'Monster fish' 20 times their original size are swarming Scottish lochs

Trout in the Scottish lochs have grown 20 times their size because of overfeeding on fish food leaking from salmon cages. The 'Franken–trout' weighs 9 kg when the regular fish weigh only about 0.45 kg. Activists have raised the alarm over the matter, saying that it is causing an imbalance in the ecosystem, as the big trout are eating the smaller fish. They have blamed Cooke Aquaculture, a Canada–based multinational, for the travesty. The company operates fish farms in 16 countries and has several fish nurseries across Shetland's lochs. Young salmon are kept in net cages in the north of Scotland, and their feed is overflowing into the water, which the trout end up gorging on.

Dale Vince, founder of the Green Britain Foundation, said, "the feed, the chemicals, the faeces and the medicines" are entering the water, which is going everywhere. "These monster fish, wild trout grown to a size nature never intended, are a direct result – Frankentrout, gorging on what pours out of the cages," he said. Most of these huge trout are located in the Loch of Cliff, the campaigners claim, where once "many small brown trout" lived. Ever since fish cages were installed, the native fish have grown much larger, a local fishing guide said.

Meanwhile, Cooke claims they are following strict environmental regulations and constantly monitor the fish farms. However, campaigners say the industry is highly unregulated and is polluting the seas and lochs. Nick Underdown, Scotland director at WildFish, told the Daily Mail that artificially fattened wild trout lead to a change in "their natural distribution and role as predators within a loch."

He further warned that chemicals also leach into the waters and are consumed by wild fish, as salmon farms use antibiotics to limit disease outbreaks. But Cooke denies using antibiotics at Loch Cliff. The company further argued that there is no proof that the medicines at salmon farms are making wild trout in the loch unsafe or unsuitable to eat.

Campaign against salmon farms in UK

In the UK, a wider campaign against salmon farms has been going on, arguing that they act as breeding grounds for sea lice, which latch onto migrating wild salmon and feed on their skin and flesh. Farmed salmon also escape and mate with the wild fish, weakening the genetic resilience of native populations.