Sunday was a beautiful spring day and we headed out to a new spot: Sandy Acres Beach on St. Ives Bay, North Cornwall. Beautiful dunes and a vast beach with very few people on it! With the kids running amok, I had only very little time to scour the high tide strand line. However, even with only 50 meters or so covered, it was the best bit of beach combing so far. Many cuttlefish bones, bits of Horn wracka and quite large mussels covered in seaweed holdfasts. Below a quick snap. At the bottom, I am not 100% sure, two Thornback ray Raja clavata- a Spotted ray Raja montagui and just above that a tiny Small-spotted catshark Scyliorhinus canicula mermaid’s purses (egg cases, see here for a useful key). Next to the mussel Mytilus edulis, some Hornwrack Flustra foliacea (a Bryozoan), two sponges which might be Mermaids glove and Chocolate finger sponge (thanks Steve Trewhella at the Beachcombing facebook group) and a spiky piece of Sea beard Nemertesia antennina, a hydroid. At the right of that a piece of a whelk Buccinum undatum egg cluster (better pic here). Not a bad haul, looking forward for a proper walk along this beach very soon!
Three weeks back I had to pick someone up from Newquay airport and decided that it would be a good idea to combine that with some rock pooling action on the North Coast. I was told that the Pentire end of Fistral Beach was a good spot for Dahlia anemones and so the decision was made. Unfortunately I did not find any anemones, but it was a beautiful day nonetheless. The relatively few North coast sites I have explored all seem a bit barren in comparison to the South coast: more exposed, with sand meeting scoured rocks, leaving only hardy seaweeds, mussels and beadlet anemones to cling on. I need to spend some more time to find the right spots that’s for sure. The top of the cliff contained some rock pools, but they were quite milky due to the recent weather. They were full of the beautiful Brown tuning fork weed Bifurcata bifurcata (as I was on an anemone hunt, I was hasty and most photos did not come out especially nice, so see this old post for a nice photo of this species). The rocks were very slippery due to the (edible) Laver seaweed Porphyra (front of the next picture).At the base of the cliffs were some gullies, the largest of which is locally known by the rather grandiose name ‘Cave of Dreams’. No major finds here, but it was nice to see the many colour varieties of the Dog whelk Nucella lapillus (egg clusters in the background). The second photo is an especially pretty specimen; I only later noticed the green worm (probably Eulalia viridis) and the reflection in the beadlet anemone of me holding my iPhone! Beadlets are super common here. It is interesting that this species has two main colour varieties (red and green), just like the Snakelocks anemone (green and purplish) and the Plumose anemone (white and orange). This might be a coincidence but I find it intriguing. Lastly, some Sea pink or Thrift Armeria maritima.
The weather has been generally awful so far this year and so I have not been out much. However it is March already so at least a small blog post is in order! There are loads of Worm pipefish Nerophis lumbriciformis around, some of the males carrying eggs (see also the blog header and the ‘about’ section). I found my smallest one yet. Next up a Sea urchin Psammechinus miliaris with what is probably the parasitic (or commensal?) polychaete worm Flabelligera affinis (thanks David Fenwick). After that, a slighlty out of focus shot of the hydroid Candelabrum cocksii. A few of these small individuals were sat under the first rock I turned over; I reckoned they were some type of spoon worm but they are something very different, thanks again David Fenwick, see for his much better photographs of this weird little thing here. Next the Wrinkled rock borer Hiatella arctica with siphon extended and the pretty acorn barnacle Balanus perforatus. Finally a picture of the Strawberry anemone Actinia fragacea, quite common and pretty, but I do not think I have ever posted a picture of it on the blog before. (All pics taken at Castle Beach in Falmouth btw.) I have three in my tank and it is high time for an aquarium update as well. I hope to go out tomorrow and the weekend as the tides are very low so watch this space!
When going out rock pooling, I always take my iPhone and Canon Powershot (for underwater use) and take at least a couple of photos. Because of a lack of time, or because a single good photo is not enough for a new post, not everything ends up on the blog. Now I have some free time, I picked a couple of unused photos made this year that seem blog-worthy. First up, In realized only what I had found on the beach at St. Ives when leafing through the The Essential Guide to Beachcombing and the Strandline: a Seabeard! This hydroid, Nemertesia antennina, grows as stiff colonies protruding from a matted base and occasionally washes up on shore. It looks a bit plant-like; at the time I did not have the opportunity to have a closer look and just snapped a quick photo. Next a Lesser sandeel Ammodytes tobianus found at Gylly beach. I always see them when snorkeling or diving (see here) but this was a good opportunity to see one up close (I get excited when I spot a dead fish on the beach (see also here) and I am not afraid to admit it!). Following are two colour varieties of the Spiny starfish Marthasterias glacialis, a Common brittlestar Ophiothrix fragilis and a shot of an Aequorea forskalea (or maybe A. vitrina) jellyfish. Next the gastropod mollusc Chinaman’s hat Calyptraea chinensis. I went back to Mylor marina for some pontooning recently but not much was growing; the only thing that stood out was the luxuriant sponge growth (I am not sure of the species, perhaps Halichondria).And of course some seaweed pictures. By iPhone: Under tongue weed Hypoglossum hypoglossoides in Flushing, Black scour weed Ahnfeltia plicata in St. Agnes and a photo showing a variety of wracks all colonizing the same patch (Flushing): Serrated wrack Fucus serratus, Spiraled wrack Fucus spiralis, Bladderwrack Fucus vesiculosis and Egg wrack Ascophylum nodosum. Next some Canon Powershot underwater pics (see also this post and this one): a random rock pool picture of mostly decaying seaweed, a closeup of my favourite the Bushy rainbow wrack Cystoseira tamariscifolia and a shot of Wireweed Sargassum muticum that has completely taken over a pool. Finally an SLR photo of a rock pool at Gylly beach with large Cystoseira baccata plants (middle, Wireweed on the left).
The winter season is the time for beachcombing and so I was very happy that Santa gave me The Essential Guide to Beachcombing and the Strandline; a fantastic guide to objects washed on British (and NW European) shores by Steve Trewhella and Julie Hatcher. One of the things that sets it apart from other guides is that it not only covers biological ‘objects’ (shells, fish, mermaid’s purses, sea beans etc) but also strandline debris of human origin (e.g. buoys and nurdles). After a walk at Praa Sands beach, it helped me to identify the Goose barnacle Lepas pectinata. A must-have book for anyone who likes to spend time on the beach! At Praa Sands I also found several Chama bivalves attached to a tangle of rope. David Fenwick has recently described three Chama species, all from (around) Florida (there are no native species), see here for much more detail. Unfortunately it is very difficult to tell what species it is from only the lower valve of the ‘Jewel Box’. It is interesting to see that even commonly encountered bits of rope and net can be from as far as the other side of the ocean. Hopefully there will be some westerly January storms to wash up more interesting species!
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!
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: