How many?: iLAKS has published news from the Institute of Marine Research that there has been an explosive increase in sea lice in the north of Norway and the numbers are some of the highest on record. However, the doubling of lice numbers in the north are no higher than lice counts recorded elsewhere in Norway. In fact, lice counts in the south and west are no different than usual.
The cause of this lice explosion is attributed to higher-than-normal local water temperatures with 16.85 oC measured at one station in August.
The report is written by Dr Anne Sandvik who collates the sea lice data collected from salmon farms across Norway. She explains what this means
“Although salmon lice are found naturally in the sea, most lice now come from salmon farms. And this year, an unwanted production record is being set in the north.
But how many lice can there be in a breeding facility? Here is a small calculation example:
– If we start from the fact that a single cage contains between 100,000 and 200,000 fish, and each of these has 0.5 adult female lice (which is the legal limit from week 27 in the north), this cage will have 50,000 to 100,000 adult female lice before there is a requirement to de-lice the fish.“
A recent paper by Solveig et al: argues that the much of the data generated about salmon farming is over-estimated. I am unable to find a specific reference to estimation of lice numbers in a salmon farm in the paper but in my opinion the approach taken by IMR as detailed above is a prime example of how such over-estimation can, and does occur.
Regular readers of reLAKSation will know that sea lice, in common with all parasites, are not distributed normally. The result of measuring lice on a small sample of fish and then extrapolating the number to all the fish in a pen is contrary to the established parasite ecology. Parasites are spread across their hosts as an aggregated distribution and thus the majority of fish in any salmon pen will be lice free with only a minority of fish with high lice counts. Anecdotal evidence from some farmers supports this view as does the imagery from anti-salmon farm activist videos which highlight just a handful of fish with high lice infestation.
I have written to IMR and have received a reply. They point out that the example was simply used to illustrate how many adult female lice there can be without the legal limit being breeched. Yet, whether the example was being used to show the maximum legal limit of lice or not is irrelevant. The fact is that the distribution shown is counter to established parasite ecology.
IMR also replied that they are familiar with the field of epidemiology.
To be clear epidemiology is a branch of medical science that studies the distribution and causes of disease and health conditions in a specific population. This is not the same as the ecological distributions of parasites and is likely to be a major part of the reason why IMR sea lice infestation assessments have led to totally wrong conclusions about the impact of salmon farming on wild fish populations.
Praise the Lord: A number of the vocal minority that post on social media has been praising the debate in the House of Lords which asked what steps the UK Government are taking to protect wild salmon populations. This was instigated by Lord Forysth of Drumlean who in 1997 had set up a task force to look at the future of salmon but most of the recommendations of which Lord Forsyth says have still to be implemented.
Apparently, this was the Scottish Salmon Strategy Task Force which was chaired by Lord Nickson and looked into the decline of wild salmon. The task force looked at the problems created by commercial netting, high seas fishing and salmon farming. They concluded that stocks of salmon on the west coast were near collapse and recommended that an agency should be established to control salmon farming but given the background of those involved, there was no mention of imposing any control on angling. It would be another eight years before conservation grading was implemented.
This latest debate in the House of Lords echoes much of previous debates in 1997 and 2003. What makes this latest debate stand out is that on the same day, the House of Lords also debated the spread of misinformation online, something of which the salmon farming sector is a major target. In his introduction to the debate Lord Forsyth said that the most important thing to protect wild salmon is to tackle salmon farming and getting it out of open cages and on to land. He talked about farmed salmon being genetically engineered, excessive use of antibiotics and lobsters and crabs with their shell’s half eaten away. Finally, he promoted the book “The New Fish’ saying that if their Lordships read the book, they would never eat farmed salmon again.
He ended by saying that he wanted his grandchildren to be able to fish for salmon as he has done over the last 27 years with a Timeshare on the River Tay.
Whilst I wrote that this was a debate, the reality was that one Lordship after another declared their interest in angling including being chairmen of various fishery boards. One declared being a member of the Salmon and Trout Association, which suggests being somewhat out of touch. One after another Lordship blamed everything and anything for the decline in wild salmon stocks except of course anglers, which was to be expected.
Their Lordships might have discussed the issues of wild salmon more than once in the past three decades, but what is apparent is that they have not been able to solve the problems and more importantly their discussions and experience have yet to halt the decline of wild salmon. Like the rest of the wild fish sector, making salmon farming the scapegoat for the ills of the wild sector will do nothing to restore wild salmon to Scottish rivers despite the views of their Lordships.
Welcome back: Wild Fish have posted a blog from a voice from the past. Andrew Graham Stewart, former Director of this representative organisation for salmon and trout anglers, has written about the conservation status of the river Carron in Wester Ross. Mr Graham Stewart is concerned that this year the river has been downgraded from Moderate (Grade 2) to Poor (Grade 3).
It is rather puzzling that Mr Graham Stewart has written about the poor conservation status of this one river when there are another 116 rivers and fisheries with the same Poor grading. I would have thought he would be concerned about them all. As he clearly points out, eight other rivers have been downgraded for 2025, so the river Carron is not unique. At the same time four rivers have been upgraded from Poor so it is not all a one-way street.
Mr Graham Stewart writes that two of the nine rivers that have been downgraded stand out. One is the Endrick Water which I have discussed in a previous issue of reLAKSation and the other is the river Carron. I would disagree as both these two fisheries have been classified as Moderate for the last five years and have only been downgraded for this coming year. In fact, there is another one of the nine rivers that is much more interesting and should merit Mr Graham Stewart’s attention. This is Dunbeath Water of the Dunbeath Fishery District. Why this is more interesting is that knowing Mr Graham Stewart’s predilection for the issues of fish farming, Dunbeath Water is located on Scotland’s east coast where there is no salmon farming. Secondly, from 2020 to 2022, Dunbeath Water was assigned a Grade 1 (Good) status which was then downgraded for 2023 and 2024 to a Grade 2 (Moderate) status and finally downgraded further to Poor (Grade 3) for 2025. Something is clearly going wrong for the fish in Dunbeath Water yet not a word about this rapid decline has appeared in print.
Instead, Mr Graham Stewart prefers to focus on the river Carron. This is for two reasons. The first is that for many years, the river Carron has been the subject of a restocking programme which boosted catches from just 5 fish in 2001 to 420 in 2012. In common with every other salmon river, catches have varied from year-to-year swinging from just 78 fish in 2015 to 316 in 2019. Despite the overall success of the restocking programme, which should have been of interest to all anglers, the restocking scheme has been dismissed because as Mr Graham Stewart writes, it was funded by proprietors and critically by local salmon farming companies. It seems to Mr Graham Stewart; the success of the project is tarnished because some of the funding comes from salmon farming. Mr Graham Stewart also writes that the restocking programme was massive and very expensive. Clearly Mr Graham Stewart never bothered to go and see this project for himself because if he had he would know that the ‘very expensive’ hatchery was effectively a tank placed in an open field through which water flow was diverted. This was a restocking programme on a shoestring budget made possible only because of the dedication of just one man – Bob Kindness,
Anyway, Mr Graham Stewart writes that from 2020 the average catch from the river Carron has been only 69 fish and this is why the river has been downgraded. As to why catches have fallen so, Mr Graham Stewart says that it is clear that the intensive stocking and ranching exercise may have boosted numbers in the short-term, but it is not a long-term solution. He says that surely now is the time for a reality check and the real priority should be to address the underlying problems that negatively influence salmon abundance including the insidious but deadly impacts of salmon farming.
Yet, the four rivers that have been upgraded are all located in the heart of the salmon farming area, something Mr Graham Stewart chooses to ignore. Equally, Mr Graham Stewart chooses to assume that the recent downturn in catches is due to the presence of salmon farming. What he doesn’t say is that the downturn of around 70% is the same that has occurred across all of Scotland including the whole of the east coast. He should also be aware that in some of the years, a lack of water has been an influencing factor. But most importantly, the Marine Directorate’s decision to restrict restocking for reasons only known to themselves, has meant the river Carron restocking programme has been cut back and the numbers of fish caught reflect this. However, I am led to understand that whilst the Marine Directorate base the assessment on catches and projected juvenile recruitment, salmon smolts in the Carron have remained numerous.
As I have written in previous issues of reLAKSation, the Marine Directorate’s assessment of the conservation grading is clearly flawed. Their documentation explains how the reported rod catch is converted to an estimate of the number of returning salmon and then how this number if converted to numbers of spawning females. From the number of females, the Marine Directorate estimate how many eggs are deposited in the river and this predicted number of eggs is used to assess the potential river grading.
Clearly, if there are less fish caught then there must be less eggs deposited in any river. I mention this because one of the areas upgraded from Poor (Grade 3) to Moderate (Grade 2) is Hinnisdal to Haultin on the Isle of Skye. Since 2020, the Marine Directorate assessment appears to suggest that catches for Hinnisdal and Haultin have been 27, 16, 13, and finally 12 fish in 2023. Based on these catches, it is a real puzzle as how this fishery has seen its conservation status improve to allow fish to be retained. Surely, with such low numbers, this fishery should not even be catch and release but closed to fishing altogether to see if the stock can recover.
If Mr Graham Stewart is really concerned about the state of salmon stocks today, then he should lift his eyes beyond its current focus on salmon farming and look towards the wider issues affecting wild salmon now. Maybe he could start by doing something he has never done before which is to engage with those who have a different opinion to him.