Sunday Times (UK)

Salmon face extinction in UK rivers

Jonathan Leake

Sep 8, 2019
Atlantic salmon, a species that once packed British and European rivers, is down to its last few million fish and faces extinction in many UK waters, according to scientists.

Just 5% of the salmon hatched in UK rivers return to breed, compared with 25% two decades ago, they found.

It means fish numbers have hit their lowest ever, with 50,000 salmon caught in the UK last year — the worst result on record and a fraction of the 600,000-800,000 caught annually until the 1960s.

“Wild salmon face extinction in many English rivers,” said Mark Owen of the Angling Trust, which has jointly commissioned research into the decline. “They are also declining fast in Scotland and Europe. It’s an absolute tragedy.”

Early results from the research — known as the Missing Salmon Project — suggest, however, that the problems lie partly in Britain’s rivers but also in the manmade hazards facing fish when they leave fresh water and head out to sea.

One hypothesis is that they are starving because fishing vessels are “hoovering up” the sand eels and small fish on which they depend to sell to fish farms. Professor Dieter Helm, chairman of the natural capital committee, which gives the government expert advice on rivers, oceans and other natural assets, wants such “industrial fishing” to be restricted.

Food shortages may continue when the fish reach their feeding areas off west Greenland and in the Norwegian Sea, where climate change is reportedly causing declines in the supply of prey.

“Salmon used to be abundant around the north Atlantic, from Spain and northern Europe to the east coast of north America,” said Andrew Wallace of the Atlantic Salmon Trust, which is co-sponsoring the research. “Anecdotally the UK rivers were full of fish, but now we estimate that just a few million remain.”

Historically, salmon was once so cheap and plentiful that workers begged not to be fed on it. In the 17th century, restrictions were placed on how often salmon could be fed to shipyard apprentices on the Tyne after they complained.

Last year Scottish wild salmon disappeared from restaurant menus after Scotland’s last netting station closed. It is illegal to sell rod-caught salmon.

Clues to the recent decline in Atlantic salmon have come from a tracking scheme in which scientists from the Missing Salmon Project tagged fish born in rivers around the Moray Firth with devices that made them visible on sonar.

Sonar arrays on the seabed up to 30 miles from shore counted the fish as they headed out to sea. “About a quarter used to return to their native rivers but now it’s just 5%,” said Wallace. “We need to know why so few are coming back.”

Fish farming is a likely factor in the decline of wild salmon, as caged fish produce polluting waste and act as reservoirs for diseases and parasites.

Helm, an angler, said fish farming also created a market for sand eels. “Wild salmon and other species rely on sand eels but they are being hoovered up by industrial fishing boats to produce fish meal for aquaculture,” he said.

Separate research into the Pacific salmon, which is related to the Atlantic species but whose populations are far healthier, suggests that a key, and unsuspected, cause of the decline is on land, because salmon are dependent on trees.

Guido Rahr, an American researcher, found that young salmon flourish in rivers lined with trees. The healthiest and most productive habitats are those that run through woods and forests.

Rahr, whose work will feature in a new book, Stronghold, written by Tucker Malarkey, published this month, said: “Tree roots bind river banks, creating clear water and protecting the gravel beds where fish spawn, while fallen trees also create exactly the right habitats for small fish to hide and grow.

“In Britain and Europe even top rivers like the Dee or Spey are surrounded by farmland, so you will never get salmon back in their original numbers unless you replace farms with woodland.”

Atlantic salmon

● Young Atlantic salmon spend one to three years in fresh water before going out to sea
● A further one to three years later, they return to their native rivers to spawn. Most die but 5% survive to spawn again
● The biggest salmon ever caught in the UK, in 1922, weighed 64lb
● Farmed salmon far outnumber wild ones, with Scotland producing 200,000 tons a year. At its peak Scotland’s wild salmon fishery produced 12,000 tons.


Pacific salmon

● Pacific salmon comprise five main species but all start their lives in fresh water before heading out to sea to grow
● Like Atlantic salmon, they mature at sea and then return to their native waters to spawn
● Females make nests in the beds of streams before courting a male, releasing eggs and then covering them in gravel
● Chinook salmon are the largest — the biggest caught, in Alaska in 1949, weighed 126lb.

@Jonathan__Leake

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