SIR David Attenborough has highlighted the threat of extinction facing the wild Atlantic salmon - a species with a stronghold in Northumberland.

In the latest episode of the BBC's Wild Isles Freshwater, Attenborough documented the life cycle of a salmon.

During the programme, he explained that “returning [wild Atlantic] salmon numbers have fallen by 70 per cent in just 25 years", adding that: “at the current rate of decline, they may disappear from all our rivers in as little as 20 years’ time."

The legendary biologist is calling for improvements to be made to the quality of freshwater and asks that barriers to the salmon's flow be removed and sea challenges better managed.

READ MORE: River Tyne only river in England where wild salmon is not 'at risk'

It comes as the Missing Salmon Alliance (MSA) has come together to further highlight the decline.

The MSA is a collective of leading salmon conservation organisations advocating for better protection of freshwater and coastal water environments and the improvement of water quality and quantity across the UK in order to reduce losses of salmon in rivers, coastal waters and the open ocean.

Jack Bloomer, deputy CEO of Tyne Rivers Trust, said: “The Tyne is the best salmon river in England and Wales, a fact that is vital for our environment, economy and communities.

"As an indicator species, salmon depend on clean water, good land management and a healthy climate.

"Therefore, reversal of the recent declines is crucial to not only safeguard the future of this iconic fish but also to protect the diverse aquatic life in our rivers and ensure we leave a healthy environment for future generations.”