Divernet

DOES GOING FOR A DIVE have to mean boarding a boat to travel to a site offshore Diving used to be concentrated far more on coastal sites, often accessed from a beach. Are we missing out on some rewarding diving in our rush to get out there
Among prime coastal possibilities that are easily overlooked are river estuaries. They offer not only sheltered diving with easy access but also a remarkable wealth of marine life. Two examples in south-west Cornwall, the Fal and Helford estuaries, have recently been designated as Special Areas of Conservation (SACs) by the European Community.
Both are examples of drowned river valleys (or rias) and offer navigable depths, reef structures, firm seabeds and reasonable visibility - all of which makes them ideal diving locations.
These river systems were drowned at the end of the last Ice Age by a combination of sinking land and rising sea levels. The Fal in particular offers quite dramatic profiles under water, from the drowned flood-plains to the remnants of the original river valley, which penetrates far inland and retains depths of 35m and more.
The Industrial Revolution and commercial expansion early this century once threatened these habitats with careless waste disposal from copper and tin mining and china clay extraction.
Fortunately, in recent decades a greater understanding of the damage caused by pollution has emerged, and marine reserve status has returned many areas to their former glory.

The Helford river estuary has a rocky foreshore of granite and shale extending as reef outcrops into the estuary. There are small coves and pebble and shingle beaches which gradually degrade to a heavy grey granite sand. As you swim out from the shore, the sand line slowly pales and becomes finer, at which point the first eel-grass beds appear.
The Helford and the Fal are among the few locations in the UK where eel-grass thrives, and it provides a rich habitat for marine life.
As the depth increases towards the centre of the estuary, the sand becomes softer and more silty and is peppered with small reef outcrops. At high water, maximum depth generally ranges from 10 to 15m and the currents are negligible except on big spring tides, though you do need to be aware of potential boat traffic in the centre of the river, particularly the silent wind-powered vessels!
Dives can be made from one of the small coves or by boat, but if you choose a beach dive, as I normally do, this can involve a bit of a trek with your kit, so small cylinders are the order of the day.

Visibility in the estuary varies with the level of rainfall, from 2-3m up to 10m during calm, dry periods in the summer. When the waters appear murky it is best to dive on the flood tide, which will push some of the brackish water upriver and often produces better visibility under a surface layer of 2-3m.
Even at high water the eel-grass beds are no more than 50m or so from the shore and begin in depths of only 6m. This is a good place to start your searches. Numerous spindly decorator spider crabs suspend themselves between stalks, almost like spiders on a web, and the seaweed on the bottom will reveal many pipefish, sticklebacks and, in late summer, juvenile cuttlefish only 25-30cm long. A variety of juvenile fish shelter in the beds and also, reportedly, mane sea horses, though these are not commonly seen.
There are also well-camouflaged hunters within the eel-grass preying on the small and juvenile species. Patient observation will reveal scorpionfish resting on the bottom, often almost covered by weed and debris, and the elegant john dory, which weaves its way slowly between the vertical stalks.
Less mobile residents include several species of nudibranchs and sea hares, which are numerous in the early spring. A telltale sign of both species are the intricate spirals and twirls of their spawn on the base of individual blades of eel-grass, and these will often lead you to the perpetrator.

Moving beyond the eel-grass beds towards the centre of the estuary brings you onto a sand and silt seabed which is home to a number of bottom-dwellers. The most common are dragonets, topknots, dabs, plaice and, if youre lucky, the occasional anglerfish and thornback ray.
In the spring and early summer you will also find adult cuttlefish, which come into the shallow waters to mate and lay their eggs in the eel-grass beds. Diving closer to the mouth of the estuary will reveal small schools of pollack in search of sand-eels or juvenile species on which to feed.
Reef outcrops host all the usual shallow-water species of anemones, sponges, wrack weeds and lettuce seaweeds. The shelves and fissures which bisect these rocks are home to edible crabs, velvet swimming crabs, prawns, squat lobsters and the occasional large common lobster, which will march out boldly to meet your intrusion.
In the summer months, investigate the arms of the snakelocks anemones. They may well shelter one or more decorator crabs which have covered themselves in a fine cloak of sponge. Fish species include tompot and blackface blennies, leopard-spotted gobies and shannies.
As you make your way back to the shore, the shallows are a good place to spot grey mullet foraging among the shingle. These mullet look approachable from the surface but are shy fish. It requires a lot of patience to get close to them.

The Fal is a much broader estuary than the Helford and has a more varied topography, ranging from the former shallow flood plains to steep reefs and drop-offs in the centre channel.
In the shallow waters are sweeping beds of maerl, a type of encrusting algae which forms little coral-like clusters.
The fauna of these maerl beds is very rich, with many species of fish, crustaceans, worms and molluscs hiding among the delicate branches.
On the eastern side of the estuary, around St Mawes and St Anthony Head, youll find further eel-grass beds, and a little further up the estuary are thriving beds of wild oysters. These can be fished commercially by hand only, from licensed punts.
The tidal movement in this estuary is much stronger than in the Helford and there is a lot more shipping and boat traffic, so planning a dive, particularly in the main channel, takes a little more effort.
Diving in the Carrick Roads (the local name for the channel area) requires the permission of the harbourmaster and you must use a surface marker buoy to ensure that your boat cover stays with you.

You can enter the water from the shore at Pendennis Point on the west side or St Mawes on the east, but to dive in the main channel a boat is the only option. Many divers start at either the East Narrows Buoy (green) or the West Narrows Buoy (red), which mark the edges of the deepwater channel on the approaches to the estuary and are anchored in shallow water (8-12m depending on tide).
On the east side, start on the bank of the main channel where swathes of fragile maerl harbour fascinating invertebrate life. From this point it is obvious where the main channel lies, as the seabed slopes gently at first and then more steeply towards a reef which appears at around 20-25m. This reef then plunges sheer for another 10m or so to the bottom of the channel.

It can be quite gloomy here, although the visibility is often surprisingly good, but using a torch will ensure that you miss none of the life in the reef. All the usual suspects are here together with soft corals, gorgonian fan corals and Ross coral (a colonial bryozoan) decorated with brittlestars.
Reaching the bottom of the channel brings a change to a fine sand and silt seabed which is home to scallop beds, numerous species of flatfish, red gurnard and the occasional anglerfish - and provides the chance to find some interesting ceramics and glassware.
In the days of sail, Falmouth was a very busy port and many ships would anchor in the Carrick Roads and, with no regard for conservation, tip their rubbish over the side. You can trace history by finding cod bottles, ceramic beer bottles and jars, numerous items of crockery and even clay pipes.

It is tempting to cross the channel and ascend the west bank, but not only is this a long swim but it would be very dangerous if you had to surface in the main channel - the harbourmaster would not be impressed! So retrace your route up the east bank until you reach 6-8m to be sure that youre well clear of the channel.
Starting your dive on the west side is a slightly different experience. The seabed is more gravelly, though with occasional beds of living and dead maerl.
The bank slopes much more gently towards the main channel and is a good area to look for flatfish, rays and anglerfish. Thornback and blond rays are most often seen, with brill, plaice, sole, flounder and even turbot on occasion.

There are isolated chunks of reef along the west bank but not the defined drop-off found on the east side. Your descent to the channel is more gradual, reaching maximum depths of 35-38m depending on the state of the tide. Both sides can be dived through the tide, although slack water is probably easiest and you should avoid anything but slack on spring tides, when the current can be very strong.
Both of these estuaries are used by local diving operators, often when conditions preclude diving in Falmouth Bay. There is even a wreck in each to be explored, the Rock Island Bridge in the Helford (50.05.52N 05.05.56W, just off Toll Point) and the Stanwood in the Fal (50.10. 19N 05.02.06W, close to the red North Bank buoy).
But perhaps you should consider these estuaries as primary dive sites and try something a little different and closer to the shore. Their protected status means that marine life will continue to thrive and conditions will improve in both rivers.

The
The tompot blenny is a favourite on any dive and will often occupy the same hole on a reef for years
janolus
janolus nudibranchs are most often found feeding on spiral bryozoans
Pendennis
Pendennis Point on the Fal estuary provides a number of beach-entry points
the
the foreshore at Grebe Beach
Lobsters
Lobsters thrive in the protection of the estuaries
Anglerfish
Anglerfish are a rare sight in inshore waters but are still found in the Fals main channel, where commercial fishing is banned
strawberry
strawberry anemones are common in shallow estuary waters
bottles
bottles and stoneware jars found in Carrick Roads in the Fal estuary
A
A shy shanny peeks out from among purple seaweed on the reef edge
Thornback
Thornback and blond rays are regularly seen in the Helford and on the West Narrows side of the Fal estuary
Beadlet
Beadlet anemones are found just below the surface and retract when exposed at low water
decorator
decorator spider crabs are unaffected by the stinging tentacles of snakelocks anemones
spider
spider crabs grow to impressive size
scallops
scallops still thrive in the deep channel of the Fal estuary

FACTFILE

AIR & NITROX: Cornish Diving (01326 311265); Dive Action (01326 280719); Haven Underwater Centre (01326 250852); Porthkerris Dive Centre (01326 280620) or Seaways (01326 375544).
BOATS: For launching use the slipway at Falmouth Watersports Centre or take off from the beach at Maenporth or Porthoustock, on the Lizard. Cornish Diving, Dive Action and Porthkerris Diving Centre can arrange dayboats or try Gamgy Lady (01326 375458) or the Patrice (01326313265).
ACCOMMODATION:Many local camping and caravan sites, holiday cottages, B&B and pub accommodation. Call Falmouth Tourist Board (01326 312300) or use www.cornwall-online.co.uk.
FURTHER INFORMATION: Falmouth Harbour Commissioners (01326 312285/314379), Fal and Helford Marine SAC - English Nature (01872 265710).