Open letter to the Sea Lice Steering Group
Dear Tor, Karin, and Eirik,
Following publication of the aquaculture white paper, many questions have been raised about the extent and accuracy of the knowledge base relating to the impact on wild fish. As members of the Steering Group, I would have thought that you might have held two or three regional meetings to meet with those who have expressed such concerns and addressed them face to face. Instead, the Steering Group has chosen to write a response published by Intrafish in which you expressly disagree with all these concerns. https://www.intrafish.no/debatt/styringsgruppen-tilbakeviser-pastander-etter-havbruksmeldingen/2-1-1823572 You write that you refute the claims that your knowledge of the environmental consequences of sea lice is not good enough. It would seem that you have dismissed all concerns without any consideration of the issues these concerns raise. You clearly have total confidence in your science and assessments, yet after 15 years of my own research, I know this confidence is totally misplaced.
You write that the Steering Group and the Expert Group have conducted annual assessment of the consequences of sea lice for wild salmon since 2016. You say that the data you analyse forms a good basis for assessing the current situation.
Clearly, there has to be a measure of how good your assessments really are, and I would suggest that one such measure is the annual total catch of wild salmon from Norwegian rivers. After all, it is the anglers who are most vocal about the alleged impacts of sea lice and the alleged damage salmon farms have on wild fish. The following is a graph of salmon catches since 1993 taken from Statistics Norway.
In 2009, Norway started to record both salmon killed and salmon caught and released, and the graph shows that from then catches were relatively stable, but after 2016, they started to decline quite quickly. Is it a coincidence that 2016 was also the year the sea lice experts began their assessments for the Traffic Light System. Clearly, attempts to prevent the decline of wild salmon have failed even though this is exactly the reason why the Traffic Light System was introduced.
You write your assessments can be just as effective (or ineffective) for the proposed sea lice quotas. Yet if they don’t work for the Traffic Light System they won’t work for sea lice quotas. It is neither the Traffic Light System nor Sea lice quotas that are wrong but the assessment process.
However, it is not just data that you and the Expert Group use to make your assessments. You also rely heavily on the use of models, something of which I am highly critical. You write that similar models to those used in the Traffic Light System are commonly used to find connections in complex problems where it is not possible to directly measure the situation precisely in nature. I shall return to this question of precise measurement in nature later but first you write that most of us follow the weather forecast, which is also based on such models. This comparison does not instil in me a great deal of confidence. This is because whilst one day weather forecasts are 96-98% accurate, they drop down to 90% for three-day forecast, whereas longer term forecasts have an accuracy of only about 50%. This is despite the fact that weather forecast models are run on super computers over many cycles every day and yet, they are still not accurate about what will happen in the next week or two.
It is also concerning that you should compare your models to something like the weather forecast. This is because sea lice are biological animals with set behaviours, yet the Steering and Expert Groups treat them like some inert particles. It is also concerning that the Steering Group rely on four different models from three different institutions in their assessments. The fact that they cannot rely on one single model of sea lice infestation is extremely worrying. This leads to far too much uncertainty.
Yet, for me the most important aspect of your response is that you say that they use models where it is not possible to measure the situation precisely in nature. I have highlighted the catch data from Statistics Norway which shows that it is only in the last decade that catches of wild salmon have so significantly declined. The controls imposed on salmon farming over this period should have prevented such declines, but they have not. The recent ICES document about salmon catches shows that wild salmon are in decline across the whole North Atlantic and most severely in areas where there are no salmon farms.
My own graph of declining salmon catches running over fifty years from two very different Scottish coasts, only one of which has salmon farms, shows an almost parallel decline for both. This graph was sent to twenty one Norwegian sea lice specialists including all the members of the Sea Lice Expert Group and yourselves, not one of whom replied, presumably because they and you cannot explain why salmon from rivers near to salmon farms are declining at almost exactly the same rate as salmon from rivers along a different coast, which has never seen any salmon farming activity at all. It isn’t necessary to run a model to understand that it is not salmon farming or sea lice that are causing the declines.
Now a new paper in the peer reviewed Journal of Fish Diseases has shown that wild salmon are infested with high sea lice numbers even after all the salmon farms have been removed. How much evidence do you need to demonstrate that it is possible to measure the situation precisely in nature instead of relying on your models. The problem is that it is their models that are being questioned and if your models are shown to be suspect then what does it say about the scientists who rely on them.
Professor Kevin Anderson of the University of Manchester wrote that ‘our progressively complex world is dominated by well-meaning experts’ use and misuse of increasingly impenetrable models’. This appeared on the back of the book ‘Escape from Model Land’, by Erica Thompson from the London School of Economics in which she writes ‘Models have an almost magical capacity to lure their users into mistaking the sharp tidy and analytically accessible work of a model with actual reality’. This is a book that should be mandatory for all sea lice modellers to read as well as anyone calling themselves an expert about sea lice. Dr Thompson also writes that once in use, models become more than tools for scientific analysis – they are also tools of social persuasion and objects of political contestation often used in ways the scientist developing them could never have imagined. Never have truer words been written.
You write in your response that an important question regarding the Traffic Light System is whether the models are good enough for the purpose. You say that they have been validated and calibrated against observations of sea lice on wild fish and are quality assured through international referred publication. I would argue that this is not the case. I question how a sea lice dispersal model can be validated again observations on wild fish. Wild fish are not stationary and can swim often great distances. You cannot be sure that the wild fish you observed were infested in the area covered by your model. Surely, the only way to validate a sea lice dispersal model is to measure the number and location of sea lice in the fjord and compare the numbers with those predicted by the models. The reason you don’t do this is because, as yet, no scientists has actually identified sea lice in the water body except in the most dilute numbers. The reason you can’t find them is because they are not there and the model is wrong. There is a big difference modelling inert particles and living biological organisms. The lure of the model has certainly done its work immunising the sea lice experts from reality. Validation using sentinel cages is also questionable because fish held this way can be infested by passing wild fish in the same way salmon farms become infested after stocking with lice free fish.
You write in your refutation of allegations that the Steering Group appointed an independent expert group consisting of nine leading scientists in the field. How can any ‘expert’ be viewed as independent if they have published papers claiming to show that sea lice from salmon farms are damaging stocks of wild salmon or if they belong to a group who say that sea lice are the greatest threat to wild salmon in Norway. The Expert Group should have included experts in associated specialisms who are more open-minded to the possibility that sea lice are not causing damage to stocks of wild salmon.
I end with a reminder of a commentary the Steering Group published in the media in October 2024. You wrote that ‘conflict is not the solution, and the Steering Group encourages the various actors to engage in open, constructive discussion. It seems that such ideas have fallen by the wayside in your attempt to force your interpretation of the knowledge on the industry. Certainly, when I submitted a 26-page document to the Steering Group as part of a review process, the reply I received was
thank you for your emails to the members of the Steering Committee.
We have all read these and they have been discussed. The scientific content are known to the Expert group and has been taken into consideration when applicable.
On behalf of the Steering Committee
If this was true, then clearly the assessments would be very different than they have been. This is because, as just one example, assessments of the majority of POs are based on extremely small numbers of sampled fish. These small samples are even below the sample size recommended by Taranger (2012). This means that they are clearly not representative of sea lice distribution of the wild fish populations.
Best regards
Martin
Discover Discovery: It would be very interesting to know the views of the Norwegian Sea Lice Steering Group about the findings of a new paper from Canada, I mentioned this in the previous commentary, and I have previously mentioned it in reLAKSation after I had seen some of the published data.
The simple fact is that the Canadian Government responded to repeated criticism of the salmon farming industry by forcing the closure of all the farms from around the Discovery Island during 2021 and 2022.
Although salmon farms had been removed, routine monitoring of sea lice infestation on wild Pacific pink and chum salmon continued during 2023 and 2024. Levels of sea lice infestation had been falling from 2020 and continued into 2023 causing anti salmon farm activist Alexandra Morton to immediately put out a paper saying that the average number of sea lice per fish had declined by 96% over the study period from 2020 to 2022. She said that similar declines were not witnessed in similar samples from the nearby Broughton Archipelago where farms remained.
This new paper looks at infestation levels over a longer eight-year period and crucially in the two years since the farms closed; a period not covered by Alexandra Morton. What the data shows is that Ms Morton was too quick to make any assumptions. The lice count in the Broughton’s did in fact dip in line with those in the Discovery Islands but crucially, two years after the closures, the lice levels then increased. However, not only did they increase, but they also reached levels which exceeded those in most of the previous years.
What critics and experienced sea lice researchers seem to forget is the there have always been high levels of sea lice infestation on wild fish prior to the advent of salmon farming but no-one bothered to look. We already know from other Canadain research over a wider area and longer time scale, that about three quarters of wild salmon are in fact totally free of lice due to the way that parasites like sea lice are distributed throughout their hosts. The problem is that uniformed observers see fish with high lice levels near salmon farms and make the totally wrong assumption.
What is of most interest about this work is the apparent redemption of one of the authors. Back in 2013, Crawford Revie was one of the co-authors of a short communication criticising the 2013 paper by Jackson et al. that showed that the impact of sea lice on wild fish was about 1-2%. Their paper stated that Jackson had incorrectly led readers to a conclusion that sea lice play a minor perhaps even negligible role in salmon survival. The paper suggests that Jackson made three methodological errors, which Jackson later refuted.
Dr Revie and his colleagues said that according to interpretations used by Jackson, there is a change of about 2% which they agree is a small number. However, they then say (by applying different analysis) that the realised impact is to reduce the number of adult spawners from say 6,000 to 4,000 which represents a one third loss. They then say this could have significant conservation or fishery implications. Sadly, the only implication was the unnecessary vilification of the salmon farming industry.
Now in this new paper, the researchers have shown that a high sea lice count on wild fish does not have to be related to the presence of salmon farming, which provides another piece of evidence that proves that the claims against salmon farming are just plain wrong.
It will be interesting to hear what the anti-salmon activists and their scientific colleagues in Canada have to say about this new research. I expect total silence.
Any other week: In any other week, this would be my first commentary, but such is the power behind other events, I had to leave this news until last.
As it is still impossible to have a proper dialogue with Scottish government scientists, it is necessary to submit questions via Freedom of Information requests to obtain any information.
It may be remembered that another FOI request brought about the publication of the Scottish sea lice monitoring data for 2024. This came with 49 entries dated 23 May 2025 which was incorrect and did not instil any confidence in the data.
I subsequently asked via another FOI if the Scottish government would supply the results of their analysis of the data so I could see what conclusion they had reached. The reply stated:
We are unaware of any analysis conducted on this data by any Marine Directorate scientists since the publication of the scientific paper titled “Association of ectoparasite Lepeophtheirus salmonis counts on farmed Atlantic salmon and wild sea trout in Scotland” in March 2024.
Since the paper published in 2024 only considered data from 2013 to 2017, it means that no sea lice monitoring data since 2018 has undergone any form of analysis. This confirms my view that if the monitoring data includes a few fish with high sea lice counts, then this is all the proof the wild fish lobby, and seemingly government scientists too, that salmon farming is impacting wild fish. This is despite the fact that high levels of parasitic infestation are an entirely normal occurrence in nature.
However, of more concern is that the Sea Lice Risk Framework is being forced on the salmon farming industry even though there has not been any evidence from the last seven years to show that there is an impact, Instead, government scientists and SEPA have relied on a few selective and dubious papers which are listed in the Scottish Governments’ highly contested summary of sea lice science document.
It says something that the scientists feel that they don’t need to undertake any analyses on this data but still claim that salmon farming is damaging to wild fish. I am not the only one to say that it is the poor science that is causing most damage to wild fish and not just in relation to sea lice.