Another missed opportunity: On Wednesday 25th March, the Scottish Government quietly published an 87-page review of SEPA’s Sea Lice Regulatory Framework. This was commissioned by Scottish Ministers due to concerns expressed by the industry about the science and evidence used to justify and inform SEPA’s framework. The author is Professor Mark Inall, Chief Scientific Advisor to the Marine Directorate. Sadly, for those of us working for an open discussion about the science, the report ensures that we are to be disappointed. The short ‘Executive Summary’ states that ‘CSA Marine concludes, first and foremost that the framework is scientifically defensible.’ This is really of little surprise since my experience is that those connected to the Marine Directorate always defend their scientists so suggesting that the science can be defended is not unexpected. Unfortunately, since the summary of science was first published in around 2016, Marine Directorate scientists have consistently refused to defend the science expecting others like me to simply accept their version. I can only wonder whether Professor Inall will be willing to defend the science in a public arena or whether yet again the salmon industry is just expected to accept his judgement.
The preamble in this new report states under number 7.
‘Neither this report nor its annexes provide a comprehensive review of the SLRF underpinning science, that is found elsewhere and reviewing the science is an ongoing process.’
The reference given for the science found elsewhere is the Scottish Government’s 2021 report ‘Impacts of lice from fish farms on wild Scottish sea trout and salmon: Summary of science.’ This is a report that has received much attention from me in the past and although dated 2021, this is the third version. This latest version clearly states that the report is just a summary and is not intended to repeat other reviews but to provide a succinct account of key information. It therefore surely cannot be described as a comprehensive review of the science, because it is certainly not.
This 2021 report continues that its science includes observational, experimental and modelling studies. It is the observational studies that are of the most interest. Despite being described by Professor Inall as comprehensive, the observational studies are described in just 145 words.
The report reviews three studies from 2003, 2008 and 2009 so this comprehensive review highlighted by Professor Inall, and which he accessed on 2nd October 2025, relies on observational data that is up to twenty-three years old. The review of the 2009 paper, which as far as I can gather is only included because it was co-written by one of the leading scientists in the Marine Directorate, states “Catches of wild salmon after the late 1980s declined on the Scottish Atlantic coast relative to elsewhere. This area covers the majority of mainland Scotland’s salmon farms although the authors stressed that this did not prove a causative link to aquaculture’. Surely, if there is not a proven causative link then this observational study somewhat undermines the argument that sea lice are impacting the wild salmon population. In addition, as regular readers of reLAKSation will already know, catches of salmon from the west coast have never declined relative to elsewhere in Scotland. The decline has been actually similar across all of Scotland. However, the scientists in Marine Directorate have avoided explaining this parallel decline because it doesn’t fit their anti-salmon farming narrative.
Considering that the impacts report is supposed to be succinct, it might also be expected that it should be accurate. The reference for the 2003 paper which has appeared in this summary of science review from the first version onwards is incorrect. The paper that is published in Pest Management Science vol 58 595-608 is not the one that is named. The science quoted is actually published in a report of the First International Atlantic Salmon Symposium organised by the Atlantic Salmon Trust and the Atlantic Salmon Federation and is published as a book under the title ‘Salmon at The Edge’ edited by Derek Mills. This error might be considered petty, but I raise it because I have pointed out this error to the Marine Directorate on more than one occasion and yet the error remains. I get the feel that anything I say is simply dismissed, even if it is just to point out a correction because they do not consider me to be a proper scientist as I don’t work in a research institution. (I will be expanding on this point in a future issue of reLAKSation).
In his preamble, Professor Inall summarises five recommendations made following a meeting with the industry. Recommendation number 5 falls under the heading – ‘Update the review of unpinning science’. In this he writes that a claim by the industry of ‘misrepresentation’ of scientific findings by the regulator is unfounded. He writes that there is a genuine scientific debate/disagreement over the quantitative statistics regarding the effect of parasites on the return rate of wild salmon. This is something of a surprise because I have seen no evidence of any genuine debate simply a scientific community who have refused to accept the findings from the Irish Marine Institute because it doesn’t fit in with the claims that sea lice associated with salmon farms are killing wild salmon. Professor Inall continues ‘A paper published in 2025 (Gargan et al.) gives some clarity to this debate’. However, I would suggest that this clarity is somewhat tarnished by the fact that a correction was subsequently submitted to the journal because data was omitted. The correction states that ‘we apologise for the oversight and thank readers for their attention to the detail and engagement with our work’. If I remember correctly, I believe that I initially raised the issue of missing data. I can only wonder why this omission was not obvious to the four authors from three different institutions. Did they not go through the data prior to publication? Regardless, this paper does not provide any clarity to the debate but adds to it.
Later in his review, Professor Inall refers again to the Gargan paper stating that ‘Recent meta-analyses (Gargan et. al. 2025) of 43 paired releases spanning the period 2001 to 2019 show a significant treatment effect against sea lice with a risk ratio of 1.22 equating to 18% fewer returns of untreated adult salmon.’ Rather than rely on Gargan’s findings, I have crunched the number myself and made the following observations. Although the fish were divided into treated and control groups, it is puzzling that the control group consisted of 10,575 more fish than the treated group. Regardless,1.99% of the control fish returned whereas 2.31% of the treated group did so. In terms of numbers, 11% more treated fish were caught than control fish. If adjusted for the uneven number of fish released, this effect is even lower than 11%.
However, what is much more interesting about this paper than any of these numbers is highlighted in the introduction. This states; ‘ Atlantic salmon is an economically and culturally important fish species across the North Atlantic and adult returns have shown a marked decline in recent decades, Between the early 1980s and 2023 , numbers of wild Atlantic salmon fell by more than half prior to any fishing taking place and the reported catch of wild Atlantic salmon in 2023 was the lowest in the time series since 1960.’
It is also interesting to note that the two lead authors work(ed) for Inland Fisheries Ireland, that is described on their website as ‘the State environment agency that protects managers and conserves fish and their habitats.’ They also promote angling as a leisure pursuit and develop its potential for tourism.
It says something that these two researchers have spent 18 years administering a smolt release programme to ascertain the impact of salmon farming on wild salmon stocks, the results of which found that a difference of just 0.32% was possibly due to the impact of salmon farming. Over the eighteen years this represented a loss of 629 wild salmon. Yet at the same time, 530,238 salmon failed to return to Irish rivers for reasons unknown. For an agency that is concerned about protecting and conserving wild salmon, one could only wonder why they have spent all this time focusing on salmon farming when 98% of wild salmon are lost due to other causes.
Interestingly, following his appointment, I was in regular contact with Professor Inall expressing real concerns, not about the science of sea lice, but about the really poor focus from the Marine Directorate about the safeguarding of wild salmon in Scottish rivers. The fact that 2025 was the worst year on record for salmon catches and yet nothing has really been done to protect these iconic fish is a complete mystery except if the conclusion is that Marine Directorate scientists favour the wild salmon sector as opposed to salmon farming. Anglers are still allowed to kill wild salmon for sport yet salmon farming is being subjected to the Sea Lice Regulatory Framework in order to save wild despite the lack of any concrete evidence that salmon farming is the reason why wild salmon stocks are now in crisis.
So, it seems that Professor Inall has decide that as Chief Scientific Advisor, the one thing that won’t be discussed is the science preferring instead to focus on the concerns expressed by the salmon farming sector at a meeting with him.
That is not to say that the report does not include reviews of some scientific literature which are discussed in Annex B2 – ‘Evidence for sea lice impacts.’
I am not yet convinced that the new regulation is scientifically defensible as Professor Inall maintains so I will discuss this science in future issues of reLAKSation. However, if Professor Inall is sure that it is defensible, then he should not have any problem bringing the scientific community together with industry and others for a proper discussion of the science rather than rely on the out-of-date excuse for science that is currently published on the Scottish Government website.
Conflicting data: Even Søfteland of PO3/4 Knowledge Incubator has written a commentary for iLAKS in which he finds it difficult to compare the numbers of returning salmon with the mortality levels predicted by the models used by the Sea Lice Expert Group. However, before I consider the numbers of fish counted back into local rivers, I would like to highlight mortality levels quoted.
According to the commentary, 64.7% of all the salmon smolts migrating from the Uskedalselva in 2023 died from sea lice infestation. In 2024, the predicted mortality increased to 74. For the rivers Kinso and Eio, the approximate mortality levels for the same two years were around 74% and 81% respectively.
One doesn’t need to be a mathematician to understand that total extinction will occur in any population experiencing such high mortality levels within three or four years. Yet salmon farming has been taking place in the Hardangfjord since the 1970s and salmon continue to return. Something is clearly wrong with the fish count or the models!!!
Mr Søfteland has provide figures for returning salmon for the three rivers for both years. These are:
Uskedal – 102/199
Kinso – 12/117
Eio – 24/250
He writes that it is important to collect field data and it is also important to combine different types of data to strengthen the knowledge picture about both salmon and sea trout. This is especially so as the differences that are emerging between modelled and real data are increasingly worrying. Clearly, more fish have returned to these river sin 2024 then in 2023.
Sadly, as my own experience shows the provision of data that conflicts with that which is modelled is simply ignored by the scientific community as just being inconvenient and irrelevant.
A report from My Norway highlights the improved returns but suggests that the scientists have emphasized that it is too early to make a final assessment of the improved trend. They argue that some of the increase may be due to fish returning to rivers early. Whether this means that fish returned in the early months of the year before counting began when normally they would return after counted had been completed or whether they mean that the fish would have been MSW fish but returned rarely as 1SW is unclear. The reality is that these scientists just cannot accept that salmon farming may not the cause of the current wild fish crisis and they don’t want to hear anything that may change this view.
Withdrawn: It is only right that as Norwegian scientists continue to suggest that the public should accept their science as they are the scientists, that I should draw attention to the fact that the Institute of Marine Research (IMR) has issued a press statement that they have identified an error in the statistical analysis that affects the main results of a peer reviewed article. IMR have therefore requested that the article should be withdrawn. Currently, the paper is still available on-line.
The article was authored by five researchers and was peer-reviewed by probably at least two reviewers yet managed to reach the pages of a journal despite containing errors. I have looked at the data supplied with a number of papers and have often come across errors such as that in the Gargan paper. I don’t have a problem with papers having errors primarily because I do not believe that any scientific paper can be held to be gospel truth, which is often how many papers related to sea lice are treated. Instead, I see papers as part of a process in which evidence is collected from a variety of sources, which may not just include published papers. This collection is then used to determine the most relevant outcome. This process also involves open discussion, which is why scientists attend conferences and seminars etc, which is why there is so much frustration about the unwillingness of the scientific community to freely discuss sea lice science. The second commentary in this issue of reLAKSation demonstrates why there needs to be such discussion because clearly the ‘science’ and the evidence do not match.