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reLAKSation no 1156

Many festive greetings to all our readers.
Thank you all for your continued support. It is very much appreciated.
See you in 2024.

Sjømatdagene: One of the biggest seafood meetings in Norway takes place in January. Seafood Days will be opened by Cecilie Myrseth, Norway’s Minister of Fisheries and Oceans.  Discussions on a wide range of subjects will take place over two days outside Trondheim.

One of the interesting talks will come from the chair of the Aquaculture Committee that recently reported its findings and is now the subject of a public consultation. Linda Nøstbakken will talk on a holistic permit system for the future. Another member of the committee, Dr Geir Lasse Taranger, best known for his method of estimating mortality of wild fish by sea lice, was also scheduled to talk about how farmers could move from a red classification of the Traffic Light System to a green one.

I was just looking again at the programme and noticed that Dr Taranger’s talk has vanished from the programme. Could it be that at long last there is now recognition In Norway that the Traffic Light System is not fit for purpose as it is based on flawed science, flawed sampling, and a lack of any understanding of sea lice ecology.

There is no explanation why the programme has changed but could this be a start of a new discussion over how salmon farming’s alleged impact on wild fish is perceived.


Endangered: Last week, the media have been widely reporting what most people already know, that a couple of scientists based in Cambridge have decided that the UK Atlantic salmon stock is now endangered. The so-called conservation charity Wild Fish had previously raised the money to initiate a review of the ICUN Red List status for salmon and this week’s news is the result. Yet, if Wild Fish had been so concerned about the status of Atlantic salmon, they may have demanded an immediate end to all exploitation of the fish in the UK rather than wait for the review’s outcome. However, not only did the not take pre-emptive action, but now that salmon have been deemed to be endangered, they still have not demanded an end to all exploitation. Of course, any long-term observer of Wild Fish in either its current or past forms, would not be surprised by the lack of decision action from Wild Fish. After all, rather than being a so-called conservation charity, the reality is that they are the leading representative organisation for salmon anglers and since they don’t believe that angling has anything to do with the current endangered status, they don’t see that anglers should be penalised for the fact that salmon is now endangered. Instead, it is business as usual for the salmon angling sector. Wild Fish are clear in their view of the problems facing salmon and they all come from salmon farming. Sea lice and interbreeding are the real cause of the declines and why salmon are now endangered.

The latest issue of Trout and Salmon magazine devotes a full page to Nick Measham of Wild Fish to tell readers not to buy or eat farmed salmon this Christmas. He points out that we don’t farm apex predators for food, which is why we don’t farm tigers, but then we humans don’t eat tigers, although we do eat plenty of other marine apex predators and we do try to farm those that we like such as tuna. We also farm trout, a fish that his membership target, yet he doesn’t demand an end to trout farming.

In his commentary, he says he has all the evidence he needs to campaign against salmon farming. Interestingly he says that wild salmon are harmed by sea lice not killed by them and that escaped farmed salmon threaten the wild salmon gene pool. Harmed and threatened are not the same as outright killing wild salmon so if Mr Measham lacks the evidence to say that salmon farming is killing wild salmon then perhaps he needs to look elsewhere to account for why there are no wild fish left. Maybe he could look to his own membership (or what’s left of them) and ask who is responsible for the nearly 5.9 million wild fish that the Marine Directorate has reported as being killed since records began by those using rod and line.


Still Endangered: In addition to the IUCN review last week, the Marine Directorate, published details of their consultation into the conservation status of Scottish salmon rivers. It seems that despite some common-sense replies, it is business as usual for salmon angling next year. The fact that catches in 2023 are possibly the lowest on record is no reason to stop salmon anglers having their fun in 2024. Even the new endangered status is not encouraging mandatory catch and release across all Scottish rivers. After all, catch and release, whether mandatory or not, has not stopped the decline of wild salmon numbers. It is only necessary to look at the river Dee which has been mandatory catch and release for many years and yet, the catches have declined along with those in other major east coast rivers, all of which are located far from the nearest salmon farm.

The social media critics continue to highlight that the smolts from these rivers must migrate north and will inevitably swim near the salmon farms of Orkney and Shetland and as they do so they pick up the lice which eventually lead to their early demise. What they seem to forget is that smolts from these rivers took the same migratory routes since salmon farming began in these islands during the late 1970s and early 1980s and from then to 2011, not one angler suggested that these farms were killing east coast river smolts. In fact, in 2011, the Rivers and Fisheries Trusts of Scotland (RAFTS) produced a paper saying that east coast salmon were doing extremely well with increasing catches precisely because they didn’t interact with any salmon farms, whilst west coast salmon were in decline because they did.

The truth of the matter is that the Marine Directorate are equally clueless about how to protect wild salmon. Their Wild Salmon Strategy has been drawn up in collaboration with those primarily with interests in salmon angling and is now being managed by the same people. How can this approach safeguard the future of wild salmon?


Norway too: (Previously published in Fish Farmer magazine) Sea lice are not constrained by international borders, so it was of interest when the bastion of sea lice research in Norway, the Institute of Marine Research, published a commentary on sea lice, written not just by two sea lice researchers, but also by the institute’s Chief Executive.

The commentary suggested that if salmon farmers wanted to farm more salmon in the north of Norway, then they must learn from the mistakes that have been made, especially by farmers in the west. The western production areas are those that have had to reduce production due to alleged reports of high lice infestations in wild fish.

The commentary says that the solution to the problem of sea lice, at least in theory, is simple. Research, industry, and government must work together to restructure the industry. They say that (their) good models that can identify the infection network will allow them to advise on which farms should be closed to reduce infestation pressure or whether farms should be fitted with lice skirts, snorkels or use submerged cages to avoid sea lice.  The commentary says that IMR have the tools that can help both farmers and managers assess the spread and impacts of sea lice.

However, having read the full commentary, I can only shake my head in disbelief. I would argue that it is not the farmers of Western Norway that have made mistakes but rather the mistakes are those of IMR with a failure to understand the true relationship between sea lice, wild, and farmed salmon.

IMR say that their good models can identify infection networks, but as in Scotland, such models have never been validated, Whilst claims that sea lice larvae pass down the fjords and lochs infesting the fish they encounter, there is so far no actual proof that the larvae disperse in this way Attempts to identify large numbers of sea lice larvae in the lochs and fjords have so far proved fruitless. Instead, scientists have resorted to using sentinel cages for infestation studies, but these are more likely to be infested by passing wild fish than any larvae spreading through the water body.

Whilst the existence of larvae in the fjords has yet to be proved and the model properly validated, the way that the existing science is applied is open to question. For example, IMR sample all 13 production areas that form the basis of the Traffic Light System. This is to demonstrate the strength of infestation of wild fish by sea lice. Unfortunately, there is a lack of consistency in the sampling across all of the thirteen areas. which could lead to a bias against those areas with the most farmed salmon production. In 2021, production area 13 (PO13) was sampled for sea lice on wild fish on just one day. By comparison, sampling of wild fish in production area 4 (PO 4 -Western Norway) took place over 71 days. PO 3 was sampled on 45 days, yet PO 8 was sampled on just 2 days. It is not difficult to predict which areas had the highest lice counts.

In the same way, how can 1,013 fish be sampled in one area whilst just 32 are sampled in another? This makes no sense, yet such numbers are part of the sampling regimes used to assess the production areas in the Traffic Light System.

There also appears to be a lack of understanding of the way sea lice are distributed throughout the wild fish population. All parasites, including sea lice, are distributed as an aggregated distribution. This is when most hosts (fish) are parasite free or carry very few parasites (lice) whilst a few hosts carry many parasites. All the data I have encountered showed sea lice as an aggregated distribution, but I have only seen this once in the scientific literature. This was in a 2015 paper written in collaboration by scientists from NINA, IMR and the Veterinary Institute. The paper focused on the statistics used to assess sea lice infestation rather than actual infestations and thus the significance of the distribution to sea lice was missed. By coincidence, the scientist from IMR who co-wrote the 2015 paper also co-wrote this commentary from IMR.

The issues of sampling highlighted previously become heightened when analysing sea lice because of their aggregated distribution. The distribution of sea lice amongst wild fish hosts is not even with most lice free. At the same time, the few fish carrying many sea lice are likely to be weakened and thus easier to catch. In his 2012 paper, Taranger recommends a sample size of at least 100 fish, but analysis of the 2021 data shows that 58% of the samples consist of between 1 and 10 fish. Seventy eight percent of the samples are between 1 and 20 fish. The largest sample was 56 fish, well short of the 100 recommended by Taranger.  The obvious question is are these fish representative of the population or are they selectively sampled from the heavily infested end of the distribution due to how they are sampled? As the sampling across all the production areas is not consistent, it is impossible to compare one production area with another especially those areas with low numbers of salmon farms and those that produce the most farmed salmon.

So, what is IMR’s view of this analysis? Unfortunately, the Chief Executive who wrote this commentary has never answered any direct enquiries. This is not unexpected, the scientific community in Norway have pronounced that sea lice from salmon farms are negatively impacting wild fish and they are sticking to that story. Any evidence to the contrary is simply ignored in the hope that it will go away. However, the mounting evidence that the declines of wild salmonid fish are not connected to salmon farming can only be ignored for so long. The threat to wild fish from sea lice has been highly overstated by this failure to understand the science and even greater unwillingness to enter into any meaningful scientific debate.

Finally, HI’s press department were sent a draft copy of this column in case they wished to comment. They have not replied.