Onefin electric ray burying himself

Sea life: Onefin electric ray

Onefin electric ray resting on the sand
Onefin electric ray resting on the sand

Tony, Kate, Carl, Anita, and I found this little fellow on a recent dive on the SS Clan Stuart, in about 6.5 metres of water. He reminded me of nothing so much as a crumpet (I hadn’t had breakfast) and obligingly lay on the sand for a little while so that we could examine him. After a while he got tired of us and buried himself in the sand.

Onefin electric ray burying himself
Onefin electric ray burying himself

The onefin electric ray (Narke capensis – “narke” means paralysis in Greek) has kidney-shaped electric organs next to their pectoral fins (which – I think – you can see in the top image), which can deliver a powerful shock – hence another of its common names, Cape numbfish. They are also apparently known as torpedo rays.

Almost gone
Almost gone

The maximum recorded size is 38 centimetres, and the one we saw was probably about 30 centimetres from nose to tail. Their bodies are cartilaginous, and they are slow-moving, spending most of their time on the ocean floor. These rays eat mostly worms, which they can find by snuffling about in the sand. For this reason they prefer soft sandy regions to rocky bottoms.

Clearing his spiracles - now completely buried
Clearing his spiracles - now completely buried

We loved watching our specimen bury himself, with vigorous up and down motions of the front of his body while shovelling sand over himself with his wings. Once he was buried, he puffed some water out of his spiracles to clear away the sand, and all that was in evidence when he was finished (see below) was his eyes. I wonder how many of these we swim over without realising it!

Now you see me, now you don't!
Now you see me, now you don't!

As an aside, it seems that this ray was causing some kind of electrical interference with Tony’s video camera. All the footage Tony took of him has horizontal lines across it, but the footage from the rest of the dive (both before and after) is flawless. Hmmm!

[youtube=http://www.youtube.com/watch?v=_9I3Xv0BV-c&w=540]

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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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