Crustacean Crevice Dwellers

I have done a fair bit of diving at Silver Steps this year and it is high time to publish some of the photos I took there, starting with the Crustaceans that inhabit the cracks in the rocks. Most pics were taken with the macro-wide angle lens, which is not only suited because of its perspective, but also because it is long and thin and so can be poked into the crevices where these creatures lurk. Above, two Velvet Crabs Necora puber, which are abundant and feisty – I only noticed the small female in the photo afterwards! Below a European Lobster Homarus gammarus, also quite common and some of them are quite big. They usually shuffle out of their den quite menacingly only then to retreat again. Although impressive animals, it is hard to get an aesthetically pleasing shot out of them I find.

Next, the Squat Lobster Galathea strigosa, also a common, but quite shy species which is just as happy upside down as right side up. Also common are Brown (or Edible) Crabs Cancer pagurus, the individual here not in a crevice but in a piece of steel wreckage.

The other big, common Crustacean here occasionally perches on rock walls but usually is found roaming the seabed: the European Spider Crab (rebranded by local fishmongers as ‘Cornish King Crab’ – sounds more appetizing than something spiderlike) Maja squinado brachydactyla. Like the lobster, the behaviour of these guys is a mixture of bravado and fear. The weird lens allows me to get close, but as it lets in very little light, I am forced to use a high ISO and slow shutterspeed, making these images not the crispiest.

The final photo is technically not great, but I like it because it shows how a range of species apparently gets on quite well at close quarters. On the left, a Common Prawn Palaemon serratus, which can grow quite large and is actually really beautiful with its blue and yellow stripes. Right behind it is a Squat Lobster, with two Edible Crabs lurking in the background and an upside down male Connemara Clingfish Lepadogaster candolii – the next post will be about the fish of Silver Steps!

a very low tide at Castle beach

IMG_7884There were exceptionally low tides this weekend so I was quite stoked to get out and find some new species in what is normally the subtidal. It was raining and even hailing quite a bit but we were on a mission! Fortunately, the sun came out later and my jeans could dry up. Sea urchins are not common in the rock pools that are usually accessible at low tide, but they are quite common a little deeper. The same goes for Sea cucumbers. These are hardly ever pretty but the following species is ugly even in holothurian terms. According to David Fenwick it is a Pawsonia saxicola (I have seen a prettier incarnation before):

IMG_7900I noticed a little gastropod which looked vaguely familiar on a Pawsonia when checking my pictures. I could identify it as a Eulimida species in my old Poppe and Goto ‘European Seashells’ book, which also mentioned that many species in this family parasitize echinoderms so that fitted. David Fenwick’s excellent site Aphotomarine has great pictures of pretty much all species occurring here in the Southwest, including a much better one of this Vitreolina philippi Melanella sp (identified through David’s correspondence with Jakov Prkic). David has also just launched a website dedicated to Stalked jellyfish: stauromedusa which looks amazing.

IMG_7891 - CopyAt the end of the ‘session’ I glanced something red, white and blue; a colour combination that I had seen only on photographs before. It was a single, juvenile Spiny squat lobster Galathea strigosa:

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IMG_8010A lot of usual suspects were found as well of course, here a Cornish sucker Lepadogaster lepadogaster and a Shore rockling Gaidropsarus mediterraneus:

IMG_7925The rockling has a groove in front of its dorsal fin filled with hairlike fin rays that are continuously beating. Finally, not a very good picture but I’ve posted it because this is the longest animal in Britain: the Bootlace worm Lineus longissimus can grow up to 10 meters!

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