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Average female lice per fish

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Salmon Scotland mortality

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Cumulative mortality over full production cycle

Gorsten Production cycle end date: Oct 2019
Total losses: 17.8 %

Gorsten Production cycle end date: Jul 2021
Total losses: 8.7 %

Gorsten Production cycle end date: Oct 2022
Total losses: 10.9 %

Gorsten Production cycle end date: Nov 2023
Total losses: 17.8 %

Gorsten Production cycle end date: Mar 2025
Total losses: 13.9 %

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Inspection reports

Case Number: 2020-0489

Download Site is made up of 3 sets of four 36 meter steel pens. All pens were inspected fish looked clean and healthy, no health issues were observed on site.
Site had 5 movements of Ballan Wrasse from Ireland from 1 supplier. [Original PDF]

Case Number: 2021-0542

Download Remote Inspection completed on the 25/11/21 physical inspection on the 1/12/2021
Site to be used as a nursery site this cycle. One more input to site due on the 2/12/2021.
No issues on site, fish feeding well. [Original PDF]

Case Number: 2022-0063

Download Wrasse mixed farmed from Anglesey and wild from Northern Ireland.
Site inspection and VMD sampling done on 16/03/2022 by , observed by .
No new movements since last inspection on 01/12/2021. The main population of fish on site appeared healthy. Small percentage of fish with lesions in pens 5 - 8 but still fairly active, the fish swam away quickly upon approach. The fish sampled for the VMD looked healthy. [Original PDF]

Case Number: 2023-0124

Download 75% of salmon mortality this cycle have been due to seal predation.
Lumpfish mortality last 4 weeks: Wk 9 - 1.86% (1103 fish), Wk 10 - 1.62% (940 fish), Wk 11 - 1.40% (803 fish), Wk 12 - 2.58%
(1,456 fish)
Currently treating with Salmosan to deal with sea lice. First in cycle but have also used SLICE.
SLICE - 24/11/2022 and 12/12/2022.
Site will move fish to Rum and Muck later in the cycle due to these sites being unable to grow salmon from smolt size.
FMA - 1 yearclass on site.
Wrasse will be used on site (approx. in 6 weeks time)
Health Check - 9/11/2022 - No significant findings found. Check conducted the week after smolt transfer.
Area not fallowed synchronously due to Gorsten and Linnhe sending fish off after one year while Leven and Kingairloch grow fish to harvest size.
Sea Lice -
Adult females: 17/06/22 - 0.53, 22/06/22 - 0.58 (Treating with Hydrolicer/Thermolicer
Treatments last year - SLICE - Between 27th - 1st Aug
Flouricol - moritella antibiotic pens 1-8 on 28/03/2022, 30/03/22, 05/04/22. 06/04/22, 16/04/22,
Salmosan - Pens 10-12 between 7th-9th June 22
Hydrolicer - Pens 1-4 between 20-21st June 22, Pens 5-8 between 22-23rd June 22
Thermolicer - Pens 9-12 on 8th July 22, Pens 6-8 on 18th July, Pens 2,4 and 5 on 19th July, Pen 3 20th July, Pens 9-12 on
25th July, 4-8th August, Pen 10 18th Aug
Inspection and paperwork by supervised by [Original PDF]

Case Number: 2025-0040

Download Paperwork and inspection by , accompanied by for Inspector Competency Audit. Mortality records, sea lice records, treatment records inspected remotely on 19/02/25, all remaining paperwork conducted on site on 20/02/35 Visibility was mixed during inspection with reduced visibility in pens 9 to 12 and clearer visibility in pens 2 to 8. Site consists on 3 groups of 4 steel pens, fitted with environets. Site will be swapping to 120m pens in future. Site is to receive an input of smolts in May 25, which will be onsite until approx Dec 25, when the stock will be moved to Creag an T'Sagairt (Loch Hourn). The site will fallow and receive an input from Loch Etive in Feb 26 for ongrowing and this is the planned production cycle for site, receiving inputs from Loch Etive and ongrowing for less than a year. 3 to 4 fish observed per pen with lesions (winter sores), most were deeper in the water and still active. One fish observed hanging vertically, but unable to catch. One moribund removed and examined at shorebase. A mock diagnostic was conducted on this fish as part of inspector competency audit. The majority of stock was observed shoaling and feeding well. Harvesting operation ongoing at time of inspection, site is conducting both live and dead haul harvests. Site has only had 1 Slice treatment and 2 thermolicer treatments this cycle Fish sampled for VMD appeared in very good condition with no sea lice observed on fish. Cleaner fish mortality (last 4 weeks) LUM - WK 4 - 515 (13.43%), WK 5 - 940 (28.32%), WK 6 - 830 (34.81%) and WK 7 - 734 (47.39%) WRS - WK 4 - 667 (1.54%), WK 5 - 1,036 (2.43%), WK 6 - 911 (2.19%) and WK 7 - 605 (1.49%) [Original PDF]

Case Number: 2025-0389

Download Three cages groups on site. Cage 2 in most northerly cage group had a breach in containment. Most southerly cage group has been empty the whole cycle. Both the northerly and central cages groups moved north in the storm. The southerly cage group was not thought to have moved as it had no nets attached at the time of the storm. The three cage groups are moored separately in groups of four cages, the three cages groups are not connected to each other using a grid system. The tidal barrier consists of a top floating section of tube (630mm), with a section of net (18mm) below, held taught by a sinker tube that is positioned 13m below the floating section. Both the floating tube and sinker tube have separate moorings. There is a meeting organised for later in October when repositioning of the tube will be discussed. It is hoped by the site manager that the tidal barrier can be moved further away from the cage grid although the effectiveness of the barrier may be affected by its proximity to the cage group. There are plans to replace metal cages with plastic rings. Planning permission was refused at the last attempt.
Cage 2 had mortality removed the day before the escape incident was observed (03/10/2025). As mortalities were removed the day before the escape and as the holes were at the top of the net and mortalities will be temporarily stored in the mort sock in the bottom of the net at the centre, no mortalities were reportedly lost.
Reserve broodstock on site at the moment. There are ~71,500 salmon on site are reserved broodstock at average weight of 2.5kg. There were at Kingairloch before arriving at Gorsten.
Wild and farmed WRS on site. No LUM in cage 2 at the time of the escape. Movements of cleaner fish are recorded separately to the movements of salmon but all required info is recorded. Both records collected at time of inspection
In feed antibiotic treatment was being undertaken at the time of the inspection. This is being fed due to SRS being detected in the population. The feed is reportedly helping to reduce mortality associated with SRS.
Some problems on site at the time of the inspection with feeding the fish. The storm dislodged and sunk some feed pipes so some cages cannot be fed using pipes. These cages were being fed using a blower positioned on the workboat at the time of the inspection.
PRV-1 (HMSI), Piscirickettsia spp. and Tenacibaculum spp. detected on site by PCR.
Breach in containment discovered Saturday (04/10/2025) morning. All power to the cameras lost during the storm as these are powered using mains power. The breach in containment was discovered by . The tidal barrier at the north of the site remained in place and the cage group moved north, blown by the wind and tide, towards the barrier. It is estimated by the site manager the site moved at least 10m, although individual anchors moved varying distances. A metal bracket that connected the tidal barrier to an anchor chain broke (see diagram in attachments) and the chains that connected the tidal barrier to the cages also broke in the storm. The tidal barrier itself is not thought to have broken, it is the bracket and chains that are thought to have broken causing the eastern end of the barrier to move in the waves and tide freely. The tidal barrier has been submerged since the incident and inspection has been difficult due to bad weather. The end of the tidal barrier came in contact with the cage net causing approximately four holes along the northern side of cage 2. The plastic at the end of the tidal barrier had developed sharp projections due to the tidal barrier striking the metal cage group. According to the area manager, mobile phone signal was down at the time of the incident which is thought to have hampered getting boats together to stabilize the cages. A wellboat, two mooring boats and a large multipurpose boat from Inverlussa arrived on site Sunday (05/10/25). The wellboat began to remove fish at 12:20 on Sunday. According to the wellboat log, 5,028 fish were recovered from the cage from the 80,591 that were thought to be in the cage making a total loss of 75,563 fish. The remaining fish were moved to pen 8. Mooring boats began work on repositioning the mooring anchors on Sunday. The damaged net and tidal barrier are still on site. The tidal barrier maybe removed completely later in cycle. The plans for the tidal barrier will be discussed in the meeting in mid-October. No attempt to recapture fish was made due to bad weather. Samples from the remaining fish from cage 2 were sent for emergency sampling at the Mowi lab to establish if antibiotic residue are still present in the fish. Results from these tests have not been reported yet. There has reportedly been no increase in seal activity since the incident. Seals have been continually observed since August and are thought to have killed fish. Manager does not think any salmon will get past the Corran narrows due to high seal activity in the area. A known seal haulout is present close to the narrows with reportedly more than 100 seals active in the area. Reportedly many fishermen have been fishing in the area for salmon since Saturday but the manager is not aware of any fishermen catching any salmon. Reportedly no additional checks were done on barrier before the incident. The barrier is too heavy to inspect with the work boat usually used on the site.
Four holes found in total on the north side of the net closest to the tidal barrier. Two of these bigger holes are rectangular and approximately 4-5 meters wide and between 1-5 meters below the water line. Two of the smaller holes were about 2 metres wide at about 4 metres from the bottom of the net. Net is 12m deep. Damage reported at 8am on Saturday. According to site staff, mobile phone signal was reportedly OK at the site on Saturday morning. Mobile signal in other areas of the west coast of
Scotland may have been poor or absent [Original PDF]

Case Number: 2026-0153

Download Fish came on from Loch Etive in Feb 26 and have had low mortality since input. Health of the fish has been good, with low
PGD/AGD scores and good body condition noted. A grade was completed last week and the fish are expected to remain on site until the end of the year when a portion will be deadhaul harvested, and the remaining stock will be moved to another SW site for ongrowing until harvest.
Site has not had any escapes since the last reported escape incident in October 2025. The move to sealpro nets and the removal of the tidal barrier are two of the improvement measures that were implemented following the escape. The site manager has reported that although seals are still observed around the site, damage to equipment and stock has significantly reduced.
The only medicinal treatment that has been conducted on site since input (with the exception of anaesthetic for sealice counts) was SLICE in March 26.
The general population of fish on site were in good physical condition and were active in the cages. There were several individuals with physical damage observed in each of the cages, with around 20 individuals with damage observed in cage 1.
This had been caused by the handling event the week before. No clinical signs of disease were observed and fish were still relatively active so no diagnostic samples were taken on this occassion. Fish sampled for VMD was in good condition externally and internally.
Thermometer 337 was used. [Original PDF]

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