Aplysia depilans | Cornish Rock Pools

There are lots of benefits to having a summer birthday; the sun usually shines, the rock pools shimmer and it’s just about warm enough to put my snorkel on and jump in. The beach has lots of presents in store for me today, including a huge greater pipefish, a cousin of the sea horse, and a rare sea slug. No unwrapping required.

A juvenile Aplysia depilans - a rare sea hare in UK waters. — A juvenile Aplysia depilans – a rare sea hare in UK waters.

It’s holiday season , but a little planning and some walking is all that is needed to find a peaceful cove. We set off to Port Nadler in perfect, calm conditions loaded with wetsuits, buckets and an ample picnic.

A typical rock pool at Port Nadler near Looe

Under a rock I spot what I think is a very large anemone, but it looks odd. I’m still trying to puzzle it out when it crawls away, unfurling long ear-like tentacles from its head. It’s a sea hare but more bulky than the ones I normally see (Aplysia punctata).

I think I've found a strange anemone — I think I’ve found a strange anemone

As it oozes towards me across the rock I’m struck by its face, more like a hippo than a hare with wide flapping ears and a broad snout. Very occasionally larger sea hares, Aplysia depilans, have been found around the southern shores of the UK, and I begin to wonder.

Aplysia depilans - looking more like a sea hippo than a sea hare — Aplysia depilans – looking more like a sea hippo than a sea hare

I contact experts who have seen them before and they confirm it is a juvenile Aplysia deplians – a rare find and a species I’ve never seen before. Happy birthday to me!

It’s still cold for snorkelling and I only last about a quarter of an hour before my teeth start to chatter, but it’s worth it. After several minutes of seeing nothing but kelp, silt and the occasional two-spot goby, a long snake-like body catches my eye. It’s the unmistakeable shape of a greater pipefish (Syngnathus acus).

The greater pipefish looks out from the weeds

These fish grow to about arm length and have a hexagonal cross-section. This one hardly moves, relying on camouflage for defence, its long nose stretching out over the sand.

Greater pipefish - a cousin of the seahorse — Greater pipefish – a cousin of the seahorse

I drift back into shore, and find a compass jellyfish (Chrysaora hysoscella) stranded in the shallows. It takes its name from the beautiful markings on its back, but I don’t go too close – sea nettle is its other common name.