More than 1,000 miles of the Tay river system is to be surveyed in a bid to improve the fishing.
The aim of the project is to improve fishing on the river
The £70,000 project will aim to draw up a list of all the problems and the work that needs to be done.
The Tay river system is the most extensive in Scotland and the study's aim is to attract more fish by making it easier for them to spawn.
The project involves the Tay Ghillies Association, the Tay Liaison Committee and charity Scottish Native Woods.
The work is seen as vital to the economy.
Some of the problems already identified include:
- Overhanging trees, which create too much shade;
- Cattle grazing too close to river banks, which causes erosion;
- Shallow water or blockages in some places.
Victor Clements, from environmental charity Scottish Native Woods, is leading the research along the river system.
He said the work would involve walking more than 1,017 miles of tributaries over the next 12 months.
Mr Clements said: "There are likely to be stretches of erosion on the river.
"There could also be tree canopies that are too dense or possibly no tree cover at all, or even blockages in the burn.
"Sometimes we can see non-native species of tree like sycamore and beech that can cast a very dense shade and shade out the vegetation and cause erosion."
Jock Monteith, from the Tay Ghillies Association, said the project could bring future benefits to the local economy.
He said: "There are issues in the habitats in all of our headwaters that closely need scrutinised.
"If we maximise our juvenile fish output, down the line we'll see more mature adult fish returning to these Tay headwaters.
"The knock-on economic effect to all the communities up and down the river throughout Perthshire will be where the real winners are."