One of the finest birthday presents my wife ever bought me was three days' salmon fishing on the Tay. Unfortunately she booked it when there were no salmon in the river. After two days' fruitless casting, we went down to Pitlochry to check the fish counter, which records the number of salmon passing through. The answer? Just one.
"Never mind. Perhaps you'll catch that one," my wife said optimistically. "There's more chance of the world ending tomorrow," I replied.
Around the same time I would have discovered an important meeting I couldn't avoid if someone had offered me the chance to spend my birthday on the River Carron in Wester Ross. In 2001, the West Highlands river produced just six salmon.
Last year, though, the total rose to 262. This extraordinary revival is largely down to Inverness College. Among the heather and midges, it appears that they study useful things like fishery management rather than media studies, ethnic cooking or the characters in 'Coronation Street'. So when salmon numbers on the local river slumped, the fisheries research department came up with an answer.
The problem wasn't habitat, as it usually is. Like California in the 1700s, it was a great place to be but nobody knew about it. Stocks were so low that even if the young salmon all made it to sea, escaped the cormorants and seals for a couple of years and came home, there still weren't enough of them to set up a Friends Reunited site.
The college caught what salmon they could, set up a hatchery and gave them free food and lodging. Some went back as tiddlers, but most were reared to maturity.
Numbers improved a little in the next two years, but in 2004, when the restocking plan really kicked in, 141 salmon were caught. Bob Kindness, a lecturer in freshwater fisheries research and one of the prime movers in the scheme, said: "I would have been delighted to reach 100 in five years." Things kept getting better. Numbers rose to 166 the next year, 200 in 2006 and 262 last year. Following the axiom that a salmon is too valuable to be caught only once, every fish is returned.
"I don't know if we are at the top yet," said Kindness. "The recovery has been as dramatic as the initial decline. We can only put this down to the stocking programme. The results demonstrate a way forward for fisheries that have suffered in the same way as the Carron."
The fish are bigger, too. Five over 20lb were taken in 2005, a spectacular number for a river that traditionally yields salmon of only half that weight. The river record, a 27-pounder caught by Lady Evelyn Cobbold in 1924, was beaten by Kindness himself last year when he landed one of 32lb.
Kindness, who admits to fishing the river nearly every day, has caught more than 300 salmon there over the past three seasons. Sounds like most of his lecturing has been to spotted fish rather than spotty teenagers.
Amazingly, the Carron's fishing potential is still almost unknown. Only 170 day tickets (and those at very cheap prices) were sold last year. So if my wife decides to buy me a few days in Wester Ross later this year, I'm pretty certain that the diary's empty.