Acoustic salmon trackers used to find out why population is shrinking

• Video report by Lewis Warner.

Conservationists looking into the drastic decline in the world's wild salmon population are using the River Nith in Dumfries & Galloway for their research. 

Acoustic tracking devices have been installed along the river to detect the movement of tagged Salmon. It is hoped the data will give a better picture of why the population is shrinking. 

Research shows in the 1980s, there were between eight and ten million salmon swimming in the Atlantic.

But that number has now plummeted to between two and three million with fears salmon could disappear from our seas and rivers altogether in just 20 or 30 years. 

A spokesperson for The Atlantic Salmon Trust said: “Right now, there is very little information of what happens to our young salmon as they journey around our coasts."

He continued: “This presents a number of problems when trying to safeguard this important species. If we do not know where they are going, for example, we cannot make informed decisions to minimise the impact from the dangers they face.

“The West Coast Tracking Project will fill this gap in our knowledge, tracking wild Atlantic salmon over a three-year period to better understand their migration routes and, ultimately, to inform policy on how best to look after them.”

Scotland's rivers are home to 90% of the UK's salmon population and the team behind the project says the River Nith is perfectly placed for this research.Data will be collected for around 100 days before any action can be taken to prevent salmon from slipping away.