SALMON have laid eggs in the River Sirhowy for the first time since the mining industry began in the Valleys.
Following a conservation campaign three nests have been spotted in Blackwood after the river was made more fish-friendly.
The Atlantic salmon have not been able to swim up river from the Atlantic and Irish Sea in around 100 years, due to pollution from mining and industry and from manmade barriers in the river such weirs.
Now a partnership between Natural Resources Wales, Caerphilly Council, South East Wales Rivers Trust and Groundwork Caerphilly has worked toward bringing the native species home.
Each November salmon make an “incredible journey” up the river where they were born to mate, lay their eggs and then usually die, project officer Hywel Abott, 27, said.
Their ‘nests’ – where the female moves gravel on the river bed with her tail into long runs – can contain up to 2000 eggs, of which around 10 per cent survive to adulthood.
Although salmon normally return to the river they were born in, “some of them get lost”, Mr Abbott said, which explained how the Sirhowy is populated again.
Mr Abott has been working on the project since November 2012.
He said: “We’re really pleased.
“Natural Resources Wales discovered the nests when they were conducting their survey.
“It was exciting. Now we’ll let them develop.
“Hopefully we’ll go and have a look to see if there are any young salmon in that area.”
The nests were laid at Blackwood at the Sirhowy Enterprise Way, near the Chartist Bridge and close to The Rock pub a few miles north of the town.
Groundwork Caerphilly has linked up with local schools to teach them about conservation work.
Next Wednesday youngsters from Cwmfelinfach Primary School will release young salmon raised from breeders into the river.
Gibbs Weir and another smaller weir just upstream known as Penmaen Weir were taken down to remove barriers to the salmon’s migration from the Irish Sea and the Atlantic.
The Healthy Rivers Partnership are hoping that the journey will become an annual event.