Norwegian Salmon Research Articles

Generation of IgM+ B cell-deficient Atlantic salmon (Salmo salar) by CRISPR/Cas9-mediated IgM knockout

Infectious diseases pose significant challenges to Norwegian Atlantic salmon aquaculture. Vaccines are critical for disease prevention; however, a deeper understanding of the immune system is essential to improve vaccine efficacy. Immunoglobulin M (IgM) is the main antibody involved in the systemic immune response of teleosts, including Atlantic salmon. In this study, we used CRISPR/Cas9 technology to knock out the two IgM genes in Atlantic salmon. High-throughput sequencing revealed an average mutagenesis efficiency of 97% across both loci, with a predominance of frameshift mutations (78%). Gene expression analyses demonstrated significantly reduced membrane-bound IgM mRNA levels in head kidney and spleen tissues. Flow cytometry revealed a 78% reduction in IgM+ B cells in peripheral blood, and Western blot analyses showed decreased IgM protein levels in serum. Notably, an upregulation of IgT mRNA was observed, suggesting a potential compensatory mechanism. This work presents the first application of CRISPR/Cas9 to disrupt an immune-related gene in the F0 generation of Atlantic salmon, and lays the foundation for generating a model completely lacking IgM+ B cells which can be used to study the role of B cells and antibodies. This study has implications for advancing immune research in teleosts and for developing strategies to improve salmon health and welfare in aquaculture.

“Consumers’ Preferences Toward Farmed Salmon in China: Integrating Sensory and Choice Experiments”

ABSTRACTChina's growing demand for farmed salmon is apparent, with the country importing 190 thousand tonnes valued at over $1.12 billion in 2023. In response, the Chinese government allowed rainbow trout to be labelled and sold as salmon starting in 2018, bridging the gap between domestically produced trout and imported Atlantic salmon. This study aimed to explore how country‐of‐origin information influences Chinese consumers' sensory perceptions and willingness to pay (WTP) for salmon. Using a within‐subject design with two evaluation rounds (blind and informed) we combined hedonic liking where Chinese consumers rated three salmon samples (from Norway, Chile, and China) with a discrete choice experiment. The results indicated that under the blind taste test, Chinese consumers found no significant difference in sensory preference between domestic rainbow trout and imported Atlantic salmon from Norway and Chile. However, when informed of the product origins, consumer preferences shifted in favor of Norwegian and Chilean Atlantic salmon. Furthermore, consumers' WTP for salmon was unaffected by the country of production unless provenance was disclosed, at which point the origin significantly influenced their preferences. Ecolabels, price, overall liking, education, frequency of aquatic food consumption, and prior experience with salmon were also found to impact WTP for salmon. These insights offer valuable insights for salmon producers/importers/marketers to customize their approaches in response to consumer preferences, refine product positioning, and seize upon opportunities within the competitive salmon market in China.

A governability lesson for the Blue Economy: the collapse of mobile salmon aquaculture in the Norwegian coastal zone

Inspired by governability and evolutionary governance theory, this paper studies innovative aquaculture technologies that aim to contribute to the transition toward a sustainable blue economy. By tracing path, inter-, and goal dependencies, we explore a case related to developing new production systems in the Norwegian salmon aquaculture industry. As further development using conventional production systems is deemed unsustainable, the government has incentivised technological innovation to alleviate environmental and spatial pressures limiting industry expansion. We describe the work behind enrolling one innovative technology into the coastal governance system. As we find, there are conflicts between the conditions in governance that technological innovations depend on for realisation versus the conditions the governance system depends on for governability. Through our relational approach, we display how innovation challenges governability and that achieving Blue Economy objectives may require considerable political and administrative reorganisation of the existing governance setup.

Identifying multiple configurations in global innovation system (GIS): lessons from the salmon farming industry

ABSTRACT The global innovation system (GIS) approach has until now focused on defining industries by a single GIS configuration at a given time. However, by analysing 739 innovation projects in the Norwegian global salmon farming industry, we find that the four ideal GIS configurations can be identified simultaneously. We argue that this is because we refer to an industry with a large diversity of innovation projects generating different resources along varied scales of interaction. Our analysis is based on text analysis of descriptive documents and interviews about innovation projects. With this information, we built four GIS configurations that illustrate how actors, networks and institutions form and are connected through different types of subsystems. The purpose is to understand why some actors have diverse priorities when participating in different types of innovation projects within the same industry and suggest relevant policy ideas.

Stakeholder perceptions of the Norwegian salmon farming industry and its future challenges

Aquaculture has emerged as the fastest growing sector in global food production, with salmon farming in the lead. Norway is responsible for over half of the world salmon production, but its industry faces significant challenges which must be addressed to achieve sustainability. One key issue is the lack of a unified understanding among stakeholders of how production affects the environment and intersects with the interests of other users. Given this context, this present study aims to understand the diverse perspectives of different groups of stakeholders regarding the expansion challenges faced by the Norwegian salmon farming industry. We assessed environmental, socio-economic, operational, and regulatory aspects, highlighting areas of agreement and disagreement among stakeholders using Q-methodology. Our results reveal four distinct stakeholder groups, two of which reveal polarized views, while the other two present more balanced opinions. We believe that our findings facilitate enriched dialogues among stakeholders and provide insights into the management of the industry, while addressing the dilemma of ensuring sustainability amid pressures for production growth.

Increased Liver Size and Dysfunction, Ionoregulatory Disturbance and Opportunistic Infections in Atlantic Salmon (Salmo salar) at Low Temperatures: A Case Study

ABSTRACTIn recent lab‐based experiments, some post‐smolt Atlantic salmon (Salmo salar) held at 3°C for 5 weeks exhibited a range of clinical signs. They became lethargic and swam at the water's surface, developed ulcers to the head and jaw (clinical signs similar to tenacibaculosis in Norwegian salmon aquaculture) and had fin erosion, and this was associated with significant mortalities. In addition, when fish with ‘early’ and ‘advanced’ stages of these different clinical signs were further examined, their livers were found to be large, pale and friable. Fish with this aetiology also had elevated aspartate aminotransferase levels (indicative of liver damage), elevated plasma [Na+], [Cl−] and osmolality (indicating osmoregulatory impairment), low glucose levels (likely limiting metabolic responses to maintain homeostasis) and high circulating cortisol levels (∼100 ng/mL). This suite of physiological disturbances is very similar to that observed in a condition referred to as ‘Winter Syndrome’ or ‘Winter Disease’ (WS/WD) in cultured gilthead sea bream (Sparus aurata) and other fish species. Thus, it appears that WS/WD described here for the first time in Atlantic salmon, alone or in combination with opportunistic infections, results in lipid deposition in the liver, compromising liver function and osmoregulatory capacity, and metabolic collapse that ultimately results in significant losses.

Status quo or giant ambitions? Norwegian Salmon farming SMEs' innovation responses to environmental regulations

Due to strict environmental regulations, the salmon farming industry needs to innovate to remain competitive. Despite the growing interest in how regulations impact innovation, few studies within the field of aquaculture have addressed the balancing act between tight environmental regulations and small and medium-sized enterprises' (SMEs') innovations for continued competitiveness. Here, SMEs refer to firms with less than 250 employees. To examine the innovation responses of firms, this paper applies an in-depth case study of four SMEs in the Norwegian salmon farming industry. We identify four innovation responses influenced by existing and anticipated regulations. These responses vary in terms of levels of innovation (incremental and radical), as well as ambitions and proactiveness towards innovations. When environmental regulations are uniformly imposed on all companies, smaller firms bear a disproportionate burden from these governmental regulations compared to their larger counterparts, particularly in their capacity to access regulatory incentives motivating radical innovation. However, our findings show that despite these constraints, some small firms pursue radical innovations, contrasting earlier studies on environmental regulations and innovation suggesting larger firms being the ones pursuing radical innovations in response to regulations. This study provides valuable insights for practice and policy regarding the regulatory regime of the Norwegian salmon farming industry and how and why different firms adapt to changing regulatory landscapes.

Correlation Between Texture Profile Analysis and Colour Characteristics of Fish: Case study: Black Sea Large Rainbow Trout and Norwegian Salmon

Correlation Between Texture Profile Analysis and Colour Characteristics of Fish: Case study: Black Sea Large Rainbow Trout and Norwegian Salmon

Haematological and Biochemical Reference Intervals Towards a Proactive Health Monitoring Approach in Norwegian Atlantic Salmon Farming.

Haematological and plasma parameters are used in veterinary medicine as a diagnostic tool, allowing for the early detection of potential health and welfare issues. For the implementation of monitoring strategies, reference intervals (RIs) are needed to know when deviations in those parameters become clinically relevant. Here, haematological and plasma biochemical RIs of Norwegian Atlantic salmon (Salmo salar Linnaeus) are presented for 29 biomarkers. Two subgroups were defined from the reference population based on water type, referred to as pre-adult (freshwater, 166.8 ± 118.4 g, N = 979) and adult (seawater, 2655 ± 2883 g, N = 4941), collected at 93 fish farms along the Norwegian coast. While the influence of various pre-analytical variables on RIs is well documented, aquaculture practitioners cannot always control those variables in the field. Here, RIs were calculated from blood samples collected based on local pre-analytical practices and then further processed under standardised conditions (analytical phase). RIs are therefore considered highly relevant for the application in the field. Finally, when taking blood samples in the field, it is advised to centrifuge whole blood as soon as possible, while plasma parameters investigated were stable for 168 h at 4°C or 72 h at room temperature.

Biosafety in Norwegian Aquaculture—Risks and Measures in RAS Facilities and Well‐Boats

ABSTRACTBiosafety is a central concern in Norwegian salmon farming, as diseases and parasites are common. Continued production depends on preventing and controlling diseases and parasites. A critical part of the farmed salmon's life is during smolt production and the following well‐boat transport out to sea. Biosafety here is thus essential, and there is a need for an overview of risk factors and measures. Biosafety is related to the technical solutions' design, construction, cleaning, and maintenance, that can be studied through field work, interviews, and document analysis. This paper presents results from a study identifying risk factors related to technical solutions in smolt production (with RAS—recirculating aquaculture systems) and well‐boats, and potential measures to reduce risk. Risk factors for RAS facilities are divided into four main groups: Introduction of pathogens to the facility, spread of pathogens inside the facility, growth of pathogens inside the facility, and additional risks. Risk factors for well‐boats are divided into three main groups: Introduction of pathogens through intake water, spread of pathogens between fish groups, and spread of pathogens from well‐boat to the environment. Measures are proposed to mitigate the identified risk factors. The lists are not exhaustive, and risk magnitude is not quantified, so effect of measures is not calculated. Still, the measures' potential for risk reduction and implementation (cost/benefit) are discussed, suggesting measures vital for biosafety in RAS facilities and well‐boats.

Opportunities and challenges in new production systems for salmon farming in Norway—Industry perspective

The Norwegian salmon farming industry is characterized by an increasing technological diversity with new production systems emerging. The objective of this paper is to provide knowledge about challenges and opportunities with new production systems as perceived by industry representatives with hands-on experience. Interviews and workshops with fish farmers and suppliers illustrate that even though environmental issues concerning salmon lice, escapes, and diseases can be reduced, and in some cases solved, new challenges might arise. Semi-closed containment and land-based system concerns pertained to water quality and fish welfare, while exposed and offshore systems were more concerned about harsh conditions and their effects on fish, structures, and work operations. However, possibilities for beneficial new production strategies, the potential for a more stable production environment, and increased biosecurity are seen as important advantages. These findings provide valuable perspectives for industry, technology suppliers, and regulators moving forward.

Exposed Aquaculture Operations: Strategies for Safety and Fish Welfare

ABSTRACTThe expansion of aquaculture production into more exposed harsh and remote ocean environments presents both new opportunities and challenges. To manage the complexities of exposed operations, research into fish welfare, personnel safety, and facilitating technology is thus of key importance. This paper reviews recent research advances in the areas of safety, fish welfare, and technology, while the focus is on the Norwegian salmon farming industry, the results could benefit exposed fish farming internationally. Regarding fish welfare, the study summarizes the current knowledge status of salmon coping abilities and welfare indicators in strong currents and waves. On the safety front, there has been significant progress in operational safety management, accident analysis, and emergency preparedness, all of which are crucial for human personnel in these demanding settings. Human safety and fish welfare also rely on structures and equipment, and recent research results include advances in environmental load analysis, vessel design, simulations of fish farms. Notably, the development of contact‐free, autonomous lifting operations, and hole detection methods represents a significant leap in maintaining aquaculture infrastructure. This multidisciplinary study underscores the need for integrated research approaches to address exposed aquaculture, emphasizing that while recent innovations have enhanced safety and robustness, ongoing research and new strategies are critical for safety and fish welfare in exposed aquaculture operations.

Salmon lice biology, environmental factors, and smolt behaviour with implications for the Norwegian salmon farming management system: A critical review

AbstractIn 2017, a new regulatory management system, the traffic light system (TLS), was implemented to estimate the effects of salmon lice from Norwegian salmon aquaculture on marine survival of wild Atlantic salmon and forms the basis of aquaculture capacity regulation. The TLS relies on observational data and a set of models to estimate the risk for negative impact on wild salmon populations. This review of the literature that forms the basis for the TLS as well as other relevant studies is presented in the context of the currently practiced TLS and suggestions are made for immediate and long‐term improvements. The main findings of this review are that: (1) assumed timing and duration of smolt migration contribute to unreliable observational and modelled data and overestimates of infection pressure; (2) production of lice larvae from farmed salmon is overestimated; (3) TLS model systems rely on or are calibrated by the same potentially flawed data; (4) lice‐associated mortality in wild salmon smolts may be overestimated; and (5) lice infection levels on farms are not associated with measurable effects on wild salmon. Recommendations to improve the accuracy and reliability of the TLS, and hence its environmental efficiency include the more complete use of available biological and physical environmental variables, adjusting the time period that observational data are registered and modelled data are integrated, adjusting the interpretation of data including recognition of uncertainty in model outcomes, and use of more realistic assumptions concerning lice‐induced mortality thresholds.

Beyond profit margins: Orchestrating social, economic, and environmental sustainability within the Norwegian Salmon Food Supply Chain

Food Supply Chains (FSCs) have become increasingly complex with the average distance between producers and consumers rising considerably in the past two decades. Consequently, FSCs are a major source of carbon emissions and reducing transportation costs a major challenge for businesses. To address this, we present a mathematical model to promote the three core dimensions of sustainability (economic, environmental, and social), based on the Mixed-Integer Linear Programming (MILP) method. The model addresses the environmental dimension by intending to decrease the carbon emissions of different transport modes involved in the logistics network. Several supply chain network characteristics are incorporated and evaluated, with a consideration of social sustainability (job generation from operating various facilities). The mathematical model's robustness is demonstrated by testing and deploying it to a variety of problem instances. A real-life case study (Norwegian salmon supply chain) helps to comprehend the model's applicability. To understand the importance of optimizing food supply networks holistically, the paper investigates the impact of multiple supply chain permutations on total cost, demand fluctuations and carbon emissions. To address fluctuations in retail demand, we undertook sensitivity analysis for variations in demand, enabling the proposed model to revamp Norway's salmon supply chain network. Subsequently, the results are thoroughly examined to identify managerial implications.

Understanding the Causes of Lumpfish (Cyclopterus lumpus) Mortality in Norwegian Hatcheries: Challenges and Opportunities

Lumpfish are broadly used as biological sea lice removers in Norwegian salmon farming and are mostly produced in hatcheries. To date, there is little systematic documentation on the mortality causes of lumpfish in hatcheries. In the current study, data from 12 selected fish groups from four hatcheries in Norway were collected to understand the challenges and opportunities related to the categorization of mortality causes of lumpfish in hatcheries. This study indicated that a high proportion of lumpfish mortality was categorized by the hatcheries as unspecified. When specified, mortality was primarily assessed as due to fin damage. Our analyses showed that mortality categorized as fin damage correlated with the detection of infectious agents in dead fish, suggesting that mortality was due to infections rather than fin damage. It was not possible to conclude whether infection with pathogens present in the environment caused fin damage or if injuries from aggression were a gateway for pathogens. Furthermore, due to the lack of information regarding production conditions, it was not possible to assess risk factors causing eventual aggression or the presence of pathogens. This study revealed that mortality causality—the chain of events leading to death—is mainly unclear in lumpfish hatcheries because (1) mortality categorization does not focus on underlying causes and (2) there is little documentation of production conditions, making it very difficult to relate mortality rates to external factors. The present findings highlight that there are gaps in the registrations made by hatcheries and that there is an urgent need to implement standardized monitoring protocols for lumpfish hatcheries. This will help identify the causes of mortality and, therefore, allow for the implementation of proper measures that will ensure better survival.

Development Strategies for Korea's Fisheries Seed Industry: Based on Norwegian Salmon Seed Industry

Development Strategies for Korea's Fisheries Seed Industry: Based on Norwegian Salmon Seed Industry

CO2-equivalent emissions and quality evaluation of chilled and frozen Atlantic salmon transported from Norway to Japan

Atlantic salmon (Salmo salar) is the top imported fish in Japan. It is usually shipped in chilled form by air cargo to preserve its freshness but posts a high environmental impact. As a sustainable alternative, ocean freight can be implemented if the salmon is frozen. However, the question arises as to whether the quality of the frozen and thawed salmon is comparable. Therefore, the aim of this study is to evaluate the environmental impact and quality of Norwegian Atlantic salmon in chilled and frozen form. The CO2 equivalent emissions of the key life-cycle stages were calculated, and the quality assessment was carried out by colorimetry and sensory evaluation with careful preparation and execution. The results showed that the CO2 equivalent emissions of the packaging, transport, and overall cycle of the frozen salmon were 35 %, 90 %, and 60 % lower than those of the chilled salmon. Color measurements using digital imaging show that the frozen salmon is slightly redder, with a higher a* value and a lower b* value. Panelist ratings indicated that there was no statistically significant difference in perceived color, glossiness, fishy smell, texture, umami, and juiciness between chilled and frozen salmon. The study provides preliminary results that demonstrate the potential of frozen seafood and ocean freight transportation as a sustainable cold chain solution.

The battle against the introduced pathogenic monogenean Gyrodactylus salaris in Norwegian Atlantic salmon rivers and fish farms.

The introduced salmonid ectoparasite Gyrodactylus salaris has been detected on Atlantic salmon in 53 Norwegian rivers and in 39 Norwegian fish farms. In affected rivers, the mortality of Atlantic salmon juveniles is very high, estimated to a mean of 86%. G. salaris has been considered one of the biggest threats to wild Norwegian Atlantic salmon stocks. With various measures, the authorities have reduced the potential for further spread of the parasite to new rivers and fish farms, and G. salaris has been eradicated from 43 rivers and all fish farms. Furthermore, the eradication process is almost completed in five affected rivers located at the Norwegian west coast, while preparations for the eradication in the remaining five rivers in the southeastern part of Norway have begun. The goal of Norwegian management is to eradicate the introduced pathogenic G. salaris strains from all occurrences in Norway. In fish farms, the parasite has been removed by mandatory slaughter of infected fish. In rivers, G. salaris has mostly been removed by killing all the fish hosts with rotenone. The indigenous genetic Atlantic salmon stocks are re-established after eradication of the parasite. New methods are developed using chemicals that kill the parasite without killing fish in the rivers. Norwegian authorities have so far used more than NOK 1.5 billion on research, monitoring and combating G. salaris. However, the benefits are considered many times greater than the spending. Without control measures, G. salaris would likely have spread to new Atlantic salmon rivers where the same catastrophic outcome had to be expected. The Norwegian authorities seem to meet the goal in their long-term work to halt the spread of G. salaris and to eradicate the parasite in affected rivers.

Do firms hedge against political tensions? Evidence from Chinese food importers of Norwegian salmon

AbstractPolitical and economic tensions, which often jeopardise trade, are rising among the world's major powers, and countries like China are more frequently using food‐related trade actions to deal with deteriorating political relations. Using an event study approach, this paper investigates how importers respond to lasting political tensions by examining China's seafood importers' responses to the 6‐year Norway–China political tensions after Norway awarded Liu Xiaobo, a Chinese political dissident, a Nobel Peace Prize in 2010. Our results reveal firm‐level responses at both the intensive and extensive margins. At the intensive margin, firms that imported Norwegian fresh salmon before the sanction saw a 20% persistent decline in their fresh salmon import value and an 80% decrease in the import share of Norwegian fresh salmon products over our study period. At the extensive margin, we find a trade diversion effect that firms imported fresh salmon from Norway to other countries and regions, but also a consistent ‘political hedging’ effect 3 years after sanction with a 20% decline in the maximum import share from any particular country or region, even if not Norway.

Effect of diel light cycles on vertical migration patterns of Lepeophtheirus salmonis (Krøyer, 1837) copepodids measured in an in situ mesocosm

The ectoparasitic salmon louse (Lepeophtheirus salmonis Krøyer, 1837) persists as a major hindrance for continued growth of the Norwegian salmon industry. Shielding technologies or management strategies are being used to reduce the likelihood of contact in the net pens between the salmon and the sea lice’s infectious copepodid stage. Knowledge about the vertical distribution and diel migration patterns of the planktonic sea lice stages are inevitably a premise for such water-depth-dependent avoidance technologies to be efficient; however, not many studies have investigated diel vertical migration patterns of sea lice in situ or in relevant scales. In this work, we aimed to monitor the diel migration of L. salmonis copepodids in the vertical plane without the influence of hydrographical forces, using sufficient water column depth of 11 m, natural thermoclines, and natural exogenous light conditions. We followed a cohort of copepodids over the course of 4 days and measured their vertical distribution in the water column twice per hour in a custom made mesocosm, using automatic particle detection and machine learning to analyse position and migration patterns. The L. salmonis copepodid population displayed reverse diel migration, and we found a statistically significant interaction between depth and time. During the day, copepodids were found in the upper 1 m of the water column, before the majority of the population descended to 1–2 m depth during night-time. A small fraction of the population remained in the upper part of the water column also during night-time. A significantly higher fraction of the copepodid population resided in the upper metre during daylight hours compared to other depths. These results could be utilised as input in sea lice dispersal models which are important management tools in today’s sea lice prevention strategies and regulatory frameworks.