Salmon deaths double in Scotland’s fish farms – but is jellyfish to blame? | Marine life

Salmon mortality in fish farms Scotland It practically doubled final yr, official figures present, because of growing ranges of illness, parasites, and jellyfish proliferation. Activists blamed the overcrowding and known as for a boycott.

Fish Well being Authority (FHI) information exhibits nearly 15 million salmon deaths have been reported by farms in Scotland from January to November 2022, the most recent information accessible, in comparison with 8.58 million in all of 2021 and 5.81 million in 2020.

Atlantic salmon manufacturing has remained broadly steady at round 200,000 tonnes yearly for the previous 4 years, with some estimates as many as 77 million fish being farmed yearly.

Salmon farmers have blamed the rise on unusually giant numbers of tiny jellyfish that swept British waters final yr, a phenomenon that could possibly be linked to local weather breakdown, however Abigail Penny, chief govt of Animal Equality UK, mentioned overcrowding at salmon farms was responsible. that. .

“Deaths in fish pens have reached report ranges for numerous causes,” she mentioned, “together with a pointy rise in infectious illnesses amongst fish packed in abnormally overcrowded cages, in addition to poor gill hygiene and tough therapies to take away lice from infested waters.”

“Because the trade grows, so do these issues. We should take again energy and boycott farmed fish—it is the one method we are able to rein on this drawback, which is getting worse.”

Salmon mortality charges

The Fish Well being Inspectorate, a part of Marine Scotland, is chargeable for monitoring 213 seawater websites in Scotland for salmon farming. A Scottish Authorities spokesperson mentioned farms have a voluntary settlement to report salmon deaths over sure thresholds.

The spokesperson mentioned: “Demise stories record a number of elements – eg gill issues, bacterial or viral an infection, dealing with, or predation – so it isn’t all the time doable to assign deaths to a particular trigger.”

Nonetheless, the well being of the gills stays a significant concern. There was a rise in attributing environmental points, together with jellyfish and plankton blooms, and bacterial infections as a reason for deaths in 2022.”

The seas round her uk An growing variety of jellyfishIn response to the Marine Conservation Society.

Salmon accounts for 29% of all fish bought to UK shoppers, who spent £1.2 billion in shops final yr, and a couple of quarter of Scottish salmon is exported.

Salmon in their cage
Salmon of their cage. Small fish are launched by the Loch Duart Firm to manage fish lice. Picture: Murdo MacLeod/The Guardian

Atlantic salmon are raised in web pens as much as 160m vast in Scottish waters together with the longest marine loch, Loch Fyn, which means that farms are uncovered to the pure setting and marine ecosystems are affected by agriculture.

Throughout their two-year life cycle, farmed salmon are susceptible to excessive climate, predators akin to seals and sea lice, and illness, particularly when the waters are hotter throughout September and October.

Drone footage collected by Animal Equality UK It exhibits staff utilizing a “stocking mort” to scoop useless fish from the underside of pens.

“I have been kayaking out to the farms at 5 within the morning in the summertime when it is gentle, earlier than they begin working, and also you see useless fish mendacity on prime of the cages,” mentioned Don Staniford, of Scammon Marketing campaign Scotland. . “The others have sunk to the underside. So the very first thing they do is accumulate the useless fish.”

Staniford mentioned the FHI numbers for salmon deaths are probably an underestimate as a result of not all deaths have to be recorded.

“About 25% of salmon in sea cages die, about one in 4,” he mentioned. “If climbers noticed one in 4 cows or a sheep useless in a discipline, they’d be horrified, however since it’s underwater, it’s out of sight, out of their thoughts.”

He pointed to websites with large mortality charges, with one farm in Loch Nevis reporting a cumulative mortality charge of 64% final November. “There is no such thing as a moral strategy to farm salmon,” he mentioned. “They’re working liberally on the Scottish setting, impacting native communities that depend upon vacationers, and there is an affect on the welfare of fish farms.”

Scottish Salmon mentioned jellyfish blooms may power the positioning to shut or fall flat, with farmers harvesting all of the fish.

Tavish Scott, chief govt of the trade physique, mentioned: “Wild Atlantic salmon have a survival charge of simply 1-2%, in comparison with round 85% for farm-raised salmon.

“All year long there might be completely different environmental pressures affecting survival charges. Farm-raised Scottish salmon often face the most important challenges within the autumn when seawater temperatures are at their peak.

“Salmon farmers take care of their fish daily and do every little thing they’ll to supply world-class requirements of animal well being and welfare, so it’s devastating that the fish of their care are going through naturally occurring challenges.

“We’re working with trade and academia to develop an early warning system that can assist defend fish from future jellyfish blooms.”

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