Salmon are able to swim up the River Mersey to spawn in the gravel beds on the Bollin and the Goyt, but their path is blocked by weirs on the River Tame.
The fish are also unable to migrate up the River Irwell due to the Mode Wheel Locks at Salford Quays, close to the BBC’s headquarters at MediaCity UK.
Mike Duddy, from the Salford Friendly Anglers Society, said: “It would be very difficult to build a fish pass due to cost and physical space constraints.”
“If we wanted to do something for our future generations, now is the time to build a fish pass because there are huge numbers of people that would love to see salmon returning to the Roch and Irk, as well as the rivers in Bolton.”
Key pressures faced by Atlantic salmon include climate change, poor water quality, river blockages such as dams, and invasive non-native species.
An Environment Agency spokesperson said: “We will be undertaking a new salmon distribution study in early 2026, using eDNA sampling, to build an even better picture of the spawning range and assess the extent of recovery.”