Exploring rock pools

The sky was a brilliant blue with a patchy blanket of white cotton wool like clouds. The warm sun peaks through the gaps spilling warmth and sunlight onto the beach and ocean below. The sea is calm, gently lapping the sandy shore leaving ripples in the sand and puddles in its retreat. Along the beach the sandy shore the sand gives way to rock. Where exposed the rock is black as soot, everywhere else the rock is coated in greenish brown seaweeds, glistening with water held on to as the tide withdrew. The tops of the larger rocks are capped pale yellow where barnacles have replaced the seaweed. The whole scene transitions from smooth black to slippery browns and greens to crusty sharp yellow.

Closer inspection of this tri-colour vista reveals a wonderful new world; the world of tidal rock pools.

Along with the barnacles, limpets cling to the rock. Little triangular pyramids stuck fast on the exposed black. Unlike the barnacles, whose kite-shaped mouth on top, simply open up and feather like feeding arms reach out and comb the water for food when the tide covers them, limpets will go wandering. Once the water returns they will leave their spot and wander all over the rocks and seaweed grazing with their toothy organ known as a radula. Before the water has disappeared the limpet will return to their spot, gauging out a perfect edge around their shell in the rock beneath to seal them in.

Limpet with barnacle!

Nestled among the wracks of seaweed, whelks, periwinkles, topshells hide, waiting out the exposure. Stuffed into nooks and crannies of the rocks are red, glossy, jelly like blobs. Almost alien in appearance, they could be from the movie The Blob. They are in fact beadlet anemones. Their tentacles are drawn in, lying in wait for the waters return.

Between the rocks are the pools themselves. Compared to the surrounding rock and weed they are an oasis of diversity and active life. They range from shallow scrapes, small depressions to deep channels and pools. The deep ones have curtains of seaweed around their edges, creating shelter for crabs, fish, shrimps and a variety of molluscs. In the open water fish and shrimps dart, twisting and turning, but so well camouflaged with the pebbly bottom they are almost impossible to spot unless they move.

A shore crab returns to hiding amongst the seaweeds

The smaller, shallower pools are just as full of life. Here, just covered by water, the beadlet anemones let their tentacles hang loose, ready to catch an unsuspecting crab, fish or shrimp for their next meal. They are joined by greenish brown snakelocks anemones. Their long, wavy, snake-like tentacles also sway in search of food. The tips of their tentacles are bright pink and remarkably this is because it is home to an algae that produces energy from sunlight.

Snakelocks anemone

It is such an amazing world of unique and strange creatures, adapted to the ebb and flow of the tide, that capture the imagination of both adult and child alike. Soon our little bucket is full of wondrous creatures, fish, crabs, shrimps and winkles.

The morning draws on, the tide begins to slowly reclaim the exposed rocks and pools and we retreat up the shore.

Beadlet anemones


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