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!
Category Archives: sponges
Leftover Pics
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).
a shallow Maerl dive
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 the 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).
Mud pooling off the Quay
I have previously posted about exploring the more muddy sites in Flushing’s Penryn River and also about catching fish with a net from the quay (here and here). This weekend had a good tide and I decided to combine the two by climbing down from the quay with my net. No blue water and clear, colourful rock pools but black mud, waste from fishing boats and in general a lot of crap, not a pretty sight/site! Mussels and (native) oysters, rock gobies, fan worms and estuary sponge are common here. Lifting one piece of waste, i found a juvenile Eel Anguilla anguilla, which was impossible to grab and place into my cuvette for a proper photograph. One cool find were bundles of squid eggs (no idea about the species). I also found tangles of the sponge Sycon ciliatum, which before I had only seen as individuals hanging from seaweeds (see here). Also visible are some Leucosolenia botryoides sponges.
There was a heap of discarded scallop shells; I noticed they were covered by large Balanus balanus barnacles as well as the soft coral Dead man’s fingers Alcyonium digitatum (I had never seen this before but this could only be one thing!). The lower parts of the quaysides were covered in estuary and breadcrumb sponges and especially in droopy Morchellium (or Aplidium?) sea squirts. Although generally an ‘ugly’ habitat with lots of waste to boot, still plenty of interesting finds.
a very low tide at Falmouth part 2
On to some of the more tricky species to identify. The rock overhangs, the home of the Painted top shells, are covered in sponges, tunicates and bryozoans. These are organisms I need to spend some more time on, as they are diverse, pretty and easy to photograph (they do not scurry away or give any macro depth-of-field problems). First two pictures of the large, nicely textured sponge Ophlispongia papilla. After that, the cream-coloured sponge Dysidea fragilis and the yellow sponge Aplysilla sulfurea. Side-by-side the bryozoan Disporella hispidata and what might be the sponge Clathrina coriacea.
There were quite a lot of other sponges and bryozoans to see as well, so I’ll definitely investigate more the next low tide. Some other species: the tiny polychaete worm Euphrosine foliosa (first two pics). Next, Chaetopterus variopedatus, a quite large polychaete worm (thanks to David Fenwick for the ID), a tiny glossy bivalve Kellia suborbicularis (thanks to David again) and what is probably a Chameleon prawn Hippolyte varians.
Pontooning
Unfortunately, the weather turned before I had another opportunity to go diving (or snorkeling). The wind and rain have reduced visibility too much and so I’ll have to wait half a year or so before conditions improve….too bad! I missed the low tides recently as well. However, today there was time for a bit of ‘pontooning’, i.e. lying flat on a pontoon and staring at the creatures attached to it. It is quite convenient as it is not dependent on tides and the communities are very different from that of rock pools. There is a very large marina at nearby Mylor Bridge that I had visited before in summer. There was a bit more life then (schools of mysid shrimp, more seaweeds, more tunicates) but it is still looking nice now. I used my iPhone to take pictures before, but holding it above the water was tricky and did not produce good results so I brought my new Canon Powershot instead (still not easy to take pictures as at the same time I had to prevent my two-year old son falling in the water). The bulk of the biomass hanging from the pontoons consists of tunicates (mainly Ciona intestinalis). Small Plumose anemones Metridium senile are common (more about those in the next aquarium update), as well as the sponge Sycon ciliatum. I even found a small Elegant anemone Sagartia elegans (var. venusta). The invasive Bryozoan Bugula neritina is very common; it looks a bit like seaweed even though it is an animal (see here for a description). Finally, the Peacock worm Sabella pavonina is common (and very striking). Just two pictures below as the rest was subpar; I have to go back on my own sometime soon maybe.
scummy pools
For the first time in a while I had time to nip over to Castle Beach to do a little rock pooling. The tide wasn’t the best and the pools did not look to great either actually; this seemed to be due to a mix of some seaweed species dying off, and some not so great-looking species ones blooming: 
Lots of Wireweed, Ulva and very fine weeds (the latter are often very pretty under magnified and in water, but not so much as a blob on the rocks). What might be Desmarestia viridis (but don’t take my word for it): 
Still, there was plenty to see: Orange-clubbed sea slugs for instance and one very weird-looking creature I had never noticed before was clinging on in little groups on red seaweeds under overhangs, the annual sponge Sycon ciliatum:
The Breadcrumb sponge Halicondria panicea can be very nicely coloured: 
There were a lot of tunicates about. Colony-forming Morchellium argum for instance and this beauty, probably Ascidia mentula (determined by helpful folks at the ‘NE Atlantic Tunicata‘ facebook group): 
One colony-forming tunicate looked superficially like Botryllus but was much bigger and less pretty, it might be Aplidium nordmanni:
Quite a lot of Sting winkles Ocenebra erinacea were around as well:
Finally, I spotted the orange/yellow egg masses of the Cornish sucker (or Shore clingfish) Lepadogaster lepadogaster (see here for an older post on them). However, I also found some that were greyish and had a speckled band, as well as a red dot between the eyes. Local expert David Fenwick told me these are from the Small-headed clingfish Apletodon dentatus, a species I have not yet seen the adults of (see his site for pictures):Â 
low tide finds at Flushing
The day after the very low tide excursion in Falmouth, I had a look in Flushing as well. This site is less pretty, more silty and estuarine, and has a slightly different fauna as well, especially on the muddier areas below the rockpools. (I have written a post about ‘mud pooling’ before.) Lots of sponges, Variegated scallops, European cowries, Hooded prawns and Common squat lobsters. This time I noticed that Hairy crabs Pilumnus hirtellus are common here too. Two diffently coloured Long-clawed porcelain crabs Pisidia longicornis:
A pretty sponge Aplysilla rosea (determined using the Aphotomarine page as it was not featured in my otherwise excellent Collins guide):
I had seen one before, but with this low tide I found several Sea lemons Archidorus pseudoargus, large sponge-eating nudibranchs. A large one and a small one together (on the right side of each you can see the ‘naked gills’ which are not extended above water):
Another, bigger individual (European cowries and Thick-lipped dog whelks for scale) again with a smaller individual half under it:
You can see some tiny juvenile Variegated scallops Chlamys varia too. I found my biggest one to date:
They can be much prettier than that though!
I could not resist taking some stuff home to my aquarium, even though I was still waiting for the chiller and new lights (they both have since arrived, that’ll be my next post). There were loads of Painted top shells Calliostoma zizyphinum, which are very pretty and moreover do not often emerge above water so they might be better behaved in the aquarium, and I took some of those home. I also took a pair of Butterfish Pholish gunnellus and some Sea lemons, mainly to observe them for a week or so and then release them again before starting fiddling with the tank. This was not a great succes unfortunately: both Butterfish died within a couple of days. I had acclimatized them to room temperature and I don’t know what the reason could have been. Clingfish, mullet, a rockling, gobies and blennies have never died in my aquarium. I felt really bad about it; definitely no more Butterfish in my tank!
One of the Sea lemons managed to get caught by a Snakelocks anemone….however, it produced copious amounts of slime and it was eventually spat out!
Mud pooling
When it was very low tide last week, I decided to skip the ‘rock pools proper’ on my local beach in Flushing and to check out the zone just below where the rocks and the sandy bottom of Penryn River (an arm of the Fall Estuary) meet. All common rock pool inhabitants – winkles, top shells, edible crabs, worm pipefish and shannies – still live here, but some other organisms are more abundant here than in the rock pools.
Sponges are very common in this silty environment, especially the Estuary sponge Hymeniacidon perleve:
The Breadcrumb sponge Halichondria panicea:
In addition to sponges, I noticed quite a lot of the colony-forming ascidian Botrylloides leachi (see previous post). That explains why I could also find a couple of European cowries Trivia monacha, their predator. Also very common here are the Variegated scallop Chlamys varia and the Thicklipped dog whelk Hinia incrassata (top right picture). I am not sure what the slimy beige stuff is!
I spotted a couple of new things as well, the Red speckled anemone Anthopleura ballii:
Also a first, a Sea spider Nymphon (gracile?):
I found a large patch of these beautiful eggs:
and someone guarding them, a rock goby Gobius paganellus:
A Butterfish Pholis gunnellus:
Very common were little Squat lobsters Galathea squamifera (no picture), rapidly swimming backwards to escape. Even more abundant were these little Hooded prawns Athanas nitescens:
An Bollenessor 