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reLAKSation no 1118

NASCON: According Wild Fish, a new report from the inter-governmental wild salmon conservation organisation has lambasted the Scottish Government’s ‘dismal failure’ to protect wild salmon from the negative impacts of ‘industrial’ salmon farming. Yet, examination of the 146-page report finds no specific reference to any action or lack of it by the Scottish Government. There is a general reference to the wider jurisdiction of all salmon farming nations, but this is unexpected from an organisation that effectively represents the interests of the angling community,

Wild Fish also say that the report has been written by independent experts but even this is incorrect. The panel of three experts includes one who cites his own research in the report. This certainly does not give the appearance of independence.

When it comes to sea lice, the NASCO report states that wild salmon die from sea lice infestations arising from salmon farms. The is based on the Norwegian Scientific Committee for Wild Salmon’ annual reports about which I have commented previously more than once. These estimate the mortality of wild salmon in Norwegian rivers based on preconception and sea lice models rather than facts. If my view of this is incorrect, I would be more than happy to discuss their methodology with the Committee but for some reason, they appear reluctant to do so.

The report also states that NASCO is in the process of commissioning an independent review to report on the impact of salmon farming on wild Atlantic salmon but the report’s authors have said that there is already more than enough information available to make a judgement on salmon farming and this report will be largely unnecessary. I agree, but not because any forthcoming review will be just more of the same but because the independent reviewers are not really independent and yet again, industry experts are excluded from expressing any view.

Why is it that even an international inter-governmental organisation concerned about the conservation of wild salmon cannot be open to listening to an alternative narrative than the one developed on perceptions rather than fact.

NASCO once had a one-day meeting about salmon farming and invited one representative from the industry to speak but then restricted what he was allowed to say. Such a blinkered view will not bring back wild salmon.


New Research:  Researchers at Marine Scotland Science have just published two new papers about sea lice and aquaculture. These are ‘Salmon lice loads on Atlantic salmon smolts associated with reduced welfare and increased population mortalities’ and ‘Modelling parasite impacts of aquaculture on wild fish: The case of the salmon louse on out migrating wild Atlantic salmon smolt’.

The really interesting point about both these papers is that they rely on modelling to draw a conclusion.  There is no experimental work involved. Instead, the first paper relies on data collected from laboratory trials reported elsewhere of which most are at least twenty years old. The researchers conclude that there is a 50% probability of onset of mortality at 0.24 lice/g. However, there is no actual evidence to support this figure. It is just a model.

The second paper describes a simple model that appears to be one used in the SPILLS project as it was developed from parameter examples from Loch Linnhe. I have written previously that this model should be questioned because the researchers do not seem to have accounted for parasite ecology.

What I find interesting about these papers is that the work was funded by the Scottish Government through projects C45400 and FW0050. All the authors of both papers are cited as working for Marine Scotland Science and therefore are presumably salaried staff, so why does the project need to be funded because all the work is effectively desk-research? I have been working in my spare time for 12 years on sea lice research, all of which was and is desk-research. The only time I applied for research funding was through the now defunct SARF and my application was blocked by no other than Marine Scotland Science.

Given Marine Scotland Science’s focus on modelling, I have decided to create my own model for mortality associated with angling.

Angling mortality was included in the Marine Scotland Science document on ‘High Level pressures on Atlantic salmon’.  In the section about exploitation, the document states – A Marine Scotland funded 3 year PhD on rod and line catch and release mortality commenced in October 2018.

This work has been published but has been conveniently forgotten simply because the published paper was not about angling mortality at all. In my opinion there was a communication issue and the project looked at a different aspect of angling catch and release than mortality. It is surprising that Marine Scotland remained unaware of this different direction taken during all of the three years of the project as they were providing the funds and should have had updates. Perhaps they were updated and simply failed to act, but Marine Scotland appear to have now erased this project from their memory.

Yet, clearly angling mortality must be important because it was included in the pressures document. Angling mortality is also mentioned in the new NASCO report. It states ‘The Panel would like to be reassured that the mortality of released fish in recreational fisheries (no mortality is associated with release) is not playing a role in the lack of a positive response (i.e., any sign of recovery) due to increased catch and release. The panel also mention reduced reproductive success (due to the stress of being caught) or unreported catches as possibly playing a role in the lack of any recovery.

Although the NASCO report states that there is no mortality associated with catch and release, there is a footnote that some 5-10% mortality would be associated with release. In fact, I have seen reports suggesting that this figure could be as high as 14%.

The report also includes a footnote suggesting that salmon released after catch and release have nearly 30% lower reproductive success compared to fish that have not been caught.

When I first started compiling catch data, a number of people associated with the wild fisheries sector rubbished my initial conclusions claiming that the catch data is extremely unreliable which suggested that there could be some dishonesty associated with some catch returns. As I have written previously, there are major discrepancies in the catches reported by Fisheries Management Scotland in their Annual Review and the official Marine Scotland statistics.

I have placed all these parameters into my model and arrived at a figure of 511,464 wild salmon, which according to my model is the number of fish that have been released since records began in 1994 but which have failed to successfully reproduce.

I would explain how I arrived at this figure but there should be no need for any explanation or discussion and as I am a fully qualified scientist, anyone questioning the numbers will just have to accept that my figures are factually correct.


1993:  Thirty years ago, a one-day conference was held in Inverness which had been organised by The Freshwater Fisheries Laboratory, the Atlantic Salmon Trust and the Association of Salmon Fisheries Boards. This would now be described as Marine Scotland Science, the AST and Fisheries Management Scotland.

The title of the conference was ‘Problems with Sea Trout and Salmon in the Western Highlands and was opened by the then head of the Freshwater Fisheries Laboratory at Pitlochry, Dr Richard Shelton.  He began by saying that my scientific colleague’s task is to put us all in the picture about the results of the intensive investigations they have undertaken over recent field seasons.  All the presentations bar one came from scientists working from what is now Marine Scotland Science.

The big question is if the Freshwater Fisheries Laboratory could actively participate in such one-day  conferences thirty years ago to look at the reasons why fish stocks are in decline, why can’t they do so now? What is needed when it comes to the alleged impacts of salmon farming on wild stocks is this form of open discussion based on a wide range of presentations. I fail to understand why Government scientists are so reluctant to talk about their work, unless they do not have any confidence in doing so.

The 1993 meeting was summed up by Dr Tingley from Imperial College London. He began – A brief examination of the rod and line catch returns for salmon and sea trout was shown for the Northwest region by Dr Walker of the Freshwater Fisheries Laboratory. This shows that catches of salmon were not declining but rising slightly. The decline of sea trout catches in the Northwest region from an average of around 9,000 fish in the early 1950s to about 2,000 now can only be described as extremely worrying. the position of sea trout is very serious and probably the prime motivation in the arrangement of this meeting.

The report of the meeting includes a section about sea trout titled  ‘Remedial action following the depletion of sea trout populations – advice to District Salmon Fishery Boards.’

It continues ‘The following notes were prepared by the Freshwater Fisheries Laboratory on remedial measures for sea trout.’   The first point is restriction on fishing. They say that in the worst areas, there is a case for restricting fishing to make the most productive use of the depleted runs i.e ensure that every fish has the opportunity to breed.

They continue that it could be argued that directed fishing for sea trout should be banned altogether until stocks recover.  However, they then say that if for economic or social reasons banning fishing is impractical; then the next best thing would be catch and release. They recommend barbless hooks and non-removal of the fish from the water to avoid scale loss and handling stress.

During the discussion section of the meeting, Dr Shelton stressed that if there was a collapse of wild fish stock then the fishery should be closed. Clearly as no rivers were subsequently closed to fishing in Scotland, then the state of the stock could not have been so bad.

However, the part of the discussion which I found most interesting was from Mrs Penny Murch. Who explained the problems she faced with sea trout when she took over a chair of the Hope and Polla District Salmon Fishery Board. She expressed regret at the decline of these exciting fish. She said that the fish were larger now (1993) but there were much fewer of them.

This is of interest because much more recently, the former Director of Salmon & Trout, Andrew Graham Stewart wrote in Trout and Salmon magazine in 2017 that the Hope is still a flourishing sea trout fishery with 11 boats in high demand and that it was not unusual for an angler to catch seven or eight superbly conditioned sea trout per day averaging 2lb and including fish up to 5lb. This he attributes to sea trout avoiding sea lice from local farms by migrating straight out into the Atlantic Ocean. What makes this interesting is that according to Scotland’s Aquaculture, the local farms were not even established in 1993, when Mrs Murch bemoaned the decline of local sea trout stocks.

It is for this and similar reasons, that a similar one-day conference to the one that took place in 1993 should be held now so we can discuss the real issues, rather than rely on out of date and blinkered narratives. So, come on Marine Scotland Science, why don’t you meet this challenge.