Salmon were once so plentiful in the Tyne it is said that apprentices had clauses inserted in their indentures restricting the number of times employers could serve up the fish for dinner. And in Berwick, servants had a similar stipulation restraining their masters from dishing up.
Today, the salmon are back, largely through major improvements in water quality, while the Kielder hatchery in Northumberland has also played a significant part in restoring fish stocks.
The recovery of the Tyne and its current status as the best river in England and Wales for salmon rod catches is a bright spot in a picture of concerns over a marked decline in the abundance of Atlantic salmon across the species’ geographical range over the last 15-20 years.
To highlight the situation and the importance of the species, 2019 has been declared International Year of the Salmon. The Kielder salmon hatchery, run by the Environment Agency, will be holding events. But this year will be a special one for the hatchery for other reasons. It is the 40th anniversary of the first salmon bred by the hatchery being released into the Tyne.
It will also be the first full year for the £100,000 refurbished visitor centre at the hatchery, which tells the story of the salmon’s life cycle and also features a tank which replicates the underwater world of the North Tyne, containing salmon, bullhead, stone loach, minnow, dace and lamprey. It is also the year when the first hatchery-raised juvenile freshwater pearl mussels, in danger of extinction in the North Tyne, will be released into the wild.
The hatchery was set up to produce 160,000 juvenile salmon a year for stocking the Tyne to compensate for the loss of the Kielder Burn spawning grounds, which were cut off from the river by the building of the Kielder reservoir.
For seven years the hatchery also stocked an additional 200,000 salmon to mitigate for the river disruption from the building of the second Tyne Tunnel and incidents of mortality of adult fish returning to spawn from incidents of low oxygen levels in the estuary.
Last year the hatchery stocked 360,000 salmon and 20,000 sea trout in the Tyne and its tributaries. That included 4,000 sea trout offspring introduced into the Ouseburn for the first time, and also the River Team.
This year the stocking target for the Tyne catchment is 300,000 salmon and 20,000 sea trout.
Around 40,000 juvenile salmon will go into the Kielder Burn. When the fish grow to be smolts – ready to migrate to sea usually after two years – they are captured in a trap and carried around the reservoir to be released into the Tyne at Falstone.
Tagged fish have shown that the 107km journey down the river to the sea can take up to 36 days – and as little as four.
Estuary mortality for returning adults can be caused by a combination of factors such as hot, dry summers and neap – or small – tides which means lack of freshwater flow, leading to low oxygen levels. The last bad year was 2003 when around 1,000 fish died.
During the hot weather last summer, Kielder reservoir played a vital role in reducing the risk of fish deaths in the upper estuary. Additional releases of water from the reservoir made by Northumbrian Water at the Environment Agency’s request between June 22 and August 10 amounted to 35 billion litres.
Phil Rippon the fisheries technical specialist for the Environment Agency in the North East, said: “We continuously monitor the oxygen levels in the estuary during conditions such as we saw in the summer and do what we can to help migrating fish reach their spawning grounds.
“This includes additional releases of water from Kielder reservoir to increase freshwater flows when oxygen levels in the estuary become critical. Previous research from similar summer conditions has shown that releases from Kielder sometimes triggers upstream movement of salmon and sea trout, helping them during hot and dry conditions.
“These additional releases have undoubtedly saved many salmon in 2018.”
Over the last eight years, an annual average of 30,000 salmon have returned naturally to the Tyne.
The hatchery has stabilised this improvement, as has the removal of obstacles to help fish reach their spawning grounds. It begins its breeding programme in November by capturing 55 pairs of returning adults. Eggs are fertilised at the hatchery and the young fish are gown on and set free in the summer.
Schools are given 100 eggs each so that pupils can watch the hatching and growing process, ending in them releasing their fish.
A female salmon lays between 6,000-7,000 eggs and it is estimated that around two will survive to go on and become spawning fish.
“At the visitor centre, people can learn about the life cycle of the salmon and their incredible journey from the Tyne to Greenland and back,” said hatchery manager Richard Bond. The visitor centre is open from April-September.
The hatchery’s bid to save the North Tyne’s freshwater mussel began in 2003. A total breeding stock of 81 mussels are now in an artificial stream outside the hatchery.
The mussels begin to breed at 15 to 20 years old and can live to be more than 100. But no mussels younger than 40 to 50 years old have been found in the North Tyne.
“If nothing was done in 15 to 20 years the population would become so small that it would not survive,” said Richard.
The female mussel produces two to four million barely visible juveniles which float in the water and seek to attach themselves to the gills of trout. Months later they drop off and settle on the bed of the river.
This year 768 two-year-old mussels raised by the hatchery will be released into the wild.
“We are absolutely delighted to have managed to raise the first North Tyne mussels bred in captivity, with the aim of preventing the population from becoming extinct,” said Richard.