For more than 150 years, the start of Scotland's salmon fishing season on the river Tay has been celebrated in the middle of January.
But the apparent impact of climate change on spawning patterns has forced conservationists and 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, head ghillie for the Newtyle beat of the river Tay.
"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."
Mr Monteith is worried that starting the season too early could endanger fish stocks as the pattern of late spawning appears to have been repeated more than once over the past few years.
The last time fish spawned as late as this was in the early 1980s when considerable catches of spring salmon were recorded.
"There has definitely been a long-term change in the weather which has thrown the opening season out of sync," said Mr Monteith, who wants the Tay District Salmon Fishing Board (TDSFB) to bring the Tay into line with the Spey and Dee which traditionally start the season in February.
"To disturb fish when they're trying to reproduce is wrong," said Mr Monteith. "We need to protect spawning fish but if we allow fishing to start too early it is going to be detrimental to the long-term future of salmon fishing."
While other beats on the Tay are opening as usual, with a party at Kenmore on the upper Tay yesterday typical of the annual celebrations which surround the event, members of the TDSFB claim there is no reason to change the practice for the moment. "The Tay has some of the earliest runs of fish in Scotland," said David Summers, fisheries manager.
"Ever since the 1860s it has been felt appropriate to have a very early start to the Tay season."
According to the TDSFB salmon spawn at different times along the length of the river and in the greater part of the Tay spawning has usually finished by the end of November. It is only as fish progress farther down river that spawning appears to get later, often occurring around Christmas.
"As a board we have to consider the whole of the Tay catchment area, not just the experience of a particular stretch," said a spokesman. "However if it was felt there was an overwhelming case for change, we would look at the issue".
Anglers at Newtyle are being supported in their move by conservationists who point out that while January may be the traditional start of the Tay salmon season for anglers, the fish don't go by calendars but by the climate.
If anglers can't wait, it has been suggested that they might adopt a catch and release policy as practised on the river Dee.Reuse content