FISHERIES

Challenges Facing Icelandic Salmon Farming

A natural threat to fish farming and its operational impact.

By Fréttir 24/7 Newsroom

Kaldvík has reported increased salmon mortality at its Reyðarfjörður farming sites following an unusually large presence of jellyfish.

AI-generated illustration of salmon and jellyfish
AI-generated editorial illustration. Not an image of the specific incident.

According to company information reported by 200 mílur, additional mortality among the 2025 generation of fish is estimated at 11.5 percentage points since September 4.

Percentage points are not the same as percentages. For example, if mortality had been 5% before the event, an increase of 11.5 percentage points would bring it to 16.5%. This is an illustrative calculation, not a confirmed total mortality rate.

The company says conditions at the affected sites have returned to normal and has maintained its annual harvest forecast of 17,000 tonnes.

Source:Original source

Update – October 15: Conditions normalised

In its latest public update, Kaldvík says the jellyfish presence in Reyðarfjörður has subsided. Biological conditions at the affected farming sites have normalised, with fish mortality and appetite returning to normal levels.

The company estimates additional mortality of approximately 11.5 percentage points in the affected 2025 generation since September 4. Despite the setback, Kaldvík has maintained its 2026 harvest guidance of approximately 17,000 tonnes. These figures are the company's own assessment, not an independent estimate of the final losses.

Kaldvík expects to provide further information on biological performance when it presents its third-quarter results on November 13. The episode illustrates both the challenges of working in the marine environment and the importance of ongoing monitoring by fish-farming teams.

Source: Kaldvík stock exchange announcement, October 7, 2026.

AI illustration of aquaculture pens in an Icelandic fjord
AI-generated illustration of fish farming in an Icelandic fjord; not a documented location.

Why can jellyfish harm farmed salmon?

High concentrations of jellyfish can stress fish, including when they come into contact with gills or other sensitive tissue. The effects depend on the species, abundance, sea conditions and health of the fish.

When mortality rises, it is important to distinguish direct causes from contributing factors such as oxygen levels, water temperature and other stresses.

AI illustration of fish-farm workers inspecting equipment
AI-generated editorial illustration of aquaculture work.

What does this mean for operations?

Higher mortality can affect biomass, delivery plans and production costs. However, the final financial loss cannot be calculated from a single percentage without information about fish numbers, average weight and prices.

Based on currently available information, the company has not changed its forecast. That outlook could change if new information emerges.

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