The genetic dismantling of Salmo salar
Written by Integrum ESG Analyst Jack Morphet
Bakkafrost, a salmon farming company, disclosed a large-scale escape of 251,344 fish from their nets in the Faroe Islands during an extreme weather incident in their most recent integrated report.
While the transparent disclosure is positive, we must look closer into this biological impact via an ESG lens, and therefore consider the wider implications.
One of the less publicised negative externalities around salmon farming is the effect of escaped Atlantic salmon entering the wild. At face value, this may seem like a trivial issue, even exciting for some anglers.
The reality is far more problematic.
Farmed Salmon Entering the Wild
Farmed salmon have a direct impact on the existing wild salmon populations for several reasons. Introgression is arguably the most insidious issue, weakening the genetic integrity of wild Atlantic salmon in the UK, which as of 2023, were reclassified from ‘Least Concern’ on the IUCN Red List, to ‘Vulnerable’.
When breeding between wild and farmed salmon occurs, it contributes to offspring with an inferior genetic load to survive in natural conditions through each lifecycle, resulting in a slow decrease of future salmon populations’ genetic fitness on an already reduced gene pool.
A study by Bolstad et al (2021) on the effects of introgression between farmed and wild Atlantic salmon confirmed that farmed genetics contributes to an increase in the phenomenon coined ‘pace of life’ (POL). Having a faster POL in salmon contributes to an array of traits and behaviours that overall has a negative impact for a salmon’s survival, such as decreased egg size and more boldness in the context of emergence time after exposure to potential danger, meaning farmed fish and the hybridised offspring are more likely to be susceptible to predation.
Bakkafrost are not the only company responsible for such biodiversity blunders, with Arctic Fish, a subsidiary of Mowi, who allowed 3,462 fish to escape in Icelandic fjords. Such cases are not followed up with fines deemed significant by companies in this sector such as Mowi who stated in the year of this release that they had ‘No significant fines/penalties/litigation actions in 2023’ in the context of nature-related impacts.
The Future of Biodiversity
This begs the question, why are these companies not held to account? Is it a lack of education on their impact or are we happy to turn a blind eye to supermarket salmon?
This addresses a wider global issue outside of salmon farming and its many issues. By allowing the genetic resilience of the surviving wild ancestors of our domesticated farm stock to decrease through poor management of biodiversity, we expose ourselves to a huge food risk.
A good example of this is the decrease of genetic variability through introgression and loss of habitat of the red jungle fowl, the wild ancestor of the domestic chicken. The domestic chicken with a lower gene pool, is constantly exposed to epidemics that risk wiping out a species we rely on so heavily. To ignore its wild ancestor with its greater genetic diversity is a poor insurance plan for putting food on the table.
When companies play God with genetics, it doesn’t lead to a Jurassic Park-like scenario – but it does slowly dismantle the genetic fabric of animals’ key to our existence.
To put it simply, we must take greater care of the biodiversity and consequently the genetic diversity of our wild species to ensure the survival of domestically farmed animals and ourselves.