Beautiful anemone on shells at Long Beach

Sea life: Anemones

As a child I was delighted by sea anemones, and no doubt caused absolute havoc among the rock pools, sticking my chubby fingers into every hapless anemone who happened to cross my path. As a grown-up scuba diver, I am still delighted by them, and have realised that they look much prettier – and are much happier – without the interference of my digits.

Blue sea anemone at Long Beach
Blue sea anemone at Long Beach

As a novice underwater photographer, sea anemones are the ideal photographic subject. They are stationary, usually located on the sand so that I can lie right down next to them and get some solid purchase, come in a variety of pretty colours, and when there’s surge they offer just enough movement of tentacles to provide a little but not insurmountable challenge.

Anemone in a concrete block
Anemone in a concrete block on the pipeline at Long Beach
Sea anemone at Fisherman's Beach
False plum anemone at Fisherman's Beach

While they are rarely spotted on the move, they do have some element of mobility. While I was doing my volunteer training at the Two Oceans Aquarium, we were told of a specimen living in the tanks located in the classrooms upstairs who mounted a daring escape attempt and in the process completely blocked the filtering system for his tank. During the rescue/unblocking process he had to be cut in half (horizontally), and both halves survived for about two weeks before slipping this life’s mortal coil.

Beautiful anemone on shells at Long Beach
Beautiful anemone on shells at Long Beach
Sea anemone at Long Beach
Sea anemone at Long Beach with mouth visible

During our training we learned that anemones have a hydrostatic skeleton – they draw water into their bodies, and contract their muscles against the water in order to hold their shape. This is why it’s not kind or nice to touch an anemone in the centre, or to stick your finger into its mouth (the central opening). The pressure you exert can force the water out of his body, and while it is possible to recover from this, it takes a while. At the touch pool at the aquarium we encourage the kids to touch the anemones on the side, below the tentacles, and very gently.

Blue anemone at Long Beach
Blue anemone at Long Beach
Long Beach sea anemone
Long Beach sea anemone

Anemones are radially symmetric (i.e. their body structure radiates from a central point) and use their stinging tentacles to capture small shrimps, plankton and other unsuspecting prey in the water. The prey is paralysed by the stinging cells, and then the anemone draws it inwards towards its mouth.

False plum anemone at Fisherman's Beach
False plum anemone at Fisherman's Beach

A lot of the time they seem to get sand over their mouths – I always worry that it feels uncomfortable, and I wonder how they get rid of it to eat… But I guess they are accustomed to it, living where they do! I have tried purging my octo gently over one of them to blow away the sand, but it didn’t work.

Anemone at Long Beach
Anemone at Long Beach
Pink anemone at Long Beach
Pink anemone at Long Beach, mouth covered with sand

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Clare

Lapsed mathematician, creator of order, formulator of hypotheses. Lover of the ocean, being outdoors, the bush, reading, photography, travelling (especially in Africa) and road trips.

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