Millions upon millions of trees are being planted beside Scotland’s remotest rivers and streams to protect wild salmon from the worst effects of climate heating.
Fisheries scientists have found rivers and burns in the Highlands and uplands are already too warm in summer for wild Atlantic salmon as they head upstream to spawn, increasing the threat to the species’ survival.
Fisheries on the River Dee in Aberdeenshire, one of the country’s most famous salmon fishing rivers, have planted 250,000 saplings along key tributaries. They plan to plant a million in the Dee’s catchment by 2035, including native rowan, aspen, Scots pine, birch, willow, hawthorn and juniper.
2018 was the year Scotland had the lowest salmon rod catch since records began. Climate change meant that water temperatures in 70% of salmon rivers were too hot for at least one summer. They were above 23 C, a temperature of about 23 degrees Celsius. Induces stress and behavioral changes.
Atlantic salmon is a cold-water species and prefers temperatures higher than 10 C. At 33 C they can’t survive. Marine Scotland scientists found that only 35 percent of Scotland’s rivers, which stretch for 64,000 miles, have adequate tree cover.
Lorraine Hawkins, the river director for the Dee District Salmon Fishery Board, a statutory body, said: “These rivers and burns are the nursery grounds for young fish and it’s the young fish which will be affected by summer temperatures—their feeding and growth rates are affected. If it gets hotter, we will see fish dying.”
Similar tree-planting programs are offered by fisher boards in Scotland. They provide shade and cool water temperatures. Many of the trees will be fenced to protect them from deer. Hawkins stated these projects had a positive impact on the overall health and biodiversity in rivers throughout the uplands. They increased the amount of insect life, leaf fall, managed essential nutrients, and flood control.
Alan Wells is the director of Fisheries Management Scotland. This industry body said that climate forecasts are clear that water temperatures will continue to rise, even if governments succeed at limiting climate warming to near 1.5 C.
“We’ve seen situations where the temperatures in our rivers are approaching critical levels for our salmon, temperatures that they can’t tolerate,” he said. “This will get worse. We need to grow trees now to create that cooling shade.”
Many factors are responsible for the dramatic drop in wild salmon numbers: climate change affecting food supply; weirs or other obstructions in rivers; predation from soaring seal populations; fish farms attracted to sea lice; bycatch by trawlers on the sea and poor river quality. Wells stated that although Scottish ministers were proposing new conservation methods, he was still frustrated by the slow pace of change.
Two female anglers who had won a fundraising competition last season were invited by The Dee to join them for the first cast, an annual Banchory ceremony. Women are increasingly taking up the sport, Hawkins said, eroding the sport’s traditional domination by men in solitary pursuit of a catch.
Camryn Stewart, 14 years old, was one of the first cast fishermen. As it tries to increase its popularity and appeal, the sport is focusing on women and children. Stewart fishes with three girls her age, and she said that she doesn’t feel revolutionary.
“I have been surrounded by people who fish, and I’ve wanted to fish all my life,” she said. “We need more people fishing, not just women and children. It is a great way to gain so many benefits. Being outside and being in nature is a great way to gain. Even if you don’t catch anything, you come back from the day fulfilled.”