840 parasites: This week I was looking for the link to IMR’s latest risk report and I encountered the following article. Researchers have found an average of 840 Anisakis parasite, commonly known as the herring worm, in samples of hake. Given that the risk report says that an average of less than one adult sea lice represents a risk to wild salmon, finding an average 840 of a different parasite in hake must provide IMR with a quandary. The problem is that IMR fail to realise that high numbers of parasites occur naturally in the wild and finding a salmon with hundreds of sea lice doesn’t mean that the infestation came from salmon farming. Sadly. Researchers such as those at IMR are too ready to listen to the uniformed leading to wrong conclusions. I give an example of this connection later in this issue of reLAKSation.
IMR
The levels of Anisakis nematodes are much higher in the hake sampled than those observed in other species such as cod, haddock and saithe from the same waters. In addition, 76 examples of the parasite taken from 60 hake were found in the flesh rather than in the guts.
From a scientific point of view, what is interesting is that fish such as hake are not the main host of these parasitic worms. Instead, marine mammals, mainly cetaceans, are the primary host. Hake and fish are simply transport hosts, as they are not essential for the development of the parasite.
Most parasites are extremely specialist and Anisakid nematodes are no different. Eggs are released in the faeces of the marine mammal host, and these develop into a free-swimming larva in the marine environment. The larvae undergo one or two moults before being ingested by invertebrates, mainly small crustaceans. These are the intermediate hosts which are then eaten by the transport hosts like hake. There are a number of different species of Anisakid nematode, and they then have different variations to their life cycle but typically, the transport host is then consumed by the ultimate mammalian host.
Humans are an incidental host but anyone eating hake flesh containing the worms can become infected and such infections are not very pleasant. Yet, where is the public outcry. Where is the stringent regulation demanded to protect human infestation. The answer is simple, there are no anglers blaming hake for the decline of their sport.
Wednesday 1: Wednesday 26th was somewhat a momentous day for sea lice regulation. Fish Farming Expert reported that Scottish salmon farmers have mounted a mass challenge to SEPA’s Sea Lice Risk Framework by appealing the revised licence conditions. SEPA have ordered that farming sites will have a specific limit on the number of adult female sea lice calculated to be attached to farmed fish and this limit will form part of the farm’s license conditions.
FFE say that SEPA believe that changing the rules will better safeguard wild salmon smolts from lice from fish farms as they pass by on their migration. Sadly, what SEPA believe, and the truth, are two very different things. The industry has said that the sea lice dispersal models used by SEPA to predict the possible threat to wild smolts are wrong. Regular readers of reLAKSation will know that I have been arguing that point for some years, but SEPA have never wanted to understand what is wrong with their model. They said at a meeting some time ago that they weren’t interested in the science as that was the Marine Directorate science responsibility and as I have pointed out the Marine Directorate say that the science has been settled as posted in 2021. Clearly, the raft of papers published over the last four years have added nothing to the science.
I can only hope that the industry’s new challenge will initiate the one thing that has never taken place and that is a proper discussion about the science behind alleged salmon interactions.
Wednesday 2: Also on Wednesday, the Institute of Marine Research published their latest risk report on salmon farming. This event was videoed and can be watched for the next month. I would have loved to have attended the accompanying meeting, but as might have been expected it was in Norwegian. Of course, I am not sure whether IMR would have wanted me there.
The following is taken from the risk report with regard to sea lice (via Google Translate)
“Ever since the volume of farmed salmon began to increase, the parasite sea lice has been a problem, and infection of wild salmonids is today the environmental indicator that limits further growth in Norwegian salmon farming. Sea lice affect both farmed salmonids and wild salmonids. After the Scientific Council for Salmon Management (VRL) determined that sea lice, genetic inbreeding and infectious diseases from farmed fish are the greatest threats to Norwegian wild salmonid populations, the focus for delousing was largely shifted from farmed fish to wild fish. In order to reduce the impact on wild salmonids, the limits for sea lice on farmed fish are low, especially during the migration of wild salmonids, and farmed fish must be deloused regularly to keep the infection pressure down.”
The risk report can only suggest that the risk to wild salmon in each production area is in line with the risk previously identified in the Traffic Light System. Thus, the risk report suggests that mortality of wild salmon smolts could be over 30% in PO3 for example but offers no suggestion of a number. Equally, I have never seen any feedback from previous risk reports saying how many smolts actually died over the previous years.
However, the most puzzling aspect of the whole of the risk report roadshow was the panel discussion that took place as can be viewed at https://www.hi.no/hi/nyheter/2025/februar/risikorapport-norsk-fiskeoppdrett (about 1 hour17 mins in). First listed on the panel was Torfinn Evensen, Secretary General of Norske Lakseelver – Norwegian Salmon Rivers. I thought that IMR was a scientific research institution so the presence of Mr Evensen in the panel talking about welfare and mortality was really puzzling. But then in my opinion, Mr Evensen is an expert on how to kill fish for sport as he represents an angling sector that since the introduction of a Traffic Light System intended to protect wild salmon, has managed to catch and kill 563,173 wild salmon weighing an average of 3.52kg each
In 2109, VRL estimate that 39,000 wild salmon smolts would die from sea lice although they have been unable to show that any of these fish actually died. If 39,000 smolts were to have died every year over the period of the TLS, then that would have totalled 312,000 smolts each weighing not much more than 30g. IMR seem oblivious as to which is the greatest threat to wild salmon.
Unfortunately, no-one attending the IMR event asked Mr Eversen about the mortality caused by angling and the loss of the future generations that might have been produced if these fish had been able to breed. The only risk that IMR considers worth talking about is the risk from salmon farming because this is the main risk to wild fish as promoted over many years by anglers and their friendly scientists. Mr Evensen was obviously on the panel as an expert of blaming salmon farming rather than as a representative of one of the biggest risks to wild salmon.
Regrettably, the IMR risk report is inherently flawed, and this is because it omits the biggest risk of all to wild salmon and that is the risk from the scientists at IMR who simply do not understand the science of sea lice and are not even willing to listen to why they are wrong.
Wednesday 3. Do you remember Peter Pollard, Head of Ecology at SEPA, who told the Scottish Parliamentary Committee that sea lice from salmon farms were not to blame for the decline in wild salmon numbers. Well, I wrote to him recently to say that I would be passing through Aberdeen, where he is based, and would very much appreciate the opportunity to meet with him for a face-to-face chat. On Wednesday I received a reply.
What Peter Pollard did not say was that he was unable to meet me because he was busy or not in Aberdeen or any of the vast number of excuses he could have used. Instead, he wrote
“As previously advised, we continue to engage with interested third parties via multi-stakeholder virtual sessions and via one-to-one virtual meetings.”
It seems that Peter Pollard would be quite happy to engage in virtual meeting with me even if I was sat outside his office block. It is not the time spent that is the issue but rather that he wants to avoid being looked in the eye and asked questions that he cannot answer. If he could answer them, we could have had this meeting well over a year ago when his manager first suggested that I speak to him.
Not just me: I am aware that Scottish Government scientists continually justify not talking to me about the science of sea lice is that they make me out to be some form of maverick activist, rather than an a scientific equal to them. However, I am not the lone voice they believe. The latest blog from Aquablogg.no is worth repeating here.
The blog says that the Lice Commission tells fly fishermen, managers and politicians that sea lice are killing wild salmon and that it is the salmon farming industry’s fault. If farmers would just close their net pens, then healthy populations of wild salmon will against be found in Norwegian rivers.
The blog continues that the Lice Commission refuses to discuss the science with people who think differently. Neither will they discuss criticism of their scientific publications. The latest example is cited as their treatment of a scientific article written by researchers form Nofima, which I recently highlighted in a previous issue of reLAKSation. This paper documents that the connection between modelled lice infestations and sea lice infestation on wild fish does not exist. The paper was originally reviewed for publication by members of the Lice Commission and was rejected but it was resubmitted to a different journal where the Lice Commission had no influence, and the paper was published. The Lice Commission now say that the paper misunderstands the IMR researchers modelling but refuses to explain why. Furthermore, the IMR researchers claim that the Nofima work was paid for by the aquaculture industry and therefore is not relevant.
Aquablogg ends by saying that over many years the contradictions that exist between the alleged science and reality have been ignored. For example, wild salmon and sea trout can thrive in fjords where models show the greatest infection pressure from sea lice. At the same time, large numbers of lice can be found on wild fish in areas where there is no salmon farming. The blog also says that the large interannual variation in modelled infection pressure do not explain variations in the numbers of returning wild salmon. The only conclusion is that the models do not bear any relation to reality and must be discarded. Instead, the models are still used as the basis for maintaining lice levels on farms at extremely low levels, demanding a delousing regime that is the cause of poor fish heath and high mortality.
Aquablogg says that the disregard for common sense has penetrated far into the core of scientific institutions in Norway. Their techniques are widely condemned by right minded people but managers, politicians and some farmers are unable to recognise the irrationality and the anti-science in their closest circle.
Sadly, this account can be reproduced for Scotland. Why is it so difficult to enter into a rational discussion about the issues. As recently highlighted by the Wild Salmon Connections meeting, the wild fish sector is not interested in talking about salmon farming in case the truth will defect attention back to their own activities. It is worth considering that there are thirty rivers on the west coast where subject to local rules, the Scottish Government has said that anglers can continue to catch and kill salmon. At the same time SEPA, who are not interested in talking about the science at all, saying that the science is the Marine Directorate’s responsibility want to introduce draconian measure to protect even one fish from sea lice infestation. Meanwhile, the Scottish Government have introduced a wild salmon strategy that will not stop wild salmon heading towards extinction but will allow anglers to continue fishing until there are no fish left to catch.
It is always good to read Aquablogg.no simply because it is a reminder that I am not the lone voice that the Scottish scientific community claim me to be.