Sir Ian, known by his nickname "Beefy", was guest of honour and speaker at the launch event held at the River Teith today.
He performed a toasting ceremony to mark the opening of the season, and was piped to the river at Callander by The Tulliallan Pipe Band, accompanied by Stirling's Provost Mike Robbins and local anglers.
Botham, 58, has been a keen fisherman since childhood and throughout his cricket career.
He has spoken extensively about his knowledge and passion of fishing, as well as publishing a memoir of his experiences.
A scheme aimed at reducing illegal fishing and other river-associated crime was launched as part of the celebrations.
Riverwatch encourages members of the public to report any suspicious activity to the authorities.
Meanwhile motor sport engineer and former Formula One team principal Ross Brawn cast the first fly to open the season on the River Dee at Potarch, Aberdeenshire.
Mark Bilsby, river director of the Dee District Salmon Fishery Board and the River Dee Trust, said: "The opening of a new salmon angling season is always a time for optimism.
"Our efforts towards the restoration of north-east Scotland's most iconic river continue and we are backing a scheme that will open up access for salmon and sea trout to 80 miles of tributaries this year."
The dates of salmon fishing season range from January to November on the Tweed, with regional variations occuring at different points throughout the period.
Alex Salmond opened the salmon fishing season on the Tay last month, as well as Councillor Liz Grant, the Provost of Perth and Kinross, who was joined by Mark Stephen, presenter of BBC Radio Scotland's "Out of Doors" series as she made the first cast further upriver at the Kenmore Hotel, Scotland's oldest inn.