Rather than offering a lengthy response to the comments posted on my last article I thought it would be helpful to write a follow-up article exploring some of the issues in more detail. I’m afraid I can’t provide a rational response to the person who from behind a cyber invisibility cloak described my work as “sensationalist claptrap” but I’m happy to pick up on the intelligent points made in other comments.
The saveseilsound campaign group consists of a dedicated group of active contributors, a wider circle of occasional contributors and a host of others who simply wish to be kept informed. We are mainly local residents who share a mutual concern about the damage the current proposals would cause to an area that we feel very strongly about. We set up the website as a place where information and views can be conveniently shared. As it has developed it has become an archive of data and articles that we hope will be of assistance not only to the several hundred individuals who have registered comments but also to Council staff and others in dealing with a massive volume of documentation. We are anxious to protect our credibility and do not post anything without the most careful checking, further we will be happy immediately to correct any errors that may have inadvertently occurred. Also our membership is not closed and we welcome new contributors with something useful to offer. We can be emailed via the website.
The fish farming industry mainly impacts in two separate, but linked ways, firstly environmental and secondly economic. A moment’s reflection shows that in areas that are highly dependant on tourism and leisure damaging the environment by destroying water purity, dumping pollutants and killing off native wildlife will also impact on local businesses. Let’s look at each of these impacts in turn.
‘Allowable Zone of Effects’
I acknowledge that there are ongoing arguments between environmental campaigners and the industry on much of the science. As one commenter pointed out there are perhaps 150 new articles posted per week and as someone who tries to keep up with them I can confirm that fatigue easily sets in.
There is also the problem that, bluntly, almost all of the scientists work either for the government or for the industry and in neither case will speak out. Lay persons are faced with blindly accepting what they are told or going on a crash course in understanding concepts such as the ‘Allowable Zone of Effects’ (AZE).
Setting AZEs has been understood to be critical from the earliest days, as the government, latterly through SEPA, has always known and accepted that a certain amount of pollution would have to be tolerated. In the very beginning, with farms of about 100 tonnes capacity, the pioneers probably assumed that the myriad creatures living below the seabed would rise to the surface and diligently clean up the mess.
Given a soft sandy or sediment seabed and moderate amounts of debris that was probably a reasonable assumption, but Nature never works as we expect her to. Experience has shown that low levels of pollution actually encourage the growth of marine animals, an effect termed the “zone of enrichment” – but larger quantities smother the seabed and life becomes impossible.
Until about 2005 the AZE was usually set at 25 metres from the cage edge. Beyond that limit pollution was not allowed and if found the permitted stocking density was supposed to be reduced. By that date however farms were already becoming much bigger and studies were showing that pollution would regularly travel far beyond the 25 metre limit.
Research carried out by academics from Aberdeen University in 2009 confirmed that: ‘Above a farm size threshold of between 800 and 1000 tonnes, the magnitude of effects at farms located in areas of elevated current speeds were greater than at equivalent farms located in more quiescent waters. Sediment concentrations of total organic matter were influenced by an interaction between distance and depth, indicating that wind-driven resuspension events may help reduce the accumulation of organic waste at farms located in shallow waters. The analyses presented here demonstrate that the production and subsequent fate of organic waste at fish farms is more complex than is often assumed; in isolation, current speed, water depth, and farm size are not necessarily good predictors of benthic impact.’ The whole document can be read here on the saveseilsound website.
The researchers also noted that negative impacts had been found between 25 and 50 metres from the cage edge and that approximately one third of farms existing in 2005 were failing the tests set by SEPA. Interestingly, in Argyll there were five successful prosecutions for this in the last fifteen years. Among them Lakeland Marine Farm, who are the present applicants at Seil and Shuna, pleaded guilty to knowingly over-stocking one of their farms in Loch Shuna between September 2004 and January 2005, thereby causing unacceptable pollution and were fined £1,000.
It seems that from about 2005 two things have been recognized. Firstly the original limit of 25 metres was unrealistic if the new larger farms were to be allowed to remain in existence, so the decision was made to allow increases. Secondly the same strict limit was not appropriate in all cases. Not only stocking density but also factors such as the shape of the cages, tidal flows and directions were important too. As a result a new system was introduced, involving predictive modeling by computer and known as autoDEPOMOD.
The new system allows AZEs to be tailored to suit particular local conditions and autoDEPOMOD is now accepted as the standard by SEPA. It has been suggested by people with a better understanding of science than I have that hydrographic conditions are extremely difficult to predict accurately. This is especially so in areas where tidal flows are complex, such as in Seil Sound and the Cuan.
One of our group with extensive experience of experimentation with water flows is highly dubious about the accuracy of predictive modelling in such places. As with all computer studies what you get out is only as good as what you put in – and accurate data is simply not available in Seil. When faced with autoDEPOMOD calculations for a site in Arran waters local residents conducted actual tests, placing drogues in the sea to measure the current, with markedly different results.
Seabed conditions
Another very important issue is the condition of the seabed. AutoDEPOMOD was not developed in relation to sites located in areas of stronger tidal streams.The strong tidal streams in places like Seil produce stone or rocky boulder seabeds, where debris simply accumulates. What is dumped simply fills the rocky interstices and remains there, rendering it permanently inhabitable by marine creatures.
There doesn’t appear to be very much protection for wildlife within the AZE. Recent excursions by divers in the area have shown the seabed within the AZE to be heavily polluted, well beyond the capacity of marine creatures to deal with. For example at Pol na Gile last month the divers reported, inter alia – ‘beggiatoa was widespread …… This is a mat forming bacteria which is characteristic of areas with high levels of organic pollution and occurs in areas of anoxic seabeds. Sea mouse Aphrodita sp. and a number of echiurans were present on the surface of the sediment. These animals would normally be buried in the sediment and their presence on the surface also suggests unhealthy conditions.’
There’s a natural tendency to put things that are out of sight out of mind. As long as the surface of the sea looks lovely residents and visitors alike don’t really care what’s going on below. I suggest that this simply isn’t good enough.
The saveseilsound campaign group is calling for a comprehensive environmental impact assessment on the Seil/Shuna/Melfort waters as a condition of any further expansion of the fish farms in the area. In the absence of this we believe that the area is subject to potentially disastrous overloading of pollutants, with unpredictable consequences for wildlife and human health and safety.
Such an assessment is all the more important because these waters are surrounded on the seaward side by the Firth of Lorn Marine Special Area of Conservation (FOLSAC), which is entitled to special protection under the EU Habitats Directive. In their objection to the Ardmaddy proposal, Scottish Wildlife Trust (Lorn and mid-Argyll) state:- ‘The FOLSAC is well known for its healthy variety of wildlife and a significant number of visitors come to the area in order to observe and appreciate the marine life in its natural environment. The SNH brochure states ‘the exceptionally rich diversity of marine life of the Firth of Lorn is of international conservation importance’ and ‘common seals frolic in the tidal races of Cuan Sound’….. We object to the proposed farm because we believe that it cannot be demonstrated beyond reasonable scientific doubt that the farm will not have an adverse impact on the integrity of the FOLSAC and to consent this farm would be a breach of Article 6(3) of the Habitats Directive.’
We are not just dealing with organic waste from uneaten feedstuffs and fish faeces. Fish farms use various chemicals for antifouling purposes. Many years ago TBT antifouling was found to be deadly to local populations of oysters and mussels and was eventually banned. Their modern replacements still rely on toxicity to be effective and again it is worrying that no attempts have been made to assess their effects on a comprehensive basis. What is known is that compounds incorporating heavy metals once released will stay in the environment for ever.
Perhaps the most serious aspect of the concentration of farms in the area, and certainly the most controversial, is the impact of large populations of caged fish on native wild fish. Advocates for wild fish argue that the interaction can happen in a number of different ways, thus:-
- escapes, resulting in interbreeding and contamination of the native sub-species, which are often peculiar to particular rivers and even stretches of rivers
- infectious disease, such as the infectious anaemia that wiped out the Chilean industry in 2007
- sea-lice
Of these, the threat from sea-lice is the most serious and pressing. It is argued that sea-lice breed in their billions in the caged populations and present a toxic barrage for the wild salmon to negotiate on leaving their home rivers for the open sea. Wild sea trout don’t migrate the way wild salmon do, they swim around their native territories in close proximity to the fish farms, so also becoming infected.
I hope it’s reasonably obvious that if we allow the ongoing degradation of our environment and the destruction of our wildlife the consequences for the local tourism-based economy will be dire. It’s simply not correct to state, as one commenter did, that fish farming is the major employer. The figures in my first article came from the Scottish Government and showed that tourism and leisure employs 130 times the number that fish farming does. Automatic feeding systems ensure that a handful of operatives can service what it previously took whole squads to do.
Increasingly foreign visitors are coming to see Scotland’s unique ecosystems, often bringing with them canoes and bicycles to explore her remote corners. Those of us lucky enough to be here year-round perhaps become used to the scenery, but to visitors from, say, the industrial heartland of Germany or the intensively-farmed flatlands of the Netherlands it presents breathtaking views of the unspoilt fringe of Europe. Finally dare I say that in a way we hold this precious environment in trust for future generations and perhaps have a moral obligation not to destroy it?
Ewan Kennedy, saveseilsound
The image at the top of this article is by copyright holder, Hamish McTavish and is reproduced here with permission.
Yup, you’re right. Sensationalist claptrap again.
Hot debate. What do you think?
4 
16
School Defender: your views don’t count for much if you don’t substantiate them.
Like or Dislike:
12 
1
Robert Wakeham is correct in that School Defender attempts at “flaming” are no answer to a well reasoned article.
Like or Dislike:
8 
1
Well, where on earth does one start with that kind of diatribe?
Tourism is very close to my heart (and bank account) and I have yet to see any evidence whatsoever that fish farming has a detrimental effect on tourist numbers, either new or returning.
Environmental issues are also close to my heart, and I get angry at the assumption that fish farming must have no environmental impact- every source of food and energy production has an environmental impact. Also, please can Mr Kennedy advise just how many yachts on the west coats have sea toilets, or lochside houses with inefficient septic tanks discharging raw sewage into our pristine lochs? (I am guessing you are a lochside dwelling yachty- correct?).
As for local pollution, look to your own houses and ask what effect those have on the ground beneath? Er… destroyed in perpetuity actually. If it bothers you so much, stop griping and lead by example!
Animal welfare is also close to my heart, and I am constantly astounded at the hypocrisy of ‘anglers’ claiming that wild salmon are affected by fish farming, while gladly sticking barbed hooks into their mouths and dragging them through the water until exhausted and then hauling them out of their natural environment, ripping out the hook, removing a few scales for good measure and then putting them back into the river, in the name of sport!
For every statistic or ‘fact’ quoted from the anti something brigade, there are an equal number of oppposite arguments.
I just get frustrated when a personal view/ crusade is portrayed as indisputable fact.
Hot debate. What do you think?
7 
11
School Defender – you’re right, there are always two sides to any debate or it wouldn’t be a debate! If you wish to contest Mr Kennedy’s argument, which is well reasoned and clear, certainly not a diatribe, then contest his points in a coherent fashion. For example, your concern about sea toilets and septic tanks seems to state that because they exist then that defeats the argument that intensive fish farms pollute! Your own posts merit the description “diatribe” not Mr Kennedys. I personally support fish farming but it has to done with some sensitivity to the natural environment which means that we, the people directly effected, have to take issue when greed masquerades as the common good, whether fish farming,wind turbines, or any other attempt to exploit our natural resources.
Like or Dislike:
11 
1
Noun: diatribe (plural diatribes)
1.An abusive, bitter denunciation.
2.A prolonged discourse.
3.A speech or writing which bitterly denounces something.
QED
Like or Dislike:
2 
3
A second well-researched article by Mr Kennedy. The argument that salmon farm pollution is comparable to that from yachts & shore side properties is not credible. A 1000 tonne salmon farm produces pollution equivalent to the untreated pollution from at least 20,000 people. The proposed farms that Mr Kennedy is speaking about are both over 2000 tonnes.
Like or Dislike:
10 
4
Yes, and the problem is that these stupendous quantities of fish-farm effluent will be released in these closed waters, bounded at both seaward outlets by environmentally significant waters.
Site the fish farms on the east coast or out beyond the hebrides!
Like or Dislike:
2 
1
I live on the West Coast of British Columbia and I can tell you that the effects of fish farms are a total disaster to our marine environment. You cannot have open net pens in the water! it IS that simple!
Like or Dislike:
8 
3
We probably have a lot to learn from the problems in both the east and west-coast USA.
Can you put the local saveseilsound campaign in touch with people who can help the campaign?
Like or Dislike:
0 
1
It would be interesting to see a reasoned, accountabe response to Mt Kennedy’s reasonable, accountable points. So far it would appear (from an outsider) that Mr Kennedy has made many factual claims that have been backed up by researched references, but the opposing view is characterised by ire and bluster. . . self interest perhaps?
Like or Dislike:
6 
3
Robert wanted facts about all economical and employment levels. = http://www.scotland.gov.uk/Publications/2011/11/17152846
Like or Dislike:
2 
0
A well written, as well as being well researched article; thank you. In support of the article and in response to some of the comments:
When will this government wake-up to the concept that people don’t like or want fin fish farms on their door step; Harris, Eigg, Islay, and along the west coast in general from Oban to Isle of Bute.
Even if the fish farms were to address outstanding environmental issues such as un-sustainable food source, non environmentally practices such as shooting seals rather than fitting double skinned anti-predator nets of a mesh size so as not to trap other wildlife, dealt responsibly with its medicinal treatments and cleaned up its excreta; the bottom line is that the general public don’t want them.
With advances in technology the numbers of people actually employed by the industry has decreased, so where is the additional benefit to local communities?
With the salmon industry so well funded and supported in government and political circles why does this article need to be impartial, after all these farms may adversely affect the Scottish tourist industry and Visit Scotland is nowhere to be seen…too political and they don’t get involved in “policy”, very convenient!
In reply to the comments from School Defender; two things, have the “balls” to sign your name and respond with FACTS to the contrary!
Fallow is a fallacy; the process of leaving a site for a period of time is to help the farm and prevent the seabed from producing unwanted obnoxious gases that would adversely affect the salmon. In order for this process of “fallowing” to be of any benefit for the environment the area would have to be left for many years, depending upon the tidal flow and seabed type, not just the normal ONE! Furthermore, the more farms that are left fallow the greater the area being polluted!
With the World population now exceeding seven billion we need aquaculture but not this type of profit based, fish eating (fish meal content) aquaculture! The Scottish West Coast could become World leaders in “poly-culture” and herbivores, that way everyone could benefit, including the environment!
Like or Dislike:
6 
6
The article, and I agree, is well written but well researched is open to question depending on ones viewpoint.
I would suggest as an aside, that Mark debased his post in that he made a very ignorant remark in that HE, Mark, accuses “school defender”, whose gender is unknown, of having no “balls” and also the fact he complains that a nickname is used to put an opposing arguement, as is the norm in blogs.
I have only one point to make, in the first article in this debate the author stated that no fish farms were left fallow, that was incorrect. Fact.
To counter this mistake, it is now stated by supporters that leaving fish farms fallow is a fallacy, is that statement “fact” or “fiction”.
Like or Dislike:
3 
2
Many answers as to whether fish farming is good in general or not can be found by studying why there is not one fish farm on the East coast of Scotland. Maybe it’s because there’s no unemployment on the East coast? Or maybe the salmon companies just didn’t think about it yet?
Like or Dislike:
0 
4
Thanks to john-in-kintyre for the link to the official figures. For those who haven’t checked them it seems that in 2010 the industry employed 944 full time and 120 part time workers, supporting the 1100 figure in the Herald article. I haven’t found any support for the 6,200 figure outside of the industry itself, but noticed that on accepting a donation to the Scottish National Salmon Association (SANA) from Scottish Salmon Company (Norwegian owned) their president David Ogg said that the industry employs about 1,800 people directly and another 6,200 in related industries. I don’t know what the “related industries” are. Incidentally Richard Lochhead has stated that wild life tourism employs 3,000 people and contributes £65 million annually to the Scottish economy, so that sector alone is a bigger employer than fish farming.
Like or Dislike:
6 
3
Here’s a letter addressed to SEPA by one of our local fishermen. This man has left the islands with his family because of the damage to fishing grounds. Salmon farming does create jobs, so does the army where 9.4 billion has been spent in Afghanistan by the UK, meantime our own systems are being ‘cut’ to death as we totter on the edge of bankruptcy. O well never mind, it’s the war industry, too many jobs at stake isn’t it???
The Registry
SEPA
Graesser House
Fodderty Way
Dingwall
IV15 9XB
Your Ref: CAR/L/1001802 (Pairc A & B Mid Loch Shell)
18 November 2010
Dear Sir/Madam
I wish to OBJECT to the proposal by Marine Harvest Scotland Ltd (MHSL) to modify the site and chemical treatments used at Loch Shell, Isle of Lewis. I am one of a number of fishermen who work in Loch Shell and strongly believe that the operations MHSL are having an adverse effect on the environment and other users of the Loch.
Coinciding with sea lice treatments during the last fish cycle in Loch Shell, Nephrops stocks of all age classes in areas above the fishfarm collapsed. Initially I found dying and dead prawns in the creels close to the fishfarm. A neighbouring fisherman in the area also hauled a fleet with five dead lobsters. Soon it was not only the Nephrops that were disappearing, all other fauna, such as the tiny crabs, that usually come up on creels had also gone over an area stretching from the fish farm towards the head of Loch Shell. The loss of this area has significantly damaged our family income. There was nothing unusual noted in other areas where I fish.
I contacted SEPA and asked them to investigate. During discussion SEPA confirmed that the treatment for sea lice undertaken by Marine Harvest during the last cycle was very high in quantity and frequency. Clearly MHSL had underestimated the sea lice problems they would encounter in the loch.
SEPA tests found Cypermethrin at a level of 1.24 ug/Kg and Emamectin Benzoate at a level of 1.31 ug/Kg in an area outside of the AZE. In addition during a meeting with Stuart Baird I was told that MHSL had not submitted returns to SEPA for Cypermethrin during this period. SEPA also took away some dead and dying prawns from creels outside the lease area, hauled while they were testing.
I have occasionally tried fishing the area again but it has remained ‘sterile’, only now are animals gradually returning. These are typically mobile species such as crabs and starfish. There are no significant signs of Nephrops returning as yet and it will clearly be some time, before any commercially viable stocks reappear if indeed at all.
I am therefore absolutely opposed to the expansion in tonnage or area of the sites or any increase in the use of chemicals in Loch Shell. I believe it will cause long term damage to the environment and threaten the livelihood of fishermen who are dependent on Loch Shell including myself.
Loch Shell is clearly a poor site for a fish farm if treatment activities within permitted levels result in such a disastrous effect. I am also concerned that by reducing stocking densities the Freedom Food initiative is actually increasing the area of fishfarms and the amount of chemicals required to reduce sealice using bath treatments. This increases the impact of the fish farms on the surrounding environment and crustacean fisheries.
Accordingly I request that planning conditions are set out to bring about an absolute reduction in the bath treatments allowed in Loch Shell from the previous growing cycle. Further I request that planning conditions are also put in place that guarantee long term post authorisation sampling monitoring by SEPA to ensure that treatment authorisations are being observed and to determine if these levels impact on marine life in Loch Shell. This could include using techniques such as biomonitors and sediment analysis. The cumulative impact of the Loch Shell sites and the neighboring site nearer Lemreway should also be considered.
Thank you for the opportunity to respond to this application.
Like or Dislike:
3 
1
Comparing salmon farming to the war in Afghanistan? Grow up please.
Like or Dislike:
0 
3
Growing up quite well here thanks, even Scottish Salmon are taking our advice and withdrawing their huge fish farm. I personally like helping the fish farmer’s on planning applications, they will get better sites if they work with us : )
http://www.hebrides-news.com/harris-salmon-farm-row-71111.html
Like or Dislike:
2 
0
Please keep up your good work in helping fish farming development then. (.)
Like or Dislike:
0 
0
Just noted john-in-kintyre’s remark that I said no farms were fallow. My text actually noted that five were.
Like or Dislike:
3 
2
You will find plenty of factual information, with any number of positives supporting the industry, on the Scottish Salmon Producers Organisation (SSPO) website.
Like or Dislike:
2 
2
I think the reason that there are no fish farms of the East of Scotland is because they do not want the great salmon fishing rivers namely the Dee, Tay and Tweed ruined by escaping salmon from fish farms. It has nothing to do with unemployment which is also high in the East of Scotland.
Like or Dislike:
1 
2
Isn’t it more likely to be due to a lack of suitable farm sites – sea lochs – on the east coast?
Like or Dislike:
3 
0
The reason why there are no sea cage fish farms on the east coast is because there are no suitably sheltered locations to safely site cages, and also the seawater environment is less conducive (ie temperature profile, water quality etc) to aquaculture than other areas of the Scottish coast. Nothing to do with unemployment.
And Treblet should learn the lifecycle of wild salmon before making crass comments like that.
Like or Dislike:
1 
1
Mr Defender. Wrong on both accounts re no fish farms on East coast Scotland. 1) The sea around east coast is the same quality and temp as Norwegian waters which seem to have a few fish farms. The Norwegian Current, as it’s called, flows from Scottish waters around the coast of Norway to the Barents Sea. 2) There are umpteen very suitable & sheltered sites for fish farms on the east coast. If you have never been there or don’t have a detailed map then let me know and I’ll post a list of GPS co-ordinates and name them for you. I’ve been at sea most of my life AND worked for fish farms by the way. But you are correct that it’s nothing to do with unemployment, excellent to have spotted that : )
Like or Dislike:
1 
3
Mr Campbell- 1) If you read my post before responding you would note that I compared the east coast to the west coast regarding environmental parameters, why bring Norway into the equation? 2)Are you telling me that the east coast of Scotland has as many sheltered locations as the west coast (or Norway, if you have to bring them into the discussion)? Please post the coordinates you refer to- if a fish farming company reads this puerile thread I am sure they will delight in getting a heads up for future planning applications.
Like or Dislike:
3 
0
Mr Def. If you read the article below and the many other’s available on offshore salmon farms you may understand that the whole of the east coast is available for salmon farming, small sheltered fragile bays & lochs are no longer required. http://www.seafoodsource.com/newsarticledetail.aspx?id=12966
This then leaves your puny water quality remark to be finally put to death. The reason I used Norway was to illustrate to you that salmon grows very well in the North Sea. The North Sea extends to the Norwegian area of Sognefjord and Norway produces 5 x the Scottish tonnage. Please give more study time to the topic of salmon farming, in this way you will have more quality of knowledge : )
Like or Dislike:
1 
1
Mr Def here’s another east/west article which may interest you. CASS is supposedly a Scottish study ( Conservation of Atlantic Salmon Scotland ) relating to conservation of wild salmon. Maybe you can explain us why areas concerned with fish farms have been avoided? The Outer Hebrides and chunks of the Inner are not even on the map, our “designation” seems to have been decided for us no? Oh, I also wanted to ask your opinion why there are no postcards with salmon farms on them? I mean, some suggest that tourists are neutral regarding the visual? If your pocket does really depend a little on tourism please be careful that you see the big picture here. We know very well that the east coast is short of tourism and we see that the angler’s have been diverting there. I’ve been in the tourism industry since 1995, we cater for 30 guests so there’s some knowledge here you see.
http://www.snh.org.uk/salmonlifeproject/map.asp
Like or Dislike:
0 
1
Surely, if we can drill for oil on the east coast and maintain long term oil prodution platforms, then it shouldn’t be beyond the wit of clever marine engineers to site fish-farms in the North Sea?
Like or Dislike:
2 
2
School Defender.
As I am allergic to fish I could not care less whether there are fish farms or not. I have never been able to have a fish supper and when I was very young I used to come out in a rash when walking past a fish shop.
Like or Dislike:
0 
3
Fascinating.
Like or Dislike:
3 
1
There must be an angle in this for you. Try this. If the fish-farms didn’t feed huge quantites of sand eels etc to their fish then this nutrient would be available for animal and poultry feed. Then meat would be cheaper. Then you might be pleased!
But maybe we should not be taking the sand eels out of the food cahin at all. Then the puffins would have more to eat and not be having problems.
Like or Dislike:
1 
1
Good thinking logman: firstly,salmon convert feed to flesh at 1:1 compared to terrestrial animals at 5:1 or worse (no-brainer really). And if you want to focus on environmental issues, how about the quantity of greenhouse gases emitted from the back end of cows- why would anyone want to increase that?Secondly, taking an unpalatable protein source (sandeels being an example) and turning it into a palatable one such as salmon makes sense doesn’t it? Thirdly, you clearly would be surprised to know that sandeels are not the main component in commercial salmon diets anyway.
Like or Dislike:
1 
0
@ School defender : Two points:
1) I suspect some fishy bunkum here! Are you confusing dry weights / wet weights in these ratios? I just do not believe that 1kg of wet food produces 1kg of salmon flesh. But I might believe that 1kg of dry fish meal might produce 1kg of wet salmon. Are there any experts out there who can shed light on this?
2) School Defender, tell us more then, just what is in commercial salmon diets. Go on surprise me!
Like or Dislike:
0 
1
No bunkum in my post logboy, I never mentioned wet weight of feed. It’s a more complex argument if you want to compare kg wet fish used to convert into a kg of salmon or pork or chicken.
As for a surprise, how about “BOO!”
Like or Dislike:
1 
0
School defender: sorry to be picky but no organism converts feed to flesh at a 1:1 ratio. All heterotrophic organisms must expend energy on metabolism at least and energetic animals such as fish also expend energy on locomotion. What is left can go towards growth and energy storage.
Salmon are good at converting their feed into flesh with a typical ratio of 1.2 kg feed into 1 kg flesh but that is partly down to the high protein and very high lipid contents of their feeds. They are more efficient than, say poultry or pigs but the latter eat feed with much lower energy content so simple comparison of feed conversion rates based on mass rather than energy content can be misleading.
Like or Dislike:
3 
2
Point taken, but if you fed terrestrial animals with the same diets you would not get the same feed conversion rates. For example, if pig diets go above 15% protein, there is no advantage in growth which is why diet compositions are what they are.
And to be pedantic, it is incorrect to state that ‘no organism converts feed to flesh at 1:1′, since salmon can achieve far better than this for at least a third of their entire lives.
Like or Dislike:
1 
1
And for the other 2/3rds of the life cycle?
Like or Dislike:
1 
0
Well, that’s spent in seawater where the previously mentioned feed conversion rate of ca 1.2 to 1 applies.
Like or Dislike:
0 
0
We are dancing on the heads of pins here but the only way you can get a 1:1 conversion rate is if the energetic content of the feed is higher than the flesh. I suppose that an organism which has lots of water in its body (such as a jellyfish) might have a better than 1:1 conversion rate by weight but there is no organism that can approach a conversion rate of 1:1 by energy.
Like or Dislike:
3 
1
Exactly- feeding a dry diet to freshwater fish, where they will also ingest water, will lead to a conversion rate beter than 1:1. This does apply to salmon I can assure you.
Like or Dislike:
1 
1
All salmon farm applications in the Outer Hebrides give an answer to SEPA License Application Form 3 as follows:
2.9 What food conversion ratio do you expect to achieve?
(Kilograms of fish production (wet weight) against kilograms
of food (wet weight))
1:1.2
Note that it’s wet weight in both cases.
Like or Dislike:
0 
2
Good one Mr Campbell- but all applications in the Outer Hebrides will be for seawater sites, I quite clearly made reference to freshwater stages. Please read the posts thoroughly before replying in future.
Like or Dislike:
1 
1
Same ratio applies to freshwater feeding. Same fish, same feed, both sea & fresh water are wet also. If you take out each fish and feed them individually with a tube then it will be dry food, unless you’ve left the open bag out in the rain.
Like or Dislike:
3 
2
Def, here’s a tricky question. Why are salmon not fully raised in freshwater sites given that lice can not live in the fresh?
Like or Dislike:
0 
1
Not a tricky question at all Mr Campbell, and remarkably erudite of you to raise it. Salmon can survive their entire lifecycle in freshwater, and there are examples of farms throughout the world where this has proven effective. Chile, for example, insists that all egg producing stock are raised in sterilised freshwater for their entire lifecycle, and hence are grown to 10kg plus. And you are correct to state that lice cannot survive in freshwater.
However, we’re British and more concerned over welfare issues, and there simply is not sufficient evidence to prove that there are no long term adverse effects on salmon from continuous generations in freshwater. Salmon are anadromous, and permanent freshwater may not appeal to the fish or consumer alike.
Anyway, Scotland simply doesn’t have the volume of freshwater supplies necessary to sustain the tonnage of salmon produced, and if your next post suggests recirculation then I think you are several decades ahead of your time, and it ain’t gonna happen.
Like or Dislike:
0 
0
That’s a reasonable answer, well done.
Like or Dislike:
0 
1
(!)
Like or Dislike:
1 
0
Aye, a couple million of them gesticulating spasmodically in the lochs and it wouldn’t be fresh water for long.
Like or Dislike:
1 
1