As the twice-daily ebb of the tide drains from the foreshore, a remarkably rich world is exposed. Where scrunching shingle beaches give way to rugged rocky shores, a veritable oasis of miniature ecosystems await discovery, each containing a treasure-trove of organisms that lurk within the still waters.
Rockpooling is one of those activities that reverts you back to a child-like state of mind: you become absorbed in unearthing a myriad of fascinating creatures, derive excitement from prodding around after crabs and shrimps; each new pool presents a plethora of species to be scrutinised and investigated. The air of discovery is ever-present, as you never know what you might find in the next rockpool: there is always something different, some bizarre animal that you’ve not encountered before. And here in Cornwall, we’re very much blessed with one of the county’s most diverse intertidal communities of seashore wildlife.
There have been some particularly low tides over the past few weeks, in tune with the waxing and waning of the moon and its associated pull on the ocean. This has presented ample opportunity to don the wellies and head down to the beach in search of some rockpooling action, which has rewarded with some fantastic discoveries. I’ve been meaning to write this blog for a good week or so, but it as been somewhat manic with uni deadlines and coursework of late. I thought I’d take a brief lull in the barrage of work to detail some of the highlights from recent visits to the seashore, although I’d thoroughly recommend you check out a an eloquently-written post on the joys of rockpooling by Jack Barton, fellow student on the zoology course with University of Exeter.
When presented with your first rockpool, it’s hard to know where to start! There is so much diversity contained within such a small area, particularly if you venture to the seaward reaches of the intertidal zone at low water. The colourful assortment of different algae and seaweeds is a good place to start, from the bright pink and segmented Pink Coralweed, through to the edible Peppered Dulce and remarkably iridescent Rainbow Weed, which shimmers blue and purple as it catches the light.
Next up you might appreciate the peppering of gastropods clinging to the stone and rocks within: the wrinkled limpets holding fast via an immensely strong sucker-like foot; clusters of periwinkles, grey topshells and dog whelks, and perhaps the colourful painted and flat topshells too. A keen eye may reveal that some of these mollusc shells have been commandeered by a species of a very different kind…the characterful hermit crab. Once discovered, these innovative crustaceans rapidly retreat into their adopted home; a bit of patience will reward as the eyes, antenna, and then tightly curled appendages emerge tentatively, and the whole shell tips on its side as it trundles off across the substrate.
After appreciating the various seaweeds, shells and generally more sessile organisms, then follows the pursuit for the most exciting and generally more secretive creatures. These tend to be evading detection by remaining concealed in nooks, crannies and beneath loose rocks. To any naturalist, I think turning over rocks has to be one of the most satisfying actions to unearth hidden treasures – and this applies to virtually all habitats and ecosystems. But returning to rockpools, the simple act of flipping over a stone can reveal a host of exciting discoveries…
The underside a rewarding rock can harbour a dazzling array of organisms: the shuffling hairy porcelain crabs edge sideways upon exposure; the incredibly delicate-looking brittle stars flair their arms as they topple into the water; crabs and various fish scuttle away in a puff of sand a flick of their tail. Crustacean species can vary from velvet swimming crabs through to edible, Montagu’s , shore and brown crabs. The three-bearded rockling, the pipefish, the common blenny, butterfish and bizarre Cornish sucker are amongst the fish that we’ve encountered along Falmouth’s rockpools. The underside of over-turned rocks themselves can present some cool species too: a close scrutiny might reveal the well-camouflage Chitons (gastropods) or perhaps the flower-like Star Ascidians
An amazingly-coloured chiton that I believe to be Tonicella rubra, and then a miniature brittle star
I think the most enjoyable aspect of rockpooling is simply the feeling of discovery and seeking the unknown. There is such a broad diversity of species to be found within these island oases that you can easily spend a few hours slowly rummaging around the foreshore, totally absorbed in the activity. The advancing tide is often the limiting factor that eventually brings rockpooling to a premature end, as the shore is claimed once again by the sea and the rockpools are re-submerged.
So there is just a bit of a taste of Cornish rockpooling – it’s certainly a great way to brighten up many a dull winter’s day. However, as the sea temperature edge higher through spring and the weather (hopefully!) settles, snorkelling will definitely be my next port of call for exploring the rich marine life around our coast here in Falmouth.
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