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reLAKSation no 977

Green for Go: iLAKS has reported that salmon farmers in Western Norway are planning to challenge the Traffic Light regulations that control farm production. The Traffic Lights were launched in Norway in 2017 but it is only recently that some farmers have experienced the restrictions that these regulations can impose.

The Traffic Light System measures the risk to wild salmon from sea lice and if the infestation pressure is considered too high, then production in the locality can be curtailed. The infestation pressure is divided into three groups by colour, which is why it became known as the Traffic Light System. If an increase in mortality due to sea lice is estimated at less than 10%, the area is classified as green. For an estimated increase in mortality of between 10 to 30%, then it is yellow and if the estimated increase in mortality is over 30%, then the area is classified as red. This year, two areas in Western Norway were classified as being red as the impact on lice was considered unacceptable. Consequently, farms in those areas have had their production reduced by six percent.

According to iLAKS, farmers representatives issued a press statement saying that in theory they are not against the Traffic Light System but that they do not think that the knowledge base is yet good enough to make a proper assessment and that there are still large gaps in the data that bring the decision into question.

I think that the representatives are being too kind. My view, even going back to when the idea was first proposed, was that the whole concept was flawed. Wild salmon numbers are in decline and have been for many years, even in areas where there is no salmon farming. The number of returning salmon has fallen from 20% in the 1980s to less than 5% today across the whole of the North Atlantic. This is not due to the presence of salmon farms, yet salmon farming has become a convenient scapegoat for those looking for someone to blame and there have been plenty who want to do so, ranging from anglers to environmentalists.

Only recently I discussed the latest report from Vitenskapelig råd for Lakseforvaltning – The Scientific Advisory Committee for Salmon Management, who claimed that salmon farming is the greatest threat to wild fish stocks. Yet, they measured the threat as the potential loss of 39,000 returning fish due to the impacts of sea lice. By comparison, the deliberate killing of 82,365 fish by anglers for sport and another 53,048 killed by commercial fishermen is not considered a threat at all, even though 135,418 fish were killed by exploitation whereas the 39,000 fish claimed by the Committee that might not return due to sea lice are just an estimate and may never have existed at all.

The reality is that little information exists about the impacts of sea lice from salmon farms on wild fish. There is a lot of circumstantial evidence and assumptions. For example, surface trawls for naturally infected post smolts at sea only caught fish carrying less than 10 lice each. It is therefore assumed that higher infestation levels than 10 lice must kill these fish because they have not caught any. Could it be that wild salmon smolts are only infested with low lice numbers and this is why the researchers have not found any with a higher louse loading. This could be considered as simply conjecture on my part but there is sufficient cause for concern about the way the data is collected and interpreted.

A paper by Taranger et al. 2014 which outlines how the risks to wild salmon are assessed, states that “small groups of sentinel cages containing on average 30 farmed salmon post-smolts are placed in the fjords to monitor the salmon lice infection rate. The fish are kept in the cages for 3 weeks before the lice are counted on all the fish, and the procedure repeated three times during spring and summer”.

The fundamental question is whether wild smolts are exposed to the same level of infestation pressure during their migration away from the rivers as those fish kept in the sentinel cages. This will ultimately depend on the speed at which the fish swim through any salmon farming areas and beyond.

Reference is made in the Taranger paper about the time smolts are resident in sea water with links to other papers. This convoluted route to identifying how risks are assessed are further complicated because some papers refer the speed of salmon smolts as days per mile. However, it appears that this reference is not to the international mile but the Scandinavian one, which is 10 km in length. Fortunately, one of the two papers listed as a source of migration speed uses standard distances. This paper by Davidsen and others from 2009 measured the rate of travel of smolts from the Alta River. The researchers found that on average, post smolts spent 36 hours travelling the 31km from the river mouth to the last measuring array in the fjord. However, the rate of travel was not even throughout the journey as their speed for the first 4km was about half that of the next 27km. This was probably because the fish had to acclimatise to the changing salinity as they emerged from the river mouth and hence were likely slow getting underway.

This rate of travel is not that dissimilar to that in a paper from Chaput and others in Canada in 2019. They found that post smolt travel time from different rivers varies up to speeds of 22 km a day by post smolts from the Cascapedia river.

What these speeds suggest is that wild salmon smolts are exposed to a much lower infection pressure than the fish held in the sentinel cages because they are exposed for a much shorter time. This suggests that the estimated infection pressures gleaned from the sentinel cages and then used to assess risk have the potential to be greatly inflated. The reality is that smolts spend very little time in salmon farming areas.

In addition, there is increasing evidence that even in the short time that salmon smolts do spend in salmon farming areas, the overall risk has been overstated. Rather than delve into a detailed scientific discussion, I would like to offer a very simple analogy about parasitic life to which everyone can relate.

As human beings, we will eventually want to look for a life partner. We could do this by randomly wandering up and down the streets hoping that we might eventually bump into someone who fits the bill. However, wandering the streets doesn’t seem the most effective way to find a partner. Even if we see someone, it doesn’t mean that they are also looking for a partner. Instead, it must be preferable to reduce the effort, whilst increasing the chance of success.  To do this, we can congregate in areas where we know that potential partners might also congregate. For us, it would be pubs or clubs where the likelihood of finding a receptive potential partner is much greater.

Parasites like sea lice are no different. They want to increase the chances of finding a host rather than leave it to chance. The idea that post smolts have to swim through a soup of infective larval lice is one proposed by those who have not really investigated the science. Despite this, the risk assessments include consideration of hydro dynamic dispersion models.

It will be very interesting to see how this challenge to the Traffic Light System develops. I, for one, which will be watching how events unfold.


Shoot: The Ferret newspaper revealed last week that it had been leaked an internal document from the Atlantic Salmon Trust which sets out 14 proposed reforms to protect wild salmon. The one issue that attracted attention from the Ferret journalists was the view that a more flexible and adaptive approach should be taken to the problem of fish-eating birds. The AST are convinced that significant improvement to the current shoot to scare regime can be made that would benefit young salmon without jeopardising protected birds. Some licenses to kill birds have been issued in the past and now the AST would like to see this increased. Over the last five years over 2,600 fish-eating birds have been shot but others, including the Royal Society for the Protection of Birds, are against any relaxation of the current legislation.

Perhaps, the RSPB might be more open to discussion if they didn’t think that killing birds to protect wild salmon was only to protect the angling sector, not the fish. The strategy document states that a compulsory no kill policy would only be introduced if stocks of wild fish were not seen to be showing signs of recovery.

Opposition to the proposal also came from the anti-animal cruelty charity OneKind, claiming that the crash in wild salmon numbers is down to human practices such as overfishing at sea and salmon farming. Rather strangely, the charity has not included sports fishing in their concerns. Could this be because OneKind have linked up with Salmon & Trout Conservation to fight against salmon farming. Last week, S&TC communication advisor Corin Smith was the guest on a OneKind video presentation about salmon farming even though Mr Smith admitted on another podcast that salmon angling is inherently cruel!

However, what I found more interesting were the two sections of the report that relate to salmon farming. In terms of fish health, the Atlantic Salmon Trust appear to want to see salmon farms move to closed containment to protect wild fish. If this is the case, it seems that spending £750,000 on the west coast tracking project will be a complete waste of money. Why it is necessary to track wild smolts to check that they don’t swim near any salmon farm if all the farmed salmon are to be grown in closed containment?

Secondly, the strategy discusses genetic introgression saying this has been identified in Norway as the number one threat to wild salmon. This is from the same people that don’t think that killing 135,418 wild salmon by anglers and commercial fishermen is a threat to stocks, but the potential loss of an estimated 39,000 fish, due to the possible impacts from sea lice, is.

I was also surprised that the AST have made no comment in their strategy document about the fact that Marine Scotland Science have restricted the amount of information relating to salmon and sea trout catches that is now published. How can any decisions about the future safeguarding of wild fish stocks be made when the status of every fishery district in Scotland cannot be assessed other than by Marine Scotland Science? The underlying message is that the interests of the angling community are being put before those of the fish. This is clear from the strategy document which states that anglers are the main driver of salmon conservation.

It’s good that the Atlantic Salmon Trust are considering a wide range of factors that might impact on the future of wild salmon stocks, but any discussion should not be based on the prejudices and blinkered views of the past. Now is the time to look forward and with a much more open mind.


Sheepish: In the last issue of reLAKSation, I discussed how anti-salmon farm campaigner Corin Smith had suggested that there was no comparison between salmon farm production and rearing beef cattle on grass. One of my readers pointed out that not all free-range ruminant farming is environmentally friendly as Mr Smith had suggested.

Environmental campaigner George Monbiot has in the past written in the Guardian and elsewhere about the damaging impacts that uplands sheep farming has on the environment and how this form of farming is widely encouraged with millions of pounds of state aid.

Mr Monbiot writes that sheep farmers can graze his land to the roots, grub up any trees, poison the rivers with sheep dip and still get paid by the government. Consequently, much of the upland wildlife has disappeared as all forms of cover and shelter have been grazed to the ground creating barren land suitable only for the monoculture of sheep.

Mr Monbiot says that without subsidies, sheep farming in this environment is not sustainable and without sheep farming, huge areas could be rewilded hugely increasing the diversity of wildlife.

Of course, critics of the salmon farming industry try to paint a picture of salmon farming that suggests it alone has any impact on its surroundings. This is far from true. In fact, by comparison, salmon farming impacts on the environment are minimal compared to many forms of terrestrial farming and Mr Smith should know this. Salmon & Trout Conservation of which he is communications consultant is currently campaigning against agricultural runoff into the River Wye on the English Welsh border. This salmon river is now choked with algae at a times when river flows are much reduced.

Perhaps, the debate to be had is not about salmon farming at all but rather the impacts of humans from the local to the planet.