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SUSTAINABILITY LIBRARY 2023 Fish health and fish welfare
SUSTAINABILITY LIBRARY 2023

Fish health and fish welfare

Fish health and fish welfare

For the Group, fish welfare involves protecting fish against unnecessary stress and impact.

Challenges

Farming fish entails responsibility for ensuring that the fish have the best possible conditions. The challenge is to provide for the best possible way to protect and ensure fish health and welfare. The most significant challenges in recent years have been injuries from sea lice treatments, Cardiomyopathy syndrome, bacterial diseases, and gill disease.

Impacts: 

If Lerøy's operations are not sound, this could affect our fish's welfare and species diversity directly. In the extreme, this could give our company financial fines, reduced income, and lack of capital as well as lost reputation. Without proper management, there will also be a risk of affecting species diversity in Norwegian rivers where wild salmon spawn, as well as welfare challenges for fish in aquaculture. If we use antibiotics irresponsibly, there could be a risk of intolerance to antibiotics for the people who handle these substances without proper training.

Our ambitions in this area

We want the fish in our cages to thrive and aim to protect them as much as possible against unnecessary impact and stress. We care about our fish, and willingly accept the ethical responsibilities inherent in farming fish. Our ambitions are also to make use of procedures to standardize the processes to which the fish are subjected, and to update and implement these as soon as we gain new knowledge. As such, the entire organization has rapid and efficient access to new knowledge.

Main goals
  • Better survival rate after transfer to salmon production sites.
  • No disease and good fish welfare

Health

The key objective regarding fish health is to make sure that as many fish as possible survive until slaughter.

Measures to improve fish health include:

  • Selective breeding programs
  • Screening of broodstock
  • Risk assessment and biosafety
  • Vaccination against a variety of bacterial and viral agents
  • Early diagnosis and treatment
  • Use of functional feeds
  • Semiclosed and submersible cages (12% of volume in Q4 2023)

Welfare

The Group are working to fulfil the 5 aspects of animal welfare, commonly known as the “Five Freedoms”, for all our fish.

Our fish welfare initiatives are comprehensive and cover every part of our farming value chain.

Mandatory fish welfare training for all staff comprise legislation, animal welfare, fish health biology, stress, sedation, and euthanasia. Other topics covered are natural behavior, environmental requirements, water quality and physiology. Based on this knowledge, staff are also trained in internal fish handling protocols and policies.

Welfare indicators are used throughout the production cycle. At harvest stations, welfare indicators are used to monitor the fish prior to, and after stunning and bleeding. All our harvest stations use either electrical or percussive stunning for anesthesia. This procedure is then followed by bleeding the fish. Bleeding is performed either manually or robotic. Indicators such as eye reflex and operculum movements are monitored and recorded daily. The effect of anesthesia and bleeding is monitored, and in case of insufficient effect, a reserve system is used.

In case of loss of power, an emergency power supply will help evacuating the fish from the rig.

In case of the need to euthanize fish on the farming site, the fish is anesthetized with an approved anesthetic or by percussion followed by bleeding out. Farm personnel are trained in fish welfare at least every 5 years. In addition, they are guided by fish health professionals, who visit the farm at least monthly.

During transportation of fish in well boats, there is implemented a risk-based water quality monitoring and control program. This continuous monitoring includes parameters such as temperature, dissolved oxygen, and pH. Limit values are set according to duration of transport, density in tanks and size of the fish.

During recent years, increased use of camera technology in our pens has given us the ability to monitor a range of observable welfare metrics daily. The metrics are based on the Fishwell standard, and include scores on skin health, deformities, fin damages, eye status and maturation.

How we work in the area

Throughout the year, we have meetings, email correspondence and conversations with various stakeholders where we present and discuss topics from the areas where there is a potential for impact. We also attend conferences and meetings where we meet and discuss. Through this form of dialogue, we gain insight into what stakeholders are concerned with and feedback on what they think about the way we work, measures we have initiated and what they think we should focus on going forward. Through various forms of benchmark surveys, we also receive feedback on what stakeholders think about our measures and their implementation. The Group strive to minimize handling operations of live fish. As little handling as possible improves fish health and welfare, which is an important objective for the Group.

We use procedures as management tools for our production. The procedures help us to standardize events at each life stage, and they are updated as soon as we gain new knowledge regarding fish welfare. In this way, the entire organization acquires the new knowledge quickly and efficiently.

100% of Leroy salmon and trout production is certified according to standards outlined in GlobalGAP or ASC standards for production.

See section Sea lice for information regarding semi-closed and submersible cages.

Smolt production

Pumps, transportation pipes, sorting equipment and vaccination equipment are checked at regular intervals so that any damage or defects can be repaired before use.

During major operations such as vaccination and sorting, the fish is checked for damage at regular intervals to detect any defects of equipment.

All components used during sea transfer are checked regularly. If situations arise where an increased incidence of mechanically inflicted damage is registered, delivery is stopped until the cause of the damage has been investigated and corrected.

On-growing phase

During sea transfer, dead fish are controlled for mechanical damage that may have been inflicted during transport. If it turns out that there is presence of mechanically inflicted wounds, a thorough review of the delivery process will be taken.

When fish are crowded during various forms of handling, we have our own handling procedures describing how this is to be carried out to ensure fish welfare.

In all non-medical lice treatments, welfare screening of the fish is performed before and after treatment. In this way, we have documentation of the impacts for the fish, and whether measures may need to be taken to reduce negative consequences.

ZONE COOPERATION 100%

All our on-growing sites take part in a zone-based cooperation with other farmers. In all regions where the Group has operations, fallowing, washing/disinfection, and restocking are coordinated in zones every second year. This cooperation also involves coordination of operations, collaboration relating to lice, disease management and other issues where the solution to the problem requires a joint, coordinated effort.

Disease Management

Disease management is of essential importance for all animal farming. Within the Group, disease management is based on a preventive operational practice, where the primary goal is to prevent problems before they occur.

Our work on disease management is based on recognized principles. These are in turn based on biological know-how and attitudes, in which training for our employees and a live internal control system lay the foundations for operations. 

Disease prevention and management are monitored by fish health professionals (authorized animal health personnel), who also play key roles related to Lerøy's continuous learning and development of best operational practice.

We aim to farm fish under production conditions that safeguard the biological requirements of all species. Density and water quality parameters, such as temperature, salinity and oxygen shall be adapted to the requirements for fish at different life stages. We operate a specific vaccination program and vaccinate all our farmed fish before sea transfer.

The main target for fish health and welfare is to increase fish survival rates throughout the production value chain. All employees involved in handling live fish undergo training focusing on fish welfare.

Fish welfare is developed and monitored by keeping use of medicines to a minimum, with careful assessment of use, using only approved medicines which have documented environmental impact in accordance with the requirements of The Norwegian Medicines Agency, monitoring and documenting tolerance, and following up biological feed factors if administered by feed.

Use Of Medication

Medication is used only when this is deemed appropriate and necessary.

We exclusively make use of licensed products, and all medicine prescriptions are issued by authorized animal health personnel. Lerøy Seafood Group currently employs more than 20 fish health professionals (authorized animal health personnel).

Policy: Use of medication

Cleaner Fish

The company is supplied with self-produced lumpfish. This ensures predictability for deliveries and enables us to control targeted improvement measures, aiming to ensure predictability and biological improvements within the production.

In some regions, The Group also make use of wild-caught wrasse species. Fishing quotas of wild-caught wrasse species are regulated by the Norwegian Directorate of Fisheries. The Norwegian Institute of Marine Research (IMR) states that fisheries of wild-caught wrasse species are sustainable.

Welfare for cleaner fish has been debated, and we acknowledge that there are challenges involved in the use of cleaner fish in salmon farming. However, we experience that our targeted measures listed further down are moving us in the right direction regarding health and welfare of the cleaner fish.

Our onshore production facilities for cleaner fish have over the years implemented measures within operations and biosafety, providing significant improvements to both health and welfare.

These measures encompass a wide range and comprise of:

  • Pathogen screening and selection of parent fish
  • Vaccination of all fish
  • Value chain regionalisation
  • Providing optimal environmental conditions
  • Providing customized feed
  • Improvements within logistics, transport, and handling
  • General biosafety measures such as input water disinfection, hygiene zones in time and space

After vaccination and immunization in onshore production facilities, the farmed cleaner fish are transferred to the salmon farming sites at sea. Here they perform their function by eating sea lice. In the pens at sea, cleaner fish are provided with artificial kelp for resting, and they are supplied with customized feed daily. Despite that, we experience mortalities above expected levels at times. The causes of terminal losses during the sea water phase are dominated by bacterial diseases.

Measures to improve health and welfare are: 

  • Dedicated personnel that provide daily care specific for the cleaner fish
  • Facilitate natural behavior by providing a customized habitat (artificial kelp)
  • Offer a feed that is adapted to the different species
  • Stimulate good health condition by preventive measures
  • Perform health and welfare controls based on industry standards (e.g. vaccination)
  • Additionally, we aim to not use more cleaner fish than necessary for lice management.
  • We provide at least monthly health assessment, performed by authorized animal health personnel.

Over the years, we have participated in several collaborative projects with research institutes aimed at improving health and welfare of cleaner fish.

When the salmon is harvested, remining cleaner fish are anesthetized and euthanized either at the site or at the harvest station.

Policy: Cleaner fish

How we measure our impact

Daily, all facilities electronically register the number of dead fish and the likely cause of death. Dead fish are collected and delivered for silage, which in turn is included in animal feed for other species.

We calculate a fish welfare score before and after treatment for all non-medicinal delousing. This provides us with documentation of the scope of the impact, and whether we must take action to reduce the negative consequences.

When using de-lousing agents and other drugs, there are strict routines for how these should be handled. Personnel who will handle the funds have received training in how to handle the substances.

The fish are monitored throughout every part of the slaughter process by personnel who have received the obligatory training in fish welfare. All fish are anesthetized before slaughter, either by electric shock or a blow to the head. The system and method for slaughter require the follow-up of the Norwegian Food Safety Authority. Every day before starting slaughter procedures, the fish are checked and logged to verify a sufficient level of anesthetization.

Targets and results

Target 2023: Survival in sea, last 12 months according to GSI: 94,5% 

Result 2023: 91,5 %

This is mainly due to challenges involving stress and injury of treatment/handling, jelly fish, gill disease and bacterial and viral disease and wounds.

 

What action has been taken

The Group have many ongoing projects and initiatives aiming to improve health and welfare of our fish, and thus, increasing survival rates. Examples of recent measures implemented to reduce mortality:

  • Risk analysis and management of time of sea transfer
  • Testing of new vaccines against bacterial wounds
  • Use of functional feeds to improve wound healing
  • Several improvements in onshore production to ensure a more robust smolt
  • Investments in post-smolt facilities (RAS) to reduce production time at sea

We make use of procedures as governance tools for production. These procedures help us standardize the processes to which the fish are subjected, and they are updated as soon as we obtain new knowledge that must be taken into account. As such, the entire organization has rapid and efficient access to new knowledge.

R&D projects within fish welfare and farming

The group participates in many different research projects to be at the forefront in terms of the best possible fish health and to implement new technology and expertise as soon as possible.

The various projects can be roughly divided into 3 different areas:

  • Sea lice management
  • Vaccines and functional feeds
  • Risk management, biosecurity and production improvements

Most of our ongoing projects fall into one of these groups.

Several projects have been implemented to improve fish health and fish welfare. This includes:

 

  • Feed ingredients and resistance to CMS: Aims to investigate if use of specific feed ingredients can improve survival and growth after CMS diagnosis.
  • Lerøy internal wound projects: Different projects that aim to reduce prevalence of bacterial wound-infections. In recent years, several projects have been carried out to identify risk factors for wound development on both large fish and fish recently released to sea.
  • Vaccine trials: Contribute to development of new and more effective vaccines.
  • R&D license and Prolaks project: Aims to map effect of post smolt size on health, welfare, and performance.
  • FHF 901736 – Knowledge base of biological relevant welfare indicators for salmon in aquaculture (BIORELEVANS): Aims to provide necessary biological knowledge for establishing health- and welfare data from automatic scanning. Establish limits for when different indicators reflect a normal situation.
  • FHF 901434 - Tenacibaculum spp. Project: Aims to increase knowledge of tenacibaculosis, identify risk factors of disease, describe toxin production, and perform trials with use of toxins as antigens in vaccines.
  • Lerøy internal robust smolt project: Aims to find the causes of why some smolts develop poorly after sea transfer.
  • FHF 901680 Pasteurellosis in Norwegian salmon: Characterizing, epidemiology, and dynamics of pathogen transmission.
  • Prevention of salmon associated Pasteurella project: Aims to find effective preventive treatment against Pasteurella.
  • Pathogen project: Aims to map infection pressure of several pathogens during the production cycle, including finding risk levels for transmission of disease by vectors.
  • Welfare project: Aims to map fish welfare related to different “non-medicinal” treatments.
  • Lerøy internal project: Aims to increase survival rate and robustness of fish in smolt production.
  • Lerøy internal project: Aims to increase survival rate and growth in sea.
  • Lerøy internal project: Aims to find measures to reduce risk for mechanical injuries to fish.
  • NFR 326980 Welfare Severity: frameworks for classifying the welfare of farmed Atlantic salmon based upon the principles of severity assessment
  • FHF 901835 Best practice measures to prevent winter ulcers: aims to identify best practice for handling and mapping wound risk related to handling.
  • FHF 901838 Wound bacteria in sea-based salmon farming: aims to identify to what extent the risk of ulcer development depends on the composition of marine bacterial communities
  • FHF 901692 Causes of mortality and loss of cleaner fish (DOKUMETAR): aims to map the causes of the loss of cleaner fish, and developing handbooks with guidelines to reduce loss
  • FHF 901693 The influence of feeding strategy on nutrition and lice grazing efficiency in lump fish (STRATEGI): aims to make recommendations to satisfy the nutritional needs of farmed lump fish, which will contribute to better lice grazing efficiency
  • FHF 901798 The path to the best possible production of lump fish to ensure a robust and efficient fish (VEIEN): aims to develop new and improved production protocols for lump fish in order to improve welfare, robustness and survival at sea

The Group aims to improve the health and welfare of our fish. Ensuring good health and welfare is first and foremost an ethical responsibility, however reduced health and welfare can also negatively impact our biological and economic results. To ensure good health and welfare, the Group actively work to make sure that the fish thrive, grow and survive.

Improved fish health is monitored by number of disease outbreaks and survival rates.

What measures do we take to handle the fish as gently as possible

The Group strives to minimize handling operations of live fish. As little handling as possible improves fish health and welfare, which is an important objective for the Group.

We use procedures as management tools for our production. The procedures help us to standardize events at each life stage, and they are updated as soon as we gain new crucial knowledge regarding fish welfare. In this way, the entire organization acquires the new knowledge quickly and efficiently.

Smolt:

Pumps, transportation pipes, sorting equipment and vaccination equipment are checked at regular intervals and any damage or defects are repaired before use.

During major operations such as vaccination and sorting, the fish is checked for any damage at regular intervals to detect any defects of equipment.

All components used during sea transfer are checked regularly. If situations arise where an increased incidence of mechanically inflicted damage is registered, delivery is stopped until the cause of the damage has been investigated and corrected.

On-growing stages:

During sea transfer, dead fish are controlled for mechanical damage that may have been inflicted in connection with the transport. If it turns out that there is presence of mechanically inflicted wounds, a review of the delivery process will be taken.

When fish are crowded during various forms of handling, we have our own handling policies describing how this is to be carried out to ensure fish welfare.

In all non-medical lice treatments, welfare screening of the fish is performed before and after it has been treated. In this way, we have documentation of the impacts for the fish, and whether measures may need to be taken to reduce the negative consequences or not.

Cleaner fish

The company produces around 10 million Lump sucker per year. This implies a high ratio of self-supply, which in turn ensures predictability for deliveries and enables us to control targeted improvement measures, aiming to ensure predictability and biological  improvements for production.

Welfare for cleaner fish has been debated for some time, and we acknowledge the challenges involved in farming  cleaner fish. At the same time, we are aware that our  measures are moving us in the right direction, biologically.

Our onshore production facilities have implemented improvement measures within operations and biosafety, providing significant improvements to biology and cleaner fish welfare.

These measures encompass a wide range and comprise of:

  • Screening and selection of parent fish
  • Value chain regionalisation
  • Providing optimal environmental conditions
  • Providing optimal nutritional values
  • Improvements within logistics and handling
  • General biosafety measures such as input water disinfection, hygiene zones in time and space
  • Production biology

After transfer to salmon production sites, when the cleaner fish perform their function by eating salmon lice, we continue to experience challenges. The causes  of terminal losses are dominated by bacterial disease.

Measures to improve welfare are: 

  • Dedicated personell that provides daily care specific for the cleanerfish
  • Facilitate natural behavior by providing a good habitat
  • Offer a fed that is adapted to the species
  • Stimulate good health condition by preventive measures (t.ex. active immunization)
  • Perform health controls

Additional, we aim to not use more cleanerfish than necessary for lice management.

We provide a (at least) monthly health assessment, performed by authorised animal health personnel. Cleaner fish in the harvest stations are anesthezised and euthanized.

Main goals
  • Work for a better survival rate after transfer  to salmon production sites.
  • No disease and good fish welfare

Use of medication

Medication is used only when this is deemed appropriate and necessary.

We exclusively make use of licensed products, and all medicine prescriptions are issued by authorized animal health personnel. Lerøy Seafood Group currently employes 20-30 fish health professionals (authorized animal health personnel).

Chemical used in delousing, active agents (kg) per ton gross weight (administered via feed and bath)

Year  Via feed (kg) Via bath (kg) Hydrogen peroxide* (kg)
2023 0,000057 0,02 0,14
2022 0,000026 0,004 0,00
2021 0.000062 0.014 8.72
2020 0.0001  0.00012 5.3
2019 0.000149  0.000030  2.5
2018 0.000023 0.000003 6.11
2017 0.000162 0.000076 1.83
2016 0.00160 0.000547 18.40
2015 0.00132 0.001361 50.45
2014 0.002474 0.003034 40.87
2013 0.00006 0.002321 4.35

*Both lice and BKD treatment

Antibiotics

Challenges

Excessive use of antibiotics can result in antibiotic resistance in some areas, a major risk factor for health and for fighting diseases, particularly for humans.

In general, food production from animals requires the use of medicines to treat diseases, not least with a view to animal welfare. If not controlled, the use of antibiotics and other medicines in conventional fish farms could contribute to an undesired and negative affect on humans and the environment.

Impacts 

If disease is detected on our fish and if the fish must be given antibiotics for fish welfare reasons, this will also lead to an increased risk of fish mortality as well as increased costs for Lerøy. The use of antibiotics, on the instructions of Lerøy´s fish health personnel, will have very little risk of causing any kind of damage to the environment. Without proper training and protective equipment, the use of antibiotics can ultimately cause intolerance in personnel who handle antibiotics. Note that the volumes that Lerøy has used during the 15 last years are extremely low.

Our ambitions in this area

Lerøy Seafood Group avoids unnecessary use of all antibiotics, including MIAs, CIAs and HPCIAs and veterinary antibiotics, in production of all fish for consumption. We aim to achieve this goal via organization-wide measures involving disease management, including preventive operational practice, 100 % vaccination, early diagnosis, and appropriate measures to handle outbreaks.

How we work in the area

The use of antibiotics is close to zero in the Norwegian fish farming industry. Lerøy Seafood Group applies a very restrictive policy when it comes to use of antibiotics, and use is only on exception and to safeguard fish health. Antibiotics are seen as the last resort, only applied in situations where use has been assessed by veterinarians as necessary to handle a confirmed disease-related situation. The Group´s policy on use of antibiotics is compliant with WHO (World Health Organization) guidelines on use of Medically Important Antimicrobials in food producing animals and the WHO list of Critically Important Antimicrobials for Human Medicine.

The Group has specifications for special brands saying that there is not used any kind of antibiotics during the production time. These brands are certified by a 3rd party.

All medicines used must be prescribed by authorized fish health personnel. Before starting medication, a risk analysis is carried out to assess measures not involving medicines, and the impact on any vulnerable habitats and species close to the facility.

Risk assessment and measures are in place to prevent any risk of employees developing antibiotic resistance.

How we measure our impact

All use of medicines is logged in our own production management system. Details such as the name of the person who prescribed the medicine, approved assistant, active substances, quantity, treatment period and retention period for the fish are all registered each time treatment is administered.

Environmental surveys are conducted at least once a year in the zone surrounding each facility. These surveys are conducted by an independent company. The analyses are in three parts: fauna, chemical and sensory. The analyses result in a score from 1 to 4, where 1 is the best result. If the score is 3 or 4, action must be taken to improve conditions at the facility. Similar and more extensive surveys are conducted outside the immediate surroundings at least every five years.

Targets and results

Target 2024: Annual use of antibiotics in the Group: 0 kg

Annual use of antibiotics in the group

Comment

2023 

0 kg

-           

2022

0 kg

-           

2021

0 kg

-           

2020

18,99 kg

*See result 2020

2019

0 kg

-           

*Result 2020: 18,99 kg One treatment with 18.99 kilo total, which is 0,08mg Florfenikol/kg produced fish. This was treatment administered to small, newly released fish, for a bacterial infection, Tenacibaculum sp. and Moritella viscosa.

Action taken due to results

Lerøy avoids unnecessary use of antimicrobial agents. To achieve this, several of different preventive measures are implemented and are part of a preventive operating practice including vaccination, risk management, disease control, structural measures, early diagnoses etc.  A number of preventive projects have been initiated to prevent future use of antibiotics. These include:

Tenacibaculum spp. as the cause of atypical winter wounds on Norwegian farmed salmon – Norwegian Seafood Research Fund (FHF) project:

https://www.fhf.no/prosjekter/prosjektbasen/901434 Project period: 01.10.2017-30.09.2021. The aim of the project is to identify risk factors for the outbreak of Tenacibaculosis and to characterize toxin production in Tenacibaculosis spp. The project also aims to test “proof of principle” for the use of toxins as antigens in vaccines.

Limit the effect of tenacibaculosis in Norwegian fish farming (LimiT) – Norwegian Seafood Research Fund (FHF) project: https://www.fhf.no/prosjekter/prosjektbasen/901433/ Start/finish: 10.10.2017 – 15.12.2020. The goal with this project has been to gain a better understanding of how a disease or illness progresses, and to identify virulence factors in the bacteria. Trials involving infection have shown that the skin on smolt that have been kept in waters with lower salinity (26 per thousand) than normal sea water prior to release to sea may be better able to combat infection. Comparisons over time in the infection model demonstrate that the skin is in significant development, and that this most likely affects the outcome of the infection. This implies e.g., that the outcome of exposure to skin pathogens will largely be affected by the post-smolt phase of the skin. The results indicate that the industry may be able to reduce the consequences of tenacibaculosis by exposing the smolt to lower salinities during a period prior to release to sea.

FHF 901835 Best practice measures to prevent winter ulcers: aims to identify best practice for handling and mapping wound risk related to handling.

Lerøy internal wound projects: Different projects that aims to reduce prevalence of bacterial wound-infections. In 2020, a project was implemented to identify risk factors for wound development on large fish and fish recently released to sea.

Vaccine trials: To contribute to development of new/more effective vaccines.

The use of antibiotics is close to zero in the Norwegian fish farming industry. Lerøy Seafood Group applies a very restrictive policy when it comes to use of antibiotics, and use is only on exception and to safeguard fish health.

Sea lice

Challenges

Salmon and trout farming entails a relatively higher level of host density compared to in the wild. Infection pressure of wild salmon stocks with sea lice from farmed salmon is one of the main challenges in terms of environmentally sustainable aquaculture.

Due to the host density in farming, Lerøy attempts to keep average numbers of mature female sea lice as low as possible throughout production. Controlling sea lice levels entails higher costs and have the highest priority in Lerøy.

Impacts 

Salmon lice live naturally in the sea and will be able to use our fish in aquaculture as host animals. It is important for Lerøy that we monitor the level of lice in the sea and on fish when the fish is under production. Undesirable quantities of lice will increase the risk that possibly escaped fish from our farms, and smolts that are migrating from the river and passes our farms to the sea, may be attacked by lice. If the lice surcharge becomes too high on our fish, it may exceed the limit values in Norwegian regulations and lead to increased costs for the company, fines, downgrading of fish, reduced fish welfare and, in worse case, fish mortality. Lice infestation on wild smolt could have a negative impact on this species.

Our ambitions in this area

The Group´s efforts to control salmon lice follow the principles of an IPM strategy to control salmon lice and keep the numbers at a low level in the long term. The overall goal is to reduce any negative impact on the environment and the need for active interventions.

The overall principles underlying this control strategy includes establishing acceptable levels (see details in Policy), preventive measures (as structural measures relating to use of locality, coordinated operations over larger geographical areas, zone collaboration, fallow periods in between production cycles, smolt quality and smolt weight as measures to reduce period of exposure, use of various types of physical barriers, (e.g. skirts), monitoring, biological control (i.e. cleaner fish) and active interventions.

We work to minimize levels of adult female lice per fish as close to zero as possible.

How we work in the area

We use targeted measures to reduce the number of lice by reducing exposure in the sea. To do so, we produce larger smolt using RAS technology so we can have shorter production periods in the sea. Biological delousing using our own produced cleaner fish is also a target area for Lerøy.

Since 2010, Lerøy Seafood Group ASA (LSG) has developed technology for semi-closed facilities. This technology takes water from depths of 20-30 meters and transports this via a laminar flow in a tube. Water from these depths helps reduce infection exposure for the fish in the facility as the majority of lice larvae are found in the upper water layers, down to depths of 10 meters.

Requirements from the authorities provide a definition, at any given time, of the upper maximum limit for fully grown female lice. Lerøy has also established their own limit values to provide guidelines for when to implement preventive and active measures to control sea lice levels.

The average values for lice in the facilities shall be reduced by more than 50% during the period from April to June when compared with the rest of the year. This is when wild salmon migrate as smolt from the rivers to the oceans.

How we measure our impact

Sea lice counts and registration are carried out at a minimum of every seven days for all cages in each facility. This is either done manually by catching the fish in a landing net or automatically by underwater camera technology. If done manually, the fish are anesthetized in tanks and controlled individually. A representative selection of fish is taken from each cage. Lice are counted in the following categories in terms of stages:

1) Adult female (with and without egg strings)

2) Mobile pre-adults (including adult males)

3) Attached juveniles

An average figure is calculated by totaling the number of all lice from all fish (plus lice in the tank for counting) and dividing this number by the total number of fish studied. The weighted average for the farm is calculated based on sea lice counts and the number of fish in each pen.

Infestation of wild fish by lice from Norwegian fish farms is calculated regionally by the Institute of Marine Research, by counting lice on wild salmon and using modelling. To read the Institute's report for 2023, use the following link: Lakselus – risikovurdering og kunnskapsstatus 2023 | Havforskningsinstituttet (hi.no).

Target and results

Target 2024:

  • No exceedances of limits set by the authorities
  • Number of red spots: 0

Limits for levels of adult female lice per fish set by the authorities varies throughout the year and differ depending on region. This is described in detail in the Group´s Policy for control of sea lice.

Norwegian regulations require that the average number of adult female lice per fish per farm must be below the maximum limit of 0,5 at any time. In addition, during spring where smolts typically migrate from the rivers to the ocean, the average number of female lice per fish per farm must be below 0,2.

This period is defined as:

Week 16 up to and including week 21 in Trøndelag County and further south.

Week 21 up to and including week 26 in Nordland County and further north.

 

  2023 2022 2021 2020
Average number of adult female lice per fish 0,18 0,18 0,18 0,16

 

  2023 2022 2021 2020
Number of cages treated for lice (number)  1772 1853 1576 1428

 

  2023 2022 2021 2020
Volume of delousing agents used via bath (kg active substance) 26626 1553 3171 28
Alphamax 0 1,42 0,83 0,64
Azasure 0 0 16,8 20,78
Salmosan 67 44,5 103,4 6,3
Ectosan 3131 1 507 3 050 0
Hydrogenperoxide 23428* 0 0 0
         
Volume of delousing agents via feed (kg active substance) 9,1 14,1 23,3 30,4
Slice 9,1 14,1 23,3 30,4

* included AGD treatment

Action taken due to results

Lerøy’s efforts to control salmon sea lice shall continue to follow the principles of an IPM strategy to control salmon sea lice and keep the numbers at a low level in the long term. The goal is to reduce the negative impact on the environment and the need for active interventions. Below is a description of the overall principles underlying this control strategy.

Preventive measures: Prevention is the first line of defense, aiming to control the levels of salmon sea lice by making use of passive control mechanisms. The methods utilized depend on local prerequisites and entail use of one or more of the following measures: Structural measures relating to use of locality, zone collaboration, fallow periods in between production cycles, post smolt strategy and different types of physical barriers.

Biological control: cleaner fish represent a method for treatment prevention, and the goal is to reduce the need for active measures.

Non-medicinal methods: These methods are based on different types of measures that do not include the use of medicines. Lerøy makes use of methods within the categories for fresh water, flushing and temperate water.

Medicinal methods: These methods are based on the use of medicines. In cases where medicines are utilized, these shall be 1) prescribed by authorized fish health personnel and 2) evaluated with regards to the risk for fish welfare, food safety, environment and resistance, and 3) where only medicines approved by Norwegian medicines authorities can be used.

New semi closed technology: Lerøy has made significant investments (>500 000 000 NOK) in coastal production technology recently. A combination of submersible and semi-closed cages is now being rolled out at selected locations in Lerøy Midt and Lerøy Sjøtroll (13% of total biomass). We believe this will have a positive impact on fish health and reduce the lice load. This is because the cages are lowered below lice level in the sea, thus protecting the fish from lice.

The aim is for 30 percent of the salmon to be in shielding technology at the start of 2025.

Policy: Control of salmon lice

 

 

 

Survival rate

It is an essential goal for us to keep the survival rates as high as possible.

It is an essential goal for us to keep the survival rates as high as possible.  

Lost fish is undesirable both from a fish health and welfare perspective and from a financial perspective. Thus, our goal is to get as many individuals as possible throughout the whole production phase from egg to slaughter. Farming robust smolts, good husbandry, disease control and careful handling are key factors.  

 

Main goal

2024: Survival in sea, last 12 months according to GSI: 94.5% 

 

2023

2022

2021

2020

2019

Survival in sea (%)

91,5

92,5

92,5

92,2

93,4

Survival on shore (%)

91,3

91,4

88,8

93,5

91,5

Different biological factors contribute to the result, in 2023 viral diseases, jelly fish and gill disease where main mortality reasons.

Departments in the Group´s Farming division, contributes to the work to achieve the main goal, by identifying and working towards their own specific goals for survival. This includes land- and sea-farms.   

Read more: This is how Lerøy works with fish welfare

Policy:  Fish health and fish welfare