Diving the Helford

IMG_8454After the success of last weeks snorkelling session, it was high time for a proper dive! Again the Helford did not disappoint. In the end, my Sea hare stroking proved a bit inconclusive; also, my estimate of 30 cm long individuals might have been a slight exaggeration, 20-25 cm is more likely for the larger individuals. My guess is that it might be Aplysia punctata after all, and perhaps this is just a very good year where they reach their maximum size. (Note that three individuals can be seen in the first photo and two in the second photo.)IMG_1081IMG_1014This was not the only Ophistobranch activity going on, as I spotted a small nudibranch sitting on the eelgrass. Probably Eubranchus farrani, although it could well be something that is deserving of a new name, there is a lot of (cryptic) species discovery and taxonomic revision ongoing in nudibranch biology. I also spotted several largish egg masses on the eelgrass that are likely to be from a larger, shelled Ophistobranch; I am waiting for suggestions from various facebook groups *could be Haminoea navicula*. I found a beautiful Wooden canoe bubble shell Scaphander lignarius, these animals live buried in the sand so are not commonly spotted. Next time I’ll bring a small garden rake to see what is hidden below the sand (I am serious!), lots of echinoderms and molluscs to be sure. Pelican’s foot shells Aporrhais pespelecani live in sand, but I found some on top of the sand too, so full of muck that they were barely recognizable. I have found empty shells of this species washed up on holidays before, but it was cool to see them alive for the first time.IMG_1012IMG_1065IMG_1058No cuttlefish in sight this time, but loads of eggs so it is likely that this is an important breeding ground for this species. We encountered one Thornback ray Raya clavata, which, like cuttlefish, are not very shy. These species occur in very shallow waters (we probably did not dive deeper than 7 meter) and the influence of the surrounding woodland is clear, with decaying oak leaves and pine cones amidst the seaweeds and eelgrass.IMG_1083IMG_1085IMG_1032IMG_1031IMG_1039One very well-camouflaged species is the Scorpion spider crab Inachus dorsettensis. Medium-sized Common hermit crabs Pagurus bernhardus are common, running around in Turban top shells covered with hydroids. Although present in the last post, another pic of a Mud sagartia Sagartia troglodytes anemone Red speckled anemone Anthopleuris ballii. Filterfeeding worms are abundant too, including the beautiful¬† Fan worm Myxicola infundibulum as well as a large tube-dwelling worm and worms in white calcareous tubes with bright red bristles that I could not identify. As we got out of the water, we saw a Comb jelly Beroe cucumis, very pretty but hard to photograph. The next dive will have to wait two weeks or so, but then I hope to finally play around with my GoPro.IMG_1041IMG_1035IMG_1019IMG_1026IMG_1072IMG_1048IMG_1090

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.