Tag Archives: nature

Periwinkles

Posted on by under Macro, molluscs

Long time no post – the idea was to spend time taking photos during spring and summer and enjoy the underwater world vicariously by blogging in autumn and winter. However, something terrible happened on my only dive of 2025: my underwater housing sprung a leak! The housing was not flooded to an extent that it damaged my camera but it needed to be repaired before I could get back underwater. Unfortunately there is only one place that can do that, backscatter all the way in California, and even more unfortunately, U.S. customs decided to keep my package on a shelf for over a month. I have never seen an octopus in my decade of diving but of course people reported eight or so per dive last month so I was feeling very sorry for myself!* Anyway, I have been confined to the shoreline so far. To cope with that, I bought a weird chinese macro-wide angle lens to play with which I will post about later. I also used my ‘normal’ 60mm macro lens (sometimes with a Raynox lens attached to the front for extra magnification) and took some time to focus on periwinkles.

At the top and below a Flat Periwinkle (Littorina obtusata or maybe L. fabialis – distinguishing is very hard as it requires investigating differences in penis shape!). As you can see the locations are not always glamorous, but if you zoom in you can still find beauty!

Flat periwinkles tend to be most active above-water, followed by the smaller Rough Periwinkle (Littorina saxatilis – below) with the Common Periwinkle (Littorina littorea – below that) only occasionally moving about.

Finally, a tiny species the Small Periwinkle (Littorina Melharaphe neritoides). Probably overlooked by most, as it is tiny (up to 8mm, usually smaller) and hidden between barnacles (or even nestled in empty barnacle cases) high on the shore.

* and no, I could not bring myself to go diving without a camera…

Scorpion Spider Crabs

Posted on by under anemones, crustaceans, diving, EMWL, photography, Silver Steps
I recently posted on the Crustaceans inhabiting my local shore dive site Silver Steps (see here), but left out one species: the Scorpion Spider Crab (Inachus spp.), which deserves a post on its own. I have blogged about this crab before (see here), specifically in the context of ‘macro-wide angle’ for which this species, perched on- or under a snakelocks anemone, is ideally suited. My previous efforts were based on an affordable inon wetlens, but I have since bought a super-duper nauticam lens. Although very good at macro-wide angle, this lens lets in very little light, which basically gives you three options: 1) lie on some bright white coral sand in the Maldives and shoot upwards to the sun at midday (so actually not really an option), 2) increasingly compromise the exposure triangle to keep a blueish/greenish background (higher ISO>more noise, lower shutterspeed>more camera shake, greater aperture>smaller depth of field), or 3) keep all settings in a ‘normal’ range, resulting in a foreground lit up by strobes on maximum output, but a black background (only if you are shooting critters in rock crevices you can get both fore- and background well-exposed, as strobe light has something to bounce back from – see for some examples the Crustaceans post). I quite like the clean black background and dislike bluer, but grainier images, so have mainly tried option 3. Hopefully, next year in summer I can try going for some blue background shots. Sorry if this blog is occasionally turning into a photography borefest by the way, but I have been really getting into that stuff! ;-). Anyway, these scorpion spider crab pics have turned out quite nicely.

Moods

Posted on by under Macro, photography, tunicates

The inhalant (left pic, 8 lobes) and exhalant (right pic, 6 lobes) siphon of the Sea Vase seasquirt (Ciona intestinalis). The pigments are thought to function as photoreceptors. This is a common species, especially in habitats disturbed by humans, and not too pretty (the latin name means ‘pillar of intestines’…) but if you zoom in everything reveals beautiful features! Quite moody shots, to which I have gravitated this year. I like the black backgrounds, which is achieved by letting very little light into the camera, with the strobes only lighting up the subject in the foreground – unable to illuminate anything in the open water (‘negative space’) behind. (A similar effect can be achieved using a ‘snoot’, but I have never managed to get that to work…) I have also tried to get closer and closer up with my macro wetlens, ideally I’d have some sort of microscope underwater! If you are on instagram, check out @an_bollenessor for more pics as ‘posts’ and as ‘stories’.

Black-faced Blennies

Posted on by under diving, EMWL, fish, Macro, Silver Steps

Dear reader, it has been a while! With the weather taking a turn for the worse, I thought it would be high time to start updating the blog again. I have taken more photos this year than ever before, and actually have dived my local shore site “Silver Steps” in Falmouth ‘to death’, so now have plenty of material. I’d thought I start with a post on one of my favourite fish, the Black-faced Blenny (Tripterygion delaisi). This is a beautiful little fish (a triple-fin blenny, not a ‘true’ blenny) that lives under rock overhangs, usually perched upside down. Breeding males are bright yellow with a black head and an electric blue edged dorsal fin, while females and males outside of the breeding season have a mottled brown-white coloration (which is equally beautiful testified by the pic on the top right). These fish (especially the females) are skittish and also require a bit of contortion to photograph under the overhangs but it is more than worth it! Below a photo-dump of fish shots taken with my 60mm macro lens and a combination of that lens and a superduper macro-wide-angle wetlens (details of which I am bound to bore you with in coming posts!).

Inachus

Posted on by under anemones, cnidarians, crustaceans, diving, Macro, Silver Steps

This seems like a familiar way to start a blog post but here I go again: ‘the weather has been terrible lately and I have not been in the water!’. March used to be my favourite time for snorkeling because the seaweeds look at their best, but the last three years it has been windy and wet, surely because of climate change…

To keep the blog going (a bit), I have dug out some images from a few dives last year featuring Inachus spider crabs. There are three species, I. phalangium, I. dorsettensis and I. leptochirus, which can be told apart by the arrangement of tubercules on their carapace, but these are often obscured by epiphyte growth, and so I am keeping it to Inachus sp. All species are associated with Snakelocks Anemone (Anemonia viridis) hosts. The photo above is taken using a weird ‘wide angle macro’ wetlens (INON UFL-M150 ZM80). This perspective always fascinated me but it is difficult to achieve. This lens does the job, although it is incredibly ‘soft’, especially around the edges. The close focusing also makes it difficult to direct the strobe light on the subject. So there is a tradeoff between getting the surroundings in view and sharpness. Below first some sharper shots using my 60mm macrolens, followed by some macro wide angle shots (they happen to be each of the different Anemonia colour morph):

I will leave you with the following interesting bit on the biology of these crabs by Diesel (Ethology, 1986):

I. phalangium females are site-constant, and live in the protection of one anemone or group. Males travel frequently between anemones harbouring females due to spawn; they copulate and guard the females until spawning, after which the male leaves again. A male operates in a patrol area containing 3-8 anemone groups and up to 8 females, visiting each female in turn repeatedly just before it is due to spawn. Patrol areas of different males may overlap, with resulting competition to fertilize a female’s next brood. Large males have higher reproductive success than small ones. Females live up to 8 months after the moult of puberty and hatch up to six broods, and males live up to 7 months as adults. A male could fertilize a calculated 26,000 eggs, whilst a female’s reproductive potential is ca. 4,200 eggs. Mortality risks are higher for males than for females, probably because of increased predation while leaving the protection of anemones in order to visit females. Males learn the positions of anemones harbouring females in their patrol areas, and when these are due to spawn. This allows a male to travel with a target and arrive punctually to fertilize the next brood due in his circuit. I. phalangium is the first marine invertebrate reported to use a “schedule” of localities and times for visiting prespawning females. In this way males minimize searching time and mortality risk, and maximize the number of broods fertilized.