Even the rich and famous are beginning to take notice of climate change. First their skiing holiday has been delayed because there is no snow and now their fishing holiday because the fish are confused.

For over 150 years, the start of Scotland’s salmon fishing season on the River Tay has been celebrated in the middle of January. But the impact of climate change on spawning patterns is forcing has forced anglers to postpone this year’s official seasonal opening on sections of the waterway for two weeks.

For the first time in decades, salmon fishing in parts of Perthshire has had to be delayed because the fish, which begin breeding in earnest as soon as the first heavy frost of winter starts to bite, have been thrown into confusion by the mild weather.

“We’ve got a lot of fish in the river due to mild water temperatures but they have not had the big nudge from Mother Nature yet to get about their business,” said John Monteith, a local “ghillie”.

He added: “For the past four or five years, about 60 per cent of the fish caught on the opening day and subsequent weeks are fish that haven’t spawned. It is clearly related to climate change and warmer water temperatures. We need a good hard frost to trigger the breeding season.”