'An average day's fishing depends on what river you are fishing. I was on the Spey last week and I was averaging 11 pearls a day - 11 saleable pearls I mean - some of them worth £5. You never lose the thrill of getting a pearl that's perfect, unblemished, you know it's a thing of beauty. It's not really the money, it's the beauty and the challenge because it takes you a long time and experience before you can get a pearl like that out of the river.' The tools of his trade are a glass-bottomed bucket and a cleft ash stick, his job is an eternal treasure hunt - he is Bill Abernethy, the only man in Britain to have on his passport, 'Profession: pearl fisher.'