Salmon deaths double on Scottish fish farms – but are jellyfish to blame? | sailor life

Salmon deaths in fish farms Scotland Nearly doubled last year, official figures show, due to rising levels of disease, parasites and jellyfish blooms. Campaigners blamed overcrowding and called for a boycott.

Fish Health Inspectorate (FHI) data shows nearly 15 million salmon deaths were reported in Scotland from January to November 2022, compared with 8.58m in all of 2021 and 5.81m in 2020, the most recent data available.

Atlantic salmon production has remained stable at around 200,000 tonnes per year for the past four years, with some estimates of 77 million fish being farmed annually.

Salmon farmers have blamed unusually large numbers of micro-jellyfish in British waters last year, a phenomenon that may be linked to climate change, but Animal Equality UK executive director Abigail Penny said overcrowding on salmon farms was to blame. .

“Mortality in fish pens has reached record levels for many reasons,” he said, “from infested water including a sharp increase in infectious diseases among fish held in abnormally crowded cages, as well as poor gill health and harsh treatment to remove lice.

“As the industry grows, so do these issues. We must take back power and ban farmed fish – it’s the only way we can begin to control this ever-worsening problem.”

Salmon mortality

The Fish Health Inspectorate, part of Marine Scotland, is responsible for monitoring 213 seawater salmon farming sites in Scotland. A Scottish Government spokeswoman said farms had a voluntary agreement to report salmon deaths within specified boundaries.

“Death reports list multiple causes – such as gill problems, bacterial or viral infections, handling or predation – so it is not always possible to assign a death to a specific cause,” the spokesperson said.

“However, gill health remains a key issue. Environmental issues including jellyfish and plankton blooms and bacterial infections have increased as causes of death in 2022.”

The UK is surrounded by sea Growing number of jellyfishAccording to the Marine Conservation Society.

Salmon accounts for 29% of all fish sold to UK consumers, who spent £1.2 billion in shops last year, and almost a quarter of Scottish salmon is exported.

Salmon in their cages
Salmon in their cages. Wrasses are small fish introduced by Loch Duart Farm to control fish lice. Photo: Murdo McLeod/The Guardian

Atlantic salmon are raised in net pens up to 160m wide in Scottish waters including its longest marine loch, Loch Fyne, meaning farms are exposed to the natural environment and marine ecosystems affected by farming.

During their two-year life cycle, farmed salmon are vulnerable to rough weather, predators such as seals and sea lice, and disease, especially when the water is warm in September and October.

The drone collected the footage Animal Equality UK Workers use a “mort sock” to dredge dead fish from the bottom of the pen.

Don Staniford of the Scammon Scotland campaign said, “I’ve kayaked to the farm at 5am in the summer, when they start working, and you see dead fish stomachs lying on top of the cages”. “Others have sunk. So the first thing they do is collect the dead fish.”

Staniford said the FHI statistics on salmon deaths may be an underestimate because not all deaths are required to be recorded.

“About 25% of salmon are dying in sea cages, so that’s about one in four,” he said. “If the ramblers saw one of the four cows or sheep dead in the field, they would be horrified, but as it is under water, it is out of sight, out of mind.”

He pointed to sites with huge mortality rates, reporting a cumulative 64% mortality last November at a farm on Loch Nevis. “There is no ethical way to farm salmon,” he said. “They are freeloading into the Scottish environment, impacting on local communities dependent on tourists and affecting the welfare of farmed fish.”

Salmon Scotland said jellyfish blooms could force a site to close, or collapse, with farmers collecting all the fish.

Tavish Scott, chief executive of the industry body, said: “Wild Atlantic salmon have a survival rate of around 1 to 2%, compared to around 85% for farmed salmon.

“There will be various environmental stressors throughout the year that will affect survival rates. Farm-raised Scottish salmon typically face their greatest challenges in autumn when seawater temperatures are at their highest.

“Salmon farmers care for their fish every day and do everything they can to provide world-leading animal health and welfare standards so it’s devastating when the fish in their care are exposed to naturally occurring challenges.

“We are working with industry and academia to develop an early-warning system that helps protect fish from future jellyfish blooms.”

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