reLAKSation no 1151

Five years on: Its quite amazing how those who have an agenda against salmon farming keep on referring to the 2018 Scottish Parliament’s ECCLR and REC committee’s inquiries into salmon farming as if they were the absolute pinnacle of expertise and knowledge. It was only in September (12th) that Edward Mountain MSP said in a debate on agriculture that the REC committee report made 65 recommendations asking the industry to rise to the challenge, however the only rise we have seen in the last five years is a 168% increase in the use of antibiotics in salmon farms.  Perhaps if he had waited a few more weeks, he could have reported that antibiotic usage on salmon farms had fallen by nearly 65% in 2022.

I would also point out that recommendation 38 of the REC Committee report states:

There needs to be a recognition that any work taken forward on the issue in the short term (such as the SEPA sea lice risk framework) may be hampered by a lack of scientific data. The Committee supports the proposal from the EDCCLR committee for more research into the interactions between farmed and wild salmon as a matter of priority, although it acknowledges the evidence heard suggest that these may be difficult to deliver.

In the last five years, I have seen very little evidence of new research on sea lice interactions and certainly very little scientific data. Most work appears to have focused on modelling and as the SPILLS report has shown, this is backed by minimal scientific data. Most of the data used in SPILLS was generated long before the REC Committee inquiry took place. However, this does not mean that no research has taken place. For my part I have continued to investigate the interactions of sea lice between farmed and wild fish but neither the wild fish sector and its Parliamentary supporters nor the Marine Directorate appear interested in hearing any new science unless it supports their own narrative.

Just for information, I will be presenting a short paper on my own research at the forthcoming Marine Alliance for Science and Technology for Scotland conference in December. This follows on from the Marine Directorate who presented on sea lice there last year.

This week an anti-salmon farming critic, who referred to the ECCLR Committee report which suggested that planned expansion to up to 400,000 tonnes by 2030 did not take into account the capacity of the environment to farm that quantity of salmon. Perhaps if the ECCLR had called more than just the one witness (out of 12) from the salmon farming industry they might have got some better answers, I would suggest that if current production takes up the area of two 18-hole golf courses then double that would covert the area of four such golf courses. The promontory at St Andrews is home to five golf courses and compared to the area of sea around Scotland its size pales into insignificance.

The imbalance in the number of witnesses called to address the ECCLR inquiry reminds me that the committee had also commissioned a consortium led by SAMS Research Services Ltd to review the environmental impacts of salmon farming in Scotland. The first page of the report lists the contributors who according to the report contributed areas of their scientific expertise. Section 2 lists, Professor Eric Verspoor, Dr Donna-Claire Hunter and Dr Mark Coulson, all from UHI Rivers and Lochs Institute. Section 2 is titled: ‘Sea lice & disease impacts on wild sand farmed stocks’.

Following publication of the report, I did raise the question as to the expertise of the lead responsible for writing section 2. I have met Professor Verspoor and know him to be a fish geneticist. His personal profile on the UHI website states that his academic expertise is in ecological and population genetics.  Dr Mark Coulson ‘s expertise also in molecular ecology and population genetics. He came to Scotland from Canada to manage the 2012 FASMOP genetic project on behalf of RAFTS. I believe that Dr Coulson has now returned to Canada. Finally, I am unable to ascertain the exact experience for their colleague Dr Donna-Claire Hunter. I gather that she also used to work for RAFTS between 2010 and 2012, working alongside Wester Ross Fisheries Trust. It appears that in 2013 she spent time at Stirling University working on the area of aquaculture site selection. By 2017, she is associated with the Scottish Salmon Festival (a celebration of angling and wild salmon) held at UHI in Inverness. A UHI press release mentions that Donna-Claire Hunter from Beauly leads the local charge in the festival’s female ‘Speycasting Tournament’.  More recently a Donna-Claire Hunter is reported as working for the Shetland and Orkney coastguard. I cannot find any single reference to sea lice expertise for any of these three members of the UHI, Rivers and Lochs Institute team. How they came to write the section on sea lice and disease is a compete mystery,

However, more importantly, there is a big question mark hanging over the issue of sea lice as covered by both the ECCLR and REC Committees. This is not a recent complaint, but one raised at the time of the inquiries but as with any questions about sea lice that don’t fit the accepted narrative, any concerns were simply ignored.

Considering that the Norwegian scientific committee for salmon management claim that sea lice is one of the major threats to wild salmon, it might be considered surprising that the coverage of interactions of sea lice with wild salmon didn’t even manage to cover a whole page. However, the section begins with the statement that:

Infestations of the parasitic copepods called sea lice are a threat to fish welfare and farm economics as well as, possibly, to wild salmon populations.

As these experts have included the word possibly in the text do they mean that sea lice are a threat to wild fish or that they are not? Their later text appears to suggest that they are based on selective research paper. However, on reading their comments, I can only wonder whether they have read the papers they have cited or simply repeated what others have said. If the second is the case, then they did not do a good job,

The section titled ‘Salmon farming increases sea lice abundance and infects wild salmon’ begins:

A clear relationship between the increased abundance of sea lice due to salmon farming and presence on wild hosts in the sea has been demonstrated outwith Scotland (Marshall, 2003; Morton et al., 2004; Serra-Llinares et al., 2016). For Scotland, there are no published accounts of systematic counts of sea lice levels on wild salmon and its association with salmon farming. The only reported scientific study relates to wild sea trout monitored over five successive farm cycles (Middlemas et al., 2010; 2013)***.

This appears to say that there is a clear relationship between increased sea lice on salmon farms and on the wild fish, but this has only been demonstrated outside Scotland. By comparison, there are no accounts of infestation of salmon in Scotland. only of sea trout and these are papers from 2010 and 2013.

I suggested that the experts hadn’t read the papers and the first one they cite is Marshall 2003 which is of sea trout, not salmon, in Scotland. If they can’t get such basics right, how can anything else they propose be trusted to be correct. The Marshall paper is from Shona Marshall of the West Sutherland Fisheries Trust and concerns examination of sea trout in Loch Laxford. The abstract of the paper states that there is only a weak relationship between lice abundance on wild salmonids and the stage of production of the neighbouring farm. Marshall concludes that other factors have a greater importance to lice abundance than the farm. This is one of the reasons why this paper is now rarely quoted, as it doesn’t support the accepted anti-salmon farming narrative.

The other papers cited are also poor examples of showing links between salmon farming and lice abundance on wild fish. However, I don’t intend to go through each paper here to explain why the UHI team misunderstood the science they were writing about.

Instead, I want to focus on one paper that is cited in the section titled ‘Sea lice effects in wild salmon populations.’ The experts write that quantifying wild salmon population mortality due to sea lice infections is complex and the magnitude depends on environmental, biological, and ecological variables that have not been studied in depth. They cite a paper by Helland and others from 2015 which tried to identify the best statistical method that could determine mortality.

For me the significance of the paper relates to a single figure showing two graphs.

Although they included the graphs in their paper, Helland and her colleagues were too busy trying to work out how many fish might die from sea lice they ignored the number that didn’t die. Anyone with an open mind might ask how there are so many fish in the sampled population that are free of lice or carry just one or two lice. Whilst Helland recognised the spread of lice as a zero inflated statistical distribution, they remained unaware that this form of distribution is a defining feature of parasite distributions and that most host fish will have no or few lice and thus are not at risk of mortality.

The UHI experts also failed to ask the same question and thus omitted the most significant part of sea lice impacts from their review.

As well as citing Helland, the UHI team cite a paper by Vollset and others from 2015. Interestingly the abstract begins by stating that ‘Parasites, in theory, have large impacts on the survival of fish populations’. The abstract ends that ‘the results suggest that the population level effects of parasites cannot be estimated independently of other factors affecting marine survival of wild salmon.’ These comments have not stopped the scientific community from estimating high levels of mortality of wild fish and blaming salmon farming.

I do not have the data from Vollset’s 2015 paper, but I have revisited a later paper from 2018 for which I do have the data. The first graph is the sea lice distribution across 1164 sampled by nets and traps over eight years (2009-2016)

The bumpy look to the graph and the low overall percentages of lice free fish, or with few lice, can be attributed to low sample numbers. Overall, the average number of fish caught per year was just 145 and these fish were caught over several week. For example, in 2011, the first sample using gill nets was caught on the 3rd May and the last on the 8th of August. In total, sampling occurred over 26 days and, in that year, the total number of fish caught was 63 fish. That year they also sampled using traps and the first trap was put out on the 5th of April and the last on the 30th of June.  Between the two days a total of 23 trapping attempts took place catching a total of 53 fish. In 2011, 49 sampling attempts achieved a total catch of 116 fish.

The second graph shows the number of fish caught in each sampling attempt whether traps or net. Out of 294 separate sampling attempts, 98 of them caught just one fish and a further 50 caught two. I would ask whether in this example, are the 98 fish caught separately as representative of the population as one sample of 98 fish. Taranger (2012) suggests that the sample size should be 100 fish, which is close to the 98 fish in this example. The largest sample in this dataset was just 30 fish.

I have suggested this before now, but just because it is proving difficult to obtain large samples of wild fish to measure sea lice infestation pressure should not be the reason to penalise salmon farms. Instead of focusing on salmon farming, the researchers should be identifying new ways to obtain truly representative samples of sea lice infested fish.

I would argue that the inquiry into salmon farming by two Scottish Parliamentary committees did not provide a representative impression of salmon farming in Scotland today, nor did the resulting Salmon Interaction Working Group. SEPA are due to report on their latest consultation which is supposed to be evidence based. The time has come to stop looking back at Parliamentary Committee reports and engage in a paper discussion of the science and the way it is applied.

(*** Data on sea lice infestations has been collected since 1997 and there has not been a single published paper on the data’s analysis since. Surely this is a major omission given that such analyses were a recommendation of the 2018 REC report).