Salmon in Yorkshire Rivers
Extract from the Yorkshire Post 29th November 2008
Salmon have been seen on the Derwent and are being caught on the Ouse. Roger Ratcliffe reports on preparations for the king of fish’s
return to the upper reaches of the River Aire.
A grainy photograph taken of a leaping salmon on the River Derwent last week opens another chapter in the success story of cleaning up Yorkshire’s rivers.
The photo was shot by a landowner on the river’s stretches above Malton but cropped to prevent poachers from finding the location. It is all the more remarkable for the fact that on its way up from the sea to find spawning grounds the salmon had somehow managed to clear the large barrage which keeps out the tidal Ouse at Barmby.
The Derwent was one of the cleanest rivers in England half a century ago, together with the Ouse, more than seven tonnes of the fish were caught there.
However, problems of pollution and obstructions like weirs and dams saw numbers dwindle. On the Derwent in fact, there had been no salmon since the barrage was built in the mid-1970s to preserve the river’s fresh water for drinking.
But in the past decade they have been returning, and the quantity of salmon to Yorkshire rivers is now the region’s greatest wildlife triumph. The River Ure is now said to be as good as many Scottish salmon rivers. The River Don – once among the most poisoned rivers on Earth – for the first time in living memory has salmon as far up at Sprotbrough Weir, just 15 miles from the heart of Sheffield.
Salmon are also regularly swimming up the River Aire to Chapel Haddlesey, near Eggborough Power Station, and occasionally are seen in flood conditions 10 miles upstream at Knottingley.
It is on the former industrial rivers like the Don, the Calder and the Aire that much of the effort is being concentrated. Toxic pollution from textile mills, dyestuff factories, chemical works and steel plants has become a thing of the past.
Discharges of filtered and treated sewage effluent (now known by the friendlier name of waste-water) have become less and less dangerous to aquatic life.
The River Aire now presents the biggest challenge of all Yorkshire’s rivers, and this week the ground – or rather the water – was being prepared for the salmon’s eventual return to its upper reaches.
In a low-key operation, the Environment Agency released thousands of fish at four points along the Aire to see if they will survive. Bred at the agency’s fish farm at Calverton, Nottinghamshire, they were brought up the M1 in large tanks.
A fisheries officer with the agency, Peter Turner, divided 1,000 young barbel between release points at Kirkstall and Apperley Bridge, and 1,000 grayling – a member of the salmon family – on the west side of Bingley.
Each barbel has been injected with a tiny piece of red polymer which sits just underneath the skin and does not hurt it or cause irritation.
When the river is surveyed next year the discovery of untagged barbel will mean that the fish have survived to establish a breeding population.
The grayling were too small to tag. But the mere survival of any grayling in the Aire will be a sure sign that the river is also good enough for salmon – for grayling are considered to be one of the best indicators of a river’s quality. They can live only in clean, well-oxygenated water.
On other Yorkshire rivers like the Don and Calder, Peter Turner says, conditions are now so improved that they don’t require restocking with fish.
“But on the Aire it isn’t as good as it could be. There are some stretches of the river which are still quite patchy for fish, so the populations need a bit of a kick-start.
“We don’t fully understand why fish don’t thrive on some parts of the Aire, but we’re trying to improve things by putting in buffer fencing to stop cattle churning up the banks.”
Bank erosion means that earth is flushed into the river by rain, and silt covers up the vital spawning gravels.
However, Peter adds that there are no plans to try releasing salmon into the Aire.
Artificially introducing salmon parr (fish that are between one and three years old and capable of breeding) would not be a good idea.
At least not while we have so many weirs in place.
“It would screw the fish up, because they would want to get back to the stretch of river they believed they had come from.”
It’s the weirs that pose the biggest obstacle to making the Aire a salmon river once again. Although a £400,000 fish pass has been built to circumvent a large weir in Castleford, there is no evidence that salmon have managed to reach beyond that point on the river in significant numbers.
Beyond Castleford there are a further two dozen weirs, at least six of which would require similar fish passes if salmon have any chance
of swimming through the centre of Leeds to suitable spawning grounds.
Kevin Sunderland of the Aire and Calder Rivers Group and a founder of the Derwent Salmon Group, lives in Bingley and campaigns for the removal of weirs and the building of fish passes.
He has successfully got commitments for new salmon passes written into strategic plans for the Aire and for Leeds and believes that the official will is now there to make it happen. All that is required is the money.
Meanwhile, the water quality is set to improve even further next year when £64m of improvements to the sewage treatment works at Esholt are completed. The stretch of river between Apperley Bridge and Kirkstall has been identified as a likely area of salmon to spawn.
“I’m not a salmon fisherman but a conservationist,” says Kevin. “I simply want to see the Aire become a proper river once again. I can remember it in the Sixties when it was nothing more than a sewer. My dream is that in my lifetime I will see salmon return to Bingley and spread all the way up to Skipton.”