Site Details: Grey Horse Channel Outer
Loch Maddy
North Uist
HS6 5AT
Water type: Seawater
Cumulative mortality over full production cycle
Production cycle end date: Aug 2020
Total losses: 15.8 %
Production cycle end date: Dec 2020
Total losses: 8.9 %
Production cycle end date: Jun 2022
Total losses: 55.9 %
Fish Health Inspectorate mortality
17/01/22-23/01/22
8,864
1.27%
07/02/22-13/02/22
7,886
1.16%
28/02/22-06/03/22
7,184
1.08%
07/03/22-13/03/22
7,551
1.22%
14/03/22-20/03/22
8,705
1.43%
21/03/22-27/03/22
6,268
1.04%
28/03/22-03/04/22
6,174
1.04%
04/04/22-10/04/22
7,065
1.39%
25/04/22-01/05/22
6,213
1.26%
02/05/22-08/05/22
5,763
1.19%
16/05/22-22/05/22
1.08%
06/06/22-12/06/22
7,858
1.76%
13/06/22-19/06/22
11,693
2.67%
08/04/24-14/04/24
4,131
1.32%
Inspection reports
Case Number: 2021-0378
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Issue with AGD in recent weeks.
Lumpfish will be delivered in November to be stocked at 6-10%.
Stock from Inchmore Hatchery.
Issues with Caligus, treated twice with Alphamax at the end of August. No consent for Slice.
Week 37 2021: 4-8,000 dead fish per pen. Peroxide treatment delayed, treatment started on the 18th of September, treated 3 pens before machine broke down, treated the rest of the pens after 3 days. Mortality reduced once treatments were completed.
Peroxide treatments ongoing - Pen 51 (worst affected) treated on 3/10, pens 48-50 on 4/10, pens 41-42 on 5/10 and pens 43-
44 on 6/10 (treatments ongoing during inspection). The most recently treated pens had a number (between 10 to 40) of floating mortalities on the surface, while those treated earlier in the week had much lower numbers of moribunds and no dead fish on the surface.
Physical inspection carried out by and on 06/10/21. VMD and diagnostic sampling done by , observed by
The fish sampled had poor gills but showed no other clinical signs of disease. [Original PDF]
Case Number: 2022-0164
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Remote inspection carried out 18/05/2022. Site to be visited following reports of increased mortalities.
The main cause of mortality has been attributed to seal predation. Complex gill disease issues have also been identified and an extended freshwater treatment was conducted in week 18, which exacerbated mortalities but alleviated the gill problems.
The site is in the process of changing nets from nylon to SealPro to try and reduce seal damage. Two nets are left to change and these are the pens still experiencing higher mortalities, the remaining cages are currently experiencing background mortality numbers.
Mortality events: weeks 40 to 44 2021 plus weeks 3, 6, 9, 10, 12, 14, 18, 20 2022 reported to FHI.
Week 11, 13, 17 not reported to FHI, see mortality events for additional info.
The weather conditions during the site inspection made it harder to observe the fish as they were deep in the water column.
Fish with seal damage could be observed swimming amongst the main population. The site staff was observed removing mortalities from one of the nylon net pens and the majority of the dead fish also presented seal bites. A small number of anorexic, lethargic fish was also seen in most cages, however these fish would swim away when approached. Three surface dead fish seen on site. Very little sea lice was observed on the fish.
The stock has been problematic since input - not feeding well, lethargic, high percentage of poor performers. Some of the fish were transferred to Grey Horse Channel in early April to thin out the cages. Three lethargic fish from this stock were removed from Grey Horse Channel and upon internal examination, it was found that the fish were sexually maturing. No gross pathology observed.
Harvesting will begin at the end of May and the site expected to be fallow by August 2022. [Original PDF]
Case Number: 2024-0153
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Main salmon mortality causes are seal predation (particularly pens 50 & 51) and poor performers. Looking at adding extra measures to prevent seal predation. Main cause of lumpfish mortalities is Tenacibaculum.
Salmon on site are from Groatay and Grey Horse Channel, lumpfish are from Ocean Matters. Site currently has 8 pens
(permission for 12), but will be adding another 2 to thin out stock and will also transfer some fish to Grey Horse Channel.
Harvested some salmon in May.
Freshwater treatments in March and April.
Site known as Greanem within company.
No moribund fish observed, fish deep in water. Two fish removed for VMD sampling appeared healthy. [Original PDF]