Last weekend I went down to Gylly Beach in Falmouth for a bit of rock pooling. However, the tide was not very low (especially with the inshore wind) and the weather was crap. Moreover, I could not find anything that I had not seen many times before; although rock pool life is very biodiverse, there have started to be dimishing returns when looking for non-microscopic organisms. Clambering over yet another rock, I decided to stop and play around with my Canon Powershot instead. I focused on a tiny pool (around two by four feet) completely covered in corraline algae. It does not look like much but taking the time for a carefully look was really rewarding. It is tricky to take photographs without being able to see the viewfinder though. My strategy has been to just take loads of pictures and hope some of them work out. The miniature underwater landscape was really beautiful. Pink plates Mesophyllum lichenoides made up the largest proportion of corraline algae (some bearing ‘reproductive conceptacles’). Another species is Corallina officinalis or Common coral weed (third photo). I had some Corallina growing in my aquarium at some point, but it grew very slowly and has now disappeared. Being able to create the right conditions for coralline algae to thrive in a coldwater aquarium would be fantastic, but I have not seen any evidence of anyone being able to cover their aquarium in them yet. (I have tried ‘planting’ Corallina and although it looked very nice at first (fifth pic), these seaweeds quickly died off, turning orange and then white (second pic).)Some other seaweed species were present as well; Irish moss and Harpoonweed (not pictured), False eyelash weed Calliblepharis jubata occurred in multiple patches, Rhodophyllis divaricata?, an Osmundea species and Red grape weed Gastroclonium ovatum. There were also a few brown seaweeds, the characteristic Thong (or Spaghetti) weed Himanthalia elongata buttons and the invasive (and pervasive) Wireweed Sargassum muticum. I did not spot too many animals, although I am sure there is an enormous hidden diversity present among the seaweeds. I noticed a red-white Dahlia anemone Urticina felina as well as some patches of a colonial brown tunicate. I’d like to go back soon and take some more pictures, with my Canon powershot or with my GoPro. I have an SLR as well that I have not been using lately as my iPhone is such a good camera and hassle-free. SLR underwater housings are really expensive, but I recently discovered that there are quite cheap waterproof SLR bags available which might be an option to try to take higher quality photos (in rock pools, I would not go diving or snorkeling with them). It would be very cool to try to make panorama pictures of rock pools, especially when taking one each month in the same spot to capture seasonality. More seaweed photos, Canon powershot or otherwise, to follow soon!
Summer is really over and the water temperatures are down from around 17°C to 13°C. We have not made it to any of the wrecks or rocks off The Lizard and the last set of dives was just of the good old Silver Steps in Falmouth. We had set ourselves some goals though: Chris needed Snakelocks anemones for his student projects and I wanted to catch myself some Leopard-spotted gobies for the aquarium. The Snakelocks were collected quite easily as they are so abundant. For the fish, I had bought a cheap foldable trap. The idea was to set it up in a little overhang housing the gobies, weighing it down with some rocks and come back the next day to take it back out. For bait, I had brought a chickenbone leftover from someones lunch at work. Below, a crappy pick of the trap wedged between rocks and below that a snap of some of the catch the next day (I had a two-piece websuit and in combination with an almost empty tank I was getting too buoyant to take decent photos): Three nosy Tompot blennies and also a small Conger eel; no Leopard-spotted gobies. So at least I know that in principle next year I can try trapping fish, but it might be hard for the gobies as they are very reclusive and do not barge into nets as Tompots do. The first dive, the visibility was OK(ish) and we saw a Cuttlefish Sepia officinalis. Although I have seen them before, you never get tired of them!
No other special finds. The place was absolutely swarming with Spiny starfish and most Snakelocks seemed to have multiple Leach’s spider crabs underneath them. I saw another Blackfaced blenny. Next year it is high time to dive further and deeper and also to finally get some gobies into the aquarium!
The weather was not great last weekend and we were too late at the diveshop on Saturday to be back in time to get the tanks refilled for a dive on Sunday but the one dive was (as always) worth the effort! We took dive buddy Chris’s boat from Loe Beach in Feock over to the other side of the Fal Estuary (between St. Just and St. Mawes) to explore the Maerl beds. See an earlier post on a snorkel trip to see this bed of ‘Cornish coral’ for some more background information. After the usual faffing about with equipment on board we plunged in the water. I took a single photo of the boat which turned out quite dramatic:Although we were diving 1-2 hours before high water (the best time, as clear seawater is pushed in the estuary), the visibility was quite bad. After going just a couple of meters down, fields of maerl loomed into view (the dive was really shallow, 5.9 meters max I think!). There were quite a lot of Thornback ray Raya clavata egg cases (foreground first picture) but we did not see the rays themselves. There are two main Maerl genera around here, Phymatolithon and Lithothamnion but their growth forms are varied and there are other encrusting Pink paint weeds that could look similar. We saw a number of golf balls that were completely covered in coralline algae, quite cool.We saw a couple of *very well* camouflaged crabs sitting about. They were completely covered by sponges, coralline algae and seaweeds. There are a number of crab species shaped like this but most of them seem too small. Best guess is th
e Toad crab Hyas coarctatus the Europan spidercrab Maja squinado in a particular extravagant mood. There are lots of little things hiding in the Maerl; gobies (rock gobies I think), squat lobsters, swimming crabs, hooded prawns and things that hide faster than I can identify them. I noticed a dainty little prawn sitting about which is probably Thoralus cranchii, although it could also be Eualus occultus (second picture is cropped). Swimming crabs were common and probably mostly were the Harbour crab Liocarcinus depurator. The first picture was the only one with flash and shows the Maerl colours a bit better. The second photo shows a Velvet swimming crab Necora puber under a snakelocks anemone sitting on top of a bottle. This species can be very commonly seen rockpooling. Lastly an empty shell of the largest European sting winkle Ocenebra erinaceus I have seen so far and probably the largest sponge I have seen so far too (with a human head for scale).
In the series ‘pontooning‘, I returned to Mylor a week ago Friday to have a quick look around in the marina. The water was choppy, but visibility on the sheltered side of the pontoons was OK. I noticed a brown slug-like thing flapping about next to a boat. My first thought was a sea hare (I have seen plenty but have not yet seen them swimming). Upon closer inspection, I saw that it was something else, it had a shell like Haminoea or Akera, species I had never seen, especially not swimming. It turns out that it was Akera bullata, an Ophistobranch mollusc that is rarely seen in Cornwall and generally is observed crawling on the mud, not swimming. Why they swim is not well understood, but they usually swarm in numbers and so there must be some general response to the environment or mating behaviour going on. I saw four other individuals nearby so that fits. I made a couple of movies but as I could not look through the viewfinder the footage is not great (I went back Saturday and Sunday to try and find them back but was not able to). The shell can be clearly seen hanging down (Akera is related to the Sea hare but has retained its external shell). When lifted out of the water, the animal folds its mantle around its shell.
There were some other interesting things to see. The dominant organism on the pontoons is the tunicate Cione intestinalis (I see there are some other tunicate species hiding in these pictures; I will have to take a closer look next time). Amongst it grows the purple invasive Bryozoan Bugula neritina. Next, a colonial tunicate thta could be Botrylloides violaceus, Trididemnum cereum or Didemnun maculosum (or something else again). After that, the beautiful Lightbulb sea squirt Clavelina lepadiformis.Plumose anemones Metridium senile are always common here. I for the first time noticed another species Diadumene cincta, very pretty!
A quick post on a dive a couple of weeks ago, my first boat dive in Cornwall. Four divers left from Loe Beach in Feock on the Fal Estuary to find the wreck of the Rock Island Bridge at the mouth of the Helford River. On our way we saw a Harbour porpoise which was a first for me, great! The mouth of the Helford is only slightly deeper (nine meters) than it is off Grebe Beach where we usually dive. There is no eelgrass here, just some Divided net weed Dictyota dichotoma and very large Sugar kelp Saccharina latissima lying flat on the bottom. The seabed is an expanse of gravel covered with quite a lot of bivalves: Great scallop Pecten maximus, Rayed artemis Dosinia exoleta, Norway cockle Laevicardium crassum, Dog cockle Glycymeris glycymeris, Common ottershell Lutraria lutraria, Warty venus Venus verrucosa, Pullet carpet shell Tapes corrugata and Hardshell clam Mercenaria mercenaria amongst them. Next time I will collect shells so I can take a good picture of all of them back on land. The place was swarming with starfish feeding on these bivalves, I’d say 90% Common starfish and 10% Spiny starfish. Below a Common starfish Asterias rubens feeding on a clam, a small brittlestar Amphipholis squamata and a Warty venus and Pullet carpet shell.Although the seabed was relatively featureless and we did not manage to find the wreckage, it was fun to watch the Thornback rays Raya clavata (including a large individual with distinctive black headmarkings) and the many Small-spotted catsharks (or dogfish) Scyliorhinus canicula which are very easy to approach. We also saw a Red gurnard Aspitrigla cuculus (see also this old post). However, it is high time we are going to explore some other, deeper dive sites. With the weather deteriorating, I hope we can find some more good days to dive this year though!
During this spring and summer I have taken my Canon Powershot 130D to the shore in addition to my iPhone. I have been trying to take underwater pictures of seaweeds with it, which is a bit of a challenge as (when you are not snorkelling) you usually have to take the photos ‘blind’. Some of ’em however turned out quite nice, here is a selection. I still find it hard to identify species. Here are some I do know. First, Hairy sand weed Cladostephus spongiosus. Second, a pool with many reds, in the foreground Discoid forkweed Polyides rotundus. Third, the invasive species Grateloupia turuturu. The big plants bleached and died off in summer but the young ones are growing already. Fourth, (probably) Sea flax weed Stypocaulon scoparium. I will post some more pics soon.
Went on a good dive at Silver Steps in Falmouth yesterday.The visibility wasn’t that great, but for the most part we were rummaging under overhangs in gulleys just off the coast. Sweeping aside the kelp reveals many fine red seaweeds, sponges, bryozoans and small Devonshire cupcorals. We saw the ubiquitous Tompot blenny Parablennius gattorugine as well as a Bib (or Pout) Trisopterus luscus. Overhead there were many Sandeels as well as some relatively large Pollock Pollachius pollachius hunting them:However, there was a much more remarkable fish we spotted, namely the Black-faced blenny Tripterygion delaisi. We first saw a male, bright yellow with a black head and beautifully skyblue-lined fins. Only after a while we noticed the inconspicuously coloured female. The male is coured this way only in the breeding season. (We later saw another larger male, no female, although that was probably closeby.) My fish guides tell me that this Mediterranean species was first spotted in the UK in the 70s and that it is currently present in only two or three locations on the South West coast. Some browsing on the web has told me that in recent years they have been recorded in more locations but they still must be relatively rare (and I therefore won’t be attempting to catch them). Global warming will likely extend the range of this species more firmly northwards; one of the very few positive effects of our addicition to carbon… Lastly, I now managed to get a shot of the Candy striped flatworm Prostheceraeus vittatus:
After the success of last weeks snorkelling session, it was high time for a proper dive! Again the Helford did not disappoint. In the end, my Sea hare stroking proved a bit inconclusive; also, my estimate of 30 cm long individuals might have been a slight exaggeration, 20-25 cm is more likely for the larger individuals. My guess is that it might be Aplysia punctata after all, and perhaps this is just a very good year where they reach their maximum size. (Note that three individuals can be seen in the first photo and two in the second photo.)This was not the only Ophistobranch activity going on, as I spotted a small nudibranch sitting on the eelgrass. Probably Eubranchus farrani, although it could well be something that is deserving of a new name, there is a lot of (cryptic) species discovery and taxonomic revision ongoing in nudibranch biology. I also spotted several largish egg masses on the eelgrass that are likely to be from a larger, shelled Ophistobranch; I am waiting for suggestions from various facebook groups *could be Haminoea navicula*. I found a beautiful Wooden canoe bubble shell Scaphander lignarius, these animals live buried in the sand so are not commonly spotted. Next time I’ll bring a small garden rake to see what is hidden below the sand (I am serious!), lots of echinoderms and molluscs to be sure. Pelican’s foot shells Aporrhais pespelecani live in sand, but I found some on top of the sand too, so full of muck that they were barely recognizable. I have found empty shells of this species washed up on holidays before, but it was cool to see them alive for the first time.No cuttlefish in sight this time, but loads of eggs so it is likely that this is an important breeding ground for this species. We encountered one Thornback ray Raya clavata, which, like cuttlefish, are not very shy. These species occur in very shallow waters (we probably did not dive deeper than 7 meter) and the influence of the surrounding woodland is clear, with decaying oak leaves and pine cones amidst the seaweeds and eelgrass.One very well-camouflaged species is the Scorpion spider crab Inachus dorsettensis. Medium-sized Common hermit crabs Pagurus bernhardus are common, running around in Turban top shells covered with hydroids. Although present in the last post, another pic of a
Mud sagartia Sagartia troglodytes anemone Red speckled anemone Anthopleuris ballii. Filterfeeding worms are abundant too, including the beautiful Fan worm Myxicola infundibulum as well as a large tube-dwelling worm and worms in white calcareous tubes with bright red bristles that I could not identify. As we got out of the water, we saw a Comb jelly Beroe cucumis, very pretty but hard to photograph. The next dive will have to wait two weeks or so, but then I hope to finally play around with my GoPro.
A nice long snorkel in the Helford ‘River’ from Grebe Beach today. The weather was great and so was the water temperature. The timing was good too, close to low tide, so the Eelgrass beds started at only about one meter depth. There were a lot of cool new finds. What was most striking was the extremely large number of Sea hares Aplysia. There was almost one every other square meter, ranging from 5 to 30 cm, and from grey to light brown to very dark brown. The common species Aplysia punctata ususally reaches 7 cm (occasionally up to 20 cm), so the size and often reticulated veining probably make it A. depilans. From David Fenwicks aphotomarine site: “An easy way to distinguish this species from (a third species) Aplysia fasciata is to run a finger from front to back on the dorsal surface. If the finger cannot travel all along the animal from head to tail then it is A. depilans.” This I did not know so I need to go back and stroke some slugs! I see that these large (up to 40 cm!) beasts have been found here before. A not particularly large individual on my hand, as well as an orgy, with some orangy strings of eggs visible:
Another interesting mollusc to see was the predatory Necklace shell Euspira catena (not a very good shot, would be nice to go back diving soon so there is more time to take pictures). Other nice finds include a Mud sagartia Sagartia troglodytes anemone (I think!) and a small Sagartiogeton undatus anemone. Finally, at only 2 meters depth, we found a good-sized cuttlefish Sepia officinalis, lying still trusting its camouflage. In places, black Sepia eggs could be seen attached to the Eelgrass. Some of us also spotted a juvenile thornback ray in the shallows:
Another small post. I went out to the marina in Mylor Harbour to check what the pontoons looked like. It turned out OK-ish but no Peacock worms and only a few little Plumose anemones. However, the trip was worth it solely by the find of a hydroid colony, which my Seasearch guide told me was the Oaten pipes hydroid Tubularia indivisa. Very pretty! By taking 30 photos with my Canon Powershot, I ensured I had a couple in focus. Also in the frame some little Sycon ciliatum sponges (these are a lot more rounded than some of the others I have seen, see here).