Breadcrumbs
South East Undersea Landscape
Chalk reefs and extensive gravel beds, some of them ancient flooded river valleys, characterise the regional undersea landscape off the South East coast. These, such as the Hastings Shingle Bank, host carpets of sponges and anemones and are rich feeding grounds for fish. At Mixon Hole off Chichester, the seabed plummets suddenly into a sunken Roman remain where large lobsters and fish shelter. Around the Isle of Wight there are pupping grounds for several species of shark, and caves with dead men’s finger sponges.
This area is home to:
- Shark central – all around the Isle of Wight there are nursery grounds for sharks such as tope, smoothound, the rare porbeagle and the thresher. The truly ‘electric’ electric ray is also found here.
- Mantis shrimp warrens. These are small but feisty shrimps which burrow in muddy seabed areas - in captivity they have been known to break aquarium glass but, out in the wild, cod somehow manage to catch and eat them.
- Kelp forests sheltering cuckoo wrasse and sea urchins.
- Chalk and sandstone reefs encrusted with kelp, red algae, ‘boring’ sponges, baked bean sea squirts and dead men’s fingers. Cuttlefish live here as does the cute tompot blenny.
- Seagrass meadows - home to the enchanting sea horse that bobs around in the swaying fronds of seagrass.
- The mysterious Mixon Hole – a deep incision in the clay seabed off Selsey Bill. It is filled with lobsters, sponges, anemones, tope and thornback ray.
- Communities of anemones and sponges forming meadows on large furrowed gravel beds.
If you couldn't make our events in person, why not try out our activities?
Panorama
Click the numbers on the image below to find out more about the diverse range of species and habitats.
1. New Forest
The New Forest is a National Park and the most intact surviving example in England of a medieval hunting forest. Its unique landscape includes woodland, open heathland, riverside and coastal land. [back to panorama]
2. Southampton
3. Chichester Cathedral
Chichester harbour has a population of common seals as well as native oysterbeds. [back to panorama]
4. Brighton
5. Dungeness
East of Dungeness lies the Pomerania, one of dozens of wrecks that litter the seabed floor and create reef conditions teeming with life. It lies at about 30 m on a flat seabed of cobbles, gravel and shell fragments. The wreck now supports a rich mix of carrot, goosebump and elephant-hide sponges, antenna hydroids, plumose and other anemones, dead men’s fingers, common mussels and finger bryozoan. Also found here are two types of sea slug, and fish including bib, wrasse, gobies and tompot blennies, edible and swimming crabs, and starfish. [back to panorama]
6. Dover
7. Seagrass meadow – home to the delicate seahorse
Seagrass is the only flowering plant fully adapted for life in the marine environment. It is home to a wide variety of animal life including fish such as sea horses which are often found in water less than one metre deep. [back to panorama]
8. Mantis shrimp warrens in muddy seabed
On the north side of the Isle of Wight there are warrens of quick moving, burrowing and highly predatory mantis shrimp. These shrimps can grow up to 10 cm in length and kill their prey by spearing it and grabbing it with powerful arms, hooked like a preying mantis. These feisty little creatures feed on crabs and clams and can inflict a painful jab on divers, delivering a punch as powerful in proportion as a .22 bullet! They have been known to break the glass of an aquarium. Somehow, cod manage to catch and eat them. [back to panorama]
9. Roaming cuttlefish
Cuttlefish are the chameleons of the marine world. They are capable of rapid colour change and use this ability to camouflage themselves. Cuttlefish often feed along the sandstone reefs, which occur from Beachy Head to Selsey Bill, and the chalk and limestone reefs offshore between Selsey and Brighton as well as around the south of the Isle of Wight. [back to panorama]
10. Living cliff of reef worms
At the eastern mouth of Chichester harbour, there is an underwater cliff which is 25 m deep. The cliff is made of sand glued together into a living mass by the ross worm. This tube-making worm glues together sand particles to make a protective home from which it projects its delicate tentacles to filter food particles from the seawater. Other tube worms, including the mason and peacock worms also occur here. [back to panorama]
11. Mystery of Mixon Hole
Mixon Hole, a nationally famous dive site, lies 1.5 km off Selsey Bill. It plunges from a shallow shoal of sand down a precipitous wall of clay rock, dropping 29 m to a gravelly seabed. Thought to be a former Roman fort or quarry, Mixon Hole is at the entrance of a submerged river entrance, and filled with lobsters, hermit crabs and hundreds of fish.
Used by the Romans to supply the garrison town of Chichester, it is now home to sponges, anemones, dogfish, thornback ray and tope sharks. On the seabed floor there are mysterious ball-shaped rocks covered in algae and sponges, which some say were once hurled from Roman ballistas. The Hole is swept by fierce currents. [back to panorama]
12. Submerged ancient river valley
Off Dungeness there is a large ancient river valley filled with gravel, now flooded by the sea. Dungeness forms part of a site of special scientific interest which is the largest shingle foreland in Europe - remarkable for its shingle beaches and sand dunes as well as the rare and threatened species associated with these habitats. [back to panorama]
13. Treacherous Goodwin Sands – site of numerous shipwrecks
Off Kent lie the Goodwin Sands, parts of which are exposed at low tide and which are notoriously treacherous to shipping. Here many wrecks lie half buried in the sand after foundering during storms. These sands, and others found off Dungeness, form a landscape of underwater dunes and ridges up to 50 km long and 40 m in height.
Living in the often mobile sands are a host of sea creatures including the heart urchin or sea-potato, the masked crab, and the furry, iridescent-green sea mouse, which is in fact a mobile form of seaworm. [back to panorama]
14. Chalk reef with dead men’s finger caves off Isle of Wight
The underwater chalk reefs fringing the Isle of Wight are home to a colourful garden of red algae and anemones such as the snakelock and jewel anemones.
At the western end of the Isle of Wight there are submerged caves packed with the soft coral-like dead men’s fingers, a yellow-white sponge. [back to panorama]
15. Beds of maerl – a rare slow-growing algae
Off Culver Spit on the Isle of Wight, the gravels are covered in a solid layer of coral-like red algae known as maerl. Beneath the upper pink crust-like layer, the maerl branches create a delicate three-dimensional lattice which allows sea water to penetrate the seabed and creates conditions where dozens of sea creatures thrive. [back to panorama]
16. Sandy seabed
Most of the seabed is gently sloping, reaching a maximum depth of 85 metres and covered in a mixture of sands and gravels. The plains created in this way are hunted over by many fish, and molluscs such as scallops live on the seabed. [back to panorama]
17. Shoal of the Lead cascade – an undersea ‘waterfall’
The dramatic underwater falls or cascades known as Shoal of the Lead occur 8 km south of Selsey Bill where the seabed plunges dramatically from 0 to 67 metres, causing strong ‘overfall’ currents. [back to panorama]
18. Harbour porpoise
There is a front (ie a separation line in the sea between warmer and colder water) which runs from the east to the south of the Isle of Wight. This front brings up seabed nutrients which attract fish such as mackerel, and these in turn attract dolphins, porpoises, the occasional whale and many seabirds which feed on them. [back to panorama]
19. Sole on the sandy seabed
Flatfish such a brill and, dab, dover sole and plaice hunt over the sand hills and plains on the seabed and sole spawn in great numbers in an area running seawards and east from south of Brighton. [back to panorama]
20. Chalk reef and underwater caves where tompot blennies lurk
A very rich variety of animals - including the breadcrumb sponge, the shredded carrot sponge, the sandalled anemone, and the lightbulb seasquirt - cover these underwater chalk cave walls, boulders and cliffs.
Lobster, squat lobster and tompot blenny live in nooks and crannies. Golfball sponge also occurs in the Solent and off the Isle of Wight. [back to panorama]
21. Shoals of mackerel and cod and the occasional pilot whale
Shoals of mackerel are attracted to the seabed nutrients brought up by the front (ie the separation line between warmer and colder water) which runs from the east to the south of the Isle of Wight. Cod spawn just north of the Hastings Shingle Bank. The fish attract whales, including pilot whales, and dolphins, which may be encountered offshore. [back to panorama]
22. Shark pupping ground
All around the Isle of Wight but especially across the gravely anemone and sponge meadows of East Wight and South Wight, there are nursery grounds for sharks. These include the tope, smoothound and the rare porbeagle shark. The most commonly sighted shark in this area is the harmless filter-feeding basking shark. [back to panorama]
23. Rocks with dahlia anemone, sea urchins, crab, light bulb sea squirt
Dahlia anemone, slipper limpet and keelworm are typical of this gravel and rock area, along with scallops, sea urchins, sea slugs, starfish, crabs and lobsters. The light bulb sea squirt is a transparent-looking sea creature, half the size of a person’s little finger which looks like an electric light bulb. It is a filter feeder sucking in water and filtering out microscopic organic particles. [back to panorama]
24. Hastings Shingle bank with anemones and sponges
Very large gravel beds exist near the half-way line to France south of Beachy Head, and at the Hastings Shingle bank south of Eastbourne. These places are rich in sealife, including many commercially important fish, and large areas rather like meadows are covered in a dense sward of anemones and sponges. At least 48 species of Atlantic fish have been recorded in the area. [back to panorama]