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reLAKSation no 1131

FASMOP 2: Just over a decade ago, Marine Scotland Science (MSS) published a series of reports relating to salmon stocks in various river systems as part of the ‘Focusing Atlantic Salmon Management on Populations (otherwise known as FASMOP) project. The intention of this £1 million project was to identify genetically distinct breeding populations of wild salmon from a range of rivers throughout Scotland.

The FASMOP project has almost been wiped from living memory because despite costing a huge amount of money and covering several important river systems, it failed to identify the predicted distinct populations of salmon that the wild salmon sector claimed existed across Scotland.

Most of the separate reports of river catchments contained the same statement as explanation of the lack of any conclusive results. This said that there were two possible reasons for the low levels of genetic structuring (i.e., the absence of genetically distinct populations). The first was the possibility of reproductive mixing of salmon from different parts of the river system although this explanation did not include the possible mixing from straying salmon. The second, and more interesting, reason was that the microsatellites in the study did not give the resolution required to show genetic similarity.

At the time, I posed a key question, which has never been answered. Surely, if the plan is to spend £1 million on this research, the experimental method should be tested first to ensure that analysis of the genetic microsatellites would be at the correct resolution to arrive at the anticipated conclusion. Without any answers, I can only assume that such testing did not take place.

I have been recently revisiting the SPILLS project report to help me frame my response to the SEPA consultation. I can see a parallel with the FASMOP project because even though ‘Wild Fish’ claim there to be up to 400 billion sea lice circulating in Scottish waters in any one week, the SPILLS team found just 20 larval lice. Even if the focus is just on the farms in the experimental area, there might be expected to be 10 billion lice in circulation. MSS has said to me that they don’t recognise Wild Fish’s numbers, but equally they have not provided any indication of the larval sea lice numbers that they would recognise.

The SPILLS report states that the failure to capture sea lice larvae does not equate to their absence. Unlike FASMOP, this project included testing of the methodology, and this took place during March 2021, a month before the field sampling trials began in April. Surely, this was insufficient time to determine the most effective method of determining whether the number of lice identified matched those predicted in the model.  In the end, the project team used two different methods to collect sea lice during the whole project: pumps and nets. The final report determined that the pumped method was most effective because 16 samples contained larvae compared with 3 samples by netting. However, this reference to samples is not about samples of sea lice but about the collected sample. Regardless neither was effective because in total they caught 21 lice of all stages. The absence of any numbers of sea lice in their samples led to the suggestion that care must be taken to avoid conclusion that there were no sea lice present at the time and place sampled. I would argue otherwise.

What I find puzzling is the project report considers the sampling strategies employed by other studies. One of these is from 1991 but looks at other marine copepods not those affecting salmon. Three papers are cited of which the earliest is 2016, however, regular readers may remember that I have previously highlighted at least one Norwegian study from 1997 that attempted to identify sea lice in the water column. This was because like the SPILLS research, they failed to find any larval lice during their research.

What the SPILLS report has not included for consideration are other research papers from 2002 to 2011 which did collect lice from Scottish waters, specifically around Loch Shieldaig. The maximum density identified was 423 lice m-3.  Clearly from these results, it is possible to identify sea lice in significant densities as long as the search is in the right place. The key point here is that the researchers who identified these larval lice all worked for Fisheries Research Services, the former name of Marine Scotland Science. How the SPILLS team could not be aware of this research is more than a mystery. With this research in Scotland and similar well-publicised work in Ireland from the 1990s, it is unclear why the SPILLS team had not identified a reliable method of catching and identifying sea lice prior to April 2021. SPILLS should not have been about seeking reliable methodology as this should have been established well before the project began. The project itself should have focused on matching evidence of sea lice in the sea with the predictions of the model as stated at the beginning of the report.

Instead of producing a clear result, the SPILLS project failed to come up with any meaningful result, the consequence of which is the key point in the report which states that failure to capture sea lice does not equate to their absence. The reality is that yes it does. Unfortunately, those who produce these models seem unable to accept that they do not reflect what actually happens to sea lice in the marine environment. Larval sea lice do exist in the sea, but just not where the models predict. This is because the models are based on the dispersion of inert particles, not on real biological organisms.

Another of the key points raised in the SPILLS report says that low capture success is in agreement with other zooplankton sampling methods for sea lice which is likely due to patchiness, temporal movement and low overall abundance in the water column. This statement is not supported by a scientific citation, but if it is accepted that there is an overall low abundance of lice in the water column then the risk to wild salmon is clearly also low.

Finally, I find it interesting that evidence of sea lice in certain areas of sea was prevalent before the development of complex hydrodynamic models after which sea lice detection has seemingly fallen to very low levels. Could it be that this focus on modelling has led to focus on areas of the sea where sea lice are simply not present?


Peas in a pod: Anyone listening to the latest of Ariane Burgess’s podcasts about aquaculture might be forgiven for thinking that the seas around Scotland are one massive cesspit

Ariane Burgess, MSP and Green Spokesperson for Rural Affairs provides Coastal Community Network’s spokesperson for aquaculture, John Aitchison nearly three quarters of an hour to rant on about everything he considers bad about salmon farming. Even natural biological organisms such as sea lice are considered by John to be pollution.

What is surprising is that given all this pollution that salmon farming generates, and that salmon farming has been present along the west coast for over forty years, then there should be plenty of evidence for John to produce that supports his views and as yet, I have not seen any.

I acknowledge that the salmon farming sector is not without impact and the area under net pens is affected. However, the area under all the net pens in Scotland equates to about two 18-hole golf courses, which is miniscule, compared to the area of seas around Scotland.  Equally, if John is correct then farms which have been operating for over forty years should be submerged by their own pollution and they are not.

My commentaries normally relate to aspects of sea lice that are in the public domain, but this week SEPA have been holding workshops to discuss their proposed regulation. During one session, attended by John, he referred to wild fish swimming through lice clouds. I always find it interesting when opponents of salmon farming use terminology which they are unable to justify. Perhaps, someone might like to ask John to provide some scientific basis for the idea that there are clouds of sea lice in the sea through which wild fish must swim. I did offer to present to the CCN’s aquaculture group about sea lice, but they refused saying they know all they need to know.

However, CNN are not the only ones unwilling to hear the other side of the debate. I have offered to speak on Ariane Burgess’s podcast, but she too doesn’t appear to want to hear from those with a different point of view as she refused my offer. This latest episode of her podcast is numbered 2 out of 4. I wait with interest to see if any future episode includes discussion with anyone from the salmon farming industry or only those who oppose it.


Blinkered: I am always amazed that opponents to salmon farming whilst expressing concern about the impacts of sea lice on wild salmon appear never to show any interest in other aspects of salmon conservation. For example, whilst the Coastal Communities Network blame salmon farming for the decline of wild fish numbers, they don’t appear to suggest that anglers stop killing wild fish for sport.

They blame salmon farming for causing pollution and especially the use of licenced medicines but they don’t appear to criticise farmers for using biocides and fertilisers that eventually end up in the sea.

Last month, it was reported in the Guardian that a study that took place on the southern English coast revealed high levels of potentially harmful chemicals that had come from human waste. These include recreational drugs and prescribed medicines including antidepressants. It is already known that oestrogen can feminise male fish and that even small amounts of antidepressants can affect many forms of wildlife.

It appears that there is a staggering list of prescription drugs that pass from humans to wastewater treatment plants and then receiving stream, estuaries and the seas yet there is not a peep of outrage from the coastal communities that the same could be happening in Scotland.

However, I suspect that CNN’s main concerns have more to do with NIBYISM than whether a range of chemicals are actually found in the seas.


Tagged: Whilst the argument whether salmon farming is responsible for declines in wild salmon numbers, Fly Fishing and Fly-Tying magazine has reported that a smolt tagged with a PIT tag in France’s river Scorff on April 21, 2022, was caught by an Icelandic mackerel trawler some 200 km north-east of Iceland on July 25th that year.

The report focused on the hope that others who tag fish with PIT tags will also register their tags on the International PIT Tag database that can match tagging and recapture details. Such information might help improve knowledge of the migration and fate of salmon whilst at sea.

Much of the narrative about salmon being caught at sea seems to focus on larger fish which may then be sold on the black market however, the likelihood is that it is smaller fish are being caught are just lost in the system of bycatch. It is not impossible that many fish leaving Scottish rivers are scooped up in the hunt for pelagic fish. Sadly, those trying to influence research have always argued that the focus should be on those pressures that can be changed. This has always meant salmon farming. By comparison, the pressures at sea have been dismissed as being too expensive to research and also outside of local control. Yet, this new finding could lead to much better understanding of what is happening to wild fish and show that salmon farming is not the guilty party as the wild fish sector maintain.