nauticam CMC-1 wetlens for a bit of extra magnification) out to the pools. Sometimes I stick to the surface of rocks and seaweeds (to look for stalked jellyfish for instance), but other times I turn over rocks under water to see what hides beneath. Quite a lot! There are larger animals, such as Topknots and different types of crabs (and Worm pipefish as pictured here) but mainly they are quite small (around a centimetre or even less). See the selection below (Tricolia, Bittium and Limacia were not from under rocks but I had to make the grid fit!).