Opinion: ‘Not our remit’
Ten years ago, I attended a meeting in Copenhagen organised by the International Council for the Exploration of the Seas (ICES). This was part of a programme aimed at assisting NASCO (the North Atlantic Salmon Conservation Organisation) in their quest to save wild salmon.
The meeting considered the impacts of sea lice and escapes, and was attended by various scientists from both sides of the Atlantic. My overriding memory of this meeting was the extremely fixed views of some of the participants and the fact that every question I asked was answered with the statement that: “This is not within our remit.”
I was reminded of this meeting during my attendance at the Norwegian Sea Lice Expert Group seminar held in Bergen towards the end of April. This seminar had been prompted by criticism from the International Evaluation Group back in 2021, who said that the Expert Group did not appear to be open to views from those outside the group. As a result, the Expert Group organised this seminar, but whether it was just a tick box exercise for them or whether they were really interested in hearing new science is open to question. The signs were not good.
Before the seminar began, I happened to speak to one of the members of the Expert Group and said that I was puzzled by the total lack of interest from Norwegian researchers about the 50 years of evidence I presented in my graph of salmon exploitation from rivers along Scotland’s east coast compared to that from rivers along the west coast.
The graph shows that the rate of decline from both coasts is extremely similar, questioning the alleged impact of sea lice and salmon farming on wild salmon populations. The reply was, again: “It is not in our remit”.
I can only wonder how a group looking at the impact of sea lice on wild fish do not consider a comparison of populations from coasts with and without salmon farming should not be within their remit!
The other sign of a lack of interest in new science was apparent from the response to the handful of presentations that in some way challenged the Traffic Light System, which in Norway determines in which regions salmon farming can be allowed to operate and expand.
In each case, during the question time, a member of the Expert Group gave a long commentary as to why they did not accept the new findings. As the whole event was in Norwegian, I was unable to ascertain exactly what was said but in speaking to others afterwards, they felt their work was being dismissed. What I can report is what was said to me after I gave a presentation.
When the invitation to the seminar was originally sent out, it was more of an invitation to apply to attend. Applications could also be made to present as long as the presentation was “new science”. I certainly felt that the Expert Group were not keen for me to attend as they kept writing to say that the event was in Norwegian and not in English and that only new science could be discussed not science that had already been considered.
As it happens, I had been working on new evidence and so was in a position to present the new science they requested.
The decision process of the Traffic Light System in Norway relies heavily on the use of models. Yet, the Expert Group are clearly so confident in the modelling that they use three different sea lice dispersal models, which are backed up by some sampling on wild fish, some sentinel cage data and the count of sea lice from farms to assess how many sea lice may be released in the fjord systems.
These counts are highly overestimated because the Expert Group multiply the sample sea lice count from the farm by all the fish in the pens but as this is not how sea lice are distributed amongst the farmed salmon, the estimated numbers are far too high.
What the (actual) figures tell us
For my research, I looked at the actual lice counts on farms rather than a modelled version. I consulted the Barentswatch website which lists all the farm lice counts for every farm over several years. The data is presented as a graph with number of attached, mobile and adult lice. When the numbers are lower than the limits of 0.5 adult female lice, (0.2 between weeks 16 to 21) the bars of the graph are blue. When the lice count exceeds the limits, the bars are shown in red.
Every year, researchers from the Institute of Marine Research trawl a number of fjords for migrating salmon post smolts and count the lice on them. I selected six of these fjords to consider the actual impact of lice from the local farms. Two of the fjords are located in production areas (POs) that are classified as green, two from yellow POs and two from POs that are classified as red. In total these six fjords are home to 372 farms and for each one, I looked at the lice counts for each of the nine years that the Traffic Light System has been in place.
For each week that Barentswatch highlighted a bar of the lice count graph as being red I recorded it as an “infraction”. I totalled the infractions for every farm, for every year for weeks 1 to 22 and then divided this total by the number of farms where infractions had occurred to obtain what I describe as the Farm Infraction Index (FII). It is this index, which reflects the lice pressure, and which I have compared for the six fjord systems. I selected data from week 1 to ensure that it covers any lice in the system prior to the beginning of the smolt migration. I also selected out the data for weeks 16 to 21 as this is assessed as being the most sensitive period for smolt migration. Week 22 is included because it is the last week that trawl sampling takes place.
The two POs that are classified as “green” are located in the far north where water temperatures are low and hence so is lice development. The FII also is low. It is the POs that are located towards the south of Norway, where most salmon farming takes place, that are of most interest. The results are shown in the table.
What is immediately apparent is the FII is lower in the two red POs than in those that are yellow. This occurs for both the longer and the most sensitive periods. This conflicts with the assessment made by the Sea Lice Group. How can the two areas be classified as red when the actual, rather than modelled, lice pressure is lower than areas judged to be less of a threat to wild salmon?
The question and answer session following my presentation was dominated by a statement from one of the members of the Expert Group in which he eventually admitted that they were aware that the lice pressure might be lower in the red areas but their decision to assign a red light to these areas was because the fjords in the red areas were very long and the fish had to swim further and would be exposed for longer to the lice pressure, even if it were lower. What this means is that the modelled lice pressure is actually irrelevant and it is the length of the fjords that dictate what Traffic Light classification each production area might receive.
To give some scale to this issue, the Hardangerfjord, which is home to 82 farms, of which 34 suffered an infraction during the sensitive period, is 179 km long. The Sognefjord has 47 farms of which 27 were infracted, is 205 km long. Both these fjords are located in POs that are classified as red.
In the yellow area Romsdalfjord, for example, has 34 farms of which 14 were infracted. The fjord is 88 km long.
As a further comparison, Altafjord in the north of the country is just 38 km long with 54 farms of which 17 were infracted and is located in a PO which is classified as green. Finally, the sixth fjord does not even register on the list of Norway’s longest fjords.
Perhaps SEPA just needs to measure the length of all the sea lochs in Scotland in order to rate their threat to wild salmon rather than spend thousands on a model that, if the Norwegian example is followed, is unlikely to be very accurate and certainly has done nothing to prevent a decline in wild salmon numbers.
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