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Wild gadoids are known to have close associations with open-net fish farms, leading to concerns about changes in natural fish distribution and feeding patterns. However, the nature of the relationships between non-pelagic fish and mobile benthic invertebrates and aquaculture facilities remains poorly documented, even though this group contains widespread commercial North Atlantic species. This study utilizes baited remote and towed underwater video surveys to resolve the ecosystem-level effects of open salmon aquaculture cages and organic enrichment on the spatial structure and relative abundance of demersal fish and crustacean communities. Towed camera surveys were carried out 50 to >600 m downstream of three farms producing finfish in Western Finnmark and four in the Frøya region of Norway. Towed camera surveys were paired with baited remote underwater video surveys at the four Frøya farms. The declining enrichment gradient with distance downstreamof the farm cages was confirmed by modeled and observed depositional flux measurements and benthic infaunal community composition. The community structure of wild demersal fish and crustaceans in close association with the seafloor varied with the distance from the aquaculture sites. In addition to the established pattern of the attraction of gadoids, the edible crab (Cancer pagurus) and flatfish (Pleuronectes platessa andMicrostomus kitt) showed a preference for areas 10--150mfromfarmcages where organically enriched sediments contain a rich food source of opportunistic polychaetes. In contrast, the cuckoo wrasse (Labrus mixtus) and the common hermit crab (Pagurus bernhardus) exhibited higher numbers in locations over 600 m from the farms. Findings show how changes in the benthic food web from aquaculture enrichment can affect the spatial distribution of poorly studied but commercially important fish and crustaceans. Such changes in distribution can impact the availability of these species to coastal fisheries, especially in dense aquaculture regions. [ABSTRACT FROM AUTHOR]

The principles of three Rs—REPLACEMENT, REDUCTION, and REFINEMENT—govern the protection and use of animals, including fish, for research purposes in the European Union and Norway. In this paper, we discuss some straightforward steps to simplify the delivery of these principles at the idea stage and adapt some of these examples for conducting fish trials related to health and welfare. Although some of the approaches are well established in other animal science arenas, we believe there can be a timely recap of their key facets. We discuss a number of simple strategies to emphasize how a reduction in fish numbers can be achieved from initial project conception to implementation, highlighting not only their advantages but also their limitations. We also highlight the role that funding agencies can play in the implementation of the 3R principles in aquaculture research. These simple points can be used in frameworks to initiate a broader and dynamic intersectoral dialogue among stakeholders of aquaculture research on how to promote ethics and embrace opportunities for this within the tenets of the 3Rs. [ABSTRACT FROM AUTHOR]

Syndromic surveillance (SyS) is an important tool for early warning and monitoring of health in human and animal populations, but its use in aquaculture has been limited. Our study objective was to design a SyS system for Atlantic salmon aquaculture and to evaluate its performance in detecting pancreas disease (PD) outbreaks caused by salmonid alphaviruses on farms. We defined SyS outbreak alarms as cases where monthly farm mortality exceeded predefined cutoffs or deviated significantly from expected values based on predictive generalized linear models. These models were trained for each salmon production area in Norway, using data from 2014 to 2017. The outcome variable was fish mortality per farm-month, and input variables were production and environmental predictors, as well as an offset for the number of fish at risk. We also added autoregressive components to explain temporal dependency within fish cohorts. Subsequently, data from 2018 to 2021 was used to parameterize and validate the SyS system's performance against the current national PD surveillance program, which relies on routine farm-screening tests using molecular techniques and reports of clinical findings. The study covered 19,119 farm-months, involving 1,618 fish cohorts. The performance of our SyS system varied across production areas, with sensitivity ranging from 80.5% to 87.4% and a false alarm rate of 45.3%–53.2%. The absence of alarms was usually observed in farms that were truly negative for PD, i.e., a negative predictive value range of 81.2%–94.0%. The median time for alarms being raised was either in the same month as the current PD surveillance program or 1 month prior or after it. Our results indicate that the SyS system is a valuable tool for monitoring mortality on salmon farms, but alarms are unspecific if evaluated against an individual disease (PD). Increasing the frequency and granularity of mortality reporting might improve the SyS system's performance. [ABSTRACT FROM AUTHOR]

Elucidating the effects of domesticated organisms escaping into the natural environment represents a topic of importance in both evolutionary and conservation biology. However, when excluding the abundant data on salmonids, there is a lack of knowledge on this topic for marine fish aquaculture, which continues to expand globally. In order to bridge this empirical gap, we investigated a suspected escape of sexually mature domesticated Atlantic cod from a commercial marine fish farm in northern Norway. This involved genotyping samples of fish from cages on the farm, putatively identified escapees and wild cod captured in the region and samples of recently spawned eggs collected in the sea. Genetic analyses confirmed a farmed ancestry of the suspected escapees, and significantly, 27% of the sampled cod eggs. Furthermore, statistical analyses revealed a strong reduction in genetic variation in all samples of the farmed cod, including low effective population size and high degree of siblingship. These results thus document the escape of sexually mature adult cod and the release of fertilized domesticated cod eggs into the natural environment. Although it is possible that some of the mature escapees spawned post‐escape, the fact that only a single egg of potential hybrid farmed × wild origin was identified, together with the high number of mature cod in the farm, points to within cage spawning as the primary source of these eggs. This suggestion is supported by oceanic particle‐drift modelling, verifying that transport of eggs between the farm and the egg sampling locations was plausible. This study represents a rare documentation of interaction between domesticated and wild populations for a marine fish, pointing towards potential impacts on the local wild population. [ABSTRACT FROM AUTHOR]

Effluents resulting from fish farming activities can alter the structure and functioning of benthic ecosystems. In Norway, recent technological advances within the salmon industry have facilitated the expansion of aquaculture into shallower locations, leading to additional pressures upon coastal habitats.Maerl/rhodolith beds are important bioengineers in coastal waters—supporting highly diverse associated macrofaunal communities—and are likely to be particularly at risk.This study aims to investigate the environmental changes induced by fish farms in their vicinity and their impact on the structure and functioning of maerl bed macrofaunal communities.High dissolved nutrients and organic enrichment levels were observed close to the cages, associated with lower live maerl cover.Overall, the most substantial impact of salmon farms on macrofaunal communities was observed within 100 m from the cages. Nevertheless, changes in the structure and functioning of assemblages were evidenced up to 300 m.In the vicinity of the cages, communities were characterized by the dominance of endobenthic subsurface deposit feeders and opportunistic species, notably the polychaetes Chaetozone sp., Capitella sp. and Scoloplos armiger. Conversely, sites situated farther away from the cages exhibited higher abundances of epibenthic taxa, including crawlers, grazers and species sensitive to organic enrichment.Sites unaffected by the presence of fish farms were described by high abundances of the ophiuroid Ophiura robusta, the polychaete Proclea graffi and ostracods, reflecting more favourable environmental conditions.Such changes in macrofaunal communities highlight the vulnerability of maerl beds to the impacts of aquaculture, thus emphasizing the importance of rigorous site selection when establishing new fish farming facilities. [ABSTRACT FROM AUTHOR]

Aquaculture is one of the fastest growing food production sectors in the world and further expansion is expected throughout the 21st century. However, climate change is threatening the development of the sector and action is needed to prepare the industry for the coming challenges. Using downscaled temperature projections based on the Intergovernmental Panel on Climate Change (IPCC) climate projection (Shared Socioeconomic Pathway, SSP2-4.5), we analysed potential future temperatures at a selected Atlantic cod (Gadus morhua L.) farm site in Northern Norway. Results showed that the farming area may experience increased temperatures the next 10-15 years, including more days with temperatures above 17°C. Based on the predicted future conditions, we designed a study with Atlantic cod (Gadus morhua L.) to evaluate effects from high temperature alone and in combination with Fransicella noatunensis infection. Fish were kept at 12°C and 17°C for eight weeks and samples of skin and spleen collected at different timepoints were analysed with transcriptomics, histology, scanning electron microscopy and immunohistochemistry. Results showed that high temperature had a stronger effect on the barrier functions of skin than the infection. Increased temperature induced gene expression changes in skin and spleen, heat shock protein 47 and cold inducible RNA binding protein were identified as potential gene markers for thermal stress. The effect of bacterial challenge was small at 12°C. At high temperature, the development of severe pathology in spleen coincided with a significant decrease of immunoglobulins transcripts, which contrasted with the activation of multiple immune genes. In addition, we used an in vitro model of skin biopsies and scale explants exposed to hydrogen peroxide (H2O2) to assess the effects of thermal and oxidative stress. High temperature and H2O2 reduced proliferation and migration of keratocytes, and increased expression of stress markers, and compounding effects were observed with combined stressors. Results suggest that the projected increased seawater temperature will pose a significant threat to Norwegian cod farming, affecting various biological processes and making fish more vulnerable to stressors and pathogens. Cod farming needs high attention to temperature changes, and special precautions should be taken if the temperature increases beyond cods' thermal optimum. [ABSTRACT FROM AUTHOR]

Introduction: The food-energy-water (FEW) nexus highlights the interdependencies between the systems that people rely on for these essential resources. For example, globally, over two thirds of freshwater withdrawals are used to produce food, and another 10% is used during energy generation. In addition, the food system uses one eighth of global net energy. Seafood is a nutritionally important food, and it is critical to use freshwater and energy resources efficiently throughout seafood supply chains to safeguard future supplies and to reduce environmental impacts. Diverse seafood production methods result in highly variable resource use across supply chains, which may contribute to siloed efforts within supply chains to improve efficiency, instead of larger efforts that involve multiple seafood supply chains. Additionally, efforts to develop and implement efficiency strategies must be informed by fishers, aquaculturists, processors, and other seafood supply chain actors to avoid investing time and resources into strategies that will have low uptake. A significant proportion of seafood is imported into the U.S., so engaging with industry and stakeholders in the U.S. and abroad is critical for understanding and improving the FEW nexus associated with seafood consumed by Americans. Methods: To understand how resources are being used, current and potential strategies to improve resource use, and relevant motivations and barriers, we conducted 47 semi-structured interviews from 2019 to 2021 with seafood supply chain actors, including producers and processors. Seafood supply chains included were farmed catfish produced in the U.S., farmed pangasius and shrimp produced in Vietnam, farmed Atlantic salmon produced in Norway, and wild-caught sockeye and pink salmon caught in the U.S. Results: We provide detailed descriptions of stages within each supply chain regarding resource use and efficiency strategies, and report higher-level findings that apply across supply chains. There was variation across settings regarding how resources are used and opportunities and barriers for improving efficiencies, but we also found commonalities in settings, indicating that resource-saving strategies or innovations could lead to increased efficiency across multiple supply chains. Interviewees shared that cost savings drove past adoption of, and high interest in, energy conservation practices. Generally, direct costs did not motivate reduced use of freshwater, but associated costs like energy to run pumps and supplies to treat contaminated surface water drove interest in reducing water use. Discussion: Efforts to improve resource use in the U.S. seafood supply should focus on identifying and scaling-up strategies that (i) involve improved efficiency of more than one resource and/or (ii) apply across multiple settings. This work should involve partnerships between industry, government agencies, and academic researchers, and should be informed by supply chain actors' experiences and insights. The qualitative insights from this study encompass rich descriptions of FEW-relevant factors at the level of specific supply chain stages as well as findings across six major seafood supply chains in three countries. The study provides an essential complement to existing quantitative characterizations of resource use, and enables nuanced and informed responses to challenges. [ABSTRACT FROM AUTHOR]

Previous research has shown that Norwegian aquaculture did not report being much affected by COVID-19 but had a strong response to the pandemic regarding cost reductions, market development, and business network development. In this study, we take a step further and investigate if COVID-19 affectedness and responsiveness were consistent across the aquaculture industry's value chain. Also, we investigate if aquaculture industry involvement explains how firms were affected by and responded to the pandemic. Reexamining survey data from Norway shows that the firms, independent of value chain position or industry involvement, were not hit particularly hard by COVID-19 compared to firms in the manufacturing industry as a reference group. In addition, we show that the response to the pandemic in terms of cost reductions, market development, and business network development was strong across the value chain – chiefly among firms involved in producing or selling sea products and providing equipment and consulting services – compared to firms in the manufacturing industry. Finally, the response to the pandemic was consistently strong, independent of industry involvement. We conclude that aquaculture firms, across the value chain and independent of industry involvement, had a strong positive response to COVID-19, albeit not much affected. [ABSTRACT FROM AUTHOR]

Pests often evolve resistance to pest controls used in agriculture and aquaculture. The rate of pest adaptation is influenced by the type of control, the selective pressure it imposes, and the gene flow between farms. By understanding how these factors influence evolution at the metapopulation level, pest management strategies that prevent resistance from evolving can be developed. We developed a model for the metapopulation and evolutionary dynamics of the salmon louse (Lepeophtheirus salmonis), which is a major parasite affecting salmon aquaculture. Different management scenarios were simulated across a network of salmon farms covering half of Norway, and their effects on louse epidemiology and evolution were investigated. We compared louse controls that differed in how they were deployed through time (discrete vs. continuous), how they impacted the louse life cycle, and in their overall efficacy. We adjusted the strength of selection imposed by treatments, the dominance effect of the resistant allele, and the geographic location at which resistance originated. Continuously acting strategies (e.g., louse‐resistant salmon) were generally more effective than discrete strategies at controlling lice, especially when they increased louse mortality during early developmental stages. However, effective strategies also risked imposing frequent and/or strong selection on lice, thus driving rapid adaptation. Resistant alleles were more likely to be lost through genetic drift when they were recessive, had a low‐fitness advantage, or originated in low‐farm‐density areas. The north‐flowing current along the Norwegian coastline dispersed resistant genes from south to north, and limited gene flow in the opposite direction. We demonstrate how evolutionary models can produce quantitative predictions over large spatial and temporal scales and for a range of pest control scenarios. Quantitative outputs can be translated into practical management decisions applied at a regional level to minimise the risk of resistance developing. [ABSTRACT FROM AUTHOR]

Aquatic products fulfill the protein needs of people and play an important role in food safety. And aquaculture is prized for its high productivity, sustainability and environmental friendliness. Considering the importance of aquaculture, the legal risks exposed during the aquaculture process deserve attention in order to prevent them from hindering the development of the aquaculture industry. Through online research, literature analysis and practical communication, it is shown that the current legal risks with commonalities include land use violations, lack of legal documents, failure to meet tailing water criteria, unquarantined fry and misuse of prohibited agricultural pharmaceuticals through online research, literature analysis and practical communication. By analyzing the reasons for the formation of legal risks and combining the experiences in sustainable development of three major aquaculture countries, which are Korea, Norway and Chile, this paper provides targeted preventive remedies and suggestions for aquaculture operators, administrative parties, legislators and other parties on legal risks. It includes promoting the improvement of the rule of law in multiple aspects, clarifying the positioning of the aquatic breeding certificates, improving and propagating the standards for wastewater discharge, increasing the self-sufficiency rate of aquatic fry and fingerlings, as well as making use of the synergy of soft law and hard law. [ABSTRACT FROM AUTHOR]

Aquaculture production is typically located in rural coastal areas where the industry's economic and environmental impact is highly visible. Aquaculture industry is at times controversial and subject to criticism regarding its externalities. For the industry to continue and expand, it needs support and acceptance from the public. We empirically examine the social support yfor aquaculture production in Norway using survey data, investigating the impact of economic as well as social factors. We find that people living in municipalities with aquaculture activities have a more favorable view of aquaculture production and become more positive with increasing presence of the industry. However, people also report that the economic benefits generated are not fairly shared in the communities where the production occurs. Our results show that proximity to aquaculture activities improve social acceptance, while perceptions of how equitably the economic benefits of aquaculture are distributed within communities also play an important role. [ABSTRACT FROM AUTHOR]

Aquaculture of the lumpfish (Cyclopterus lumpus L.) has become a large, lucrative industry owing to the escalating demand for "cleaner fish" to minimise sea lice infestations in Atlantic salmon mariculture farms. We used over 10K genome-wide single nucleotide polymorphisms (SNPs) to investigate the spatial patterns of genomic variation in the lumpfish along the coast of Norway and across the North Atlantic. Moreover, we applied three genome scans for outliers and two genotype–environment association tests to assess the signatures and patterns of local adaptation under extensive gene flow. With our 'global' sampling regime, we found two major genetic groups of lumpfish, i.e., the western and eastern Atlantic. Regionally in Norway, we found marginal evidence of population structure, where the population genomic analysis revealed a small portion of individuals with a different genetic ancestry. Nevertheless, we found strong support for local adaption under high gene flow in the Norwegian lumpfish and identified over 380 high-confidence environment-associated loci linked to gene sets with a key role in biological processes associated with environmental pressures and embryonic development. Our results bridge population genetic/genomics studies with seascape genomics studies and will facilitate genome-enabled monitoring of the genetic impacts of escapees and allow for genetic-informed broodstock selection and management in Norway. [ABSTRACT FROM AUTHOR]

With the rapid growth of the aquaculture production since the 1980s, there has been a concomitant increase in disease outbreaks. The injudicious and/or incorrect use of antimicrobial agents against diseases of farmed aquatic species poses a considerable threat to the development and growth of a successful and sustainable aquaculture industry. An increase in antimicrobial resistance (AMR) is an important consequence, resulting to the difficulty in treating common bacterial diseases in populations of aquatic organisms, combined with the presence of antibiotic residues in food fish and their products, leading to import refusals and negative impacts on international trade. To reduce the frequency of AMR, good aquaculture and effective biosecurity practices should include the prudent and responsible use of antibiotics and also consider the use of alternatives to antibiotics, in addition to disease prevention management. This article reviews the literature discussing the scope of the problem pertaining to antibiotic use, the emergence of AMR in aquaculture and to consider and discuss viable alternatives (e.g., vaccination, bacteriophages, quorum quenching, probiotics and prebiotics, chicken egg yolk antibody and medicinal plant derivative). We also discuss lessons learnt, from specific case studies such as the vaccination of farmed salmon in Norway and the use of 'specific pathogen‐free' seed—as primary and essential part of a biosecurity strategy. [ABSTRACT FROM AUTHOR]

Although exclusive common pool resource management regimes have locally been applied since time immemorial in many coastal and fjord areas, in the legal conceptualization of space, the oceans and their living resources were traditionally treated as a "global commons." The idea of restricting access to coastal oceanic resources and delegating their governance to state instruments has become increasingly popular since the middle of the previous century when political economy models predicted the eventual overexploitation or degradation of all resources used in common. While state jurisdictions overall continue to preserve the idea of common access to marine living resources for a state's people, the rapid privatization of marine living resources and the subsequent development of aquaculture over the last few decades, often confront this understanding, leading to enclosure of a delineated maritime area that was initially intended to be accessible to the public. Enclosing the sea for the purpose of aquaculture development leads to a semantic change in property institutions that govern coastal areas and provides for a form of enclosure of the commons in key locations designated for marine aquaculture development. This article explores the concept of "ocean commons" and debates how the enclosure of common areas for the purposes of aquaculture development may collide with Indigenous and local conceptions of common pool resource management. The article applies this theoretical investigation on two examples from Canada and Norway, and suggests that rethinking aquaculture development in coastal waters through the lens of "ocean commons" may provide a guiding ethos for revisiting current approaches of access to the sea and ensuring the harmonious coexistence between aquaculture development and local/Indigenous traditional activities. [ABSTRACT FROM AUTHOR]

A harmful algal bloom occurred in late spring 2019 across multiple, interconnected fjords and bays in northern Norway. The event was caused by the haptophyte Chrysochromulina leadbeateri and led to severe fish mortality at several salmon aquaculture facilities. This study reports on the spatial and temporal succession dynamics of the holistic marine microbiome associated with this bloom by relating all detectable 18S and 16S rRNA gene amplicon sequence variants to the relative abundance of the C. leadbeateri focal taxon. A k-medoid clustering enabled inferences on how the causative focal taxon cobloomed with diverse groups of bacteria and microeukaryotes. These coblooming patterns showed high temporal variability and were distinct between two geographically separated time series stations during the regional harmful algal bloom. The distinct blooming patterns observed with respect to each station were poorly connected to environmental conditions, suggesting that other factors, such as biological interactions, may be at least as important in shaping the dynamics of this type of harmful algal bloom. A deeper understanding of microbiome succession patterns during these rare but destructive events will help guide future efforts to forecast deviations from the natural bloom cycles of the northern Norwegian coastal marine ecosystems that are home to intensive aquaculture activities. [ABSTRACT FROM AUTHOR]

In salmon aquaculture, the sustainable management of salmon lice (Lepeophtheirus salmonis) is limited by the adaptive capacity of the parasite. This is evident in the repeated evolution of pesticide resistance in the salmon louse population. To better prepare for resistance, we constructed a numerical metapopulation model that predicts the evolutionary dynamics of lice across an interconnected farm network. This model integrates within-farm population dynamics and between-farm louse dispersal, the latter using outputs from a state-of-the-art particle-tracking model. Distinct from previous metapopulation models, it also simulates spatial and temporal genetic variation arising from selection. The model was parameterized to simulate the evolution of resistance to the pesticide azamethiphos on farms in southern Norway. It successfully reproduced the rapid (within 10 years) evolution of azamethiphos resistance following extensive delousing treatments. It also identified strong spatial patterns in resistance, with regions of high farm connectivity being potential hotspots of louse adaptation. Rates of infestation and evolution were significantly reduced when highly connected farms were excluded from the simulation, compared to when low-connectivity or random sites were excluded. This model can be a valuable tool for coordinating pest management at a regional scale, in a way that slows or prevents the spread of resistance. [ABSTRACT FROM AUTHOR]

The seafood sector is facing difficulties to meet the increasing demand for product greenhouse gas emission (GHG) assessments. We quantified GHGs of important seafood products of Norway, the world's second largest seafood exporter. We present results and improvement options for products of farmed salmon and wild‐caught shrimp, king crab, cod, and herring, followed to their dominating markets, based on detailed data for 2017. To enable more frequent monitoring, without engaging in a full assessment, we then suggest a simplified approach, focusing on the main drivers of production‐related emissions. The simplified approach is used to analyze temporal trends from 2007–2017 for fisheries and 1990–2017 for salmon aquaculture. Finally, the simplified approach was compared to the comprehensive assessment for 2017 to define species‐specific upscaling factors. Results show that salmon and crustacean products in 2017 caused higher emissions than cod and herring products, with feed and fuel use being the main emission drivers, whereas airfreighted products had the highest emissions of all products. Large improvement potential from average to best performers within each production system exists. The simplified approach shows that the fuel‐use intensity of Norwegian fisheries has increased by almost 50% for shrimp over the past decade whereas it has decreased for fish by 20% for demersal species such as cod and 5–10% for pelagic species such as herring. Feed‐related emissions for salmon, on the other hand, have increased by almost 30% during the same period, because of an increasing feed conversion ratio and increased inclusion of emission‐intensive feed inputs. [ABSTRACT FROM AUTHOR]

Deviating heart shapes and poor cardiac health is a recurring concern in farmed Atlantic salmon. Morphometric analysis has so far improved our understanding of salmonid cardiac morphology, but assessment of morphological cardiac variation is usually performed manually through measurements of lengths, ratios, and angles. Manual assessment of heart shape is tedious, time-consuming, and not very standardized. It also requires training and alignment of personnel to achieve reliable results. Considering these challenges, we aimed to automate this process using a deep learning model for computer vision to measure the morphological variations of the heart. Here we developed an algorithm for a diagnostic tool to detect variation in cardiac morphology in farmed Atlantic salmon, which we believe can assess cardiac morphological variation in a more objective, reproducible, and reliable manner compared to the manual process. The knowledge derived from this study may represent a crucial step in comprehending and eventually reducing cardiac abnormalities in farmed salmonids, which is essential for improving fish health and welfare and ensuring aquaculture's sustainable growth. [Display omitted] • Automated measurements of Atlantic salmon cardiac morphology using computer vision. • Classification of cardiac morphology in Atlantic salmon using machine learning. • Comparison of hearts of farmed Atlantic salmon from Norway and the Faroe Islands. • Novel method may support risk assessments and sustainable growth in aquaculture. [ABSTRACT FROM AUTHOR]

Fishmeal and fish oil (FMFO) have historically come from capture fisheries, although supply from capture fisheries is constrained and demand for FMFO is increasing. Fish production losses and by-products are an alternative raw material for FMFO, however, there is little systematic data collected on the use of these raw materials and limited knowledge about barriers to their use in FMFO production. This study collected data on production losses and by-products from seven fisheries and aquaculture sectors that are important in supplying the US seafood market. From 2019–2021, quantitative surveys (n=47 businesses), semi-structured qualitative interviews (n=31 businesses), and secondary data were collected for the study period of 2014–2018. There was significant variation in utilization of production losses and by-products across sectors (range: 37–99 %), and overall, the aggregate utilization rate was 72 %. Scale appeared to be the most important factor leading to use of production losses and by-products. Aquaculture industries in this study had a large and relatively steady supply of by-products year-round, which made investments in FMFO plants worthwhile and led to moderate to high rates of by-product utilization. Wild-caught fisheries in this study had lower rendering rates due to short fishing seasons, smaller scales, operations in remote locations, and regulations that allow dumping of by-products. There were several examples of companies that invested in rendering plants because it was profitable to sell the rendered waste, while other sectors and industries require better coordination and policy supports to make use of this valuable resource. • This study analyzed by-products from 7 industrialized fisheries and aquaculture sectors. • On average 72 % of by-products were rendered with wide variation among sectors. • Aquaculture used a higher proportion of by-products compared to fisheries. • Scale of operation was an important factor in explaining by-product utilization. [ABSTRACT FROM AUTHOR]

Avoiding genetic interactions between wild and farmed Atlantic salmon is regarded as one of the major requirements for a sustainable salmon aquaculture industry. For this reason, farming functional sterile triploids has been suggested as a possible solution. However, knowledge about how triploids cope under commercial conditions is lacking. In the present study, we compared the performance of diploid and triploid Atlantic salmon among four Norwegian aquaculture companies. Diploid and triploid groups of the same genetic line were farmed in western, mid, and northern Norway under commercial conditions from seawater transfer until slaughter.Overall, triploid salmon exhibited reduced survival, higher incidence of emaciated fish, and scored, on average, a lower quality rating during primary processing. The results highlight the need for further research on how to improve the welfare and performance of triploid salmon in commercial aquaculture operations. [ABSTRACT FROM AUTHOR]

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., (© 2024 The Author(s). Journal of Fish Diseases published by John Wiley & Sons Ltd.)

Piscine orthoreovirus-1 (PRV-1) is a prevalent agent in Atlantic salmon (Salmo salar) and the causative agent of heart and skeletal muscle inflammation (HSMI), an important disease in farmed Atlantic salmon. Investigations into the introduction and dissemination routes of PRV-1 in a field setting have been limited. This study aimed to better understand PRV-1 infections and HSMI-associated mortality under field conditions. We tracked introduction and spread of PRV-1 over one production cycle in a geographically isolated region in Norwegian aquaculture. From five sites, a total of 32 virus isolates were sequenced and genogrouped. The results indicated multiple introductions of PRV-1 to the area, but also revealed a high level of genetic homogeneity among the virus variants. The variants differed from that of the previous production cycle at two out of three sites investigated, suggesting that synchronized fallowing can be a useful tool for preventing dissemination of PRV-1 between generations of fish. Exposure to PRV-1 at the freshwater stage was identified as a potential source of introduction. A low level of HSMI-associated mortality was observed at all sites, with the onset of mortality showing some variation across PRV-1 genogroups. However, the study highlighted the complexity of associating viral genogroups with mortality in a field setting. Overall, this study contributes valuable insights into PRV-1 dynamics in a real-world aquaculture setting, offering potential strategies for disease management and prevention., (© 2024 The Author(s). Journal of Fish Diseases published by John Wiley & Sons Ltd.)

Although a number of genetically diverse Yersinia ruckeri strains are present in Norwegian aquaculture environments, most if not all outbreaks of yersiniosis in Atlantic salmon in Norway are associated with a single specific genetic lineage of serotype O1, termed clonal complex 1. To investigate the presence and spread of virulent and putatively avirulent strains in Norwegian salmon farms, PCR assays specific for Y. ruckeri (species level) and Y. ruckeri clonal complex 1 were developed. Following extensive screening of water and biofilm, the widespread prevalence of putatively avirulent Y. ruckeri strains was confirmed in freshwater salmon hatcheries, while Y. ruckeri clonal complex 1 was found in fewer farms. The formalin‐killed bacterin yersiniosis vaccine was detected in environmental samples by both PCR assays for several weeks post‐vaccination. It is thus important to interpret results from recently vaccinated fish with great care. Moreover, field studies and laboratory trials confirmed that stressful management procedures may result in increased shedding of Y. ruckeri by sub‐clinically infected fish. Analysis of sea water sampled throughout thermal delousing procedures proved effective for detection of Y. ruckeri in sub‐clinically infected populations. [ABSTRACT FROM AUTHOR]

Aquaculture is one of the largest, and fastest growing industries in Norway. Recently, the industry has experienced significant development in the daily operations acquiring new technologies and systems that capture data and automate the different processes. These emerging technologies enable the generation of enormous amounts of data from sensors in the fish cages, cameras, boats, and feeding control rooms. Additional information relevant to the aquaculture industry is based on e-mails, manual notes, or intrinsic experiences and knowledge exchanges. One of the critical aspects of successful fish farming operation management, which is yet not achieved, is to allow domain experts to gain insight into the interconnection between the broad spectrum of heterogeneous data currently realized. This paper describes a framework for storing and retrieving critical information connected to fish farming based on a graph database approach. The overall architecture is presented with detailed illustrations of how data is visualized and interpreted through a user-friendly interface. Accordingly, this work demonstrates how aquaculture users can benefit from the system to identify possible connections in the data and reveal previously undiscovered causalities and correlations that suggest optimal actions. Further, studies and evaluations of the querying system are conducted, evaluating the capability of the proposed design to process complex relationships. This work showcases that the system helps fish farmers and aquaculture users gain knowledge, reveal hidden links in the data, and improve aquaculture operations. [ABSTRACT FROM AUTHOR]

• People have different associations for animal-sourced food from land versus from sea. • Livestock and hunting are mostly associated with traditions, habits, and food. • Capture fishery is associated with production, consequences, and evaluations. • People reported to have little knowledge about aquaculture. • Livestock elicited the most positive associations, and aquaculture the most negative. To get an understanding of drivers of animal-sourced protein consumption, we explored laypeople's affective images of animal-sourced food. A national representative sample of the Norwegian population (N = 783) provided free associations to six food products originating either from livestock, capture fishery, aquaculture, or hunting. Subsequently, participants evaluated their own free associations as either positive, negative, or neutral. We found that people show different associative patterns for animal-sourced food from land than from sea. Livestock and hunting are mostly related to traditions and food, whereas capture fishery relates to production, consequences, and evaluations. People reported to have little knowledge about food products in the aquaculture category. Livestock was the most positively evaluated category, followed by hunting and capture fishery; aquaculture elicited the most negative associations. The current findings suggest a need to consider different strategies to encourage consumption of specific categories of food products. [ABSTRACT FROM AUTHOR]

Non‐motile strains of Yersinia ruckeri, known as Y. ruckeri biotype 2, now dominate amongst clinical isolates retrieved from rainbow trout internationally. Due to an acute increase in the number of yersiniosis cases in Norway in recent years, followed by introduction of widespread intraperitoneal vaccination against the disease, an investigation on the prevalence of Y. ruckeri biotype 2 in Norwegian aquaculture was conducted. We biotyped 263 Y. ruckeri isolates recovered from diseased salmonids in Norway between 1985 and 2020. A total of seven biotype 2 isolates were identified, four of which were collected between 1985 and 1987, and three of which belong to the current epizootic clone, isolated from two different sea‐farms in 2017. Whole‐genome sequencing revealed single non‐synonymous nucleotide polymorphisms in the flagellar genes flhC in isolates from the 1980s, and in fliP in isolates from 2017. In both variants, motility was restored both by complementation with wild‐type alleles in trans and via spontaneous mutation‐driven reversion following prolonged incubation on motility agar. While biotype 2 strains do not yet seem to have become broadly established in Norwegian aquaculture, the seven isolates described here serve to document a further two independent cases of Y. ruckeri biotype 2 emergence in salmonid aquaculture. [ABSTRACT FROM AUTHOR]

Futures on fresh farmed salmon traded at the Fish Pool market in Norway are analyzed in the context of the Capital Asset Pricing Model (CAPM) and a corresponding three-factor model where contracts are separated based on their maturities. Looking into 1 month; 6 months and 12 months contracts, we find that all alphas and most betas are statistically insignificant. We conclude that the CAPM equilibrium condition holds and that Salmon futures prices move largely uncorrelated with the market portfolio and therefore offer no systematic risk premium. The latter documents that Fish Pool futures should be considered as a pure hedging instrument rather than an investment asset. [ABSTRACT FROM AUTHOR]

The red sea cucumber, Parastichopus tremulus, a cold water species with commercial potential, has recently attracted attention for wild harvest as well as for potential use in integrated multi‐trophic aquaculture in Scandinavian countries. Overharvesting has put natural stocks of sea cucumbers at risk in several countries. Our goal was to develop a rearing protocol for P. tremulus to enable sustainable production of this species. This study presents results from spawning and larval rearing conducted in both Norway (NO) and Sweden (SWE) during May–August 2019. We describe spawning induction and behavior, fertilization success, embryonic and auricularia larval development rate for this species under laboratory conditions. The larvae were fed a mixture of three species of live microalgae (SWE) and algal paste (NO). Larval development rate and survival were monitored at four different temperatures (7, 10, 13, and 16°C). Results showed faster development with increasing temperature. Daily food consumption rate was highest at the highest temperature. The combined effects of temperature and food availability on survival were investigated for the same four temperatures and three different feed concentrations. Only food availability affected the mortality rate, with the highest mortality in the low feeding regime of 1,000–2,000 cells ml−1 day−1. [ABSTRACT FROM AUTHOR]

Atlantic cod is a historically abundant species in the North Atlantic region and has contributed to the prosperity of many nations. But a decline in stocks in the last century has prompted to initiate commercial farming of cod in captive conditions. Several approaches have been employed ranging from stock enhancement, capture‐based aquaculture and intensive cod farming. However, except for the enhancement efforts which were carried out for almost a century, efforts on other methods were intermittent coinciding with lower quotas. Intensive farming was attempted in Norway, Scotland, Ireland, Canada, Iceland and Faroe Islands in the 2000s. But it was carried out hastily to cash in the demand for cod in the market even though there were many biological knowledge gaps that are required for a successful aquaculture venture. The reasons for the failure of commercial farming in Norway during the 2000s were not only because of limited knowledge of the biology of cod but also the economic meltdown in Europe in 2008. Cod farming came to a halt; however, the Norwegian National Cod Breeding Program (NCBP) initiated in 2003 continued to operate and produced a fifth generation of a domesticated cod in 2019. Efforts to fill the gaps and the selective breeding for better growth and disease resistance within NCBP have improved the quality of the juveniles produced. We will discuss the past efforts and reasons for failure in farming of cod, how the current situation looks and the future direction in terms of cod biology, political atmosphere and market. [ABSTRACT FROM AUTHOR]

During recent years, there has been a renewed interest in establishing farming of Atlantic cod (Gadus morhua) in Norway. However, a fatal abdominal disorder compromises animal welfare and causes economic losses. A similar problem was present during a previous attempt to establish Atlantic cod farming more than a decade ago. In this paper, we provide the first in-depth description of this intestinal disorder, which is correctly denoted 'strangulating obstruction'. In affected fish, part of the intestine is permanently entrapped (incarcerated) under fibrous strands in the mesentery. The entrapment interferes with blood flow and physically blocks the intestine, causing a strangulating obstruction with severe venous congestion and ischemia of the intestinal wall. Furthermore, comparison of macroscopical and histological anatomy of farmed and wild Atlantic cod is presented and risk factors associated with the anatomical differences are discussed., (© 2024 The Authors. Journal of Fish Diseases published by John Wiley & Sons Ltd.)

Disease interactions between farmed and wild populations have been poorly documented for most aquaculture species, in part due to the complexities to study this. Here, we tested 567 farmed Atlantic salmon escapees, captured in a Norwegian river during 2014-2018, for five viral infections that are prevalent in global salmonid aquaculture. Over 90% of the escapees were infected with one or more viruses. Overall prevalences were: 75.7% for piscine orthoreovirus (PRV-1), 43.6% for salmonid alphavirus (SAV), 31.2% for piscine myocarditis virus (PMCV), 1.2% for infectious pancreatic necrosis virus (IPNV) and 0.4% for salmon anaemia virus (ISAV). A significantly higher prevalence of PMCV infection was observed in immature compared to mature individuals. The prevalence of both SAV and PMCV infections was higher in fish determined by fatty acid profiling to be 'recent' as opposed to 'early' escapees that had been in the wild for a longer period of time. This is the first study to establish a time-series of viral infection status of escapees entering a river with a native salmon population. Our results demonstrate that farmed escapees represent a continuous source of infectious agents which could potentially be transmitted to wild fish populations., (© 2024 The Authors. Journal of Fish Diseases published by John Wiley & Sons Ltd.)

Fillet discoloration by red and melanized focal changes (RFCs and MFCs) is common in farmed Atlantic salmon Salmo salar. In farmed rainbow trout Oncorhynchus mykiss, similar changes have been noted, but their prevalence and histological characteristics have not been investigated. Thus, we conducted a study encompassing 1293 rainbow trout from 3 different farm sites in Norway, all examined at the time of slaughter. Both macroscopic and histological assessments of the changes were performed. Reverse transcription (RT)-qPCR analyses and in situ hybridization (ISH) were used to detect the presence and location, respectively, of potential viruses. Only 1 RFC was detected in a single fillet, while the prevalence of MFCs ranged from 1.46 to 6.47% between populations. The changes were predominantly localized in the cranioventral region of the fillet. Histological examinations unveiled necrotic myocytes, fibrosis, and regeneration of myocytes. Melano-macrophages were found in the affected areas and in myoseptal adipose tissue. Organized granulomas were observed in only 1 fish. Notably, the presence of inflammatory cells, including melano-macrophages, appeared lower compared to what has been previously documented in Atlantic salmon MFCs. Instead, fibrosis and regeneration dominated. RT-qPCR and ISH revealed the presence of piscine orthoreovirus 1 (PRV-1) and salmonid alphavirus (SAV) in skeletal muscle. However, these viruses were not consistently associated with lesioned areas, contrasting previous findings in Atlantic salmon. In conclusion, rainbow trout develop MFCs of a different character than farmed Atlantic salmon, and we speculate whether the observed pathological differences are contributing to their reduced occurrence in farmed rainbow trout.

Biofouling is a serious challenge for global salmon aquaculture and farmers have to regularly clean pen nets to avoid impacts on stock health and farms' structural integrity. The removed material is released into the surrounding environment. This includes cnidarian species such as hydroids, whose nematocyst-bearing fragments can impact gill health and fish welfare. There is also increasing evidence of the association of parasites and pathogens with biofouling organisms and cleaning fragments. It is unknown whether and how far local current regimes disperse biofouling material and whether this material reaches and interacts with adjacent pens or even neighbouring farms downstream, or wild fish populations in surrounding environments. We focussed on the cnidarian hydroid Ectopleura larynx, one of the most abundant biofouling species on Norwegian aquaculture installations. Using a 3D hydrodynamic model parameterised with physical and biological properties of hydroid particles (derived via field and laboratory studies), we simulated the dispersal of net cleaning waste from two Norwegian salmon farms. Our results demonstrate that net cleaning waste is extensively dispersed throughout neighbouring pens, and even to adjacent aquaculture facilities. Salmon were exposed to concentrations of biofouling particles up to 41-fold elevated compared to background concentrations, and for up to 30.5 h. Maximum dispersal distance of hydroid particles was 5.5 km from the point of release, achieved largely within 48 h. Least-cost distance calculations show that this distance exceeds the nearest-neighbour distance of 70 % of Norway's salmon farms (654 farms). Our study provides some evidence that actions taken to manage biofouling at salmon farms may affect neighbouring farms and surrounding natural environments. The results highlight the potential risks associated with net cleaning: the dispersal of harmful cnidarian particles, associated pathogens, and non-indigenous species, thus underlining the need for novel farming or net cleaning technologies that prevent the release of potentially harmful cleaning waste., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Nina Bloecher reports financial support was provided by Research Council of Norway. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Aquaculture has been the world's fastest-growing food producing method and grown to become the second-largest export industry in Norway during the past 40 years. Usually, the high-value fish such as Atlantic Salmon (Salmo Salar) is raised in a multi-cage fish farm, where the flow interactions between fish cages exist. In this study, the interactions between fish cages are implemented into the numerical program, FhSim, to investigate its influences on the responses of a multi-cage fish farm. Tensions in anchor lines, drag force, and cultivation volume of each cage in a full-scale 4 × 2 multi-cage fish farms under different flow directions are analyzed numerically. The discrepancies of the responses based on three cases, i.e., (i) without any wake effects, (ii) with only cage-to-cage wake effect, and (iii) with all the wake effects, are compared and discussed. The results indicate that neglecting the wake effects will overestimate the total drag force of the eight cages up to 128% and underestimate the total cultivation volume of the eight cages as much as 42%. This study can provide suggestions on how to consider the wake effects during the design of the multiple-cage system. [ABSTRACT FROM AUTHOR]

The concept of green transformation is burgeoning in the academic literature and policy discourses, yet few empirical studies investigate what the concept actually means to diverse actors, and how it manifests in practices. This paper contributes to filling that gap. Through an analysis of policy documents and interviews, we investigate how central policy actors and interest organisations in Norwegian farming, fisheries and aquaculture conceptualise and enact transformation. The analysis of the policy documents shows that the concept 'transformation' is mentioned more frequently, and a rhetoric with close connotations to green growth is increasingly applied, which may leave the impression that there is consensus concerning what the concept means and entails. The interviews however leave a more nuanced picture. Among most of the actors, transformation is interpreted in terms of green growth, while a minority of the actors argue for a deeper sustainability, pointing to planetary limits. Clearly, what transformation is and what it entails is embedded in interpretive flexibility. The concept 'transformation' is plastic enough to be applied in several different, and partly conflicting, policy discourses and arenas. We argue that transformation can be understood as a boundary object, and different actors perform different sorts of boundary work to adapt the boundary object of 'transformation' to fit their agendas. Thus, it makes more sense to think of transformation in plural – transformations – instead of a single, consensual discourse. We find that the very practices of most of the actors are not transformative in the theoretical understanding of the concept and that inadequate attention is given to potential negative sides of transformation. Consequently, both scholarly and practical discussions on how to achieve transformation should take into account that different and (partly) conflicting interpretations will continue to exist and contribute to distinguish between different degrees of sustainability and related pathways. [ABSTRACT FROM AUTHOR]

Climate change can hamper sustainable growth in the aquaculture industry by amplifying and adding to other environmental challenges. In Norway, salmon lice-induced mortality in wild salmonid populations is identified as a major risk factor for further expansion. Higher temperatures will induce increased production of salmon lice larvae, decreased developmental time from non-infective nauplii to infectious copepods, and higher infectivity of copepodids. In a warmer climate, a modelling exercise shows how these three factors lead to a significant increase in the infection pressure from farmed to wild salmonids, where the infectivity of copepodids is the term with the highest sensitivity to temperature changes. The total infection pressure gradually increases with increasing temperature, with an estimated twofold if the temperature increases from 9°C to 11°C. Thus, making it even harder to achieve a sustainable expansion of the industry with rising water temperature. This study demonstrates how bio-hydrodynamic models might be used to assess the combined effects of future warmer climate and infection pressure from salmon lice on wild salmonids. The results can be used as an early warning for the fish-farmers, conservation stakeholders and the management authorities, and serve as a tool to test mitigation strategies before implementation of new management plans. [ABSTRACT FROM AUTHOR]

Marine aquaculture holds great promise for meeting increasing demand for healthy protein that is sustainably produced, but reaching necessary production levels will be challenging. The ecosystem approach to aquaculture is a framework for sustainable aquaculture development that prioritizes multiple-stakeholder participation and spatial planning. These types of approaches have been increasingly used to help guide sustainable, persistent, and equitable aquaculture planning, but most countries have difficulties in setting or meeting longer-term development goals. Scenario analysis (SA) for future planning uses similar approaches and can complement holistic methods, such as the ecosystem approach to aquaculture framework, by providing a temporal analogue to the spatially robust design. Here we define the SA approach to planning in aquaculture, outline how SA can benefit aquaculture planning, and review how this tool is already being used. We track the use of planning tools in the 20 International Council for the Exploration of the Sea member nations, with particular attention given to Norway's development goals to 2050. We conclude that employing a combination of an ecosystem framework with scenario analyses may help identify the scale of development aquaculture goals over time, aid in evaluating the feasibility of the desired outcomes, and highlight potential social-ecological conflicts and trade-offs that may otherwise be overlooked. [ABSTRACT FROM AUTHOR]

This retrospective descriptive study estimates cage‐level mortality distributions after six immediate delousing methods: thermal, mechanical, hydrogen peroxide, medicinal, freshwater and combination of medicinal treatments. We investigated mortality patterns associated with 4 644 delousing treatment of 1 837 cohorts of farmed Atlantic salmon (Salmo salar) stocked in sea along the Norwegian coast between 2014 and 2017. The mortality is expressed as mortality rates. We found distributions of delta mortality rate within 1, 7 and 14 days after all six delousing treatments, using mortality rate within 7 days before treatments as baseline. The results show that we can expect increased mortality rates after all six delousing methods. The median delta mortality rates after thermal and mechanical delousing are 5.4 and 6.3 times higher than medicinal treatment, respectively, for the 2017 year‐class. There is a reduction in the delta median mortality for thermal and freshwater delousing from 2015 to 2019. There is a wide variability in the mortality rates, in particular for thermal delousing. Our results suggest that the variability in delta mortality for thermal delousing has been reduced from the 2014 to 2017 year‐class, indicating an improvement of the technique. However, a significant increase in the number of thermal treatments from 14 in 2015 to 738 in 2018 probably contributes to the overall increased mortality in Norwegian salmon farming. [ABSTRACT FROM AUTHOR]

Introduction: Metabolomics applications to the aquaculture research are increasing steadily. The use of standardized proton nuclear magnetic resonance (1H NMR) spectroscopy can provide the aquaculture industry with an unbiased, reproducible, and high-throughput screening tool, which can help to diagnose nutritional and disease-related metabolic disorders in farmed fish. Objective: Standard operating procedures developed for analysing (human) plasma by 1H NMR were applied to fingerprint the metabolome in plasma samples collected from Atlantic salmon. The aim was to explore the metabolome of salmon plasma in relation to growth stage and sampling site. Methods: A total of 72 salmon were collected from three aquaculture sites in Norway (Lat. 65, 67, and 70 °N) and over two sampling events (December 2017 and November 2018). Plasma drawn from each salmon was measured by 1H NMR and metabolites were quantified using the SigMa software. The NMR data was analysed by principal component analysis (PCA) and ANOVA-simultaneous component analysis (ASCA). Results: Important metabolic differences were evidenced, with adult salmon having a much higher content of very low-density lipoproteins and cholesterol in their plasma, while smolts displayed significantly higher levels of propylene glycol. Overall, 24% of the metabolite variation was due to the growth stage, whereas 12% of the metabolite variation was related to the aquaculture site and practice (p < 0.001). Conclusion: This study provides a baseline investigation of the plasma metabolome of the Atlantic salmon and demonstrates how 1H NMR metabolomics can be used in future investigations for comparing aquaculture practices and their influence on the fish metabolome. [ABSTRACT FROM AUTHOR]

Translocation and introduction of non‐native organisms can have major impacts on local populations and ecosystems. Nevertheless, translocations are common practices in agri‐ and aquaculture. Each year, millions of wild‐caught wrasses are transported large distances to be used as cleaner fish for parasite control in marine salmon farms. Recently, it was documented that translocated cleaner fish are able to escape and reproduce with local wild populations. This is especially a challenge in Norway, which is the world's largest salmon producer. Here, a panel of 84 informative SNPs was developed to identify the presence of nonlocal corkwing wrasse (Symphodus melops) escapees and admixed individuals in wild populations in western Norway. Applying this panel to ~2000 individuals, escapees and hybrids were found to constitute up to 20% of the local population at the northern edge of the species' distribution. The introduction of southern genetic material at the northern edge of the species distribution range has altered the local genetic composition and could obstruct local adaptation and further range expansion. Surprisingly, in other parts of the species distribution where salmon farming is also common, few escapees and hybrids were found. Why hybridization seems to be common only in the far north is discussed in the context of demographic and transport history. However, the current lack of reporting of escapes makes it difficult to evaluate possible causes for why some aquaculture‐dense areas have more escapees and hybrids than others. The results obtained in this study, and the observed high genomic divergence between the main export and import regions, puts the sustainability of mass translocation of nonlocal wild wrasse into question and suggests that the current management regime needs re‐evaluation. [ABSTRACT FROM AUTHOR]

The commercialization of a new species through aquaculture is much more complex than the mastery of the production process, or closing the loop, as it is sometimes referred to. Commercial aquaculture is a layer within the global seafood industry, much as wild capture is; however, it places human control at a much earlier phase in the life cycle of the harvested product. As an important species on both sides of the Atlantic, the commercialization efforts for the culture of Atlantic cod are described for four locations, Norway, United Kingdom, New England, and Atlantic Canada that highlight many similar technical challenges and the progress made from the late 1980s through 2012. We also describe some of the marketing challenges faced and how they differ. Technically, the species has been commercialized. Hatcheries and farms in all four countries were successfully established. However, there are clear differences in access to capital for research and industrial expansion from both the private and public sector, social acceptance of farmed fish, as well as the impacts on sales when marketing farmed cod in the context of a global seafood supply. Lower cost species substitution, from either the farmed or wild catch, is also a factor that can have a significant impact on long‐term successful commercialization. [ABSTRACT FROM AUTHOR]

The requirements to rear spotted wolffish, Anarhichas minor, a cold water, demersal fish, native to the north Atlantic Ocean, have been developed over the past 25 years (since 1990s) and it now is commercially produced in one fish farm in Norway with additional plans for commercial development in the near future in Quebec, Canada. Spotted wolffish have numerous attributes that make them a desirable species to culture in the United States including, but not limited to: having a high value; desired by consumers and chefs; not supplied by U.S. or Canadian fisheries; an established broodstock available in neighboring Quebec; well‐developed hatchlings that do not require live feed; high rearing density tolerance; and low disease susceptibility. Here, we review the advancements made in broodstock management and spawning, egg incubation, juvenile rearing, and on‐growing of fish, as well as future research and development needs. Areas requiring further focus include reducing variability in gamete production; nutritional studies at all life stages; health expertise; genetic selection; and further refinement of standard operating procedures at the commercial level for all life‐stages. Given the state of advancement of wolffish cultivation and the existence of a commercial operation in Norway, we propose that spotted wolffish is commercially ready for production in the United States with the primary barrier being a steady source of eggs to supply emerging pilot‐scale or commercial operations. [ABSTRACT FROM AUTHOR]

The assessment of the effects of aquaculture and fisheries on greenhouse gas (GHG) emissions is crucial, especially within the framework of environmental sustainability and global efforts to mitigate climate change. This study investigates the effect of the aquaculture industry, Blue R&D, green energy, and maritime transport on GHG emissions in Ireland and Norway from 2000 to 2019 using quantile-on-quantile regression (QQR) and wavelet coherence (WC). The results of the QQR model indicate a negative effect of aquaculture production at a lower quantile in Ireland. However, the effect turns positive at upper quantiles, showing that aquaculture increases GHG emissions. The strict regulation and efforts to address sustainable aquaculture practices can explain the impact of aquaculture production on GHG emissions in Norway. Maritime transport positively affects GHG emissions in both countries, yet the blue R&D seems more considerable in Norway than in Ireland. The causal relationship between variables implies a substantial impact of the explanatory factors on GHG emissions that have policy directions for policymakers and investment managers. • Quantile-on-quantile regression and wavelet coherence are applied in this study. • Aquaculture increases GHG emissions in both countries but to a lesser degree in Norway. • A strict regulation to address sustainable aquaculture practices is essential. • Maritime transport positively affects GHG emissions in both countries. • Blue R&D seems more considerable in Norway than in Ireland. [ABSTRACT FROM AUTHOR]

In the 21st Century, marine plastic pollution emerges as a prominent wicked issue, posing threats to planetary boundaries, biological and anthropogenic systems. Such complex and multiscale issues significantly contribute to the degradation of our land and ocean ecosystem. For example, loss of aquatic life due to ghost fishing or microplastic pollution from broken-down plastics in the oceans. These 'wicked societal issues' can no longer be resolved through our existing societal structures and methods. The aquaculture and fisheries sectors are significant contributors to plastic marine debris globally. However, research and practices on this matter have been fragmented, siloed, and often limited to specific value chain sections (material science, waste). If more sustainable circular practices are to be realised in the use and management of plastic in the fisheries and aquaculture sectors, interdisciplinary-cross sector co-operation is required, which addresses such global issues at the local level. Using Norway and early findings from the SHIFTPLASTICs project as a case study, this paper presents how interdisciplinary co-production framed by the Systems Design Approach + has enabled creative spaces whereby: 1) a clear identification of the most problematic areas of plastic pollution across the whole service model value chain, and, 2) targeted measures in enabling the transition to more sustainable circular practices and plastic pollution mitigation in the sectors. Key findings include the logic, development, application, and outcomes of the SDA + methodological approach. This includes enabling interdisciplinary co-development and critiquing the Norwegian service model value chain of plastic pollution in the fisheries and aquaculture sectors. The identification and potential solutions in tackling 16-plastic pollution 'hot spots' of the most problematic plastic-based products for the sectors. We conclude that the Systems Design Approach + framework, as undertaken, has enabled collaborative spaces and interactions suitable to generate knowledge, insights, tool development, and creativity in pursuit of innovation and circular transitions for these wicked societal issue. This approach has potential for scalability. • Fisheries and aquaculture sectors are the most significant contributors to marine plastic pollution. • Contemporary complex issues require collaborative interdisciplinary working to decipher and mitigate these wicked problems. • Sustainable management of wicked resource problems demands a new set of cultural attributes. • Systems Design Approach+ is a robust framework that enables such working practices. • We mapped and identified the 16 most problematic areas across the fishing and aquaculture value chains of Norway. [ABSTRACT FROM AUTHOR]

The viability of wild Atlantic salmon populations is threatened by genetic introgression from escaped farmed salmon. Farmed Atlantic salmon are genetically improved for important commercial traits and a life in captivity but are poorly adapted to the natural environment. The rate of gene flow from escaped farmed to wild salmon depends on their spawning success and on offspring survival at various life stages. We here investigate relative survival of introgressed juvenile Atlantic salmon (parr) in a river in northern Norway. The studied population has experienced genetic introgression from farmed salmon for about four generations (20 years). We followed two cohorts of parr from the year of hatching (0+) to the age of 2 years (2+). Farmed genetic introgression was quantified at the individual level and on a continuous scale using diagnostic SNPs. Population‐level genetic introgression decreased from 0+ to 2+ by 64% (2011 cohort) and 37% (2013 cohort). This change was driven by a 70% (2011 cohort) and 49% (2013 cohort) lower survival from age 0+ to 2+ in introgressed parr compared to parr of wild origin. Our observations show that there is natural selection against genetic introgression with a potential cost of lower productivity. [ABSTRACT FROM AUTHOR]

This study investigates potential economic reasons why the production of trout is maintained in Norway by analyzing prices and production for Norwegian Atlantic salmon and trout. The species Atlantic salmon dominates the global salmon market, but its two largest producers, Norway and Chile also farm in sea pens significant quantities of large rainbow trout (as opposed to portion-sized Rainbow trout farmed in freshwaters in other parts of the World, e.g., Iran, Peru, Turkey, and others). Suggesting that these trout have some attributes that make it a useful complement to Atlantic salmon. We investigate development in supply volumes of these species and conduct a cointegration analysis using monthly prices from 2000 to 2018. The results show that the markets for fresh and frozen rainbow trout are tightly integrated with fresh Atlantic salmon, and, where the latter is a price leader. This means that many consumers consider the two products as substitutes, with no clear preferences. There is no apparent productivity argument for the continued production of rainbow trout vis-à-vis Atlantic salmon. However, there may exist a fringe of consumers that prefer its characteristics, motivating firms to maintain its production as a means of diversification. [ABSTRACT FROM AUTHOR]

The production of Atlantic salmon in aquaculture has grown substantially over the last 40 years. The unintentional release of domesticated salmon poses a significant risk to the long‐term persistence of wild Atlantic salmon populations through ecological interactions and genetic introgression. Our ability to link aquaculture production to farmed escaped salmon in rivers is still limited and hinders identifying the appropriate production capacity of salmon aquaculture to reduce unwanted interactions between wild and escaped Atlantic salmon.Here we use a 14‐year dataset of farmed escapee abundance in rivers to model how the a priori selected covariables of wild salmon abundance, aquaculture intensity, river discharge, hydropower and fjord placement of the river affects escapee abundance across 54 rivers in western Norway. Then, we evaluate the predictive strength of the model to provide context for its use to minimize escapees.We found that the abundance of escaped farmed Atlantic salmon in rivers is correlated to aquaculture intensity. Furthermore, the abundance of wild Atlantic salmon, mean yearly discharge, and the interaction between fjord placement and wild salmon abundance were important predictors of escapee abundance in rivers.The model was 40% accurate when predicting the abundance of farmed escaped salmon in rivers. However, the accuracy improved to 75% when using risk categories derived from modelled intrusion rates that induced long‐term genetic changes to the wild population (low < 4%, medium 4%–10%, and high > 10% escaped farmed salmon).Synthesis and applications. This study links aquaculture production, at relevant spatiotemporal scales (75 km from rivers), to the abundance of escaped farmed Atlantic salmon in rivers, and provides governmental agencies with a tool to help regulate domesticated salmon production based on the carrying capacity of the system to buffer against introgression between conspecifics. Furthermore, understanding this relationship will be beneficial when establishing new aquaculture sites in pristine ecosystems where they would overlap with wild Atlantic salmon. Finally, future mitigation efforts should continue to focus on new technologies (e.g. triploid females) that can eliminate the risk of introgression without limiting aquaculture production. [ABSTRACT FROM AUTHOR]

Integrated coastal zone planning seeks to balance competing interests, with aquaculture representing an increasing pressure fuelled by a dominant discourse of 'blue growth'. Recently, more regional-level approaches to planning and mapping in the coastal zone have emerged. Maps, however, are not neutral artefacts, but are infused with particular values and meanings, strengthening some interests rather than others. Drawing on a case study from Hordaland in western Norway, we demonstrate how mapping came to play a pivotal role in regional coastal planning – through analysing relevant documents and interviews, we explored how the conflicts between aquaculture and environmental concerns were explicitly visualised and brought to the fore through mapping. This triggered latent conflicts between the local and regional levels of governance, with several municipalities contesting the map. We suggest that the practice of mapping served to strengthen the authority of the regional planning body in mediating between conflicting interests. [ABSTRACT FROM AUTHOR]

This paper focuses on the availability of economic indicators and metrics to assess effects of marine aquaculture production in the North Atlantic area (the EU, Norway, Canada and USA), including also social and environmental effects. We consider how aquaculture planning and management is organised in the different countries and the usefulness of economic information to address different aquaculture‐related policies. We find that the most relevant economic data for aquaculture management should be at the local and regional levels rather than nationally. The availability of such economic data is mapped for national, regional and local level. The focus is on data that are publicly available from authorities or research institutions. The availability of data is generally fairly good for national and regional data on the direct economic effects of aquaculture. Data on how aquaculture‐related products or input markets are affected are however poorly available, as are economic data on external effects from aquaculture. Countries with a larger aquaculture sector tend to have better availability of aquaculture‐related economic data than those with a smaller sector. An index is developed and calculated to show more specifically where the countries have relatively good or poor data availability compared to their needs. While it will not always be cost‐effective or meaningful to collect economic data on the effects of aquaculture, our study indicates that several countries could benefit from expanding such data collection. It can make trade‐off decisions more consistent and easier to perform, and aquaculture policies and measures can be better tailored to specific contexts. [ABSTRACT FROM AUTHOR]

Norway had historically been considered free of marteiliosis in bivalves since the disease surveillance programme began in 1995. However, in 2016, Marteilia pararefringens, a protistan parasite of mussels Mytilus spp., was described in a heliothermic lagoon-a poll-previously used to produce flat oyster spat. To study whether the parasite was introduced, and possibly spread, via the historical flat oyster networks on the south and west coast, we sampled aquaculture polls that were part of different networks of farmers and wild, natural polls with no aquaculture activity. Additionally, we sampled mussel banks influenced by polls and sheltered bays that could have a similar environment to that of polls. We identified 7 sites with M. pararefringens-infected mussel populations: 5 were polls used in flat oyster production and 2 were in fjord areas with no known connection to any bivalve aquaculture. Prevalence ranged between 2 and 88%. At one site, Trysfjorden, we found M. pararefringens in atypical organs, including the gills, mantle, and intestine. Marteilia-like cells were also observed in the epithelium, lumen, and surrounding connective tissue of metanephridia and in the sinus of the anterior retractor muscle. Our results demonstrate that the parasite is more widespread than previously thought and is neither isolated to polls nor connected directly to aquaculture activity. Lastly, our findings highlight the need for an improved sampling strategy in surveillance programmes to detect marteiliosis in mussels.