A quick snorkel this Tuesday to check out my favourite rock pools at Castle Beach here in Falmouth. The tide was low, the water still and the sun was shining, creating beautiful shimmers of light. The Wireweed, Thong weed, Sea lettuce and also the Bushy rainbow wrack are in full swing, but most of the other species are in decline, with for instance the Harpoon weed and False Eyelash weed bleaching. Still, it is very pretty! The most common fish encountered so far this year have been Two-spot Gobies, with the occasional wrasse or dragonet. Now, loads of juvenile Pollack Pollachius pollachius have appeared (ID thanks to the excellent folk at the Seasearch Cornwall facebook page). The following photos are all variations on the same theme; I could not decide which ones were best so I just posted the whole lot: In the photo above you can make out some Snakelocks anemones on the right; compare with the last two photos of this post from six weeks ago to see how the same scene has changed. The stalked jellyfish seem to have largely disappeared along with the decline of seaweeds. However, you can still spot the odd interesting animal. The photo below is of the small gastropod
Mangelia costata Haedropleura septangularis. Probably not very rare, but small (<15 mm) and well-hidden and so not that often seen:
David Fenwick (Aphotomarine), Matt Slater (Shoresearch Cornwall) and Thomas Daguerre (HydroMotion Media) had all tipped me off about the elusive ‘Cave of Dreams’ at Pentire/Fistral Beach in Newquay. Recent posts by Cornish Rock Pools and The Marine Enthusiast reminded me of the stunning Scarlet and gold star coral Balanophyllia regia that live there and made me decide to drive all the way (well, it is a good 45 minutes) to the North Coast. I did not find the cave on two earlier visits (see this post from almost exactly one year ago), but today Thomas showed me exactly where it was. Cave is a big word, it is more of an overhang, and I don’t think I would have ever managed to discover it myself (you can find a photo of it behind the aphotomarine link). The corals are tiny, 5-10 mm in diameter, but there are many of them, in the low hundreds. Unlike most corals, this species relies solely on catching food with its tentacles, and it does not have algal symbionts (zooxanthellae) to provide energy from photosynthesis. Dark ‘caves’ with lots of waterflow are thus a good habitat for them. They look a bit like the tropical sun corals, who I was lucky to see in Hong Kong last year, and which are quite popular in the reef aquarium hobby. I had to carefully position myself on the rocks, dipping my camera in the water. It was too shallow to stick my head in, and I did not want to enter the water anyway, to prevent disturbing this widespread, but uncommon species. There were some interesting sponges (one of them Polymastia boletiformis) and red seaweeds, but I decided to only focus (no pun intended) on the corals. I was quite excited, this is definitely one of the most interesting species I have seen so far in Cornwall and I am sure that many people would be amazed to learn that corals live on our shores. I played around with my wide-angle lens, my new macro lens and took shots without the wet lenses. The light was low and I had to contort myself a bit but some of the shots turned out nice. The macro is still difficult, but maybe I might be expecting too much from the setup I have (without strobes). I hope to go back soon and try to get more photos, I would love to try an underwater panorama shot!
I now am the proud owner of a nauticam CMC wetlens. It arrived too late for my first encounter with a nudibranch this year, however, it came just in time for a proliferation of stalked jellyfish. These tiny (around one centimeter), sessile relatives of jellyfish are not very well-known, but seem to be getting more popular, see for some other recent finds the other local blogs Cornish Rock Pools and The Marine Enthusiast. To find them, you need to carefully scan seaweeds in rock pools (they are not very picky when it comes to which species they attach themselves to). The key resource for UK (European even) rock poolers is David Fenwick’s Stauromedusae website. Above, the most common species, the Spotted kaleidoscope jellyfish Haliclystus octoradiatus, recognizable by the primary tentacles or anchors (the white ‘balls’ inbetween the tentacles). Below, St. John’s stalked jellyfish Calvadosia cruxmelitensis, with a zoomed out photo and finger nail to give an idea of scale. Finally, two not so good photos of a third species Calvadosia campanulata taken above-water as these were located just below the surface. One more species can be found on mainland Cornwall (the Goblet stalked jellyfish Craterolophus convolvulus) and one on the Scillies (the Horned stalked jellyfish Lucernaria quadricornis, but who knows this species is also present on the mainland). So some more searching to do!
The last day of January I took an hour to explore a pool at the upper part of Castle Beach. The resulting shots turned out a lot better than they did the last time. As most of the pools are bare rock, there are no problems with sand/silt, but they are very shallow and on the receiving end of drainage pipes resulting in rain water mixing with the salt water, affecting visibility (this is not necessarily bad as it can make a photo more interesting). It was overcast and I did not experience problems with overexposure; I actually found that tweaking in Photoshop made the photos look worse. Below a Beadlet anemone Actinia equina, the most common anemone on rocky shores. They can be bright red or a drab brown (the green version is rare here) but have bright blue beadlets, or more technically acroraghi. These contain stinging nematocsysts used in territorial fights. After that a small Daisy anemone Cereus pedunculatus, which are usually more mottled in appearance (and not common here, or perhaps I do not know how to look for them…).Next up, a red growth which I should have investigated further, I am not even sure if it is a sponge or something else. After that, a worn Thick top shell Osilinus lineatus, a young Dumont’s tubular weed Dumontia contorta, a red Banded pincer weed Ceramium sp. happily producing oxygen and finally Patella limpets covered in Brown limpet paint Ralfsia verrucosa.
Coralline algae, pink and purple, feathery or encrusting, are a conspicuous part of the local rock pools. When viewed close up, even the crusts are not boring, as they reveal little stalks and holes forming reproductive structures. The above species could be Common pale paint weed Lithophyllum incrustans or Common purple paint weed Phytamoliton purpureum; it is hard to tell species apart and there are likely more species than the few described on websites or in books. In the third photo, the thinner crusts are probably Phymatolithon lenormandii. Only when looking at close-up photos it becomes apparent that juvenile limpets (Patella spp) and White tortoise shell limpets Tectura virginea are very common. Coralline algae are desirable in tropical reef aquariums, as they cover the brownish live rock in pretty colors. There are even special supplements for sale to promote their growth. They need low phosphates and sufficent calcium (as well as magnesium) to grow well, just as hard corals do. Good light helps, although there are also species that thrive under low light. I have a bit of coralline algae in my tank, but only in spots with high flow, so that seems important too. It might be a nice experiment to take a small tank, with a good light source and a decent pump (with rowaphos to keep phosphates down), and add some coralline algae-covered rocks to see what happens. Doing frequent 100% water changes will replenish calcium and magnesium, and not adding animals and food will keep nutrient levels minimal. With some interesting rock formations, it could develop into something pretty.The species Titanoderma pustulatum grows on other seaweeds, such as Irish moss Chondrus crispus on the photo above. Pink plates Mesophyllum lichenoides are coralline algae that are very common on the mid- and lower shore here in Falmouth. They look a bit like a miniature version of Montipora corals. At the moment, some individuals are covered in knobbly reproductive structures housing spores. Pink plates grows epiphytically on Common coral weed Corallina officinalis, the species that makes up the bulk of the coralline algae in the rock pools (see second photo of this post, on the right). Slender-beaded coral weed Jania rubens is also quite common at the moment. Corallina and Jania can be seen growing side by side in the second-last photo. Jania here grows epiphytically on Hairy sand weed Cladostephus spongiosus (this species is normally fuzzy but in winter the branches are bare and slender). I hope to go diving soon and take more photos of the most ‘spectacular’ coralline algae: maerl.
I have not posted as much on the blog as I would have liked this year (in fact, I keep posting less and less: 24 times this year, compared with 33, 46 and 64 posts the previous years). My new year’s resolutions will be to dive more, to go rock pooling more and to blog more. For now, I will post some miscellaneous photos from this year that I did not bother to put on the blog at the time (as I did last year). Below a Beadlet anemone Actinia equina on the beach in St. Ives as well as a young cormorant looking for food taken with my new Canon G16:I caught a number of different fish this year, the first photo shows a small Montagu’s blenny Coryphoblennius galerita in an aquarium net which were fun to watch in a little aquarium. Next a Longspined scorpionfish Taurulus bubalis caught with my big net off the quay and a Sand smelt Atherina presbyter (see here for a movie). The latter species did not last long in my tank unfortunately. I mentioned in the last aquarium update that a Topknot I caught seemed to have died in the tank too, but I found out it is still there, it just likes to hide behind the rocks.I visited the quirky Victorian Horniman Museum and Aquarium on a trip to London which features lots of stuffed animals and diorama’s which I find quite fascinating. The aquarium part is small; there is some behind the scene coral (sexual) propagation research going on which sounds very interesting. There were two or three coldwater tanks too, the larger tanks were not much too look at (I know how hard it is…) but I really liked the Victorian fountain-style aquarium. A quick snap here; see this video for a nice overview. I would like to collect some Black brittlestars Ophiocomina nigra next year, they can be very abundant at slightly deeper sites.I also visited the National Marine Aquarium in Plymouth for a second time. It features the deepest aquarium in the UK, complete with plane wreck and some Sandtiger sharks. I was more interested in the coldwater stuff, of which there was quite a bit. I especially liked the Lesser weever Echiichthys vipera which can be caught on sandy shores; their venomous sting would make handling a bit tricky though. There were some cute pipefish (these need live food and I do not want to commit to that) and a round display with loads of Snakelocks anemones (see the first picture posted on this blog). I have placed a couple of these in my aquarium again, perhaps I need to get a few more, as they are so pretty and easy to keep. I did not manage to get a good shot of the very impressive Wreck fish or Stone bass Polyprion americanus in the large coldwater display unfortunately. Next up a washed up sponge in Falmouth (species unknown) and a live one (Aplysilla sulfurea) under a rock, both taken in Falmouth with my iPhone. I have only been diving a couple of times this year and did not post about the rocky shore dives (here some photos of the maerl and eelgrass beds). I have seen a variety of interesting animals, including cuttlefish, a conger eel and lobsters but next year I hope to go out a bit further and dive a bit deeper to finally see jewel anemones and dead man’s fingers. I am not sure I want to commit to a flash and strobes though, instead I’d like to practice my rock pool (seaweed) photography.
I recently sat down at a very small rock pool high up on the shore on Castle Beach in Falmouth. Just sitting down and concentrating on one square meter for a bit is essential to discover small organisms (see also this old post). If you want to end up with some half-decent photo’s, it is essential to go back several times to the same spot too, so that is what I did. The pools in this spot are very shallow, too shallow to stick your head in and look through the view finder, and often too shallow to even get the camera submerged. Biological diversity this high up the shore is relatively low. Common in these pools are periwinkles, flat top shells and thick top shells, beadlet anemones, prawns and shore crabs, as well as Serrated wrack and a diversity of small red seaweed species.Along with Shanny’s, juvenile Montagu’s blennies Coryphoblennius galerita are very common here (larger individuals must move to deeper pools lower on the shore). I only saw fish between 1.5 and 2.5 cm, tricky to photograph, I need a macro lens! Looking more closely, this tiny pool harboured snakelocks anemones alongside the beadlets, as well as a tiny Gem anemone Aulactinia verrucosa.
I had a few rock pooling sessions recently to play with my new camera (and wide angle lens). The main one was a workshop with North coast-based Thomas Daguerre of Hydro Motion Media (facebook). I am just a beginning photographer and so learning the ropes from an experienced hand proved immensely valuable. The session started with going through some of the basics (white balance, focusing etc), after which we headed out to the rock pools to put some of the theory in practice. We headed down to Thomas’ stomping ground of south Fistral Beach (I visited once before). Although the timing was not the best tide-wise, it was a beautiful day. This was the first time I actually submerged myself in rock pools to take photo’s; of course, being able to look through your view finder is the only way to do it right. It is hard to not stir up sediment though and in some pools salinity gradients made for bad viz. I used Thomas’ G16 setup with video lights and a strobe on a tray (something like this; should have taken a picture of it) which was very difficult! As a result of all the experimentation I ended up with few blog-worthy photos, but this session made clear that trying to capture ‘rock pool scapes’ is what I would like to focus on, the variety of seaweed species, colours and shapes I find especially cool. I really need to try to go back to these pools and try to get better photo’s. I also will arrange a second session with Thomas later in the season to start learning how to post-process RAW files. What was very interesting to see is that the pools here teem with Giant gobies Gobius cobitis, a protected species in the UK. We saw two lying side by side in a crevice but they are shy and it was hard to get a good shot. Thomas has recently made an excellent series of short films highlighting various charismatic local marine species, and one of them features the Giant goby (see the Hydro Motion Media site for the other eleven films):
Friday a week ago I helped out colleagues to collect speciments for the rock pool exhibits of the annual Science in the Square event here in Falmouth. Leaving the house at 05:45 was ‘not ideal’ but seeing Gylly beach lie serenely in the early morning sun this was immediately forgotten. Low tide was not very low at all, and so it was a bit of a struggle to find animals. In the end a variety of crabs, fish and other critters could be collected. I managed to catch a Compass jellyfish and haul it from one end of the beach to the other in a full bucket of water thinking this would be a unique addition, only to find out that five others were already caught. The one really cool find was a little shark stuck in a rock pool. It was a Nursehound Scyliorhinus stellaris, also known as the Large-spotted dogfish, Greater spotted dogfish or Bull huss (distinguishable by the frilly nasal flaps from the smaller species the Small-spotted catshark Scyliorhinus canicula). (Its eggs can be frequently found here, see for instance these older posts.) It was quite dark and hissed a little bit. Way too big to bring back and so it was happily set free.