Falmouth Seaweeds: End of April

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:

Black-faced blenny Tripterygion delaisi

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:IMG_1151IMG_1143IMG_1133IMG_1139However, 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:IMG_1160IMG_1164

aquarium update 11

The aquarium was in desperate need of a make-over (again…). I hauled a ton of rocks over from the beach and stacked them up. (I thought at first that I would need something to stick the rocks together (epoxy, superglue or waterfall foam) but that wasn’t really necessary). I also removed most of the gravel and replaced it with sand. So quite a big change but it really looks a lot better. However, my nice burrowing Red-speckled anemones suffered a bit when putting the sand in, and even after siphoning it off again I could not really find them anymore….hopefully they turn up again!IMG_7849 The aquarium is still a bit bare and I have to go out and collect things that will live on the rocks, such as anemones and seaweeds. However, there is some progress on the seaweed front. There is a bit of Irish moss Chondrus crispus growing spontaneosly from the back wall. There are also some patches of pink corraline algae; which must be Coral weed Corralina officinalis judging from one outgrowing patch. Having this species grow would be great, but they do not seem like fast growers. Chrysymenia wrighti is still thriving on the circulation pump; I remove a bit every now and then, so it acts as an ‘algae scrubber’, removing nutrients from the water. I have placed a couple of other seaweeds in the aquarium, a bit risky as they can die off and start trouble, but I can’t help it. The red Soliera chordalis below has done well before but unfortunately has started to die off a little already (first pic). I have a big piece of a flat red species that has started to grow from nowhere as well (second pic).IMG_7908IMG_7652One day, the aquarium was full of strings of Painted topshell eggs. I noticed when feeding a day later that the water was not very cold: I had forgotten to switch the pump/chiller back on two days previously! So the trick to breed this species is to increase the temperature, although I am not expecting much to happen with the eggs. Either the Thick-lipped or Netted dogwhelks are also occasionally sticking their egg masses to the glass. I placed a chunk of orange Estuarine sponge in the aquarium; this was devoured by Painted topshells and Cushion stars, so it is a good bit of live food to add. I had planted a little washed-up eelgrass plant to see if it would survive and indeed it has grown more roots. (If you want to try this yourself, please always use washed up plants and don’t dig out any, as eelgrass beds are vulnerable habitats.) It would be great to have a second tank dedicated to eelgrass….The little scallop is still happy (see close-up). I have added another filter feeder: a Leathery sea squirt Styela clavata. Butt-ugly, but that is actually fun too. I am trying it out as they are an invasive species and so probably pretty hardy. A Sting winkle seems to like it (but not eat it). I have never seen my two Sting winkles eat anything actually. They move about very slowly, but they have grown.IMG_7651IMG_7914Now the snakelocks anemones are gone, I have added some more fish. I have caught some juvenile Pollack Pollachius pollachius with my net. At first I caught ones that were less than an inch, but they did not survive. Of the six two-inch or so ones I caught, three dissappeared after one day, but the remaining three are going strong. Very nice looking fish! I also caught a little Tompot blenny Parablennius gattorugine (by hand at low tide). It is quite shy, but is increasingly showing itself. A beautiful little fish! I have one remaining Two-spotted goby. The Common goby is doing very well and eats from my hand. I think I’ll go for another little tompot, more Pollack and Two-spotted gobies. Ideally I would catch some Leopard-spotted gobies with a trap when diving, let’s see….The other fish I would like to have again is the Goldsinny wrasse: very pretty and not as nervous as Corkwing wrasse. IMG_7887

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first dive in Cornwall

A couple of weeks ago I went for a bit of a spur of the moment after-work dive with colleague Andrew (like me a quite unexperienced diver) and his friend Charlotte Sams. Charlie is an experienced diver and natural history photographer, who has her own blog: Charlottesamsphotography, which you should check out. We dove in Falmouth off Pendennis point. The water was not very clear (maybe 5-6 meters visibility) but the temperature was quite nice. We saw (amongst others) Sand eels (do not know which of the two species), Pollack Pollachius pollachius, Dragonets Callionymus lyra, Two-spotted gobies Gobiusculus flavescens, a Tompot blenny Parablennius pararugine, very large Ballan wrasse Labrus bergylta and a beautiful little John dory Zeus faber:

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We also saw some very large Common starfish Asteria rubens and also a nice Spiny starfish Marthasteria glacialis. We dove only to about 5-7 meters, which meant we could stay in quite long, over an hour. At seven meters, the bottom was a sandy expanse, interspersed with mounts of Laminaria Kelp covered in hydroids. In-between the kelp were other seaweeds, such as Red rags Dilsea carnosa but I was more focused on the animals during the dive. In shallower water were enormous bundles of Wireweed Sargassum muticum (also known as japweed but that is not very pc…) and the very long slimy Mermaid’s tresses or Bootlace weed Chorda filum. Snakelocks anemones were very common, and we managed to also see Leach’s spider crab Inachus phalangium, which lives associated with these anemones. All in all a fantastic experience, and I hope to find the time to go diving very soon again!