Snorkeling in summer is nice because it is sunny and warm, but the seaweeds are turning a bit manky. That has its charms too though!
Above: Furbelows Saccorhiza polyschides. Middle: Thong Weed Himanthalia elongata covered in epiphytes (Ceramium?). Bottom: seaweed assemblage with Red Rags Dilsea carnosa, Irish Moss Chondrus crispus, Forkweed Dictyota dichotoma, Harpoon Weed Asparagopsis armata, Sea Lettuce Ulva lactuca and other species.
A whole bunch of photos of yesterdays snorkel at Castle Beach. The viz has cleared up, although nothing like the fabled June 2017 viz, will it ever be as good again?! (see here). There are lots of yellows and browns, some greens, a substantial dash of blue of the rainbow wrack but hardly any reds and purples at this time of year. The glow of the sun exarcerbates the yellowish vibe, but somehow I suspect the colour temperature of the Olympus somehow is a bit off compared to my old Canon. I am not entirely sure about this though, and in theory this is all correctable postprocessing, I just don’t know how! The photo below shows some of the common species, from the bottom right to top left: Cladostephus spongiosus, Dictyota dichotoma, Asparagopsis armata, Cystoseria baccata with Sargassum muticum in the background. Ij the second photo it is obvious that the Wireweed and Rainbow wrack are quite dominant, same for the Hairy sandweed Cladostephus spongiosus. The Thong (or Spaghetti) weed is covered in fuzzy epiphytes. I will keep practicing for when the reds and purples come back in autumn!
To my regret I did not manage to take a look at the seaweeds at Castle Beach in September (it was my aim to go in at least once every month). Last Friday however, the sun was shining, the wind was gone and the tide was low (and I was able to escape work) so I at least could make October. Not only was the viz excellent, to my surprise, the seaweeds looked very healthy. It seems that there is a second, autumn seaweed bloom that I was not aware of. Some of the bleached corraline algae have regained their pink colour, the Harpoon weed Asparagopsis armata increased in abundance and I saw species such as Red grape weed Gastroclonium ovatum growing again. The Bushy rainbow wrack has partly died back, forming dense, dark-brown mats (fourth photo) but also show fresh growth. This species is covered in many epiphytes such as Brown fan weed Dictyota dichotoma, and remnants of Bull huss mermaid’s purses still cling on. Interestingly, Wireweed Sargassum muticum has almost completely disappeared. It is tricky photographing rock pool seaweeds. One main issue is to not disturb any sediment, especially as I keep it *very* shallow, sometimes lying on my stomach (I definitely do not need fins). The other main issue with using a (wide angle) wetlens is that there are three glass surfaces in front of the lens collecting bubbles and so need regular wiping. Light is also a challenge: photographing against the sun causes glare, but having the sun in your back results in casting shadows over your subject. I continuously fiddle with the exposure correction, but it remains difficult with the white sand and pebbles around the seaweeds. Below, some healthy looking Solier’s string weed Soliera chordalis, two photos of an ‘unknown’, Norwegian fan weed Gymnogrongus crenulatus, Under-tongue weed Hypoglossum hypoglossoides, seaweeds starting to grow on a pebble, and a rock covered in a variety of seaweeds.
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.
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!
This snorkel session was also the first time I took a proper look underneath the kelp. Mowing through this forest is very interesting. Besides the gobies and starfish, there are a lot of sponges, bryozoans and hydroids to be seen. A picture from this ‘turf’ with many hydrozoans and a larger erect bryozoan (perhaps an Alcyonidium species?); these are groups I know very little about. A photo beneath that of some worms Bispira volutacornis, very beautiful:
The kelp is covered by a not so pretty, large, fluffy brown seaweed which might be Pylaiella littoralis (first picture). Large bushes of the slightly iridescent Dictyota dichotoma were also common, this is a species I have never seen in rock pools (second picture). The rocks underneath the kelp are also home to many red seaweeds, notably Sea Oak (I have to get back for some pictures).
In the deeper channels there were many Mermaid’s tresses Chorda filum, more than five meters in length. The shallow rocks were covered with Thongweed Himanthalia elongata and Grape pip weed Mastocarpus stellatus with assorted epiphytic tufts of fine red seaweeds.