Sunday, 19 February 2012

Billions of barnacles ~

My first acquaintance with the term 'barnacles' was in the Tintin cartoon books I read as a child: one of Captain Haddock's most common exclamations was "Billions of blistering blue barnacles!"  - what a wonderfully memorable line that was!  Later on I came to know that barnacles form encrustations on the bottoms of boats, where they are a nuisance to boaties and shipping companies alike as they have to be cleaned off regularly.  But I never knew what they actually looked like until very recently.  Once more, my favourite cluster of rocks at the nearby beach proved to be my educator.  

I came across this unusually pretty specimen on a freshly gathered mussel shell, and enquiry and a little reading indicated that it was a barnacle, probably a 'pink' barnacle


I put the host mussel shell into a dish of seawater and watched to see if it would 'do' anything.  If you look carefully at the photograph you can see a little bubble has formed just over the top of it.  Note the two little 'pea' crabs which had been removed from live mussels when they were shelled!

In the image below you can see something beginning to emerge from within the little shell:


I carefully moved the neighbouring shell away to give it more space, and the little soft creature within put its 'head' out:


And looked for all the world as if it was sticking out its tongue and lapping at the seawater!  It went in and out quite slowly and deliberately:


According to what I have read, the bit that pokes out and waves about is actually a 'leg' or hairy feeler, with which the barnacle sweeps plankton and other minute food particles into it's mouth. You can see a short video of how barnacles do this on Wikipedia's barnacle page.

Having done this reading I quickly recognised that the sharp encrustations I climbed over so often at the beach were also barnacles - column barnacles, in fact.  They cover large areas:


Here they are closer up:


Smaller ones, which I'm guessing are juveniles, cover other areas of rock in honeycomb patterns.  They're less sharp but even so...


... this is no place to go barefoot!


Large column barnacles have even encrusted some of the mussels:


Once you have a little information it tends to lead to more, and I was able to identify other types:

These are goose barnacles, or stalked barnacles, I'm not sure which:


And these ones on a paua shell look like 'flat' barnacles to me.  The other possibility is the 'modest' variety:


My purpose here is not to provide definitive answers - I don't have the knowledge for that, but to share my experiences along with some background information and sources.  I hope this adds enjoyment to your own explorations.

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

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