Traffic Lights: According to iLAKS, salmon farmers in Production Area no 4 are hoping to return to court to challenge the latest measures imposed on them by the Traffic Light System that is supposed to protect wild salmon and sea trout from the alleged impacts of salmon farming. Production Area no 4 has been assessed as being in the highest risk category with a ‘red ‘ classification. A new analysis of the available data has shown that the classification is likely to be incorrect.
By total coincidence, I have just completed my own analysis of the 2023 NALO sea lice data, which is used as the basis for the Traffic Light assessments. It had been a struggle to obtain this data which should have been posted by the Institute of Marine Research for public viewing. I had previously obtained the data for 2018-2021 but 2022 data had not been published even towards the end of 2023, but my complaints must have eventually been heard as both the 2022 and 2023 data were suddenly made available,
I have conducted an overview of all the data from 2018 to 2023 which appears in my report, but I primarily focused on the most recent data. The full report can be downloaded from
or email relaks@callandermcdowell.co.uk to request a copy.
As a scientist interested in comparing the impacts of sea lice across 13 different production areas I would attempt to conduct an identical analysis for each area. I would also attempt to sample a similar number of fish from each area using the same methodology. Unfortunately, instead of adopting this strategy, the Institute of Marine Research have targeted the areas that they think will result in the highest risk to wild fish. Thus, PO3 and PO4 were sampled 42 and 50 times respectively, whilst PO13 was sampled just 3 times.
In terms of the number of fish sampled, IMR sampled 1,097 from PO 4 and 729 fish from PO3. By comparison less than 100 fish were sampled from the following production areas, PO1, PO2, PO7, PO8, PO9, PO12 and PO13 with PO1 sampling just 54 fish for sea lice. In their 2012 review, Taranger and others recommended that a minimum of 100 fish should be caught in each sample so seven of the production areas failed to meet the minimum requirement for sampling sea lice, yet the Expert Group appeared happy to accept such low numbers in order to produce their assessment.
Whilst the number of fish caught from PO3 and PO4 was high, analysis of the number of fish caught per sampling was extremely low. For example, 18% of all samplings during 2023 caught just one fish with a further 16% catching 2 fish and another 16% catching 3 fish. Thus 50% of the samplings caught 3 fish or less. This is hardly representative of an sea lice population. In addition, because of the way sea lice are distributed on wild fish, something IMR and the Expert Group appear to ignore, the likelihood is that most of the fish sampled carry high numbers of sea lice. Sea lice are naturally spread across their host fish as an aggregated distribution, the main feature of which is that the majority of hosts carry no or very few parasites whilst a very few fish carry many parasites. The way that IMR sample fish means it is these few fish with high lice numbers that tend to be caught.
These fewer fish are also easier to catch in traps rather than nets. This is also apparent from similar methods employed in Scotland. In 2023, 2706 samplings took place using traps whilst 1025 samplings were made using nets. The way in which these two methods were deployed shows no consistency throughout all 13 production areas. For example, Jarford in PO13 was sampled using just traps, whilst Straumfjord in PO11 was sampled only with nets. In total nets were used in 19 of the 29 locations sampled whilst traps were used in 25. Fifteen of the locations were sampled with both nets and traps although the balance between the two could be large. For example, Rosendal in PO3 was sampled 29 times using nets and 116 times with traps.
The fundamental issue is that the poor sampling undertaken by IMR does not reflect the natural distribution of any parasite, let alone sea lice. In effect, they are sampling only part of the sea lice population, and this tends to be those few host fish with high lice numbers. This is extremely misleading.
At the start of the report, I reproduce the first page of a standard 548 page parasitology textbook, the first chapter of which is titled ‘What is a parasite’. This includes reference to the distribution of the trematode parasite Displostomum spp which commonly occurs in the eyes of fish throughout the world. The lens of a few fish are found to be infected with enormous numbers of larvae (over 400 in one fish) but most contain relatively few. This sounds very familiar to those working with sea lice. High numbers of larvae occur naturally but the anti-salmon farming narrative has meant that people believe that such numbers are unnatural, when they are not. iLAKS interviewed the outgoing Fisheries Minister who said that there are too many lice in some production areas. Unfortunately, she has been misinformed. Hopefully, the new Fisheries Minister will be more open to listening to those outside the very blinkered scientific community in Norway.
However, it is not just sea lice sampling that is flawed. The Traffic Light System assessment involved the use of three separate models, Institute of Marine Research, Veterinary Institute and SINTEF. There are differences between the three which begs the question as to how much these organisations really understand sea lice ecology if they can’t agree on one model. At the same time, none of these models has been properly validated. They all rely on some form of particle dispersal model, yet despite many years of research, the predicted swarms of sea lice larvae have never been found in any water body in Norway or even in Canada, Scotland, or Ireland. The hard reality is that any sea lice larvae that are dispersed from salmon farms are so diluted within one kilometre that they are undetectable. This dilution also means that these lice larvae pose no risk to wild fish.
I am not the only one who is sceptical of these models. The farmers of PO 4 have concluded that previous Traffic Light decisions are flawed. For example, the IMR model was amended in the autumn of 2023. When past data is applied to this amended model, it is clear that for 2019, the previous red classification for PO 4 is wrong. In addition, the 2019 assessment was based on theoretical calculations and the limited number of observations contradicted these calculations.
Finally, the PO3/4 Knowledge Incubator show that in 2023, lice levels on farms in the Sognefjord were historically low. Yet at the same time, lice levels on migrating smolts were exceptionally high. The scientific community have failed to explain how this could occur. The answer is simple – exceptionally poor sampling.
The simple fact is that the Traffic Light System is not only flawed, but also pointless. Wild fish are at much greater risk from exploitation that they are from sea lice and yet it is sea lice that are subject to regulation, whilst anglers continue to catch and kill wild salmon for sport as is their want. The Traffic Light System should be scrapped.
Meanwhile: According to Fish Farming Expert, the Scottish Fisheries Minister, Mairi Gougeon, who was at the Seafood Expo in Barcelona said in regard to the sea lice framework that ‘we do want to make sure that we are using the best available science and evidence’.
However, despite her assurance that the best science will be used, the reality is that it is not but what is more concerning is that whist the Minister may want to use the best available science and evidence, neither SEPA nor the Marine Directorate do not.
I have responded to two consultations expressing concerns about both the science and the evidence and both responses have been ignored. This was not unexpected as the best science contradicts the existing narrative and SEPA are not interested in anything but imposing a sea lice risk framework on the industry simply because they have been told to.
I wrote at the end of last year expressing my concerns and was told that I could meet a representative to discuss them. I replied that I would welcome a face-to-face meeting as this would be the best way to explain the science. I offered to travel anywhere in Scotland to attend this meeting. However, the response received was not that they were interested in hearing any alternative science or evidence, but that they weren’t prepared to meet over a PC link. The ensuing discussion was not about the science but about their refusal to meet face to face. My offer to meet anywhere at any time to explain why their science is wrong still stands. From my perspective, if SEPA prefer to pursue this framework based on flawed science then they will eventually have to face the consequences.
The Marine Directorate is another story. I first contacted them about nine years ago after someone from the wild fish sector suggested that I speak to them. However, my request to meet was rejected out of hand. I have had repeated contact over the intervening years, but the scientists have consistently refused to discuss the science. This remains the case today. The only possible explanation is that having argued for many years that salmon farming has had an impact on wild fish; they cannot accept that they might be wrong, and the truth is that they are.
The glimmer of hope is that both SEPA and the Marine Directorate place great faith in the Norwegian science that supports the Traffic Light System. The PO3/4 knowledge incubator is gaining significant support in Norway, and it is unlikely that they will be ignored for much longer.
Meanwhile, I challenge anyone from the Marine Directorate or SEPA to debate the science with me face to face. However, I am not holding my beath. They clearly don’t have sufficient faith in their narrative to be openly challenged.