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SUSTAINABILITY LIBRARY 2023 Biodiversity Escapes


The Group invests a considerable amount of resources in optimizing equipment and routines specifically to avoid accidental release of fish.

The Group invests a considerable amount of resources in optimizing equipment and routines specifically to avoid accidental release of fish.  


We operate in areas where wild populations of Atlantic salmon also exists, and release of farmed salmon could interfere with the genetics of local populations 


Wild salmon is the only species categoried by IUCN as near threatened with habitats affected by our operation along the Norwegian coast. Leroy have iniated approriate steps avoid harm and prevent extintion of wild salmon Salmo salar. We have measures preventing escapes, biosecurity procedures and action towards lice . Most important action we startet implementing in 2023 is semiclosed technology where we either submerge the cage or seal the cage to avoid lice floating in surface ofcoastal water to  contaminate the fish, which again could contaminate wild salmon.

Escape incidents can cause Lerøy financial consequences in the form of fines, reduced income and, in the worst case, a lack of capital. Repeated escape incidents could also affect the company's reputation. Fish from aquaculture that escape can find their way into the rivers where wild salmon stocks live. This can create a risk of affecting species diversity in the rivers. There will be a very low risk of any organic or inorganic impact on environmental conditions. Escaped fish from our company will have very little impact on people or human rights.


Our ambitions in this area

Lerøy Seafood Group has a vision of zero escapees. 

How we work in the area/ what action we have taken

Significant measures have been implemented to prevent escape at LSG's farming localities. The Group has invested heavily in both technology, control systems and development of new routines to prevent escape.  

All Lerøy's facilities comply with technical standard NS 9415:2009 Marine fish farms. These requirements are specified in the NYTEK regulation that governs marine fish farms, all main components, structural elements for mooring and extra equipment. 

Actual incidents of accidental release triggers measures determined in the contingency plan and are reported  in our Quality management systestem and to the Directorate of Fisheries, as are events that may lead to accidental release. 

Norwegian Directorate of Fisheries and published on the following website. 


How er measure our impact

Research has shown that escaped fish from aquaculture can have a negative impact on wild salmon that live in rivers in Norway. The Norwegian Institute of Marine Research and various interest organizations monitor wild salmon and publish reports showing the status of the various species of wild salmon. 

The national impact of escape of farmed salmon in watercourses is also measured by different projects like: The national monitoring programme for farmed salmon escapees in watercourses. 

Lerøy follows developments closely and does our utmost every day to ensure that fish do not escape from our locations. 

The Group controls the number of fish in cages at each facility. The number of fish released to each sea cage from the smolt facility is counted according to the number of vaccinations minus dead fish prior to release. All fish that is taken out of the cage after release are logged daily. When an unknown number of fish escape from the cage, a well boat is used to count the remaining fish, and by comparing the well boat count with the marine farm's own figures an estimate of the number of escapees is made. 

Targets and results 


Target 2024: Zero escape 






(number of fish)  





Date Amount of fish escaped What happend? Company Location Estimated cost
16.04.2023 11 Hole in net (*1) Lerøy Sjøtroll Angelskår 500 000
21.08.2023 16 Hole in net (*2) Lerøy Midt  Hogsnes 500 000
31.08.2023 1500 Lice treatment/pumping Lerøy Sjøtroll Naveide 1 500 000
27.11.2023 1 Handling Sjøtroll Havbruk Djupvika 500 000
06.12.2023 2 Lice treatment/pumping Sjøtroll Havbruk Flatøyflu 500 000
  15 030       3 500 000


In April 2023 Lerøy sjøtroll had an escape insident at farm location Angelskår where 11 trout escaped. A small whole in the net was detected at a routine inpection and 11 trouts where catched in a recapture net set out after the hole was detected. An investigation team consisting of operations manager, team manager, regional manager, operations manager treatment, operations manager, service manager and production manager did not give any clear root cause or learning points.

In August Lerøy had 2 insidents; on in Lerøy Midt Farm location Hognses, and one at Lerøy Sjøtroll Farm location Naveide. At Hogsnes 16 salmon escaped from a wellboat during a delicing operation. The well boat had a disconnected return hose causing 16 fish to escape. The insident was discovered by personnel on the workboat, operation was immediatly stopped and 3 recapture nets where deployed. No Fish was recapture . Investigation team has idetified human failure to be the root cause, training and new controlpoints have been implemented.
At Lerøy Sjøtroll farm location Naveide 1500 fish escaped 



In 2022, Lerøy had 1 escape incident at Lerøy Sjøtroll where 1,560 fish escaped, and 4 incidents in connection with lice counting where totally 8 fish escaped into the sea.  

In addition, Lerøy Midt was involved in an incident where a well boat was the cause of an escape incident where 8,976 fish escaped. The well boat has taken the full responsibility for this incident.

Action taken due to results

Improvements have been made to secure use of safety measures when capturing fish for delousing and when returning fish to the cage after counting sea lice, to minimise possible escape. 

Lerøy has collaborated with other businesses to establish a new company, Sporbarhet AS. The aim is to ensure efficient traceability services for salmon in order to prevent escapees with no known origin. The tracking services currently being developed are based on genotyping of all male fish used for breeding and further element analyses to distinguish between fish with the same genetic origins. 

We have implemented the NYTEK standard (minimum technical requirement) and we continuously work together with our suppliers to improve and develop new and better equipment. This is to ensure that all our farms have access to equipment of the highest possible technical standards.  

Risk analysis and a number of written procedures helps us operate our farms safely, including to prevent escapes. Among other spesific measures, we regularly check the technical condition of moorings, facilities, vessels and equipment, we use divers and ROVs to check pen farming nets and employees are trained in prevention of escapes.