Category Archives: nudibranchs

Nudibranchs caught in the act

Posted on by under diving, eelgrass, Flushing, Macro, mzuiko60mm, nudibranchs
The weather is slowly taking a turn for the worse now, so if there is a window to get in the water I am ready for it (I am absolutely dreading the coming half year of wind, rain, darkness and no snorkelling or diving!). Last weekend I took a look underwater in my local seagrass patch in Flushing. The viz was not great at all (as anticipated), so I was looking to do some macrophotography. I clocked plenty of egg masses and indeed some Polycera quadrilineata, which is one of the more common species here in Cornwall but up there with the prettiest! Individuals of this species are often white with yellow stripes and dots, but often they have black lines as well. After taking ages reviewing shots full of backscatter and re-positioning my strobe, the photos started to work out. I noticed one blade of seagrass with two individuals side by side. I suspected they were mating but as they are quite small and my eyesight is getting worse, the anatomical action that was going one only became apparent reviewing the photos back on land. Nudibranchs are simultaneous hermaphrodites and when they mate act both in the female and male role. In the pics below you can see the sexual organs protruding from their right flank. Interesting!

I was on a roll and I pretty much stayed the entire dive on the same square meter, taking photo after photo of the slugs around me. I follow the ‘spray and pray’ routine of photography to make sure at least some of the pics are in perfect focus and without overblown highlights, although the downside of this method is that you have to wade through 200+ pics afterwards. Using the nauticam cmc-1 wetlens I managed to get ‘supermacro’ and was rewarded with some really nice head shots, showing oral flaps, foraging on bryozoans on the seagrass and the slugs generally being very pretty! I am getting more and more into nudibranchs now and hope to find some other species before the sea turns too choppy!

P.S. The previous post was all about low depth of field images; for the photos in this post I took the opposite approach and used the smallest aperture available.

Silver Steps Round-up

Posted on by under crustaceans, diving, fish, nudibranchs, Silver Steps

I realised I still had photos on my hard disc from a bunch of dives taken at local haunt Silver Steps in Falmouth this summer that could do with posting, as some came out quite nicely. Several photos were taken at my secret spot ‘The Crack‘ (I have now labelled all posts with photos taken in this small spot with that tag). I took some with my trusted Olympus 60mm lens and others with my new 30mm lens. The latter worked well with a large aperture to give a nice blurry background, as seen with the Tompot Blenny (Parablennius gattorugine) above (and further below). I also managed to take a good ‘full frontal’ shot of a Connemara Clingfish (Lepadogaster candolii) showing of the sucker with which they attach to the rocks.

During one dive something caught the corner of my eye: a small Spiny Lobster (Palinurus elephas) – a very nice surprise as I had not seen one here for quite a few years! These are tricky customers to take a photo of I find: their antennae are so long that you need a wide angle scene to have them in the frame, as getting close up gets you only part of the animal. Also a photo of a prawn (Palaemon, not sure which of the two possible species); such beautiful animals! Below that a block of some more good photos.

At the end of one dive I came across a nudibranch I had not seen before: a Yellow Skirt (or Venus) Seaslug (Okenia elegans). Extravagant in its colours and proportions this was one of my finds of the year. Unfortunately I could not give it the full photographic treatment I had in mind as I was running low on air when I found it. Finally a bunch of not-so-good photos but they show a range of common local species and so I have added them for completeness. You can read descriptions when you click on individual pics.

More Macro

Posted on by under eggs, Macro, molluscs, nudibranchs

Has ‘an bollenessor’ turned into a macro photography-only blog? It seems so, I have not posted about my aquarium in ages. I still end up doing macrophotography when I go rockpooling. I tried wide-angle photography last week in the rockpools and failed miserably (so no photos for the blog). I hope to mix it up later in the year but for the moment here are some more macro photos. Above a picture I am quite pleased with: a solar-powered seaslug Elysia viridis on its favourite food the green seaweed Codium with some nice orange seaweed as a background. The pictures below show the snail Raphitoma purpurea (a first for me in Cornwall), the nudibranch Okenia nodosa (a lifer for me), a European Cowrie Trivia monacha and a patch of goby eggs (sans goby-egg eating seaslugs unfortunately).

I am a bit stuck in a limbo where on one hand I want to see interesting, new species and take good ID pictures (for recording on iNaturalist and sharing on facebook groups), but on the other hand I have gone a bit above my station and developed an interest in taking more ‘arty’ photos such as the solar-powered seaslug one at the top of this post. Sometimes the two aims converge. sometimes not. As an illustration of that, below a few shots of the nudibranch Polycera quadrilineata that ended up quite differently: a ‘good for ID’ photo but with an ugly cluttered background, a more arty photo (although the bokeh effect is due to backscatter and it is actually not that great), an overall ‘nice’ photo (posted before), a ‘shore studio’ shot of a slug (more about that in the next post) and an artsy fartsy version of a studio shot where the highlight have been so blown out that the slug basically is shown as a set of yellow stripes. I must say I can have ideas about how to take a certain shot, but my general approach is still ‘spray and pray’!

Early Spring Macro

Posted on by 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!

What is a seaslug?

Posted on by under Macro, molluscs, nudibranchs, worms

A nudibranch, a snail and a seaslug crawl into a bar…no seriously, what actually is the difference between these three types of molluscs? According to Kerney and Cameron (1979), those animals that cannot fit into their shell are called slugs, and those that can are called snails (definition brought under my attention by Ian Smith, see his amazing species accounts of British molluscs on flickr: Morddyn). Seaslugs either have an outer shell in which they cannot retract, an internal shell or no shell at all. The Solar-powered seaslug (Elysia viridis) pictured above is a species without a shell that is an example of a seaslug. Nudibranchs are a type of seaslug with ‘naked’ (nudi) gills (branchs) on their back. Nudibranchs never have a shell (although many have one when they are a larva). Books on nudibranchs often include seaslugs and sometimes they even feature snails! This happens when these species are related to seaslugs (the ‘lathe acteon’ or ‘beer barrel’ Acteon tornatilis is an example of that – a goal of this year is to take a good photo of that species). I have posted a range of photos on here as an illustrations of seaslugs (or not!); read the captions for species info.

Candy striped flatworm Prostheceraeus vittatus

Rainbow Seaslug

Posted on by under molluscs, nudibranchs, snorkeling
See here the find I alluded to in the last post: a Rainbow Seaslug! When turning rocks last Monday, on a cold but sunny (and rainy) afternoon, a multi-coloured blob (see below) immediately caught my attention. This is only the second time I found one (the first time I did not have my camera to hand) so I was very excited. This species (Babakina anadoni) is not only over-the-top in its colouration but also a newcomer to British shores, having only been reported for the first time in the Scillies in 2022 and on mainland Britain in 2023 (on the very same shore here in Falmouth). It now is sighted regularly so seems to be establishing itself.

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!

Seagrass Macro

Posted on by under anemones, bryozoans, eelgrass, Flushing, Macro, molluscs, mzuiko60mm, nudibranchs, photography, tunicates
Polycera quadrilineata

I had a couple of good snorkels at the end of summer in the seagrass beds off my local beach in Flushing. The water at the end of summer is warm enough to go without wetsuit – I just had a weightbelt to let me sink down on the sand at low tide, no fins needed. I managed to do what I normally find very difficult: spot nudibranchs! Mainly one of the more common species, Polycera quadrilineata, but that was fine by me, as they are very beautiful, especially the black colour morph pictured above. I spotted one other species, the egg-eating Favorinus branchialis (with its own eggs also visible). Not great photos, but in my defense they are very small!

Shelled molluscs are easier to find. Below 1) the ubiquitous Grey Topshell Steromphala cinerarea, 2) the Grooved Topshell Jujubinus striatus and 3) the tiny Rissoa membranacea (faecal pellets on show, even within the shell). The latter two species are strongly associated with seagrass.

Some assorted macro photos below and at the end a view at a very low tide of the Flushing seagrass site this October.

Back to Silver Steps

Posted on by under diving, fish, Macro, molluscs, nudibranchs, Silver Steps, worms

With the camera housing back, I have been in the water again lately, taking quite a few photos. I am lagging behind with posting quite a bit (this will allow me to post when I cannot get in the water later in the year) but should occasionally maintain the blog over summer, so here is! My local haunt Silver Steps provided during two dives with the macro lens. Above a Twin Fan Worm (Bispira volutacornis). These are quite shy (i.e. they retract into their parchment-like tube when their composite eyes detect a curious diver) but also are attached to cluttered rock walls. To blur this unappealing background, I used a very shallow depth of field (f 2.8); this also has the advantage of letting a lot of light in so ISO can be decreased to 100 – sorry non-photographers!). Below a collage of other ‘usual suspects’ (names under the photos) but ALSO I SPOTTED AN OCTOPUS! Crouched in a crevice and with only a macro lens I could not do it justice but it was still a very nice encounter.

A Gray Seaslug

Posted on by 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!

Rockpools from the top

Posted on by under Flushing, molluscs, nudibranchs, rock pooling, seaweeds

I tried my hand today at taking photos of rock pools above water – tricky! I used my Leica wide angle lens with a polarizing filter and a handheld strobe in a diffuser. It was fun playing around, although felt my back after an hour or so trying! It is difficult to keep the reflection of the flash out of the shot. The tide was not low so these are small, mid-shore pools dominated by coralline algae and some (fine) red seaweeds. Beadlet and snakelocks anemones, limpets, periwinkles, thick- and purple topshells are the most common animals. Some sunshine and blue sky – let’s see when I can try my hand at underwater photos again!

P.S. two extra pics taken a day later (without flash) near Bream Cove featuring an anemone-eating Aeolidia nudibranch.