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reLAKSation no 1096

More Ewe than me: October always proves to be an interesting month for me, not least because it is the month of my birth, but also because in October 2010 I was invited to speak in the ‘Aquaculture Debate’ at the Fishmonger’s Hall in London with the then head of NASCO, Malcolm Windsor. It was because of this meeting that I began my journey of discovery into the relationships between salmon farming and wild salmon. After twelve years, it could be said that I am now one of the leading authorities on the subject especially concerning actual interactions, rather than the modelled ones that seem to be the focus of much of sea lice research. I only say this because this October, I was contacted by a major scientific journal who wrote that ‘given your expertise’ would I be willing to review a manuscript submitted for publication. The manuscript is titled – A Gap Analysis of Salmon Lice Infection Pressure from Fish Farms: Where is knowledge lacking and how can this be rectified? This manuscript has several authors including at least six from Marine Scotland Science, one of whom is the lead author. Interestingly, I had some correspondence with the lead author in October 2021 in which I asked about the observational studies in the Marine Scotland Science Summary of the Science regarding sea lice posted on the Scottish Government website and received a reply that my query isn’t within their specific field of expertise and my query would be passed on to someone else. As it happens, I never did get an answer to my question.

With regard to the journal request, I turned down their kind offer, so I actually don’t know what was in the paper. I have to earn a living and don’t have the luxury of time paid by employers to review other scientists’ papers as do those working in academia or for the Government. Also, I am very much aware of the gaps in the knowledge of sea lice and found that those working for Marine Scotland Science have been very reluctant to discuss any gaps unless these fit exactly within their established narrative. As my narrative is very different, Marine Scotland Science has never been interested in any discussion. My first contact with someone from MSS was around 2014 when I asked if I could come in to have a chat. This was met with a reply saying that they would be happy to talk to me once I had had a paper published on the subject. I have since had two papers published and I am still waiting.

October also saw the passing of Bruce Sandison in 2016 whose obituary in the Herald describes him as renowned angler and author and journalist. The paper also describes Mr Sandison’s guide to the Rivers and Lochs of Scotland as an epic undertaking. This book is now considered to be the enthusiast’s bible, but more about that later.

The Herald also said that Mr Sandison was much concerned about the future of wild salmon and campaigned to preserve the sport. He was highly critical of the spread of salmon farms and warned of the perils of salmon farming and formed the Salmon Farm Protest Group which lobbied government to adopt a sustainable fish farming policy. He especially called for a ban on the salmon farms at the mouths of salmon rivers.

Mr Sandison and I corresponded several times. He has been the only critic of salmon farming to actively do so. Others prefer to hide behind their computer screens. As far as I could ascertain, Mr Sandison’s view of salmon farming was limited to the fact that wild fish catches appeared to have declined at the same time salmon farming became established on the west coast. He was also aware that some wild fish had been caught with high numbers of salmon lice and in common with groups such as Wild Fish Conservation, he assumed that sea lice were the reason why wild fish numbers had declined, but like Wild Fish Conservation, could not actually provide any hard evidence to support this claim. It is completely circumstantial (and if any of the wild fish lobby disagree with me then I would be more than happy to sit down with them and discuss why I make this statement).

I mention Bruce Sandison because I was referencing his ‘angling bible’ in some other work I was undertaking and happened across the entry for the River Ewe. The Ewe System is where my own journey on wild fish interactions began because Butler and Walker’s 2006 paper on the collapse of the Loch Maree sea trout fishery and their mistaken view that this was due to the presence of a salmon farm in the adjacent Loch Ewe was one of the first accounts I encountered. Like most of the critical works of salmon farming, the graph of catches was truncated, and I was interested to know what sea trout catches were like before 1969. Their graph also referred to the catches from the Loch Maree Hotel, not the whole Ewe System. At the time, the Scottish Government were not so forthcoming about accessing historic data, but I eventually came across the annual reviews published by the Association of Salmon Fishery Boards (now Fisheries Management Scotland) and found the following graph.


The graph shows that sea trout catches in the loch had been in decline long before salmon farming arrived on the west coast, a fact that was ignored by Butler and Walker. However, I was more intrigued by the other data on the graph – catches of salmon and grilse. In all the references to the Ewe System, I had not heard anything about salmon catches. However, as the salmon catch was much smaller than that of sea trout, it was difficult to see what was happening to salmon in the loch and the River Ewe. Also why did the salmon data only begin in 1976?

A number of years later the ASFB or Wester Ross Fisheries Trust, did amend the graph without any explanation.

The impression from this graph is that salmon catches have remained relatively unaffected by the presence of the salmon farm, unlike the claimed impacts on sea trout. I therefore began my quest to get the data for Loch Ewe and other areas of interest too. I believe that it was my repeated requests for catch data which led Marine Scotland Science to publish the full data set every year. It is so easier now. When I obtained this data, it was not of a uniform nature and required extensive work to put it in a usable form.

My graph of the catches of salmon and grilse from the Ewe System looks like this:

Clearly catches vary from year to year but the overall trend is clear, catches have increased from 1952 onwards including the time the farm was in operation. The average catch throughout the whole period has been 195 fish. This brings me back to Bruce Sandison. His angler’s guide to Rivers and Lochs of Scotland, a book that is peppered with references to the disastrous impact of salmon farms on west coast rivers, as might be expected from the founder of the Salmon Farm Protest Group. The 1997 edition of the book states that ‘the annual average catch is in the order of 100 salmon’. It seems that he was playing down the river’s salmon production. The fourth edition of the book was published in 2013, some sixteen years after the book was launched. The entry for the River Ewe now reads ‘The annual average catch is perhaps in the order of 100 salmon’. It seems that even Bruce Sandison has admitted that the salmon farm has had no impact on wild salmon catches.

The actual impact can be easily measured. As stated the average catch since 1952 was actually 194.9 fish. The average catch from 1952 to 1987 when the farm opened was 194.0 fish. From 1987 onwards, the average catch was 204.2 fish which somewhat suggests that the presence of the farm has seen catches increase rather than suffer a negative impact as the wild fish lobby would have others believe.

I should mention that almost every week, I am accused on social media of manipulating the data to suit the salmon farming sector. The data I use comes from the Scottish Government and is freely available to download from their website. Perhaps, such critics might like to analyse the data for themselves and see if it tells a different story.

The Ewe System salmon catch data does hide another story. Analysis of the salmon and grilse catches separately as seen in graphs I produced some years ago shows that catches of large salmon have been in decline over the years until 2010 whilst catches have risen.


This is a change which is reflected across Scotland and has been highlighted by Dr David Summer of the Tay Salmon Fishery Board and the now retired Dr Ronald Campbell of the River Tweed Foundation. These changes account for significant changes to the west coast salmon fisheries rather than it being attributable to salmon farming however, Marine Scotland Science have shown no interest in looking into these changes, presumably because it is contrary to their established narrative on sea lice. Yet, how can the grilse catch in the Ewe System have increased if sea lice from the salmon farm are killing wild fish? Perhaps this might be one of the gaps in the knowledge which they might have written about in their latest manuscript?

In his angling guide, Bruce Sandison says fish farm sea lice infestations in Loch Ewe have impacted sea trout so that they have all but disappeared, although he makes no similar claim for wild salmon in the Ewe System. So, the question is what were these infestations actually like in Loch Ewe?

The sea lice data as published earlier this year by Marine Scotland includes a run of twelve years of sampling at Boor Bay in the loch. Over the twelve years a total of 282 fish were sampled. The sampling can be summarised in the following table:

In a couple of years, the local fisheries trust managed to net Boor Bay six times, but twice they managed only once. The number of fish caught ranged from just 2 to a maximum of 50 fish. The spread of lice on infested fish is shown in the following graph which summarises the lice numbers on the 282 fish over all twelve years:

Unsurprisingly, the graph shows the typical aggregated distribution which is expected for sea lice. The majority of fish have very few lice whereas only a handful carry many. Just two fish have the type of highest lice numbers that the wild fish lobby like to promote as typical for infested wild fish. One fish had 152 lice and the other 412 lice. It is important to remember that these are mainly the tiny larval lice and not the large adult lice. Wester Ross Fisheries Trust have in the past recaptured sea trout and found the lice level to be lower than at the first capture.

It is necessary to combine all the samplings to produce the above graph because most of the nettings caught very few fish. In fact, of the 33 attempts to sample fish, only three (one in 2008, one in 2011 and one in 2015) captured more than 30 fish. This is key because Marine Scotland Science agreed with the Scottish Fisheries Coordination Centre (SFCC) that the protocol for netting should be for a minimum of 30 fish. No explanation is given why the number of 30 fish is required but presumably it is because anything less would not be statistically acceptable. At Boor Bay, if the protocol had been followed, then the trust should have captured 990 fish not the 282 they managed to catch. What is the point of this protocol if it is not followed?

In Norway, Taranger’s 2012 report recommends a minimum of 100 fish which greatly exceeds the Scottish target. As the table shows, the number of fish caught falls far short of both targets and therefore makes this data relatively meaningless unless part of the greater dataset. Of the full dataset published by Marine Scotland Science, 82% of the nettings, over a period of twenty-three years, fell below the 30 fish minimum. Perhaps, this is why Marine Scotland Science have not published any analysis of this data. It is certainly another gap in the current sea lice research.

Of course, the wild fish sector’s lack of meaningful data does not stop them highlighting the very few fish carrying high numbers of lice. For example, Wester Ross publicised that a sea trout with over 500 sea lice was featured on Scottish TV. The trust had sampled fish near Gairloch as part of a wild fish workshop and managed to catch a total of two sea trout, one of which carried 560 sea lice. It was fortunate that a TV crew were on hand to film this catch!  Interestingly, the trust didn’t record this fish for the sampling database as the highest lice count was 534 on a fish caught in 1998.

Regardless of these few examples of high lice counts, the reality is that most sea trout have no or very few lice. This distribution will occur regardless of the presence or absence of salmon farms because this is how sea lice are distributed in nature (another gap in Marine Scotland Science knowledge). This shows that the infection pressure on wild fish from salmon farms is very low, yet on the advice of Marine Scotland Science, the Scottish Government seems intent on imposing a risk -based framework, even though the risk is clearly minimal.

I will leave the last word about Loch Ewe to Andrew Graham Stewart director of the greenwashed Salmon & Trout Association now known as Wild Fish Conservation, who wrote in his book ‘The Salmon Rivers of the North Highlands and the Outer Hebrides’ that the marked fall in salmon caches since 1996 shows no sign of being reversed. The relentless growth of fish farms in Wester Ross has surely contributed to this decline.

History shows that Mr Graham Stewart was wrong and that salmon catches from the River Ewe have been remarkedly healthy. There was a fall in catches in the mid-1990s and this was repeated across the whole of the west coast. It is a pity that Scotland had not followed England’s example then and measured fishing effort because the decline in the mid-1990s was not due to the impact of salmon farms but because the wild fish lobby had screamed so much about the presence of salmon farms and claims that wild fish were being wiped out, anglers avoided fishing the west coast and  went off to other areas where they believed that there was a better chance of catching a fish. Eventually, word spread that the claimed lack of fish was not true, and anglers started to head back to the west coast and consequently catches recovered, and in the case of Loch Ewe bettered the catches of the times prior to the arrival of salmon farming.

Despite such evidence, Andrew Graham Stewart’s Wild Fish Conservation has this October launched a new campaign to get farmed salmon off the table, although Mr Graham Stewart appears to be taking more of a back seat. Could this because he has so far been unable to bring about the changes he wants to see in the way salmon are farmed. WFC’s latest video promotes the idea that salmon farming should move to closed containment and cites the example of Atlantic Sapphire as the future vision of salmon farming. Unfortunately, this October has seen Atlantic Sapphire suffer more fish deaths leading to emergency harvesting and a massive plunge in the company’s share price. I certainly don’t think that this is the example to which the salmon farming industry should aspire.

WFC are promoting the new campaign as being the end of the line for farmed salmon with a fillet of salmon on the end of a hook and line. However, WFC have got it wrong again. Sadly, if we are coming to the end of the line for salmon, it is not salmon farming but salmon angling whose future is in doubt.

All the focus being placed on salmon farming, whether it is WFC, AST, FMS or MSS will make no difference. Salmon farming is not the reason for the decline in wild fish. Even SEPA agree. Even if the critics got their way and salmon farming became history on Scotland’s west coast, it would do nothing to save wild salmon because no action is being taken that would actually do anything to save them. Meanwhile, the wild fish sector appears to be more interested in protecting wild salmon fisheries and salmon fishing than wild salmon.

The level of urgency of the wild salmon sector to do anything to protect wild salmon can be seen by the fact that the Wild Fish Strategy was launched by the Scottish Government on January 14th and as yet, and to the best of my knowledge, there has not been a single meeting since to even talk about how the strategy will be implemented, let alone implement anything. On the basis of that the most basic conservation measure – catch and release – is to remain voluntary, the expectations for the wider strategy achieving anything are extremely low.

Mr Graham Stewart’s last attempt to persuade consumers not to eat salmon failed and there is no reason why this one should be any different.

Finally, I would mention that the salmon farm in Loch Ewe has now gone, and production has been moved to a larger site much further out at sea. The closure of this site would have provided a unique opportunity for Marine Scotland Science to study what happens to wild fish populations when a farm is removed and to see whether there was an impact on the wild fish. This is a gap in knowledge of sea lice research that would have been worth investigating and a real missed opportunity.