I have been diving three times last week but due to internet problems have not posted about them. I hope to do that in the coming days, but first wanted to blog about this mornings snorkel session in the shallow rock pools at Castle Beach in Falmouth, as I experienced the best viz (visibility) ever here. Apart from the stunning viz, I was very lucky with the fish: I spotted a Tompot blenny, Two-spot Gobies, Fifteen-spined stickleback, Rock goby, Pollack, Ballan-, Corkwing- and Goldsinny Wrasse and Sand eels (above and below). However, I mainly wanted to check what the seaweeds looked like, and things have definitely changed over the last month (see here).The Wireweed Sargassum muticum and Spaghetti (or Thong) weed Himanthalia elongata are thriving and at low tide hang over the surface creating ‘tunnels’. The Harpoonweed below is in decline, turning from pink to yellow-white (and the Bonnemaisonia is almost completely gone). The fronds of the False eyelash weed have turned from juicy and red-brown to wiry and yellow and the corraline algae are turning white. The Sea lettuce Ulva has died back and is covered in speckles (sporangia?). Some epiphytes are thriving, the very fuzzy brown Pylaiella littoralis covers kelp, a Ceramium species grows as pompoms on the Spaghettiweed. One pink and fuzzy species that is growing well I should have taken a closer look at because I am not sure what it is now (I will enquire at the Seaweeds of the NE Atlantic facebook group). The next species I think I can identify: Chipolataweed Scytosiphon lomentaria. The Bushy rainbow wrack Cystoseira tamariscifolia looks fuzzier and greyer than before. Although with less species and more subdued colours, the pools still look beautiful, and I hope the good visibility will last a bit longer!
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. Probably not very rare, but small (<15 mm) and well-hidden and so not that often seen:
Just a photo to show the beauty of Cornwall in spring! The snorkeling at the beach in Porthcurno (next to the marvellous Minack Theatre) was very pleasant this weekend, although there was not a lot to see: mainly white sand and wave-battered rocks covered in barnacles. I have simplified the “An Bollenessor” domain name and updated the Links page btw.
Above an illustration of the decline of seaweeds: Juicy whorl weed Chylocladia verticillata all white and fuzzy (see for a more healthy looking plant this post from 2.5 months ago) on a bed of the common and pretty Discoid fork weed Polyides rotundus. There seem to be around 25 or so (larger) species that are common in these pools. Many of them can be seen in the two photos below (including a stray Bladder wrack, a species that dominates the shore just a meter higher): Below, a whole bunch of individual species. First, Sea beech Delesseria sanguinea, which must have washed up from under the kelp beds (too bad I did not get the entire plant in frame…). Second, a photo of Ulva with Chipolata weed Scytosiphon lomentaria. Third, the brown Divided net weed Dictyota dichotoma. Fourth, Slender wart weed Gracilaria gracilis. Fifth, False eyelash weed Calliblepharis jubata; this plant has grown quite large and has turned from dark red/brown to a much lighter brown. Sixth, the Falkenbergia stage of Harpoon weed Asparagopsis armata (see the third photo) on the right. Seventh, Red grape weed Gastroclonium ovatum. Finally, two photos of my favourite species the blue Bushy rainbow wrack Cystoseira tamariscifolia.
Less than 12 hours back in Cornwall and I managed to slide into the rock pools at Castle Beach in Falmouth this Saturday to see what the seaweeds looked like. There was a noticeable difference with only a week ago. The speed at which seaweeds grow, and decline, still amazes me. I managed to take my best photo yet, of Red rags Dilsea carnosa (surrounded by a whole bunch of other species), above. I made so many photos that I will split them over two posts, with some general ‘seaweeds scapes’ here and with individual species in the next post. The Sea lettuce Ulva has been taking over parts of the pools, turning it a bright green. The reds of the Juicy whorl weed and Berry wart cress and pink of Harpoon weed are less bright, and the Red grape weed and Fern weeds are turning ‘fuzzy’. Still, the seaweeds are much bigger and cover most of the seabed and it looks very exuberant. The Wire weed and the Thong weed (or ‘spaghetti weed’) Himanthalia elongata have been rapidly growing; the latter consisted of ‘buttons’ in January and are now a meter long, so must grow around a centimetre a day. The fronds are covered in flakes (which must be reproductive structures) that come off when you swim through them, clouding the water and so ruining the shot if you do not take it straight away. The sun came out more in the last photos, hence the different light (I have edited most (not all) photos slightly using standard Windows Photos, mainly by decreasing the highlights). More photos very soon!
A whole bunch of photos from last Friday, starting out with the prettiest ones depicting a whole range of species, most strikingly the crimson Gracilaria and blue Cystoseira. I was so pleased with it I shared it on the Seaweeds of the NE Atlantic facebook page and Frances Bunker, one of the writers of the highly recommended Seasearch Guide to Seaweeds of Britain and Ireland, kindly uploaded a photo with all scientific names. This is a great idea and I should do the same for future posts (I have not done so yet as I am back home and did not bring the guide). As good as it is to be back in the Low Countries, I am missing out on being able to snorkel in some very good weather and likely better visibility than for the photos in this post. The rock pools have changed markedly since the last post a couple of weeks back, with hardly any patches left without seaweed growth. The colours have changed too, with much more of the green Ulva, and more brown (e.g. Calliblepharis) relative to reds. Some seaweeds seem to be in decline already (e.g. Gastroclonium) while some are more prominent (e.g. Palmaria). Below I have posted a range of photos, some are pretty good, others not so much, but they give a good impression of the diversity (most photos have at least ten species in them but I have not gone through the trouble of typing all the names): I have no clue what the brown, thin, frilly species is above. Below some individual species, first Dulse Palmaria palmata and Sea flax weed Stypocaulon scoparium. Not 100% sure about the next three: Dumontia, Lomentaria and either Laethisia or Colpomenia (I should know this…). Finally, some photos taken under the cover of Thongweed Himanthalia. More photos next week I hope!
More seaweed photos, taken a couple of days after the ones in the previous post, when it was overcast and the water was less clear. The photos are not as good, but there are still a lot of interesting species to see. Below some photos showing the diversity of species next and on top of each other. In the last two months, most species have been growing quite a lot. There are quite large patches of Slender-beaded coral weed Jania rubens. Bushy rainbow wrack Cystoseira tamariscifolia plants are completely overgrown with all kinds of epiphytes, seaweeds, sponges and colonial tunicates, and often have a Nursehound egg case attached. Next, photos of individual species. First some flat reds: Leafy rose weed Rhodophyllis divaricata, Beautiful fan weed Callophyllis laciniata, Branched hidden ribs Cryptopleura ramosa (probably), the invasive species Devil’s tongue weed Grateloupia turuturu and Under tongue weed Hypoglossum hypoglossoides. After that, two species that look a bit similar: left the reddish Discoid fork weed Polyides rotundus and right Clawed fork weed Furcellaria lumbricalis. The former is one of the most common species (also on the photo above it) but difficult to photograph as it usually sits on the white sand. After that, Juicy whorl weed Chylocladia verticillata. Last, two quite unassuming species: Black scour weed Ahnfeltia plicata and Sea flax weed Stypocaulon scoparium. Identifications made possible using the must-have Seasearch Guide to Seaweeds of Britain and Ireland, David Fenwick’s excellent aphotomarine website (and personal communication) and the good people of the Seaweeds of the NE Atlantic facebook group (any mistakes are my own).
Time for some more seaweed photos. These were all taken during a snorkel when the sun was shining and the water was very clear, and as a result they are some of the best I’ve yet managed to take. Often it is overcast this time of year which means that the colours are not vivid and the water can be turbid too, so I was very lucky. Above a ‘bouquet’ consisting of many species, including Chondrus, Dictyota, Corallina, Ulva, Cystoseira, Mesophyllum, Asparagopsis, Calliblepharis, Himanthalia and (probably) Rhodophyllis. I might look slightly ridiculous snorkelling in 50 centimeters of water but as long as I can look at this I don’t care! I really like the clarity of the next photo of Plocamium surrounded by Asparagopsis and Sargassum. The photo after shows the red Berry wart cress Sphaerococcus coronopifolius with some bright green Ulva, kelp and the brown red species False eyelash weed Calliblepharis jubata. More Berry wart cress in the photo after.In the first seaweed post of the year, I posted a photo of a tangle of species, mainly Hairy sand weed Cladostephus spongiosus, with Osmundea, Asparagopsis, Bonnemaisonia and Leathesia (here, third photo). Next, a photo of exactly the same tangle, which is now completely overgrown with the dark red Bonnemaisonia (an invasive species, just as the Sargassum and Asparagopsis also in the photo). I plan to take more photos over the months to track this succession. In the photo after that Bushy berry wrack Cystoseira baccata (still quite spindly after the winter) covered with a couple of red epiphytes and the brown Dictyota dichotoma. The last photo shows a beautiful red species covered in reproductive structures, I hope someone can tell me which species it is! Update: Spotted scarf weed Nitophyllum punctatum.
I have been snorkelling a few times in recent days and it has been generally fantastic. The pools are probably at their peak now when it comes to seaweeds, I hope it lasts a little while longer (in June it will most definitely be over, see this old post, actually, they are in decline in May already). It is the plan to get in the water again this week to take some more seaweed photos, but in the meantime some photos on one of the more common anemone species: the Snakelocks anemone Anemonia viridis. There are two colour morphs: the greys and the purple-tipped greens. In Falmouth, they seem equally common, no matter if it is high on the shore or subtidally. I recently learned that in Scotland there are almost only greys, perhaps in the Med there are mainly the other type and it has something to do with temperature tolerance, if you know please let me know in the comments! I really like thuis species, in fact, the very first blog post back in 2013 consisted of a photo of these anemones in my aquarium. I have two of these in my aquarium at the moment, they are very easy to keep. This might be because in addition to being voracious predators, they are also capable of living on sunlight, as they harbour photosynthesizing algae. In any case they grow rapidly (and very occasionally split into two).I took these photos in very shallow water. When scuba diving you can commonly observe the commensal Leach’s spider crab Inachus phalangum sitting under the anemones (see here in the aquarium and here in the wild). (In Dorset there is a beautiful little prawn that lives as a commensal, and in the Mediterranean there is a goby that is associated with this species.) Only very occasionally do Snakelocks attempt to retract their tentacles (see here); tentacles can be quite long and slender or more stout (see here), probably a response to the strength of the currents. I have tweaked some of the photos a tiny bit (but not the nicest one on top for instance). Below two photos taken on different days of the same three anemones with different light conditions and different camera settings (most importantly probably the white balance, which I use to tone down the reds caused by the seaweeds).
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!