I had the pleasure to go on two dives with Mark Milburn of Atlantic Scuba on the ‘Stingray’ RHIB this weekend and last, leaving from Mylor Harbour (see photo above). The first dive was in the Helford Pool, a deep area in the otherwise shallow Helford river. Buddied up with Sue and Al, we descended to 18 meters to swim over a gravelly area covered with tunicates and sponges. This was a drift dive but we did not get all the way to the eastern end of the pool where some small maerl beds are located. Swimming crabs and Leach’s spider crabs were very common; there were not many fish though. One exception was a cute little John Dory Zeus faber. I was struggling to take any decent photographs, in part because I have not used my strobe much yet and because I should have two, not just one! Sue Barnes kindly let me use a photo she took of the John Dory for the blog; also added is a photo of a sponge, one of the few half-decent ones I managed to take:
The dive today took us to the cannon ball site, roughly a mile from Pendennis Castle, and an area where many of the cannon balls fired for practice ended up. With buddy Alex we descended to around 16 m using a shot line. Again a flat ‘rubbly’ area with few fish. The seafloor was covered with Common brittlestars Ophiotrix fragilis. The viz was quite good, and it was much lighter than the previous dive. I also had *a bit* more luck with the strobe. Leach’s spider crabs were common, and we also saw some Sea lemons, Doris pseudoargus, a large seaslug. 
Up next three common species: a little Rock goby Gobius paganellus, the colonial Antenna hydroid Nemertesia antennina and the colonial sea squirt Aplidium elegans (thanks David Fenwick). I keep my eyes open for seaweeds too of course, there were some small red species and what I suspect is Desmarest’s prickly weed Desmarestia aculeata. I found out back on the boat that I completely missed a small octopus that Alex pointed out, argh! I was very happy though that I managed to spot an Imperial anemone Capnea sanguinea, which is an uncommon species. The photo of this all-white individual was taken without a strobe; I really should have taken more time to get a decent shot. A good reason to go back though, and maybe we can spot some cannon balls then too. The water is 13-14 degrees and so it is still doable to dive with a wetsuit. 
Monthly Archives: November 2017
recent rockpool sightings
During my ‘seaweed sessions’ I of course keep my eyes open for animals too. Most prominent are the beautiful Snakelocks anemones Anemonia viridis (see also here). Other anemone species seem much more rare, such as the Dahlia anemone Urticina felina. Little schools of Mysis shrimp are very common (and very hard to photograph) but fish seem less common than a few months back. The common dragonet Callionymus lyra is (as the name suggests) not uncommon but hard to approach, the third photo was the best I could do and demonstrates how masterfully it is camouflaged (but see here what fullblooded males can look like!). Next a very pretty pink sea squirt species and a Broad-clawed porcelain crab Porcellana platycheles, completely flat so, very-well adapted to living under rocks. Finally, a tiny stalked jellyfish Calvadosia campanulata. Stalked jellies seemed to have disappeared over summer, but like the seaweeds are making a little comeback during autumn. There are not many around though, I have seen less than one per hour snorkelling (see this post for better stalked jellyfish photos; I need to work on the depth of field!).
Falmouth Seaweeds Mid-November
Above the spot where I have been snorkeling all year at Tunnel Beach, between Castle- and Gylly Beach, in Falmouth (Pendennis Castle can be seen in the background). The best time to snorkel is before low tide, as when the tide comes in the viz gets worse. I try to aim for 50-100 cm above the low tide mark which is really shallow. This area is not a real rock pool but rather a gravelly zone between the rock pools proper and the kelp forest which begins past the last row of rocks on the photo. Last week I went snorkelling three times but only last Thursday had decent viz. The photos below show the abundance of pink Harpoon weed Asparagopsis armata, green Sea lettuce Ulva lactuca and new growth of Thong weed Himanthalia elongata and older plants covered in red fuzzy epiphytes. The old wireweed Sargassum muticum plants have died off and the remnants are covered in many epiphytes such as Juicy whorl weed Chylocladia verticilata, Cock’s comb Plocamium cartilagineum and the pretty Iridescent fern weed Osmundea truncata. However, there is new growth everywhere as well so, like Himanthalia, this species seems to have a half-yearly lifecycle. 
Below some Irish moss Chondrus crispus next to Wireweed. After that, lots of little fuzzy Falkenbergia growing on top of Discoid forkweed Polyides rotundus. This combination grows in a large patch and looks interesting but I struggled to get decent photos, as the dark seaweeds on very white gravel mess up the white balance big time. Next one or two different species of fine flat reds, the last probably Nitophyllum punctatum. The Bushy rainbow wrack Cystoseira tamariscifolia is dying off (here overgrown with Asparagopsis and Dictyota) but the related Bushy berry wrack C. baccata is doing well. Among its epiphytes Spiny straggle weed Gelidium spinosum (ID thanks to Seaweeds of the Atlantic facebook page members) which is also freeliving, and finally the green Codium fragile. 
One time, when the tide came in, the water was super oxygenated, and all surfaces were covered with small silver bubbles which was beautiful (and annoying as the camera lens was also covered). The following photos show a very different looking Codium fragile, C. tamariscifolia overgrown with Sea beach Delesseria sanguinea and more Thong weed. 
