• Rockpools

Battered by waves then exposed as the tide retreats, rock pools are tough places to live. The extraordinary snakelocks anemone harnesses solar power through symbiotic algae, which live in its bright green stinging tentacles. The algae turn sunlight into energy for the anemone, which is why snakelocks live in the sunniest spots in the pool. In return, the algae get benefits in the form of protection and nutrients.

With rockpool space at a premium, the seemingly serene beadlet anemone defends its place by deploying a ring of bright blue beads full of stinging cells and battling against opponents. 

Clamped tight until the tides cover them, cone shelled limpets zigzag around, feeding on algae scraped off rocks with  their tongue, one of the world’s strongest biological structures! Returning to their home patch, limpets sometimes clash shells; trying to tip each other over or prise their opponent from a rock. No one’s quite sure why, it could be territory or feeding disputes, but one thing’s for sure they’re not the motionless shells they appear to be. 

• Tompot blenny

Colourful fish with a punk hair do, and a big character. Rusty brown with an impressive pair of red head tentacles, occasionally spotted in rockpools, more often in rocky crevices in shallow water. Marine biologist and Wildlife Trust supporter, Dr. Paul Naylor, studies the complex social lives of tompot blennies and recognises fish on a Devon reef, where they’ve lived in the same spot for years. He can identify individuals by their face markings, and has given dozens of them names, all beginning with B!

Paul Naylor says:

“Knowing the fish means I can work out what’s going on. For example, it’s important for males to fertilise and then guard batches of eggs. But challengers are always trying to get in on the act. I watched as Bradley was fooled by a young rival, Bertram, who sneaked in whilst Bradley was distracted by a female and fertilised his batch of eggs. Since then, ‘sneaker’ Bertram has become a respectable parent himself. 

“Crabs and conger eels try to ‘evict’ the fish from their crevice homes, with shoving matches between homeowner and intruder. Bradley, who is now getting old, recently lost out to a young conger eel, but Buster successful tackled a velvet swimming crab. It’s an underwater soap opera!”

• Chalk reefs

Chalk reefs are the UK’s equivalent of the Great Barrier Reef, and support a huge diversity of marine life, from starfish and sponges, to shoals of fish. Marine chalk is a globally rare habitat, 75% of all chalk reefs in Europe are found off the South coast; many of them protected by Marine Conservation Zones.

Reefs off Sussex are home to exotic looking cuckoo wrasse, which have a sex change survival strategy. They all start life as pink-coloured females, changing to males when there is a need; if a top male on a reef dies, often the most senior female will change sex and become the dominant fish, displaying male electric blue head markings. 

Holes in the chalk are the work of piddocks, also known as angel wings because of the shape of their long oval shell, which has very sharp teeth at one end to burrow into the soft rock. At night, bioluminescence means the edge of the shell glows blue-green.

Underwater chalk cliffs are home to sponges and shelter catsharks, lobsters, and spider crabs. Spider crabs pick seaweed and sponge to decorate and camouflage themselves, using their claws to fix the ‘decoration’ onto hook- like hairs between spines on their shells.

North Norfolk’s chalk reef, with boulders, stacks and arches, is 20 miles long. It supports 350 species; from red seaweeds to shoals of silvery scad or horse mackerel. Ten years ago, during a National Marine Week survey, divers found a distinctive purple sponge which hadn’t been seen before, later identified as new to science! This year children in Norfolk were asked to name the sponge, it’s now called the Parpal Dumplin, because it’s purple and looks like a dumpling!

Joan Edwards, director of marine policy, The Wildlife Trusts says:

“Our seas are home to over half of all our wildlife, they provide oxygen for every other breath you take, and visiting the coast can improve mental and physical health. This is why it’s so important that more and better protection is given to the waters around our shores. National Marine Week is a chance to celebrate our amazing seas, and I’d urge people to make the most of the coast and enjoy events hosted by Wildlife Trusts throughout the UK.”