Scotland Saves Their Wild Salmon Population by Planting Trees to Shade Rivers

Scotland Saves Their Wild Salmon Population by Planting Trees to Shade Rivers

wild salmonEnvironment

Wild salmon in Scotland face increasing threats from rising water temperatures due to climate heating. In fact, fisheries scientists have found that remote rivers in Scotland have already become too warm for Atlantic salmon during summertime. In an attempt to protect them, officials have decided to plant trees along the riversides.

For instance, fisheries have planted 250,000 saplings along vital tributaries of the River Dee, one of the most popular salmon fishing rivers in the country. By 2035, they aim to plant one million trees of various species in the River Dee’s catchment. The trees planted would include native rowan, Scots pine, willow, birch, aspen, hawthorn, and juniper trees.

Wild Salmon Facing Multiple Threats in Scotland

Sadly, salmon catches along the River Dee have declined by a staggering 80% since 1957. In 2018, Scotland recorded the lowest number of catches since records began, which fueled recent conservation efforts.

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That summer, climate change caused water temperatures in 70% of rivers to rise beyond safe levels on at least one day. Records showed they surpassed 23C, a dangerously high temperature that can result in stress and abnormal behavior in salmon.

Since Atlantic salmon live in cold waters, they can’t survive in summer water temperatures above 33C. While temperatures haven’t exceeded 23C yet, it’s a possibility without direct climate action.

Luckily, trees offer a natural way to shield salmon from rising temperatures. However, marine scientists discovered that only 35% of Scotland’s rivers had optimal tree cover.

wild salmon

Lorraine Hawkins, the river director for the Dee District Salmon Fishery Board, said that the rivers and burns in Scotland provide nurseries for young fish. When it gets too hot, it impacts their feeding and growth, which can lead to massive dieoffs.

Unfortunately, temperatures aren’t expected to cool off anytime soon. Even if we can limit temperatures to 1.5C warming or less, water temperatures will still keep rising.

Wild salmon populations also face other threats besides climate change, making it difficult for them to survive. Dams and weirs in waterways block them from traveling upstream to migrate and lay eggs.

In addition, rising seal populations endanger salmon since they feed on them. Bycatch from trawling the ocean floor along with unhealthy rivers also threatens wild salmon. Finally, parasitic sea lice can infect salmon, especially around fish farms.

Trees Provide Relief by Shading Rivers

The rivers meander through 64,000 miles of the countryside, providing habitats for salmon, birds, insects, and other marine animals. Fisheries hope that the massive tree-planting project will improve overall biodiversity and have already seen positive results. In the uplands, marine scientists have noted an increase in insect life and leaf fall.

The added trees have also helped buffer areas surrounding rivers from floods. Officials have fenced off tree nurseries in order to manage vital nutrients more efficiently. Hopefully, these conservation efforts will ensure the long-term stability of wild salmon in Scotland.

Scottish ministers have proposed ideas to conserve salmon populations but have been slow to enact change. So, fisheries decided to get the ball rolling with the tree planting project throughout the country.

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It turns out that trees and salmon have a mutually beneficial relationship. The trees provide much-needed shade for salmon spawn, and the salmon offer nutrients to riverside vegetation.

When their bodies decompose, nitrogen, phosphorus, and other nutrients enter waterways and become available for vegetation. One study discovered that trees lining rivers where salmon live grow over three times faster than trees along salmon-free waterways.

Since the trees won’t take as long to mature, they will sequester carbon faster, helping us in the fight against climate change. It seems like a win-win for humans, animals and nature!

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