Toxic tentacles! External stomachs! Bristly feet! And they’re … uhm … four centimetres long and live in little rock pools. But hey, the denizens of the not-so- deep are still pretty intimidating when seen close up. And there’s no better place to see these beasts than a twist of wild coastline in the Cape of Good Hope Reserve: come with me to the Tidal Pools of Black Rocks!
Most people have never heard of the place; they’re elbowing each other for the views at Cape Point down at the bottom of the reserve. But my advice is to leave the main road and slip down a side lane to the almost unpronounceable Bordjiesrif (“bore-cheese- reef” is as much as my jaw can handle) and turn left at the sign for Black Rocks. You’ll reach an empty car park with postcard views of Cape Point in an atmosphere of aromatic fynbos and birdsong.
And if your timing is right – here’s the link to Cape Town’s tide chart -https://magicseaweed.com/Cape-Town- Surf-Report/81/Tide/ – then the Indian Ocean will have slid back a metre or two and you’ll be able to see why the place is called Black Rocks. The stone may be cold beneath your feet now but it was once violent and terrifying geology – molten jets of super-heated rock smashing their way through existing layers to leave them torn and pock-marked. The result is rock pool heaven: countless, crystal-clear pools ranging from cup-sized to something you could swim in.
There’s an order of exposure – so to speak – as the ocean retreats and the animals emerge. Tiny black periwinkles appear first, marine creatures that can tolerate being out of water the longest.Then come barnacles and close behind them the limpets – great armoured beasts that graze algae in bad-tempered herds just like antelope on the savannah. Thick shelves of edible mussels are next, which along with the limpets have sustained humans on the Cape Peninsula for over 200 000 years.
The shells close up tightly and wait for the tide to return but other animals in the rock pools are making the most of a captive audience. Predatory dog-whelks use a drill housed in their conical shell to pierce the shell of their victim, squirting in acid to make it easier to suck their prey up. Dwarf cushion stars, a kind of stunted-arm starfish, envelop their prey and extrude their stomach through their mouth in order to eat (don’t try this at home). Bigger starfish can be seen in the deeper pools, some as bright red as a matador’s cape, slowly prowling for sponges and bivalves to feed on.
It’s not just the starfish that add colour to the rock pools: Cape urchins take it to even further extremes, spiky balls of luminous red and purple with the endearing habit of wearing scraps of seaweed and shells as sunshades. There are flashes of outrageous blue and green – sponges and algae – but nothing for my money beats the delicate shades of the rock pools’ biggest predators -the creams, pale yellows and flushed-cheek pinks of sea anemones.
Home to the most toxic anemone in the world (the false plum anemone – Pseudactinia flagellifera), the rock pools at Cape Point simply heave with these tentacle-waving animals. Some tolerate being covered in sand; others can’t bear a grain of it while some can handle being out of water, hanging from a rock like a blob of shiny chewing gum. Prey is caught with the tentacles and stuffed into the mouth, and if the anemone wishes to reproduce, it has the advantage of being able to do by simple division of the body.
And then there is the unfamiliar: your eye may be caught by the sight of an animal that resembles something you might clean muddy boots with. It is a spiny chiton (Acanthochiton garnoti) – a flattened mollusc which seems to consist of a big muscular foot and a head with no eyes or sensory tentacles. But they are not entirely helpless: stiff, poison-tipped bristles keep predators away as they inch about slowly rasping away at the rocks for food.
The experience is mesmerising but you need to keep an eye on the ocean: fussy little waves are constantly smacking up against the outer rocks and it’s not long before they begin to break over and into the rock pools again, a whoosh of white water that signals the time to move back to dry land. Black Rocks sinks under water again as the tide surges forward, and the monsters of Cape Point disappear from view. The car park is still empty.
I wanted to know if we could send you photos of weird and wonderful sea life to id?
Hi Liezel – I am no expert by any means but I can give it a go! Send them to my email address at email@example.com and I will see what I can do.