It has been a while since exploring the rockpools, as the weather has been pretty horrific. However, I had a good go last week and this weekend. Although quite bleak, there was no wind and no rain. The water is getting down to 11 degrees probably (I have not measured it), so pretty chilly. There are quite some solarpowered seaslugs Elysia viridis on the Codium seaweed but I did not manage to get any good photos. In fact, I am still struggling a lot just getting the strobe to properly light up what I am aiming to photograph. A bit frustrating but that is why I keep practicing. Above a pill isopod, probably Cymodoce truncata (with the fringing hair on the rear uropods indicating it is a male). Below, a tiny Gem anemone Aulactinia verrucosa. There are a lot of small Daisy anemones Cereus pedunculatus amidst the Coral weed, they look brownish but when you zoom in there is some blue as well. Finally, a Netted dogwhelk Tritia reticulata, which are very common and active in the rockpools. Cold but always nice to be in the water. Luckily I emerged right on time when I saw my Sainsbury’s bag with glasses, car keys and phone drifting away due to the incoming tide!
I had my first two outings trying the the mzuiko 66mm macrolens with strobe this week. I managed to make some OK pics more due to luck than wisdom! It is actually not that difficult to find interesting subjects, but getting finding them back in the zoom finder is quite tricky (I usually point at a subject with my finger and then try to find a big white blob back when looking at my camera, then hoping to encounter the animal somehwre nearby). I managed to find a Least chink shell Lacuna parva spent on a Rainbow wrack Cystoseira tamariscifolia plant and spent 30 minutes looking at it. Although there is not much definition on this tiny (5mm) all-white organism, the blue background looks great. I will definitely go back to specifically look for (slightly bigger) things on Rainbow wrack! (The iridescence of this seaweed means that if the (strobe)light hits it at a different angle it is a dull brown rather than a deep blue or purple.) To give an idea of how tiny some things are see the photo above of the shell-less mollusc Runcina coronata (this is an ophistobranch, it does not have gills on its back as do nudibranchs), it was really, really tiny! This photo is nice for ID purposes but I do not expect I can take good photos of species this small (you reallly need an additional macro wetlens for that). I only later noticed the even smaller mollusc Flat skenea Skeneopsis planorbis next to it. (I identified this species using the excellent new Essential Guide to Rockpooling by Julie Hatcher and Steve Trewhella by the way, highly recommended!). I also noticed I need to clean my finger nails! (More tiny molluscs were present, including Eatonina fulgida.) Next, the mollusc Tritia reticulata (which I knew under the names Nassarius reticulatus or Hinia reticulata….) or Netted dog whelk in common parlance. These are very active and fun animals. The macrolens really brings out how battered and overgrown the shell is and the beady little eyes also stand out. A little hermit crab posed nicely as well. Another difficulty is working the strobe. Unlike the ‘normal’ ambient light photography I am used to, the image after clicking is different from that seen through the viewfinder so it is trial by error. Often the subject is not properly exposed. Also, floating particles cause backscatter. Perhaps I should try a snoot to minimise this effect, which can ruin an otherwise decent (in focus) photo, like this one of a Stalked jellyfish Haliclystus octoradiatus which are common at the moment. (Notice the tiny molluscs on the seaweed in the background.)Finally some random pics: a Light bulb seasquirt Clavelina lepadiformis, two colonial seasquirts (a Morchellium argus and a Didemnid species) and a Bryozoan (it is late and I have not looked up the species). A whole new world opens up if you look at the tiniest denizens of rock pools, all complex, colourful and fascinating!
Long time no post, just been too busy! The aquarium is doing reasonably well at the moment, especially considering the fact that I have not done any water changes since the last update and I have added a bunch of new organisms. I have added two Beadlet anemones Actinia equina. They are a dullish brown (except for a nice blue band around the base); I have not found the bright red or green individuals yet. Very similar but more striking are Strawberry anemones Actinia fragacea of which I have collected three. They are voracious, I could easily feed them a shrimp a day. The same goes for the Sea scorpion. I am afraid of sticking my hand in now as it comes after me! Time to let this buddy go. This will also give me the opportunity to add some other things such as squat lobsters.I have taken a break from experimenting with seaweeds and am focusing on anemones instead. I have added a bunch of small Plumose anemones Metridium senile that I scraped of the side of a pontoon. Weird fellas, they can fill up with water to be quite large, or just reduce to a crumpled little pancake. I have four white ones; I could only find very small ones of the orange variety and these were all devoured by Cushion stars (interesting). I’d like to have a large orange one as well, but I have to wait half a year until I can go diving again (they are very common in deeper water).
On the sheltered, silty shore of Flushing I found two small anemones attached to rock and half buried in the maerl sand. My excellent Seasearch Sea Anemones and Corals guide told me they were a Daisy anemone Cereus pedunculatus (uniform greay with many very short tentacles) and a Red speckled anemone Anthopleura balli (purplish and speckled, for a better picture of a different colour variant see this old post). Both quickly half buried/half nestled themselves under a rock so only the tentacles and the mouth are visible. They take pieces of shrimp and so hopefully they’ll be able to grow; these species should reach a decent size:
My friend marine biologist Chris gave me a snakelocks anemone that he had cured from its symbiotic algae. A very cool, bright white individual but it has returned to its original purplish colour so it must have taken up symbionts again. The snakelocks I already had, grew big, split into two and grew some more. Interestingly, one of the individuals seems to be turning from the green- to the purple colour variety:So six anemone species in all. I would really like to have some Dahlia anemones, they are very colourful, large, and not uncommon (old pic here). I need to go anemone hunting at a good low tide soon (I have not been out in ages).
I had the Chryseminia seaweed growing attached to the Tunze for a while and it worked OK, but it looks a bit messy and so I will remove it. However, I see that little Chryseminia plants have started to grow from the rock in many places (see top picture). I have to give the glass a weekly clean (with a tooth brush) and the rocks have turned a bit too greenish recently. I have noticed however that near the Snakelocks anemones, tufts of filamentous algae have appeared, as the grazers do not want to come too close to their tentacles (this reminds me of a work by an ecologist friend of mine who studies how seedlings can be protected from grazers when growing close to thorny shrubs, I’ll have to tell him of this observation!).
There has been some snail mortality. I mainly have Grey top shells but there are less than half of them left. I do not know why, part might be predation (which is not all bad as at least they serve as food for other inhabitants). I need to collects some more in any case. The Netted dog whelks are doing well. They are usually hidden below the sand, but as soon as they smell a defrosted shrimp, they come up like a Shai-Hulud. Their plowing through the sand is definitely good in preventing mats of diatoms to appear. Their little cousins the Thicklipped dog whelks are also doing fine. They tend to creep up the Daisy anemone to steal its food. I still have a Sting winkle Ocenebra erinacea which moves slowly but is very pretty. There are a variety of other species such as Blacklined- and Rough periwinkles. The best species however are the truly sublittoral large Turban top shells Gibbula magus (some of which have died as well, one of the shells has been taken over by a hermit crab, wich are also doing fine):
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
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
8: Shanny Lipophrys pholis (or Rock goby Gobius paganellus)
Shannies 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
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
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.