The sea urchin glowed in the water below me like a shining beacon – a pink shimmering resting on a large frond of kelp, and the temptation for a closer look was impossible to resist, so I dived under to examine in more detail this magnificent denizen of the deep.
It was about 15ft under, but it only took a couple of flicks of my flippers to bring me down to the creature’s stunning form in the clear waters of Ardmair Bay near Ullapool.
The colours were astonishing, a variety of pink and purple hues, the domed shell covered in a bristling array of spines.
The correct term for the shell is a ‘test’ – a calcium-based structure made up of fused skeletal plates.
The word ‘urchin’ comes from the old word for hedgehog and reflects its prickly outer body.
The spines offer formidable protection and other stalked projections on the shell can release toxins to further aid its defences.
On the underside are tiny tube-shaped feet, which help the animal move, and there is an intricate and complex mouth which is colloquially known as ‘Aristotle’s lantern’, the teeth of which scrape algae and other food from rocks.
They are fascinating creatures and belong to a group of animals known as echinoderms, which translates as ‘spiny skin’.
Soon, I spotted another echinoderm – this time a spiny starfish.
This starfish was huge, its splayed ‘arms’ easily covering the diameter of a dinner plate.
Also, about were common starfish and several sand stars, the latter being a creature I don’t often come across when snorkelling.
Sand stars have chunkier bodies than starfish, with shorter arms.
Wonderful snorkelling
Ardmair Bay, which is an offshoot of Loch Broom, proved a wonderful snorkelling location, and over the course of several days I became completely absorbed by its marine treasures.
Over the kelp beds flickered colourful corkwing and rock cook wrasses, and shoals of small pollack were omnipresent.
In amongst rocks in the extreme shallows, curious common prawns scuttled in comical fashion, and deeper down lurked large brown crabs and colourful velvet swimming crabs.
One of the most interesting fish I discovered was a greater pipefish.
It is related to the sea horse and the head is remarkably similar, although the scaled and ridged body is long and slender like a snake, rather than being coiled and upright.
The mouth acts like a miniature vacuum cleaner, sucking in mysid shrimps and other tiny creatures.
As is the case with sea horses, the female deposits her eggs in the male’s brood pouch, from which the young hatch after a few weeks.
After observing the pipefish, I continued to snorkel by the shore edge, my mind slip-sliding away in contentment at the diversity of life that continually unfolded before my eyes.
Nature never ceases to enthral, and I could snorkel here a thousand times and on each occasion encounter something new, such were the wild riches that lay beneath the waters of this tranquil and beautiful bay.
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