Inachus

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.

Silver Steps Diving V

Yet another solo dive (I know, I know, not ideal) this Thursday morning before the easterlies are kicking in. Actually, the water was already choppier than I expected, but for macro photography the viz is not as important. I did not get ‘the’ shot but it was a nice dive all around. I discovered a little swim-under and saw lobster, rock lobster (craw fish) and a huuuuge conger eel. I was focusing on a little tunicate when I looked up and saw it looking back at me from not very far away at all. Its head was as big as mine. I slowly swam backwards, thinking of this encounter…..overall they do seem to be aggressive towards people though, and with my fisheye lens this could have been a really good shot. This later happened again, this time a smaller individual but still sizable. I did not stick my macro lens up its nose but grabbed a halfhearted shot with a passing by Twospot goby almost in focus to give an idea: Some macro shots: again a Twin fan worm Bispira volutacornis and a new one for me, a big bright red Protula tubularia. It would be nice to get some abstract close-ups but these are excellent living motion-detectors so it is difficult. There are some amazing colours under the rock overhangs and I would like to try some more abstract photos such as this Spiny starfish or this Didemnun colonial seasquirt and other encrusting animals (and plants). No diving/snorkelling this weekend because of the wind, but glad I could put a couple of dives in these past weeks, and I will make an effort to go a lot more weather permitting!

Silver Steps Diving IV

A solo dive early evening at the Silver Steps site. It was a couple of weeks I last went, and this time it was already dusk when I entered the water. My intention was to find cup corals and other small creatures growing on rock overhangs below the kelp line. The viz was good and sure enough I found what I was looking for: Devonshire cup coral Caryophyllia smithii, a solitary stony coral which is relatively common. They are very beautiful and the right size for the macro lens. I will definitely go after them again. Other finds were a golfball sponge Tethya aurantium, a baby Longspined seascorpion (this shot had potential, but it swam away unfortunately), a tunicate and a Painted topshell (very common). At the end of the dive unfortunately it was getting too dark to find objects or too properly focus; I need to sort out a dive light!

Silver Steps Diving III

I will keep this post short, as my third Silver Steps shoredive of the year was a week ago. As you can see above, my dive was made by encountering the beautiful nudibranch Antiopella cristata (although I prefer the old name Janolus cristatus…). My camera battery strangely gave up straight after taking these pics (argh!), otherwise I would have bothered it for at least another ten minutes! The 60mm lens is great. Look at the European cowrie Trivia monacha below which is less than a centimeter in length. Not a great shot but it shows that it is possible. Finally, a common Phoronid worm Phoronis hippocrepia (Thanks Allison, please check out her great blog Notes from a California naturalist). I hope the wind will die down and I can go back soon.

Silver Steps Diving

Finally a shore dive yesterday evening, it has been a long time. I partnered up with buddy Shannon via instagram (@shannonmoranphoto). Instagram has been a really nice way to learn about photography from likeminded folks (such as @danboltphoto and @malcolmnnimmo). We dived (dove?) Silver Steps in Falmouth, about which you can find a bunch of old snorkelling and diving posts on the blog if you are interested. Shannon was the ideal buddy: relaxed and really into photography, so we kept the same tempo. It was a very shallow dive (maybe 5 meters), so we were only limited by getting cold, which was after an hour. I chose to use my 60mm lens, but not to use the 1:1 macro setting, but the 0.19-040 focal range to try my hand at slightly larger objects such as fish. I was thus lucky in a sense that I did not encounter any beautiful nudibranchs of which I would not be able to to take a good shot. (Edit: actually, I since learned that 1:1 is still possible using this focal range). It was however unfortunate that I could not get a good shot of a cuttlefish that hovered about two meters away, rapidly changing colour and catching a wrasse! Next time I will perhaps change settings again to try my hand at (cuttle)fish swimming a bit further away. However, I was very happy with sticking to Leopard-spotted gobies Thorogobius ephippiatus. They do not stick their little faces out of nooks as do most blennies, but usually lie on and under ledges. The trick was to approach very slowly, shooting until they swam off. For some reason, I managed to position my strobe right and did not have backscatter issues. I used Windows Photos to postprocess. See below for a before and after example: Two other common organisms below: a Squat lobster Galathea rugosa and a Twin fan worm Bispira volutacornis. And finally an out of focus, but fun photo of a tiny tiny clingfish very aptly clinging to Shannon’s housing. This was one of the most fun dives in ages and I hope to repeat it sometime soon!

Swanpool

OK, as I mentioned in  the last post, I had been on three dives before my exceptional viz snorkel session but did not have the opportunity to post pictures. So here goes for the first dive at Swanpool with Thomas Daguerre. Swanpool is a nice little beach but I was sceptical about it, as it is mainly, well, beach. Thomas wanted to try to find some sand-dwelling creatures though and I was up for trying something new so in we went. See him at work below in some seriously murky water! Again, spider crabs were common, sitting still but running away when getting closer, stirring up the sand. There is some sparse seagrass, arranged in thickets parallel to the strandline, some Sand mason worms Lanice conchilega can be seen in the foreground. A Spiny starfish Marthasterias glacialis was eating up a Pod razor shell Ensis siliqua. A little swimming crab hid in the sand, not sure which species.Also, jelly season has started, I saw several Northern Comb Jellies Beroe cucumis. They are exquisitely beautiful and very hard to focus on, which makes for a photographers nightmare. Apart from a Compass jellyfish, I noticed a Blue jellyfish Cyanea lamarcki. It appears to have two parasites, which could be the amphipod Hyperia galba. All in all not a bad dive. Also, I found a frisbee and a decent pair of sunglasses!

First Dive of 2017

Finally, time for a (solo)dive last Saturday, at probably the most accessible local site: Silver Steps in Falmouth (you can just make out the steps in the photo above). The sun and high tide had attracted quite a lot of other divers too, including University of Exeter and Falmouth University students learning the ropes. I was very keen to get in the water and take photos but my approach is probably not the best: I just shoot whatever happens to be in front of me. Better results could be obtained to specifically look for macro subjects, to stay in the water column and search for jellies, befriend the Ballan wrasse or stay put in front of a Leopard-spotted goby hide-out (or check out seaweeds of course). I’ll do one of these things next time, for now, some random shots. I spotted several Spider crabs; these are always shy and try to quickly retreat, except for one. This big crab came after me as soon as we spotted each other. I should have tried more shots, as unfortunately he did not fit the frame. You can see in the short movie why I didn’t!

The viz was not great (I find it hard to estimate it in meters though). In the water I noticed a small hydrozoan Leuckartia octona. The underside of some wreckage harboured Light bulb sea squirts (see previous post) and some were predated on by Candy striped flatworm Prostheceraeus vittatus. (I brought my new LED light with me to help bring some colour out but I just ended up with combinations of glare and shadows so stuck to my normal natural light pics.) Next, a curious Ballan wrasse Labrus bergylta. Finally, some not so clear shots that nevertheless give a good impression of how tall the invasive Wireweed Sargassum muticum are growing. Hopefully more dive posts soon!