Site Details: Colonsay

Stob Ban House
Glen Nevis Business Park
PH33 6RX
Operator: Mowi Scotland Ltd
Water type: Seawater

Average female lice per fish

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Salmon Scotland mortality

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Cumulative mortality over full production cycle

Production cycle end date: Jan 2019
Total losses: 25.8 %

Production cycle end date: Mar 2021
Total losses: 24.8 %

Production cycle end date: Aug 2022
Total losses: 34.2 %

Source

Fish Health Inspectorate mortality

Date:
18/07/22-24/07/22
Mortality:
8,308
Mortality Rate:
1.04%
Reason given: Gill infections
Gill infections
Site planned to be harvested out by early September
Site inspected 16/06/2022. FHI to monitor

Date:
25/07/22-31/07/22
Mortality:
12,397
Mortality Rate:
1.79%
Reason given: Gill infections
Gill infections
Site planned to be harvested out by early September
Site inspected 16/06/2022. FHI to monitor

Date:
01/08/22-07/08/22
Mortality:
13,182
Mortality Rate:
2.17%
Reason given: Gill infections
Gill infections
week 8/8/22 Mon to Thurs 1.07%
Site inspected 16/06/2022. Due to fallow soon

Date:
08/08/22-14/08/22
Mortality:
10,253
Mortality Rate:
1.93%
Reason given: Gill infections
Gill infections
week 15/8/22 Mon to Thurs 1.02%
Site inspected 16/06/2022.Contacted business for details of fallow date; Update site due to fallow 28/8/22

Date:
15/08/22-21/08/22
Mortality:
7,490
Mortality Rate:
2.18%
Reason given: Gill infections
Gill infections
Site now fallow (28th August)
Site now fallow.

Date:
22/08/22-28/08/22
Mortality:
5,438
Mortality Rate:
3.03%
Reason given: Gill infections
Gill infections
Site now fallow.

Date:
02/10/23-08/10/23
Mortality:
16,048
Mortality Rate:
1.45%
Reason given: AGD
AGD
Currently FW treatment
First report of cycle, FHI to monitor post treatment.

Date:
09/10/23-15/10/23
Mortality:
202,897
Mortality Rate:
18.6%
Reason given: AGD and treatment losses
AGD and treatment losses
Site contacted. - AGD, PGD and silica in water. Gills in poor state, FW and peroxide wellboat treatments for gills. Back log of morts have been cleared and are hoping to see improvement of mortality figures. On 24/10/23 little fresh mortalities and fish feeding well.
FHI visit scheduled

Date:
16/10/23-22/10/23
Mortality:
13,628
Mortality Rate:
1.53%
Reason given: AGD/'Treatment losses
AGD/'Treatment losses
Site contacted. - AGD, PGD and silica in water. Gills in poor state, FW and peroxide wellboat treatments for gills. Back log of morts have been cleared and are hoping to see improvement of mortality figures. On 24/10/23 little fresh mortalities and fish feeding well.
FHI visit scheduled

Date:
23/10/23-29/10/23
Mortality:
37,148
Mortality Rate:
4.67%
Reason given: AGD and treatment losses
AGD and treatment losses
FHI site visit scheduled

Date:
30/10/23-05/11/23
Mortality:
7,639
Mortality Rate:
1.01%
Reason given: AGD
AGD
FW treating currently underway.
FHI visited. Diagnostic samples taken, awaiting results.

Date:
22/07/24-28/07/24
Mortality:
4,342
Mortality Rate:
1.56%
Reason given: Treatment loss (FLS Flusher / FW wellboat)
Treatment loss (FLS Flusher / FW wellboat)
First report this calender year. FHI to monitor.

Date:
12/08/24-18/08/24
Mortality:
1,277
Mortality Rate:
1.09%
Reason given: Physical damage
Physical damage
Business contacted: Site is planned to fallow at the end of wk35, subject to change. FW/FLS treatment on 24th to 28th July which resulted in some physical damage. Only few fish remaining on site.
FHI to monitor.

Source

Inspection reports

Case Number: 2020-0050


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Inspection of records carried out at Croabh Haven shorebase, unable to travel over to Colonsay due to poor weather. Further inspection carried on site under case 2020-0129 in order to inspect records not available at Croabh Haven and site equipment.
Movement records, waste disposal records unavailable for inspection as these are held on barge.
Last mortality removal carried out 13/02/2020 by divers, usually mortality removal is carried out daily using dead baskets, however severe weather over the past few weeks has prevented staff accessing the site regularly.
Further inspection carried on site under case 2020-0129 in order to inspect records not available at Croabh Haven and site equipment. CNA report issued under case 2020-0129 but copied to this case for reference.
Escape investigation
On 17th January, site staff observed structural damage to cage 4, positioned in the middle of the east grid. Divers attended site on the same day to inspect the cage further, a vertical hole in the net of cage 4 was discovered, approximately 1-2 metres in length, the hole was repaired by divers. The incident was reported to the fish health inspectorate on the same day confirming the loss of 73,600 fish. No recapture attempt was made due to the poor weather and fish not being visible at the surface. The remaining fish in the cage were then transferred to Cage 11, Cage 4 is now fallow.
The steel bars are connected to the stanchions via a bracket, fixed in place by a pin and nut. The design of the pin and nut assembly is such that the thread of the pin should be destroyed when the nut is fixed in place so that it is unable to unscrew. In this instance the nut appears to have come off, allowing the pin to come loose and the fixing to fail.
The cages installed on Colonsay are the Aqualine Midgard System model. All cages where removed from site at the end of the last production cycle and taken to Kyleakin for refurbishment and maintenance. This included the installation of the steel bars, previously dyneema ropes had been used. Refurbishment work was carried out by Specialist Welding on behalf of Aqualine, an Aqualine technician was present during the work being carried out. Following completion of the refurbishment the cages were transported in batches back to Colonsay where they were installed back at the site, this work was carried out by Mowi staff. Installation of the cages took place over several weeks. An Aqualine technician was on site for 1-2 days during the installation. After the first 8 cages had been installed, inspection showed that a number of the fixing pins had lifted out of position and some cases the nut was not in place. Specialist welding attended site and replaced missing nuts and tightened all fixings. All cages and nets where inspected by site staff and divers before fish were stocked. Dive inspection records are held on site barge and so were unavailable for inspection.
During the investigation there was no evidence of records being in place for the following:
• Product specification sheets giving details on the equipment used (specs taking into account the environmental conditions equipment will be subjected to on site)
• Manufacturing guidance documents for the installation of the steel bars.
• Works sign off records to show cages had been inspected as satisfactory prior to being transported to site.
• SOP or guidance document for inspection of cage equipment on site.
During the investigation, the conclusion section from an independent investigation carried out by Scale AQ (Aqualine parent company) was inspected. The complete report was not made available for inspection.
The conclusion stated that:
• Net fastening points were incorrect – net fastening between main rope and floating collar are on handrail post.
• Occasional use of under-dimensioned ropes (10-12mm) observed for attachment of main rope on other inspected cages.
• Incorrect fastening of nets means it does not retain brackets in absence of tendon system – causing handrail posts to detach from brackets.
Mowi staff and dive teams are inspecting the remaining 13 cages on site when weather allows, at time of inspection 8 cages had been inspected, with fixings being tightened. New steel plates are being made which will be installed on the current fixings, these will enclose the pin and bolt assembly to aid in holding the fixings in place. [Original PDF]

Case Number: 2020-0129


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Following an extreme weather event (Storm Brendan) a loss of fish from pen 4 occured due to equipment failure. A pin that holds the base units that house the stanchions in the correct position on the horizontal axis failed. The base units and some stanchions had slid along the pen ring buckling the walkway due to the failure of the metal bracket. Plastic stays holding the stanchions in place had 'popped out' allowing the stanchion to lift up out of the holding bracket and resulting in the handrail collapsing into the pen beneath the waterline as well as a 1-2m tear in the net. It was reported that 73,600 fish had escaped.
A bracket has been placed around some of the pins to prevent excessive lifting. Divers have beeen onsite re-tightening the nuts (on all pens) that hold the pins in place.
Last visit to the site was 7/11/2019, partly completed an enhanced containment inspection (2020 - 0050) on the
18/2/2020 but this was completed on the mainland as access to Colonsay has been challenging due to weather and flight issues. The enhanced containment inspection was completed during this visit to the site.
Dive inspection reports were inspected and a number of repairs have been made to the nets by divers, it is reported that there have been issues with seal interaction during the winter months when there is a lack of wildfish available. [Original PDF]

Case Number: 2021-0430


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Fish were treated last week for AGD - all pens treated, and worst affected pen had a fresh water treatment.
Some pens had a post treatment mortality spike.
Further AMX treatment planned, but depending on vet advice.
PD confirmed on site, AGD progressed quickly
Weather has made it difficult to retrieve mortality everyday.
Mortality numbers dropped by 50% from Friday to Saturday and 50% again from Saturday to Sunday
Plan to thin the site down during fresh water treatments to reduce biomass in each pen.
Pen 9 - was worst affected.
Fish handled crowding fine during treatments, at next weather window fresh water treatment will be conducted on whole site.
At next weather window fresh water treatment will be conducted on whole site.
Ferguson has collected some mortality, but most is ensiled on site.
Nothing unusual noted in plankton sampling.
Mortality (last 4 weeks)
Week 41 (5.46%) - Week 39 (0.43%) week 40 (2.26%) - Week 38 (0.13%) [Original PDF]

Case Number: 2022-0201


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Fish on from Inchmore (FS8221) and Glenfinnan (FS0742) in April 21.
Mortalities above reporting threshold since last inspection:
Wk44 2021 (1.69%)
Wk43 (1.67%)
Wk41 (5.46%)
Wk40 (2.26%)
- all mortalities attribuited to AGD, PD and post-treatment losses.
Wk49 2019 (1.83%)
Wk48 (1.52%)
Wk47 (1.13%)
Wk46 (1.4%)
Wk45 (1.66%)
- all mortalities attributed to AGD and PD.
3 deadhaul and 1 livehaul harvests were completed in May 22. Going forward, site will only do deadhaul harvests to Ireland.
Fish were sitting deep in the water so were difficult to observe. Those that could be observed appeared in good health and were active in the cages. Large variation in sizes within the cages, with many runts/poor dooers observed across the site. No moribund fish were observed and 3 mortalities were noted across the site. Not fresh dead so not sampled.
Fish sampled for VMD appeared healthy externally and internally.
Escape investigation -
Seal was observed in cage 5 during the inspection. No obvious breaches in containment were identified during the inspection.
Divers were called to the site and were in the cage the same day. Findings to follow.
UPDATE 08/07/22: The incident was reported to have been a result of a froyer ring connection failure. Divers repaired the 1m hole in the net of cage 5 on the same day the seal was observed in the cage. The fish were moved into four other cages on the site and the net removed for repairs. All the froyer ring connection points (16 per cage) across the site are currently being replaced. The winch dyneema lifting ropes and the tension bar bolts are also being replaced across the site.
UPDATE 22/03/23: Recommendations in relation to the above case were made for implementation by 20th March 2023.
Following submission of the required documentation, evidence has now been provided to Marine Scotland to demonstrate that the recommendations have been implemented. [Original PDF]

Case Number: 2023-0031


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Site inspected following a large mortality event reported from week 41 to 43 2023. The site was inspected in a rough sea state in overcast, windy weather. All stocked pens were inspected with only 4 moribund fish observed across the whole site. The stocks were observed shoaling well and responding positively to routine feeding regimes. Two fish were displaying clinical signs of disease were captured in the mort sock which were removed for diagnostic sampling. Fish sampled for VMD appeared health both internally and externally.
Mortalites are ensiled on site during more normal levels of mortality, during the mortality event the site sought removal assistance from the Ben Mowi vessel which has an Ensiler on board.
Following the event, the sites company vet diagnosed AGD as the main driver for mortality. The site recently treated with freshwater from 09/10/2023 to 17/10/2023.
Sea lice levels were low at the time of inspection, the most recent treatments were Slice in may 2023 and AMX in July. [Original PDF]

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