Sea lice are tiny crustaceans in the Caligidae family. These parasitic creatures are present in wild salmon and trout populations around the world. They are not related to their human-bourne counterparts (which are insects) but they do have many things in common – they feed on the skin and blood of fish, causing a number of health and welfare issues. 

If they take hold in a farm, they can cause real damage and distress, and if wild populations are migrating near the farm they could also be put at risk. All of this makes the management of sea lice a critical factor of the ASC standard for responsible farming.

This is an issue that is tackled by numerous requirements in the ASC Salmon Standard, and is something we are always looking at: our requirements on sea lice treatments were reviewed in 2019 and in 2020 we have begun a review looking at the limits on sea lice levels permissible by the ASC Salmon Standard. 

Is the industry taking this seriously?

However, it is also an issue that the wider industry is taking very seriously. All farmers have to deal with parasites and disease, but the aquaculture industry is an innovative industry and many new solutions are being trialled to deal with sea lice that don’t involve potentially harmful chemicals. just some examples currently being used or researched include thermal treatments; ‘snorkels’ that form a barrier against sea lice while allowing salmon to reach the surface of the water; and anti-sea lice feed. This is fast progress for an industry that is only a few decades old, but there is always more to be done, and ASC will continue to encourage farms to further reduce their use of chemicals. 

The below video is from a series of documentary films by an independent Norwegian journalist and part-time angler who asked Greig Seafood how they tackle the sea lice issue.



How do ASC certified farms deal with sea lice?

ASC certified salmon farms must work with other farms (even if they are not ASC certified) in their area to create an Area Based Management plan to minimise the collective impact of the farms. No ASC farm can use chemical treatments that have been banned in any salmon producing country, and all chemical treatments must be signed off by a veterinarian before use. 

The ASC Salmon Standard also sets very strict limits on chemical treatments, requiring that farms use non-chemical treatments instead wherever possible. The number of chemical sea lice treatments is also limited, with farms required to continually reduce the frequency of these treatments until they meet the level of global best practice. Any treatment used by an ASC certified salmon farm must be permitted in the country that the farm is situated. 

The ASC Salmon Standard also requires that neither chemical usage nor effluents should have any significant impact on the local biodiversity. 

Can more be done?

At ASC we share people’s concerns about the impact of sea lice on farmed salmon, which is why are reviewing our requirements on this area. The ASC Salmon Standard already includes requirements limiting the number of sea lice that present during sensitive periods for any nearby wild salmon populations, but this review will look at the latest evidence to see if these requirements can be further strengthened. 

We have also commissioned research in British Columbia to better inform the sea lice debate. This research will dive into data from BC farms to provide in-depth insights into sea lice levels throughout the year, how and when these numbers go up, as well as what effect different treatments have. The data will come from multiple sources, including ASC certified farms which must publish such data as a requirement of certification. This will be used to inform the review of our standard, but we envisage it also having wider implications to others in the industry. 

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