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:

IMG_8030A pretty sponge Aplysilla rosea (determined using the Aphotomarine page as it was not featured in my otherwise excellent Collins guide):

IMG_8041I 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):IMG_8098

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Another, bigger individual (European cowries and Thick-lipped dog whelks for scale) again with a smaller individual half under it:

IMG_8073You can see some tiny juvenile Variegated scallops Chlamys varia too. I found my biggest one to date:

IMG_8082They can be much prettier than that though!

IMG_8026I 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!

IMG_8115One 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!

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sea gherkin

Another ‘lifer’ yesterday: a Sea gherkin Pawsonia saxicola, at Castle Beach in Falmouth. It is a small sea cucumber (a relative of the Cushion star next to it); a very cool find indeed!

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The main aim though was to collect more snails to help out in the grazing project. This was pretty easy of course. I collected a couple more Painted top shells Calliostoma zizyphinum and many, mainly juvenile, Grey top shells Gibbula umbilicalis. I also picked up a beautiful small Spiny starfish Marthasterias glacialis; this fellow will go after the snails but as long as the predation is not too severe that will be OK, let’s see. Finally, using my little aquarium net, I went after some fish high up the shore and caught a tiny Two-spotted goby Gobiusculus flavescens. I need to catch a bunch more of those, hope to post about that soon

aquarium update: snails

Time for an update. The five Snakelocks anemones have settled and are doing very well (I have fed them some defrosted shrimps which they quickly devour). The Leach’s spider crab was sitting happily under one of the anemones until it decided to move behind a piece of slate and now does not show itself much anymore. Perhaps this has to do with a prawn I introduced, although I have not seen any scuffles. I have to see what I’ll do about this. If it is really shy then I perhaps have to choose between keeping it or introducing fish. In any case I have seen it munching on some algae and a dead Cushion star and it seems to do OK.

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The main problem I have is the dreaded return of algae…There is quite a diversity of them: fuzzy green ones, darker green blotches, slimy purple ones, brown diatoms and more. All interesting organisms surely but I do not want them to take over the tank! I have used food sparingly and used the skimmer most nights, but now have also removed my daylight lamp, to leave a single actinic lamp (see this post about lighting). I still have to get used to this new look, but less light must surely help. Most interestingly, I have enlisted the help of 80 or so grazing snails. Mainly the Common periwinkle Littorina littorea and the Flat top shell Gibbula umbilicalis but also some other species, including two very small Painted top shells Calliostoma zizyphimum. I never had many snails in my aquarium, as they were always eaten by Shannies, but hopefully they will survive this time. I will dunk in a lot more snails, and keep an eye out which species does best. A Flat top shell (picture taken using my olloclip macrolens for the iPhone):

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One returning encrusting red algae is actually a seaweed, with new ‘leaves’ growing from the round crusts. I suspect it is Devil’s tongue weed Grateloupia turuturu. I have been scraping it off the glass, except from the corners where the scraper is of no use, but will let the rest sit and see how it grows:

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I also noticed that Sea lettuce Ulva has started to grow from the slate. The aquarium does not look that nice yet, but with the new animals there is plenty to watch in any case!

low tide

The tides were good this weekend and so we went out to Gylly (Gyllyngvase) Beach in Falmouth, specifically the rocks to the west of the beach (I normally go to Castle Beach to the east):

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Although the tide was quite low, no special sublittoral species were encountered, but everything time you go out you still see something new. For instance, a newly moulted Furrowed crab, Xantho incisus pink and soft next to its old brown carapace: IMG_5469

There were very many small Blue-rayed limpets Helcion pellucidum (see also here) on the kelp:IMG_5412

A tiny Rissoa parva snail:IMG_5409

and a Painted top shell Calliostoma zizyphinum:IMG_5457

Some dark green Cladophora rupestris:IMG_5437

A fine red seaweed (I do not know which one) growing on top of Dulse Palmaria palmata growing in turn on top of kelp: IMG_5455

top ten animals for the unchilled aquarium: 10 – 6

As the aquarium is currently in a state of limbo, I thought it would be fun to take a look at the critters that have been most rewarding to keep in the year or so I’ve had my aquarium. Based on my personal experience, I have made an, admittedly completely arbitrary, top 10 of animals for a Cornish (or North-Western European) marine aquarium. I picked animals that were both easy to collect (i.e. common), easy to keep (not requiring live food and resistant to water temperatures up to 25C) and fun to watch. Here goes with the first part of the list!

10: Netted dogwhelk Hinia reticulata

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Not the prettiest of molluscs maybe, but very easy to find and very easy to keep. Burrowing in sand, and moving surprisingly fast over the bottom when smelling food. Their smaller (and prettier) cousins the Thicklipped dogwhelk Hinia incrassata never survived for long in my unchilled tank.

9: Common hermit crab Pagurus bernhardus

IMG_1020Hermit crabs are especially fun to watch scurrying about. Mine never really lasted very long but that is probably because of predation by blennies and gobies (see below)….

8: Shanny Lipophrys pholis (or Rock goby Gobius paganellus)

IMG_0203Shannies are probably the most common fish to find in rock pools. They are very easy to keep, their coloration is not particularly vivid but not dull either and they are quite active. The only downside is that they prey on molluscs and other small critters. Feeding them a bit more might prevent this, but especially the rock gobies are so voracious that I doubt that (one was so swollen I thought it was dying, until I realized that it had gorged itself on defrosted artemia…). Montagu’s blenny Coryphoblennius galerita is prettier and smaller than the shanny but much harder to find (see this post for experiences with other fish species).

7. Thicklip grey mullet Chelon labrosus

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Most rock pool inhabitants live on or near the rocks, but it looks nice if the aquarium also have some fish swimming in the water column. Mullet are very common, and small individuals form nice silvery schools (which are almost impossible to photograph as you can see). They don’t really interact with the other tank inhabitants.

6: Painted top shell Calliostoma zizyphinum

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One of my favorite local molluscs: a bright purple shell with an orange colored snail inside. Shells are never covered with algae as the snail wipes it clean with its foot (the shell can still be damaged of course as seen in this individual).

The next post will feature the top 5 of animals for the unchilled aquarium.