Think you've seen it all in British waters? The latest book from Diver marine life expert Paul Naylor sheds new light on the often strange private lives of the creatures we encounter. Great British Marine Animals is an ID guide that also includes many unusual photographs. Here Paul tells the stories behind a few of them
UNWELCOME CLEANER Rock cook cleaning spider crab
Porthkerris in Cornwall is an excellent spot for observing fish behaviour in shallow water. Rock cooks can often be seen performing a cleaning service for large ballan wrasse by removing parasites. This was the first time I had seen an animal other than a wrasse receiving their attention. It was a large spider-crab. As the debris and attached material on the back of the crab serves as camouflage, the rock cook's work was probably unwelcome!
THIRD PARTY Harbour crabs
Pairs of harbour crabs in pre-mating embrace are a very common sight in many places. As in most crab species, the male holds the female beneath him until she moults and becomes receptive, whereupon the two will mate. This pair were being followed by another male, which appeared to be waiting for an opportunity to 'steal' the female away. I was able to observe this scenario for a long time, because the couple seemed far more concerned by their crab 'stalker' than by the much larger intruder with diving gear and camera.
SOFT TOUCH Common hermit crab with moult
All crabs periodically shed their armour in order to grow. When moulting, they are defenceless and have to hide away because predators and their colleagues will happily eat the soft-shelled delicacy. Hermit crabs are better equipped, because they can hide in their mollusc shell home while the new armour on their front part hardens up. This hermit crab, found near Oban, had moulted out in the open and the recently discarded armour can be seen in front of it.
HOUSING SHORTAGE Common hermit crab in damaged shell
It was late in the day when we arrived at our holiday cottage in Plockton near the Kyle of Lochalsh. Keen for a dive, but with no time to get out to our intended sites, I went for a dip next to the local harbour. The sandy seabed was alive with hermit crabs. It was presumably this high population density, and the resulting intense competition for disused mollusc shells, that led to such a badly damaged item being inhabited. This substandard home allowed me to photograph the strange, unarmoured rear of the hermit crab that is rarely seen.
CRAB'S WORST NIGHTMARE Sacculina carcini, a parasitic barnacle
Few animals have a more bizarre form than this parasitic barnacle. Nothing like a normal barnacle, Sacculina carcini is the stuff of nightmares. Its larvae land on a host crab and grow roots that penetrate the crab's body. Eventually, the parasite produces a reproductive mass visible as a large smooth lump under the crab's tail flap. It is unusual to be able to get a camera low enough to photograph the bulge, and the most obvious sign of infestation is normally the encrusting material accumulated on the crab's shell, because it cannot moult.
SO SHY Galathea squamifera, a small squat lobster
Spiny and long-clawed squat lobsters are a common sight under water, but this little chap, Galathea squamifera, is much less obvious. Though abundant, it normally stays hidden beneath boulders or within small holes. I spotted these two (the second is at the very bottom of the picture) while examining a mass of entwined Serpula worm-tubes near Oban. These tubes form small reefs in some locations, providing a home for an amazing variety of creatures.
STRANGE BEDFELLOWS Prawns and conger eel
Large numbers of prawns are often found living in the same nook or cranny as a large conger eel. They may benefit from the conger's scraps or provide a cleaning service, but it is hard to believe that some don't end up as convenient appetisers! It took me a long time to find a crevice in which all the inhabitants could be conveniently framed in a single shot.
TWICE THE FUN Limacia clavigera nudibranchs
All nudibranch sea slugs are hermaphrodites - simultaneously male and female. Their sexual organs are on the right-hand side of their bodies and this pair of Limacia clavigera clearly demonstrated how they are brought together at mating to allow reciprocal fertilisation. This means that both members of a couple give and receive sperm and both go on to lay eggs. These slugs were pursuing their activity on a colony of sea-mat bryozoan, which is their favoured prey; dinner and dance all in one!
SHELL SHOCKED Gaping file shell
Gaping file shells (also known as flame shells) are normally hidden in 'nests' made from sand and shell fragments bound up with their own byssus threads. This one was being carried by a velvet swimming crab and provided an ideal opportunity for a clear photograph, showing the striking orange tentacles. The crab was presumably going to try to break it open as soon as possible, but the file shell's acid secretions may have permitted a last-minute escape.
HANGER-ON Lamprey on pollack
Shoals of pollack congregate and cruise around at the top of the current-swept slopes in Plymouth Sound. The wealth of other life on the slopes makes it easy to overlook them and I nearly missed the fact that one of the pollack wasn't keeping up with the rest. It had a large lamprey attached. These primitive parasitic fish lack jaws but clamp their rasping mouths onto the body of the host fish and suck out food for themselves. The damage done to the flanks of the pollack is clear to see.
SENDING OUT SIGNALS Common starfish
This starfish was striking its spawning pose close to the main entry point for shore diving at St Abbs. Mating in starfish is a remote business and it was about to release either eggs or sperm into the sea water. A chemical released by the female with her eggs encourages other females and males in the vicinity to join in so that fertilisation can occur. Sure enough, a little further down the gully, other starfish were starting to spawn.
QUICK WHEN IT WANTS TO BE Short-spined sea scorpion
The short-spined sea scorpion (or bull rout) is one of those bottom-living fish that lacks a swimbladder for buoyancy and is usually considered ungainly. This one moved with startling speed to capture a shore crab that was walking across the stone wall of a slipway. Once settled back on the seabed, happily chewing its prey, it was an ideal subject for a portrait.
HIDDEN VENOM Lesser weever
Until I dived off the beach at Criccieth in north Wales, I had never seen more than a fleeting glimpse of a lesser weever, the most common venomous fish around Britain. Here, weevers were extremely abundant but still very difficult to photograph. They lie buried in the sand and it is usually only their eyes that are visible. If disturbed, they swim off surprisingly rapidly. This individual just seemed far less timid than all the rest.
LOW-PROFILE John Dory
When photographing a John Dory I have usually tried to get the standard side-on profile shot. This tends to be difficult as the fish attempts to turn head-on or rear-on, so its thin outline makes it much harder to see. During my encounter with this individual, I suddenly realised that the view it wanted to give me was the one I needed in order to show the function of its unusual shape.
BIG FAMILY Viviparous blenny
Most animal species seem to frequent all our coasts or to be more abundant in the west. The viviparous blenny is unusual in appearing more commonly on the east coast, where this one was spotted along with several others in a marina. It was the first time I had seen these fish under water, having only previously met them during shrimping trips on the Norfolk coast. As the name implies, they bear live young - up to 400 of them at a time.
HUNTER-KILLERS Saithe hunting sprats
This dive was memorable for the distance I covered (less than 5m) as well as for the wonderful sights. I dropped into the water at the bottom of the steps at Weasel Loch near Eyemouth, and was immediately surrounded by a swirling shoal of tiny sprats. They were cornered by young saithe whichrepeatedly scythed through the shoal to grab what they could. The speed of action made them extremely difficult to photograph, but I managed a few useable shots from the roll of film.
HEAVY METAL Two-spot goby
The males of many fish species take on beautiful coloration at breeding time. This two-spot goby, usually an unremarkable brownish-red, had fins decorated with stripes of the most fabulous metallic blue. He was involved in a courtship display, stretching his fins out for maximum effect. What female goby could fail to be impressed? The male goes on to guard a nest in which several females may have laid their eggs.
VERTICAL DROPPER Sand star
Sandstars have a much more slender profile than other starfish, so are ideally suited for slipping through sand in their hunt for buried prey. Their tube feet have spiked tips rather than the usual suckers, which also helps them move in sand. Until I watched this individual, I had imagined that they slid edge-on beneath the seabed. Instead, it just sank straight down, taking about 30 seconds to disappear.
ABOUT THE BOOK
Paul Naylor's Great British Marine Animals includes material from his book Marine Animals of the South-West, but greatly expanded to cover species common in other parts of Britain, plus additional information on the habits of animals such as sea anemones, crabs and starfish. Half of the 350 photographs are new.
Contents range from the dazzling jewel anemone and cuckoo wrasse to massive creatures such as the 30m-long bootlace worm; from ruthless hunters such as the starfish and octopus to creatures such as the sea hare and pipefish, with their astounding breeding habits.
Designed to aid identification of common animals in British seas, the bookincorporates as much information as possible on how they go about their lives.
Photographs show how they feed, breed, avoid being eaten and interact with other creatures in different ways.
Great British Marine Animals costs£14 from diveshops, bookshops and Underwater World, 020 8943 4288. Further details: www.marinephoto.co.uk