Compass jellyfish, Falmouth, Cornwall by Martin Stevens - “The jellyfish is a compass jellyfish, smaller individual from Falmouth, Cornwall in springtime. A nice encounter with a great species, locally. Taken under overcast skies, moody weather, one of the first compass jellyfish of the year.”

Variable blenny, Babbacombe, south Devon by Dan Bolt - “The variable blenny is a relative newcomer to UK waters, arriving from the Mediterranean as a summer visitor some years ago, but is now firmly established in Babbacombe all year round. As their name suggests they are variable in colour, not only between male and female, but also when either mating or looking after a clutch of delicate eggs for weeks at a time.”

Firework anemone (Pachycerianthus multiplicatus), Inverary, Loch Fyne by Dan Bolt - “As the UK’s biggest anemone, the Firework anemone can have a stalk and tentacles of up to 30cm long. Usually restricted to deeper waters, in many western Sea Lochs in Scotland they are accessible to sport divers. These beautiful creatures also have a party trick: under UV light they fluoresce and emit blue and green light and display patterns not seen under daylight.”

Edible crab, Ar. Abbs, Berwickshire marine reserve by Georgie Bull - “Over the summer I visited St. Abbs and was blown away by how many crabs and lobsters there were. The Berwickshire Marine Reserve is a very special place to dive because it is a voluntary no-take zone. Many of the marine animals here have no need to fear divers and exist in higher numbers than outside of the reserve.”

John Dory, Dorset by Georgie Bull - “I have always had a soft spot for John Dory. When I first started diving in Dorset, we were gifted with many summer nights full of John Dory. I hadn't seen one for years, but this summer they returned in good number, and I spent a good 10 minutes with this individual who was very keen to check themselves out in the reflection of my dome lens.”

Hermit crab and other molluscs on kelp, Shetland by Kirsty Andrews - “The closer you look, the more you see.  I was drawn to this tiny but colourful hermit crab on a piece of kelp in the shallows in Shetland, but I didn't appreciate until I looked closer that its shell was in turn covered in life, such as lampshells, pink encrusting algae and at the very top, a topshell.  Quite the vibrant community.”

Pair of wolf fish, Berwickshire marine reserve by Kirsty Andrews - “The Berwickshire marine reserve on the Scottish borders is the most reliable spot for UK divers to see charismatic wolf fish in their rocky lairs.  They usually live singly but on one September trip, I spotted five separate pairs huddled together in different rocky hollows.  Clearly, love is in the air for wolffish in the Autumn.”

Facelina auriculata, Lunna, Shetland Islands by Billy Arthur - “An absolute stunner of a nudibranch (sea slug)! Not as common as some of the other species we find here in Shetland, which makes them even more special. Caught by the sun's rays they almost seem to sparkle. It's amazing that such tiny, delicate creatures can survive in the wild seas around Shetlands coastline. Our kelp forests around Scotland are rich with life, the biodiversity in these forests is breath-taking and we need to protect them!”

Painted top-shell, Boddam, Shetland Islands by Billy Arthur - “One of the prettiest molluscs we find up here on the Shetland islands. This one looks to be feeding on a sea-mat which is a type of bryozoan which encrusts kelp fronds. Their stunning shells, which swash up on our beaches, are a prized find for beach combers, but they are much more stunning when alive. If you look closely, you can see its eye poking out from under the shell.”

Common Sunstar, Levenwick, Shetland Islands by Billy Arthur - “Typical rocky Shetland reef capped with a beautiful forest of kelp. This large common sunstar seemed to be making its way up into the kelp forest, likely in search of food. A beautiful starfish but also a voracious predator and scavenger. Once their prey has been caught by one of its many arms, they extrude their stomach out of their mouth and partially digest the meal, a gruesome end.”

Curled octopus, Toft pier, Shetland Islands by Billy Arthur - “Instantly a great dive when an octopus encounter is involved! Being quite sheltered and having lots of prey available for them, this site is a hotspot for curled octopus. It was already watching me when I finally noticed its presence, which is nearly always the case with these masters of camouflage. The plumose anemones which carpet the seabed in patches make it a very special place.”

Basking Shark, Isle of Coll by Mark Kirkland - “Through late summer the basking shark passes though the Isles of Coll and Tiree in huge numbers on its migratory journey north. Despite being the second largest fish in the sea (up to nine meters long) and a close relative to the great white shark, it's completely harmless, with a preference for microscopic plankton as it's food. This split shot was taken on a glorious evening's snorkel with three large individuals.”

Bobtail Squid, Loch Long by Mark Kirkland - “As winter creeps in, the tiny Bobtail Squid rises from the depths of the sealochs to breed. Through September and October, they can be found in depths as shallow as ten metres. Often no larger than a golf ball, a macro lens is preferable to get the glorious and colourful details. This shot shows an eye and siphon.”

Anglerfish, Lophius Piscatorius, Chesil Cove, Dorset by Jon Bunker - “Among the most beautiful of our ground-dwelling fishes, the angler fish's mottled brown tones and leafy protrusions of skin make it almost undistinguishable from the rocky, weed strewn ground that divers often encounter them in. Broad circular pectoral fins seem to grip the seabed like clasping hands on either side of the massive, dustbin-lid head. Ahead of a decreasing series of weed-like dorsal spines, the anglerfish wafts its distinctive lure or ‘illicium’ to entice unwary prey into its cavernous mouth.”