Tag Archives: Rockpool ramble

What to do when Rock pooling is cancelled? Go anyway!

After weeks of storms, the Looe Marine Conservation Group was hoping for a break in the weather for their half-term family rock pool ramble. Unfortunately the Cornish weather had other plans. With gusty winds delivering pulses of the sort of ‘light’ rain that soaks you in seconds, LMCG did the sensible thing and cancelled.

Meanwhile back at Cornish Rock Pools HQ, Junior already had several jumpers, three sets of socks and full waterproofs on and was ready to set off. Some of his friends were also set to join us on Hannafore beach. So, we ignored the cancellation, put our hoods up and set off.

Scooping up another hardy family on our way down the shore, we picked our way down to some gullies sheltered from the wind by large rocks.

“A fish,” Junior shouted. “I don’t know what it is. It looks like a tadpole.”

I made my way over to where the children were gathered.

“I think it might be a clingfish,” Junior explained.

The small dark blob was certainly suckering onto a stone. It was lying very still with its tapering tail curled around its wide head, hoping that it was well enough camouflaged that we couldn’t see it.

Bizarrely, this little fish is known as a Montagu’s sea snail. It has tiny eyes compared to the size of its head and with its fins tucked tight to its body, it does look rather like a tadpole. Under its belly, the fins have evolved to create a sucker that it can use to hold onto rocks, making it ideally suited to life around the shore.

Montagu’s sea snail (Liparis montagui) – a fish despite the name.

Montagu’s sea snails vary enormously in their patterning but have an unmistakeable shape.

In a nearby rock pool I found a group of young Xantho pilipes crabs sheltering under a boulder. These crabs have dense hairs around their back legs and thick-set claws, but their colour varies a lot. This one caught my eye as it was especially beautiful.

A brightly-patterned Xantho pilipes crab.

Most of the dead-looking crabs we find on the beach are empty moults, left behind by a crab that has grown out of its shell. I could tell straight away that this one had not been so lucky.

Dead Xantho pilipes crab being picked clean by Netted dog whelks.

Netted dog whelks are the vultures of the rocky shore. Equipped with long siphons that look like vacuum cleaner attachments, they spend their lives sifting through the sand and hoovering up any dead creatures. When something large like a crab dies, they can scent the food and quickly home in.

Unpleasant though it looks, scavengers play a vital role in any ecosystem, quickly and efficiently breaking down decaying matter. The children had a fascinating time watching the netted dog whelks at work. They wre moving surprisingly quickly, spinning their shells from side to side as they edged into spaces and were clearly competing to get at the best bits of food.

Before long the children had made lots of other finds. Among the tubs were several hermit crabs that had been given names. Junior adopted a lugworm that he found under a large stone and spent a long time watching and trying to photograph it. These worms make burrows in the sand and have a wide circular mouth that gapes open to swallow sediment, from which they filter out their food.

Lugworm with mouth open – photo by Cornish Rock Pools Junior
Junior’s lugworm

The rain had died down over the course of the morning and no-one was rushing to leave. So, after we had carefully said goodbye to all of the animals that the children had been caring for in their tubs, we took a last look around between the rocks.

As always there were plenty of treasures to be found and before long, the tide was turning and lunch was calling.

Green shore urchin.
Long spined sea scorpion
Bootlace worm – these worms are usually several metres long if fully extended but are always quite tangled!
Pheasant shell
Shore rockling (5 bearded) with a hemit crab and a prawn photobombing in the foreground.
Long-clawed porcelain crab
Another prettily patterned juvenile Xannto pilipes crab.

The Looe Marine Conservation Group run rock pooling events during every school holiday through the year and these are only rarely cancelled. There are similar groups all around Cornwall, and some across the border in Devon too. Look out for events near you!