IN MAY, I FOUND MYSELF EXPERIENCING AN UNUSUAL SENSATION. My hands were utterly numb from the cold inside my thick neoprene gloves, yet I was almost fainting from the effects of over-heating in my drysuit in the Scottish spring sunshine.
    This was at the end of the third dive of the day in Loch Fyne. By this time some of the divers accompanying me had realised the shortcomings of even the thickest semi-dry suit, whereas I was warm in my ND Flektalon-lined undersuit and perfectly dry, courtesy of Gates. 
The unchilled nitrox from the Buddy Inspiration closed-circuit rebreather was also a comfort while I was under water, but that water was very chilling indeed and my hands had finally succumbed to the low temperature.
     However, while we had been diving, the tide had fallen.
     Mike, our shore cover, had been able to tow us out to the distant mussel ropes using the Loch Fyne Oysters tender boat, but now, with the lower water level, the oyster frames were too close to the surface for either the boat to pass or for us to swim over them.
     We were confronted by a maze of metal that was almost impossible to see as we stirred up the soft mud and stumbled towards the shore. It was as effective as a set of tank traps.
     The 15kg on my belt was nothing compared to the 34kg on my back, and the big camera housing and heavy flashgun didnt make things any easier.
     I stopped for a minute to let my heart drop back from 120 beats a minute. It wasnt just that it was trying to climb out of my chest, but the thudding in my ears was deafening. It was at this point that I began to reflect that perhaps I was getting too old for shore-diving!
     Slow My progress was just as slow as Ben Eltons asthmatic ant with some heavy shopping! With only about 300m to go, I could see Mike and diving instructor Ben waiting expectantly on the muddy foreshore.
     At 21, my buddy Baz Morgan was probably the youngest PADI Course Director I had ever met. Bursting with the taken-for-granted fitness of youth, he clearly couldnt understand what was taking me so long. Had I found something interesting to look at I can only say I got back to the shore long before the tide came up again.

Oyster frames and mussel ropes can, at times, attract considerable numbers of fish. Andrew Lane of Loch Fyne Oysters had been at pain to impress on me that while certain poorly managed fish farms could cause damage to the environment, the frames and ropes in Loch Fyne have enriched the natural eco-system by acting as reefs and making homes for all manner of other marine life.
     Which is why I had enthusiastically accepted the invitation to stay at Ardkinglas House, the baronial family seat of its somewhat eccentric and aristocratic owner, Johnny Noble. The idea was for me to go scuba-diving in the loch under the mussel ropes. And whatever the diving was going to be like, I knew I would get to eat an awful lot of oysters!
     So I had sent my Inspiration by road-carrier to Puffin Dive Centre at Oban, where its tanks were filled, and it was safely delivered to Loch Fyne by Mike Morgan along with the necessary open-circuit equipment and the two HSE- qualified instructors, Baz and Ben. They were there as underwater escorts for some of the other journalists who had accompanied me on the plane from London.

Oysters used to be plentiful and cheap. Washed down with brown ale, the British working classes of the late 19th century scoffed 1,200 million a year.
     Dickens, in Pickwick Papers, describes Sam Weller driving on a coach through Londons East End and observing that oysters and poverty went together. However, industrialisation and its polluting effects on rivers, together with over-exploitation of oyster beds, meant that stocks soon began to dwindle.
     By the mid-20th century, scarcity of supply had led to rising prices. The consumption of oysters dropped to around 5-6 million a year, and become the province of an affluent minority. Brown ale gave way to champagne. It was in France that the farming of oysters first became common, and today the French consume around 1,800 million each year. Thats 33 or so for every man, woman and child.
     Argyll, on the west coast of Scotland, has a coastline longer than that of the whole of France. Loch Fyne is Scotlands longest and deepest sea loch, and at its head, the Loch Fyne Oysters company farms oysters and mussels for consumption in its own restaurants as well as in many others in Britain. Then there are supplies to retailers and home delivery, including exports all over the world.
     Back in 1978 Johnny Noble, owner of the Ardkinglas Estate, got together with Andrew Lane, a marine fish farmer, with a view to farming oysters along the tidal zone close to Ardkinglas House.
     After a lot of experimentation and a certain amount of disappointment early on, Loch Fyne Oysters now has more than 2 million oysters laid down.

So what is an oyster Its a mollusc, a bivalve, so-called because it has two shells. An oyster is also called a clam, because it can clam shut. It is this mechanism that allows it to live in the tidal zone. When the water covers the animal, it opens and feeds by filtering the water that passes over it. When the level drops, it clams shut, conserving some of the loch water within it.
     It is this regular and routine flexing of the mighty muscle which makes the oyster prized by gourmets above all other shellfish. When you eat a Loch Fyne oyster, the liquid you are sipping is in fact the water of the loch.
     Oysters prefer the salinity found in estuarine waters, as does the plankton on which they feed. The water at the head of Loch Fyne is typically 2.8 per cent salt, whereas waters in the open ocean are likely to contain 3.3 to 3.5 per cent salt.
     With the virtual demise of the original and indigenous edulis oyster, the Crassostrea angulata was introduced from Portugal to rebuild European oyster stocks. Then, in the 1960s, the Iberian import developed a disease that also wiped out stocks.
     Todays oysters are grown from Oriental seed. This variety of Japanese gigas or cupped oyster is much hardier and grows twice as fast.
The oyster has one main enemy - the starfish. The starfish alone has both the strength and tenacity to force an oyster open. It becomes a battle of life and death as the star uses its suckers and all the brute force at its command to force open the shellfish. The oysters muscle is its only defence and eventually and inevitably the starfish wins the day.
     The oysters at Loch Fyne are protected from such attack by being in mesh bags and suspended in racks - the frames - along the intertidal zone. Other than this, there are no artificial elements to the oyster fishery. Each oyster feeds naturally on plankton brought in on the tide until the time comes for them to be lifted, washed and packed.
     The company also has a licence from the Crown Estate for a number of buoyed head-ropes in the loch. About 200m long, they carry 1000 suspended ropes, each 10m long, packed with mussels.
     In nature, mussels start life as microscopic larvae floating near the surface of the sea. In early spring or autumn they attach themselves to rocks, shells or any other obstacle they encounter. So the 10m ropes provide an ideal home where they can remain suspended above the seabed and out of reach of starfish, crabs, whelks and other predators. The culture of the mussels on the ropes is an entirely natural process.
     The lines of supporting buoys have been adopted by cormorants, gulls, guillemots, eider ducks, oystercatchers and even the odd heron. 
Swimming under the vertical lines of paired mussel ropes lent this peculiar dive site a cathedral-like quality.
     We kept to around 10m, which meant we could duck in and out of the lines. Dropping to 17m meant we lost sight of them, and our level of disorientation was demonstrated when we came up, because we were always under a different line of ropes and the lines were at least 30m apart.
     The loch bottom was extremely soft and silty, and carpeted with mussel shells. To touch it was to disappear into a thick bouillabaisse. This bottom material was studded with massive starfish, enjoying the abundance of mussels that had fallen from the ropes.
     We made three dives in, around and underneath the mussel ropes. Some of these can weigh in at around 5 tonnes when fully laden with a mature harvest.
     It was all interesting enough, but I have to admit to being disappointed with the diving.
     Visibility in midwater was not very good, though that, of course, is what the mussels like. Apart from masses of opportunistic giant starfish, the odd cerianthus anemone waving its tentacles like fronds, and a few lone dogfish, each dive was almost entirely uneventful.

I set aside my disappointment manfully. Having successfully negotiated the millions of oysters between me and the shore, I regained my composure, stripped off my kit and headed back to Ardkinglas to scoff another two dozen. Delicious!

Strings of mussels - though divers may want to see only so many.
Starfish and the occasional cerianthus anemone can be found where fallen mussels collect on the loch bed