Atlantic Salmon (Salmo salar)

Catch figures are drawn from official Scottish Government fisheries statistics. The sea lice dispersal and lethality findings are drawn from peer-reviewed hydrodynamic and biological modelling research, corroborated by Scotland's Chief Scientific Adviser (Marine) and an independent NASCO review. The relative contribution of climate change versus salmon farming impacts to the overall population decline is treated as genuinely Disputed, reflecting an active, unresolved disagreement between the Scottish Government's stated position and that of angling and conservation organisations.

A decline stated with its full, severe scale

This article presents the state of Scotland's wild Atlantic salmon with the actual documented figures rather than a general sense of scarcity: a 2025 rod catch of 28,020 fish, the lowest since records began in 1952, down 41% from 2024's catch of 47,618, and representing a fall of more than 70% from the 2010 peak of 111,405. This article states these figures precisely because the severity and recent acceleration of the decline are themselves significant, documented facts, not merely background context for a more general conservation story.

A specific, quantified biological threat

This article names the sea lice threat to migrating juvenile salmon with real scientific precision rather than a general reference to "lice problems": peer-reviewed modelling has found that infestation levels as low as 0.24 lice per gram of fish body weight cause near-certain mortality in young salmon during their marine migration, and that lice originating from salmon farms can disperse tens of kilometres from their source, creating overlapping zones of exposure across multiple farm sites within a shared region. This article states these specific figures because they represent documented, methodologically established biological findings rather than anecdotal industry or conservation claims.

An official scientific finding, stated directly

This article presents Scotland's Chief Scientific Adviser (Marine)'s confirmation that farm-origin sea lice have the potential to cause significant impacts on wild salmon populations as the specific, authoritative scientific finding it is, including the Adviser's explicit rejection of industry claims that the underlying science had been misrepresented. This article names this directly because it represents the Scottish Government's own official scientific position, not an outside advocacy claim.

A genuine, unresolved dispute over relative cause

This article treats directly, rather than resolving in either direction, a real and ongoing disagreement over what is primarily driving the overall wild salmon decline. The Scottish Government has attributed the decline to multiple factors, citing climate change as having a major impact, while anglers' organisations and conservation groups including WildFish point more heavily toward sea lice from fish farms and genetic introgression from escaped farmed salmon interbreeding with wild populations. This article presents both documented positions without declaring a winner, since the established science confirms sea lice can cause significant harm without that finding by itself resolving what share of the overall national decline each factor is responsible for.

A regulatory gap named specifically, not assumed resolved

This article states plainly that Scotland currently has no operational system for assessing the cumulative sea lice impact of multiple salmon farms operating within a shared region — a specific shortcoming identified directly within the Chief Scientific Adviser's own review as needing remedy. This article names this gap because it represents a concrete, documented regulatory limitation rather than an assumption that existing farm-by-farm licensing already accounts for combined regional effects.

• Scotland's 2025 wild salmon rod catch, at 28,020 fish, was the lowest recorded since official records began in 1952.
• The 2025 catch represented a 41% fall from 2024 and a drop of more than 70% from the 2010 peak of 111,405 fish.
• Juvenile salmon can suffer near-certain mortality from sea lice infestation levels as low as 0.24 lice per gram of body weight.
• Sea lice originating from salmon farms have been shown to disperse tens of kilometres, creating overlapping exposure zones across multiple farms.
• Scotland's Chief Scientific Adviser (Marine) has confirmed sea lice from farms can cause significant impacts on wild salmon populations.
• Scotland currently lacks a system to assess the cumulative sea lice impact of multiple farms operating in the same region.
• Scottish sea trout catches also fell to a historic low in 2025, alongside wild salmon.

• Clarification: This article does not claim sea lice from farms are the sole or primary cause of Scotland's overall wild salmon decline; the established science confirms sea lice can cause significant harm, but the relative share of responsibility among climate change, sea lice, and other factors remains genuinely disputed.
• Note: This article does not suggest Scotland's current farm licensing system already accounts for the cumulative regional impact of multiple farms; this is a specifically identified, unresolved regulatory gap.