More than 50 miles of the Wansbeck river system, and 30 miles of the Blyth, are being opened up to migrating salmon and sea trout.
The Environment Agency has built fish passes at Mitford on the Wansbeck and Hartford on the Blyth this year, in time for this year’s autumn salmon run.
In the Wansbeck, this will allow fish to reach historical spawning grounds for perhaps the first time in centuries.
David Kirkland, project officer at the Environment Agency, said bringing salmon and sea trout back to the upper reaches of the two rivers reflects significant improvements to river habitats and water quality that have been made in the north east over the past 20 years.
“The water quality in headwaters is generally very good,” he said.
“It is expected that the salmon eggs laid in these areas this autumn will hatch into tiny fish next spring, live and grow in the river for two years, and then head out to sea in May 2017.”
In total, the Environment Agency said it has invested a total of £440,000 in the projects.