There used to be a romance about the life cycle of the salmon. There was something mysterious about the way each young fish left its home river and went to sea, only to return to exactly the same place as a mature fish on its way to spawn.

The image of the wild salmon that heads home, overcoming waterfalls and swimming against a rapidly flowing stream, is used subliminally in advertising. Much supermarket smoked Scottish salmon is sold with the logo of a leaping fish. A natural food is the message; raised fresh, clear, island and highland water and air is the image.

But the reality is somewhat different. Modern farmed salmon are raised in great cages in sheltered voes and bays. The product is good. It has made salmon popular and accessible – but somehow the romance has gone.

All day today a helicopter has been flying overhead. Back and for between a hatchery on Unst and a fish carrier ship at Baltasound pier. Each journey involves the helicopter carrying a canister of fish dangling at the end of a wire beneath the aircraft across the hills. Each canister is about the size of a large oil drum and during the whole operation some 150,000 smolts are transported. For each young fish this helicopter ride is its introduction to the big wide world. Scooped from fresh water in their home tanks they are taken in the hold of a ship to their new home. In today’s case the fish are on their way to Westray. So fish that started out as Unst salmon will end up in packaging describing them as from Orkney. Not that they’ll have an identity problem, but the life cycle their ancestors enjoyed is now a thing of the past for today’s modern fish. Freshwater tanks on Unst, brief helicopter ride, a couple of days in the bowels of a ship and then a new life in the sea off Orkney!