Scroll Top

reLAKSation no 1169

Informed: In the last issue of reLAKSation, I referenced the two SEPA information sessions on the new sea lice framework. As I mentioned, one of the presentations considered the Wild Salmon Strategy and by coincidence at the same time, the Scotsman newspaper published a four-page spread which highlighted that the decline in salmon numbers threatens the tourism industry. The paper looked specifically at the Aberdeenshire River Dee, which is far from any salmon farm. Having listened to the various SEPA presentations and read the Scotsman article, it seems to me that if Scottish Government scientists invested as much time and effort in actually coming up with solutions to salmon’s decline as they and SEPA have invested in this new framework, then perhaps, wild salmon might have a future. I see nothing in the Wild Salmon Strategy that will give any salmon anglers any hope that their hobby will survive for many more years, let alone the places to stay or to eat. Sadly, the greatest threat to the wild salmon sector are the scientists themselves. In the last issue of reLAKSation I proposed the formation of SIWG 2 as a forum for scientific discussion on sea lice. I can see that there is an even more urgent need and that is a forum for discussion on how to safeguard wild salmon and the associated fisheries. The Wild Salmon Strategy has shown that leaving decisions to the scientists and organisations such as Fisheries Management Scotland will do nothing but hasten the decline.

Meanwhile over on the west coast, SEPA, whilst having clearly told the Scottish Parliament Rural Economy Committee in 2020 that sea lice from salmon farms are not responsible for the decline of wild fish, appear now to have adopted an approach that assumes that salmon farms are responsible because the measures they are now taking, are all totally out of proportion. However, in my opinion, SEPA have no comprehension of the point of these measures. They are simply doing them because the scientists have wrongly advised them to do so.

SEPA have requested historic sea lice data from all salmon farms to help them validate their models, yet they are completely uninterested in the fifty years of wild fish data that has been collected since salmon farming arrived in Scotland. This shows that salmon farming is not the cause of wild fish declines and even a cursory examination of this data will show that they are wasting their time on this over-reaching framework. Unfortunately, they are so fixated with the view that they have been told by Scottish Ministers to impose a framework that they cannot see that what they propose is such a pointless exercise.

SEPA have proposed three forms of monitoring should be used to help assess the impact of sea lice on wild fish. If my understanding is correct then SEPA have also proposed that the salmon farmers should pay for this monitoring, which in my opinion, will never be properly interpreted by SEPA and thus will end up penalising the industry. Thus, the industry will end up paying for measures to be imposed against themselves. We have already seen in Norway that the failure of the so-called scientific organisations to properly interpret the data they collected has unnecessarily penalised farmers in production areas 3 and 4. Despite assurances from SEPA that most farms will not be affected, I have my doubts. Certainly, when it comes to monitoring sea lice data on wild fish, most of the wild fish people only need to find one fish with a high lice count for them to scream foul play by the salmon farming sector.  They simply have no idea what their findings mean. As I pointed out in the last issue of reLAKSation, sea lice data on wild fish has been collected since 1997 and as yet, I have not seen one published analysis on this dataset. That is twenty-six years of data. How many years of data is needed for the data to be assessed? Maybe they are looking to sixty years’ worth of data but more about that later.

My understanding is that if any farms reports high lice counts, then the local wild fish will be monitored by seine netting and the netted wild fish assessed for sea lice. However, it is unclear how SEPA will assess whether the number of lice found on the wild fish relate to the salmon farm. I mentioned last time that a new paper is soon to be published which attempts to link lice counts on wild fish to a local farm, however, despite making the request, I have not received a prepublication copy to see the detail. Given that 82% of the historic data that was collected did not meet the protocol established for netting wild fish, I already have concerns about the findings of this study. There is still a lot of misunderstanding about sea lice ecology, and this is reflected in the existing seine net programme, and I don’t expect SEPA’s version to be any different.

The second monitoring programme involves sentinel cages. During the presentations at the SEPA information sessions, reference was made to the ‘success’ of the sentinel cage experiments during the SPILLS project. This work was done over ten years ago and I am not sure what results SEPA considered in judging it to be successful but the results I saw showed a low level of infestation during the smolt migration over three years, However, for me what is more interesting and especially given that SEPA say that they have developed a good relationship with IMR in Norway is that the latest Traffic Light System report from the Expert Group says that they no longer use sentinel cages to assess the risk of sea lice infestation on wild fish. Instead, they just use it as an indication of sea lice in space of time. The latest results from the Hardangerfjord and Sognefojord showed no high levels of lice at all.

I have a real problem with sentinel cages in that there is absolutely no proof that fish were definitely infested from larva sea lice in the open water. Equally there is no proof that the fish are not infested from passing fish but there has been no work to prove that any infestation is in line with the model, just an assumption that it must be.

The final form of monitoring to come out of the farmers’ pockets is a comparative stock assessment of rivers around salmon farms. I am not sure how the size and health of any stock will be assessed given that a 2014 report from Marine Scotland Science said that the only way to assess stock in many rivers is from the rod catch, but clearly the fishing effort in many west coast rivers is now minimal.

Seemingly this comparison of river stock will compare the stocks of salmon in what SEPA consider high risk areas with those in low-risk areas. Someone at the SEPA information session asked why this comparison would not be of rivers near salmon farms with those where there are no salmon farms such as on the east coast. However, SEPA do not appear to have considered this possibility seemingly because they have not considered the possibility that that sea lice exist in high numbers outside the Aquaculture Zone.

I would argue that if the salmon farming sector is to pay for monitoring, then it must be for monitoring that has meaningful results and so far, none of the proposed forms of monitoring can offer this guarantee. Undoubtedly, the presence of any lice on wild fish will be perceived to be a negative and a trigger to impose some form of regulation.

In my opinion, it’s time the industry stood up and defended itself against this pointless regulation, made even more pointless by the Scottish Government’s refusal to stop all forms of exploitation. Either wild salmon is endangered or its not.


Sixty years: Fish Farmer reports that the most detailed long-term study ever carried out of Atlantic salmon in a Scottish river valley has yielded valuable insights according to researchers at the University of Aberdeen. The data covers sixty years of data on salmon population and river conditions in the Girnock Burn on Royal Deeside. The data comes from fish traps that were installed in the burn in 1966.

The researchers say that the research has been able to capture vital science that can support salmon restoration efforts in Scotland. The dataset provides a detailed understanding of how salmon populations and their habitat use has changed as the climate has warmed. Unfortunately, this shows an alarming decline in the number of salmon returning from the sea, which is consistent with declining angling catches observed on many Scottish rivers. However, the researchers say that from this dataset it is possible to build a scientific picture of what management responses to protect the fish are likely to be successful. For example, rivers like the Girnock Burn are getting warmer so planting trees along the banks to increase shade and cool the water is likely to help.

Yet closer examination of the paper that has been published from the research appears to suggest that it spends much of the time saying how valuable the research is without providing detailed information about what they discovered. I couldn’t even find the data that shows how the river is warming and when rising temperatures really became significant. However, the wild fish sector had already decided to planting trees without reference to this paper. The paper actually doesn’t really discuss planting tress anyway.

Interestingly, the Atlantic Salmon Trust recently announced a new twenty-year initiative to save spring salmon on the river Dee. A series of videos about the initiative are available on the AST website but interestingly, although the work focuses on the Girnock Burn, there is no reference to the sixty years of Aberdeen University data. ( The part of the video presentation that caught my attention was that from the University of the Highlands and Islands concerning the genetic variation in the river Dee. The presentation suggested that the river contained several populations of salmon that were genetically adapted to the specific part of the river they inhabited. Back in 2012, the £1 million FASMOP project proposed a similar theory but was unable to distinguish any differences between the salmon in various rivers. It is possibly genetic investigation has progressed since then, but such small genetic populations would lead to inbreeding and genetic weakness. It also ignores that salmon stray naturally to add variation and strength to the overall gene pool.

I was especially struck by the idea that as well as genetic variation between salmon in different parts of the river, there is also genetic variation within these separate populations. For example, the vgll3 gene has two variants which determine whether a fish becomes a grisle or whether it is a multi-sea winter fish. There is also another gene, the six6 gene which is supposed to have a strong effect on determining whether the fish comes back in the spring or in the autumn. I can only wonder how these genetic differences relate to the long-term data from the river Tweed which shows long term domination of catches between grilse and MSW. Equally there have been major changes in the timing of returning fish that occur across whole river systems. Neither of these changes appear related to simple genetic variation as proposed by the UHI team.

Yet, if the time of return is governed by a genetic variant, then surely, the simplest way to boost spring stocks would be to insert the spring variant into the genetic code and then selectively breed spring fish. This would negate the need for this 20-year long initiative and all that this entails. The project is focused on reconditioning spent breeding fish in tanks at the University of Stirling and then released back into the river as wild fish to breed again.

Yet interestingly, the Aberdeen researchers have said that juvenile habitat Is not limiting population, and this is borne out by the Scottish Government’s conservation grading for the river Dee which has an 87.6% chance of meeting its egg requirement based on five years of data.

However, how any of this helps the people featured in the Scotsman article is unclear. The newspaper spoke to the people who run the Banchory Legion, a hotel that has always been popular with fly fishermen, which in the past has been fully booked throughout the whole fishing season. They said that in the week they spoke to the newspaper they had hosted three fishermen for four days and that was the sum total for the month. The hotel is now selling off rooms cheaply to workmen working on projects in the area. Apparently, a number of other hotels have closed down. Those running the Banchory Legion say that the problem is getting worse, and no-one seems to be doing anything about it. Perhaps, they are unaware of Aberdeen University’s sixty-year project and the new 20-year initiative from the AST. However, I doubt that they will be reassured that this project will bring them any immediate relief, if not in the long-term. I also suspect that they won’t be reassured by the fact that most of the Scottish Government’s efforts appear to be directed at supporting SEPA’s new sea lice framework and not helping stem the decline of salmon in east coast rivers. It not as if the river Dee catch of wild salmon used to be greater than the catch from all the west coast rivers together.

It now seems the wild fish sectors chickens have come firmly home to roost. For years they have complained that salmon farming is causing a decline in wild fish numbers but now the focus has been placed on regulation of the salmon farming industry, the appeals for immediate help to save east coast salmon are falling on deaf ears, that is unless anyone wants to help plant a few more trees.


ADDS: Finally, there was one part of the Scotsman article that attracted my attention. A spokesman for the Scottish Government, talking about the Wild Salmon Strategy, said seal predation is one of the pressures acting on wild salmon, which is why they continue to support research into non-lethal solutions to address seal-salmon interactions in rivers. “In 2023, we supported fisheries’ managers through the Marine Fund Scotland to purchase acoustic deterrent devices for the purpose of managing such interactions.”  Is that the same concept of ADDs that the salmon farming sector is banned from using?