Letter to Scottish Ministers on PRV/HSMI prevalence in salmon farms, hatcheries & processing plants in Scotland

Scientists in Canada collected biological samples adjacent to 56 marine net pens from five different companies and two farm salmon processing plants with 70% of samples testing positive for Piscine orthoreovirus-1 (PRV-1). This compares to Marine Scotland Science detecting PRV in 52% (399 out of 774 samples) of farmed salmon tested in 2018/2019. 

$camon $cotland (formerly called Scottish Salmon Watch) today wrote to Scottish Ministers calling for testing of marine and freshwater salmon farms, hatcheries, harvesting stations and processing plants for PRV/HSMI – read our letter online here (see below for an email to Scottish Ministers which includes a FOI on testing for PRV/HSMI in wild fish). 

Based on information published online by the Scottish Government's Fish Health Inspectorate, $camon $cotland identify 37 salmon farms across Scotland where PRV/HSMI has been detected since November 2017.  These PRV/HSMI cases are detailed in a map (download online here) and include 14 Bakkafrost/The Scottish Salmon Company salmon farms; 10 Mowi; 6 Scottish Sea Farms; 4 Grieg Seafood, 2 Loch Duart and 1 Cooke Aquaculture; namely:

Bakkafrost/ The Scottish Salmon Company (Aird in Loch Sheildaig/Torridon)

Bakkafrost/ The Scottish Salmon Company (Ardcastle Bay in Loch Fyne)

Bakkafrost/ The Scottish Salmon Company (East Tarbert Bay in the Sound of Gigha)

Bakkafrost/ The Scottish Salmon Company (Lamlash Bay/St Molios, Isle of Arran)

Bakkafrost/ The Scottish Salmon Company (Loch Odhairn/Gravir, Isle of Lewis)

Bakkafrost/ The Scottish Salmon Company (Maragay Mor in Loch Uiskevagh, Uists)

Bakkafrost/ The Scottish Salmon Company (Portree/Torvaig in Sound of Raasay, Isle of Skye)

Bakkafrost/ The Scottish Salmon Company (Portree Outer in Sound of Raasay, Isle of Skye)

Bakkafrost/ The Scottish Salmon Company (Plocrapol in East Loch Tarbert, Isle of Harris)

Bakkafrost/ The Scottish Salmon Company (Reibinish in East Loch Tarbert, Isle of Harris)

Bakkafrost/ The Scottish Salmon Company (Scadabay in Loch Grosebay, Isle of Harris)

Bakkafrost/ The Scottish Salmon Company (Sgeir Dughall in Loch Torridon)

Bakkafrost/ The Scottish Salmon Company (Taranaish in Loch Roag, Isle of Lewis)

Bakkafrost/ The Scottish Salmon Company (Tarbert South in Loch Fyne)

Cooke Aquaculture (Lyrawa Bay in Scapa Flow, Orkney Islands)

Grieg Seafood (Cole Deep in Gon Firth, Shetland)

Grieg Seafood (Gob Na Hoe in Loch Dunvegan, Isle of Skye)

Grieg Seafood (Leinish Bay in Loch Dunvegan, Isle of Skye)

Grieg Seafood (North Voe in Linga Sound, Shetland)

Loch Duart (Loch Laxford, Sutherland)

Loch Duart (Lochmaddy, North Uist)

Mowi (Ardintoul in Loch Alsh)

Mowi (Cairidh in Loch Ainort, Isle of Skye)

Mowi (Eilean Grianain/Carradale in Kilbrannan Sound)

Mowi (Greshornish in Loch Snizort, Isle of Skye)

Mowi (Kingairloch in Loch a Choire/Loch Linnhe)

Mowi (North Shore in Loch Erisort, Isle of Lewis)

Mowi (Sconser Quarry in Caol Mor, Isle of Skye)

Mowi (Sron in Loch Alsh)

Mowi (Stulaigh in Loch Eynort, South Uist)

Mowi (Tabhaigh in Loch Erisort, Isle of Lewis)

Scottish Sea Farms (Bight of Foraness in Swinnister Voe, Shetland)

Scottish Sea Farms (Bloody Bay in the Sound of Mull, Isle of Mull)

Scottish Sea Farms (Loch Creran)

Scottish Sea Farms (Lismore North, Loch Linnhe)

Scottish Sea Farms (Nevis C in Loch Nevis)

Scottish Sea Farms (Shuna in Loch Linnhe)

Many more PRV/HSMI positive cases are reported by the Scottish Government's Fish Health Inspectorate via 'Case Information' archived for 2013-2017 (some cases are identified in $camon $cotland's letter to Scottish Ministers). 

The letter also cites a Fish Health Inspectorate report in August 2020 for Mowi's Carradale salmon farm in Kilbrannan Sound which reported 12/12 samples of farmed salmon testing positive by Patogen for PRV-1 (the causative agent of HSMI) on 10 August 2020 (ten days before the escape of 48,834 farmed salmon).  There is no record of PRV/HSMI testing of wild salmon following the mass escape – including escapees caught in the River Leven, River Stinchar, River Doon and the River Girvan.  If FMS did any testing or is aware of any please pass on.    

In September 2019, Scottish Salmon Watch published photos of disease-ridden wild salmon – tested by Scottish Government inspectors for infectious diseases – and asked: “Are Farms Spreading Infectious Diseases, Pathogens & Viruses to Wild Fish?”

The letter cites a Fish Health Inspectorate report in June 2021 which detailed the testing of 90 juvenile wild salmon caught in the River Forss – all were negative for PRV.  A further 5 samples of wild salmon caught in the River Divie (River Findhorn) in May 2022 were tested by the Fish Health Inspectorate – all were negative for PRV.  Other 'Case Information' published by the Scottish Government also details testing of wild salmon for PRV.

Whilst ca. 100 wild salmon appear to have been tested by the Scottish Government's Fish Health Inspectorate since June 2021 (you are welcome to trawl through all the 'Case Information' for yourself to get the exact number – online here), it seems that less than a dozen farmed salmon are tested each year by the Scottish Government.  Instead, private diagnostic companies (including Patogen based in Dunstaffnage and the Fish Vet Group in Inverness) and in-house company vets are carrying out PRV/HSMI testing.  The private testing is often referenced – but not included in full – via 'Case Information' published online by the Scottish Government.  More detailed information on the 399 PRV-positive tests detected by Marine Scotland Science in farmed salmon in 2018/2019 (as disclosed by the Scottish Government via FOI) was refused due to "commercial confidentiality".     

You can find out more context and information in our letter to Scottish Ministers online here.

Suffice to say that $camon $cotland have serious concerns at the lack of Scottish Government testing – including in freshwater farms, hatcheries, harvesting stations, processing plants and via imported ova. 

As I wrote to Scottish Ministers:

"The disease dangers of importing ova – whether they are sourced from Norway, Iceland or Ireland – represents all too real a risk for wild fish and it beggars belief that imported ova remains untested for PRV, ISA and other viruses, pathogens and diseases.  Government surveillance of PRV/HSMI inside sea cages, freshwater smolt farms, hatcheries and processing plants (including waste effluents and waste biological material) must close the net on the disease-ridden, virus-laden and lice-infested salmon farming sector in Scotland. The protection of commercial confidentiality and the business interests of foreign-owned companies (who control 99% of ‘Scottish’ salmon farming production) cannot be allowed to take precedence over Scotland’s iconic wild salmon.”

More background on this issue is published via:

Piscine Reovirus Ravages Scottish Salmon Farms – please follow the science in Canada & investigate the risks to wild fish in Scotland!

Going Down the Drain: Photos of Mowi's blood water treatment at "highly offensive & polluting" processing plant in Fort William

Unsatisfactory Biosecurity: Disease Control 'Improvement' & 'Further Investigation' Required at Processing Plants Operated by Mowi & Loch Duart

Heart & Pancreas Disease Ravage Scottish Salmon (according to new Marine Scotland Science report)

FOI Reveals Virus-Laden Salmon Slip Net & Into Scottish Waters

Virus-Laden Farmed Salmon – FOI reveals over half of samples test positive for Piscine Reovirus

A press release referencing $camon $cotland's concerns and letter to Scottish Ministers is also available online here (Embargoed until tomorrow). 

If you have any queries I am on 07771 541826.

Best fishes,

Don