The majority of salmon farming takes place in marine pens or cages, that are situated in rivers, lakes or seas. There are a number of benefits to this approach, such as the lower land and energy requirements compared with much land-based meat production. But it also has impacts – which are what the ASC Salmon Standard is designed to minimise.

One of the potential impacts of this type of farming that is most well-documented and reported is the risk of farmed salmon escaping. But why is this a concern and what is the industry, and ASC, doing about it?

The impacts of escapes

Why should we be concerned by salmon escaping into the wild? This is mainly a concern in areas where wild salmon populations live nearby, as there is a risk that the farmed salmon could breed with wild populations, affecting their genetic diversity, or could outcompete these wild salmon or pass on diseases. While different studies have found differing levels of impact of such escapes on wild populations, it is vital that a precautionary approach is taken when it comes to potential environmental impacts, and that’s why the ASC Salmon Standard includes a number of requirements aimed at preventing escapes. 

What does the ASC Salmon Standard say about escapes?

The section on escape prevention in the ASC Salmon Standard includes a number of requirements. Not only must escapes be limited to fewer than 300 fish in the previous production cycle, farms must ensure that they are able to accurately count any fish that do escape, and make this information publicly available. ASC certification also requires evidence of escape prevention preparation and related employee training – this includes testing net strength, ensuring appropriate mesh size, predator management, and reporting risk events.

This is important because it means the ASC Salmon Standard requires certified farms to be proactively working to prevent escapes happening in the first place, and including these checks into their routines.

What is the industry doing about escapes?

Responsible salmon farmers know that they have a duty to protect the environments they share with wild salmon, other creatures, and other humans. Any responsible farmer will take escape prevention very seriously and will work with local stakeholders to achieve this. 

One such example of this is Grieg Seafood in Norway. The film below is from a documentary series produced by an independent journalist and looks at how they prevent escapes, but work with local stakeholders and researchers to monitor the fjord for farmed salmon.



These efforts seem to be paying off. In 2013, 3% of salmon captured in the fjord were farmed, but that had fallen to 0.2% in 2019. Grieg works with ‘river stewards’, a group dedicated to protection wild salmon, and scientists, to monitor the fjord, and the findings help inform future efforts to protect wild populations.

Why do escapes still happen?

Of course, despite the efforts above, there are still occasional news reports about large escapes from a salmon farm. The causes of these can by varied, including technical failures or storms damaging nets. While bad weather can’t be prevented, the aquaculture industry is an innovative and dynamic one, and farmers are always looking for new solutions to these risks. New technology is improving the strength and resilience of nets, and other potential risks can be preventing by thorough staff training and taking a collaborative and responsible approach as demonstrated by Grieg. Ultimately, salmon farmers must take responsibility for preventing escapes which means being aware of the risks at all times, and learning from near-misses, which is what the ASC Salmon Standard is designed to encourage. 

Aquaculture explained

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