Saturday, 18 February 2012

Amazing sea anemones ~ flowery creatures of the rocky shore

I continue to be surprised at what I observe on the rocks. It is certainly true that the more species I become familiar with, the more other ones I notice that I have not previously been aware of. 

I was first alerted to the possibility of sea anemones inhabiting my most familiar set of rocks by the appearance of this tiny one which came home with a bag of freshly harvested mussels.  When I first spotted it it was lodged on a mussel shell.  I couldn't actually see what it was - just a blob of something that must be some sort of creature, and I put the shell it was on into a bowl of seawater as a curiosity.  My reward was almost immediate: once in the seawater it rapidly opened up and made its way off the shell and fastened itself onto the side of the dish. 

Here you can see it in relation to the mussel shell, which shows just how tiny it is:


When it came time to take it back to the beach I had the greatest difficulty prying it off the ceramic surface: it turned back into a dark blob, stuck fast, and its upper surface was unbelievably slippery.  Not wanting to damage it I did my best to be careful, and eventually forced it loose with the edge of a plastic shopping card.  

Once back at the beach I put it in shallow rock pool amongst other growth.  It opened up almost right away and seemed none the worse for its adventures.  I couldn't reunite it with any relations as I'd never seen any, but I realised there must be others!

It seemed almost as if by magic that I spotted a whole cluster of them in a small rock pool just a few days later.  I must have stepped over them dozens of times as I climbed those rocks!


I was astonished and delighted - they had been there all the time and I had never noticed!  How beautiful they are and how delicate.  I gently touched one to see it contract, which it did, just briefly.  Rewi climbed over the rocks after me using his stick to steady himself, and I yelped a warning just as he was about to thrust his stick into that very pool!  Fortunately my warning came in time.

The green anemone might be New Zealand's most common variety, but I had never seen one before.  These are all the more beautiful to me on account of their sensitive camouflage - how delicately and cleverly they blend into their niche!  Now when I step over that pool I always stoop down to admire them.

Later note ~ 19th February 2012:
This morning when I was looking through some earlier photographs I noticed that there were some little green sea anemones in one of them, so I had seen them before, but I hadn't taken them in!  I have often observed this sort of scenario, that once something becomes meaningful to me, I notice it as a matter of course, whereas previously my eyes had passed over just such things without much, if any, awareness.

Further observations added on 16th May 2012:
Since I first wrote this article I've come across lots more anemones and taken plenty of photographs of them from which I have learnt more:

Every time I climb the rocks where I photographed the anemones shown above I stoop down to look at them.  The rock pool in which they live is fairly bare of other little creatures and is far enough above the usual level of sand to have very little sand in it.  I hazarded a guess that they may prefer it that way.  When I checked up on them after a big storm which brought heavy seas I realised why this was likely to be the case: the pounding waves had churned up a great deal of sand and there was a lot in their pool which looked likely to smother them:


Attempting to scoop it away only stirred it up, so I had to leave them alone and see what would happen.  In the weeks that followed we had more heavy seas which washed their faces clean again!


Comparing these two images with the earlier one mades me aware of how much sand they had in them even then!

On another stretch of beach I found this fairy-like community of little ones, none of them larger then a fingernail.  They are underwater, and the water very clear and the pool free of sand.  The unusual blue and white rock is just as you see it in the picture. 


Walking along the beach at the time of an especially low tide I saw this rock face which would normally be underwater: a colony of blue mussels is co-habiting with a colony of anemones.  They are the shiny brownish blobs.  Anemones close when out of water:


It is these blobby forms that you may see on any shellfish you bring home from the beach, so it's worth looking out for them.  As soon as I became aware of what these were I began to place them in my makeshift seawater aquariums which I set up on our dining table whenever Rewi has been gathering mussels:

Here in the bottom of the bowl is a tiny green one all closed up, and no doubt feeling rather battered after I'd edged it off its host mussel shell.  Look at the little speckles of grit attached to it.  I don't know if it has acquired these deliberately as part of a camouflage as some anemones do, or not.


 It soon recovered and opened up:


One day when Rewi gathered mussels from a different group of rocks most of the anemones were orange:


The image below shows how tall their bodies can be.  This one has leant over after I moved the shell it was on and it had insufficient water to stand erect:


When the water got a bit murky and needed changing I noticed that the anemones closed.  The green one doesn't look too impressed either!


One day I was delighted to find these two little red ones.  Here they are getting acclimatised:


And here they have opened up:


Although I enjoy watching anemones in the bowl on the table I take them back to the beach as soon as I can - usually I have to wait a day or so as the pools nearest where they came from are only accessible at low tide.   Before I took these ones back I carried this bowlful out into the sun to see if I could get some nice clear photographs:


All the anemones shown in this article are small with most of them being close to the size of a fingernail.  The exceptions are the four photographed in their rock pool which are quite a lot larger and might be from three to five centimetres in diameter. 

More information can be found via these links:

You can find my other articles about exploring the beach and its rock pools via the link below: 

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