Author: marina02

Effects of the probiotic Bacillus velezensis administered to European sea bass (Dicentrarchus labrax) kept in RAS after challenge with Vibrio harveyi

Climate change and the increasing implementation of intensive farming have led to more frequent disease outbreaks in aquaculture, often requiring antibiotic treatments to mitigate the losses caused by bacterial pathogens that can suddenly induce severe disease and mortality. Consequently, the problem of antimicrobial resistance (AMR) has become increasingly important in aquaculture, both due to the limited number of authorized antibiotics and the implications that AMR can have on the sustainability of fish production. Recently, the administration of probiotics to reduce or avoid the use of antibiotics in controlling bacterial fish diseases has generated increasing interest in the global aquaculture field. Probiotics are living microorganisms that, when administered at appropriate doses, can promote a healthy balance of gut bacteria in animals resulting in various benefits such as preventing the invasion of harmful pathogens, improving digestion, promoting growth and resistance, and increasing survival rates. The aim of this study was to evaluate the effects of administering the probiotic Bacillus velezensis for a month to European sea bass (Dicentrarchus labrax) kept in an experimental RAS at ULPGC- MBS (Marine Bio-Assays Station) and challenged by with an intraperitoneal (I.P.) infection with Vibrio harveyi, a common bacterial pathogen in marine farming. At the end of the trial, the survival rate of the fish was evaluated and analyses on possible changes in the intestine were performed by histology and metagenomics. Furthermore, since both B. velezensis and V. harveyi are strong biofilm producers, the composition of the biofilm in the experimental tanks was also analyzed by metagenomics to understand whether the biofilm produced by the probiotic possibly expelled through the feces of the fish could have an antagonistic effect against the biofilm production by the pathogen. In addition to detecting a statistically significant higher survival rate in fish that had been fed the probiotic, changes in gut morphometry and in the composition of the gut microbiome and environmental biofilm were also observed. The results obtained confirm the possible role of probiotics in the prevention and control of bacterial diseases in farmed fish, thus potentially reduce the use of antimicrobials in aquaculture.
Acknowledgments: AquaExcel 3.0 AE3 TNA PID28740; NRRP Project NBFC (Spoke 2) – CN_00000033, CUP J33C22001190001.

1. BIGNAMI, GIORGIA, UNIVERSITY OF BOLOGNA, Presenter
2. MONZON-ATIENZA, LUIS, UNIVERSITY OF LAS PALMAS, Author
3. LEUZZI, DANIELA, UNIVERSITY OF BOLOGNA, Author
4. SCICCHITANO, DANIEL, UNIVERSITY OF BOLOGNA, Author
5. CANDELA, MARCO, UNIVERSITY OF BOLOGNA, Author
6. GOMEZ-MERCADER, ANTONIO, UNIVERSITY OF LAS PALMAS, Author
7. GUSTINELLI, ANDREA, UNIVERSITY OF BOLOGNA, Author
8. FIORAVANTI, MARIA LETIZIA, UNIVERSITY OF BOLOGNA, Author
9. PEDRO LUIS, CASTRO ALONSO, UNIVERSITY OF LAS PALMAS, Author
10. TEDESCO, PERLA, UNIVERSITY OF BOLOGNA, Author
11. ACOSTA, FELIX, UNIVERSITY OF LAS PALMAS, Author

Why is it so dangerous to be a cleaner fish?

Cleaner fish are lumpfish and various wrasse species that are used as a part of the strategy to control salmon lice (Lepeophtheirus salmonis) in aquaculture. Every year, millions of cleaner fish are introduced into net pens to work as delousers. However, the role as lice-eater is considered one of the most hazardous “jobs”. Why is being a cleaner fish so risky? This presentation will explore the findings of the Norwegian Fish Health Report regarding the health and welfare of cleaner fish and examine whether conditions have improved in recent years.

Methodology:

The last decade the annual Norwegian Fish Health report have described the health and welfare situation for cleaner fish. The data used in the report comes from biomass statistics provided by the Directorate of Fisheries. In addition, a survey is distributed to fish health personnel and inspectors from the Norwegian Food Safety Authority to gather further insights.

Results:

Although the use of cleaner fish has declined over the past five years, more than 24 million were still used in 2024. This reduction reflects the growing concern among fish health professionals, who report that cleaner fish are being used less frequently or are being phased out altogether due to significant health and welfare challenges. There are also uncertainties regarding their ability and effectiveness to eat lice (delousing effect), and exact mortality rates are poorly documented.

The natural habitat for the different cleaner fish species differs significantly from the conditions in the net pens that are adapted for salmonids. It’s therefore not surprising that cleaner fish struggle to adapt when tolerance limits for factors such as handling, temperature, weather, and current strength differ from salmonids.

According to the Norwegian Animal Welfare Act, animals are not only to be protected but should be ensured a good quality of life and be treated with respect. Cleaner fish are entitled to the same protection as farmed salmonids. Yet in practice, cleaner fish as tools in delousing efforts, is exposed to ie. emaciation, injuries due to handling, impact from different diseases and environmental conditions, that cause mortalities and poor welfare.

1. HARASIMCZUK, EWA, NORWEGIAN VETERINARY INSTITUTE, Presenter
2. Gismervik, Kristine, NORWEGIAN VETERINARY INSTITUTE, Author

Tissue-specific gene expression and immune modulation of stress receptor paralogues in Atlantic salmon

Atlantic salmon aquaculture is highly successful in Scotland with a value over 3.3 billion to the Scottish economy over the last decade. Despite tight control over husbandry throughout the production cycle, management practices including grading, vaccination, and transportation expose fish to stress and potential infectious or non-infectious associated mortality. Exposure to changing environmental parameters, including seasonal temperatures, pathogen diversity and environmental load is also a growing threat to fish health and welfare. The primary glucocorticoid hormone, cortisol is a key biomarker of stress responses in fish playing a crucial role in regulating metabolism, osmoregulation, and immune function. Cortisol is produced in the interrenal cells of the head kidney and so has the equivalent corticotropic functionality of the adrenal glands of terrestrial vertebrates. Cortisol is released during the stress response and binds to the glucocorticoid (GR) and mineralocorticoid receptor (MR), which in turn induces immune modulation.

Atlantic salmon have undergone two whole genome duplication events, which leads to gene duplication where paralogous genes have the potential to exhibit neofunctionalization. In this study, four GR and two MR paralogues have been identified in Atlantic salmon. To explore whether GR and MR paralogues are differentially modulated during an immune response salmon were challenged via intraperitoneal injection of the viral mimetic, Poly I:C or heat-inactivated Vibrio anguillarum, the causative agent of vibriosis in farmed salmonids. Receptor gene expression analysis via RT-qPCR was undertaken 24 hr post challenge relative to vehicle injected controls. We found that GR and MR paralogue-specific expression changes were tissue type and immune challenge dependent, suggesting that paralogous GR and MR genes may have distinct roles within the crosstalk between stress and immune responses.

Our results suggest that these paralogues bind to varying concentrations of cortisol, indicating that the level of stress the fish experiences could influence immune modulation. Through understanding GR and MR paralogue-specific functions, a clearer insight into the relationship between stress and the immune responses can be achieved. This could lead to a better understanding of the impact of fish stress within the Atlantic salmon industry, informing on future decision making leading to continual improvement of fish health and welfare.

Funding for this work was undertaken as part of a studentship funded by the Eastbio Doctoral Training Partnership, Scotland, UK.

1. Chapman, LE, University of Aberdeen. UK, Author
2. Monaghan, S, University of Stirling, Author
3. Martin, SAM, University of Aberdeen. UK, Author
4. Holland, JW, University of Aberdeen, Presenter

Effect of different biosecurity measures on pathogens in commercial land based RAS facilities

Introduction: Disease outbreaks and the presence of pathogenic microorganisms in RAS (Recirculating Aquaculture Systems) can result in a number of challenges and lead to fish mortality and reduced fish welfare in the current fish population and in later life stages. There are many uncertainties regarding the role of biofilters in either outcompeting or maintaining invading pathogens during commercial fish production.

Methodology: We investigated the effect of different biosecurity measures applied in the commercial RAS facilities producing smolt and post-smolt. We identified two RAS facilities with documented disease histories and conducted pathogen screening within their systems both before and after the implementation of enhanced biosecurity measures.

We performed pathogen screening using real time rt-PCR for Ca.Branchiomonas (causing bacterial gill disease), infectious pancreatic necrosis virus (IPNV), ISAV HPR0 avirulent Infectious salmon anaemia virus, and piscine orthoreovirus (PRV). Screening was based on samples from: swabs from several risk assessed areas in the RAS environment, biomedia, water and fish. The assessment was conducted both pre- and post-implementation of the biosecurity measures to evaluate intervention efficacy in three different cases. The cases are presented with a timeline adjusted from when the positive/ infected fish population were removed from the system and from a period post implementation and after introduction of new fish group.

Results and conclusion: In general, replacing all water in the system and a fallowing period between two fish generations showed reduction of most of the pathogens that were assessed in this study. There were some areas in the system where we could detect DNA/RNA for specific agents post implementation of biosecurity measures. The results are based on bacterial DNA/RNA and does not give an overview about whether these were infective or not. The results from screening of naïve fish that were introduced to the same RAS post biosecurity measures often showed that fish tested positive at varying times after introduction indicating that eradication of pathogens is complex.

1. PATEL, SONAL, NORWEGIAN VETERINARY INSITUTE, Presenter
2. Vik, Elisabeth Midtbø, Patogen As, Author
3. Furne, Miriam, NORWEGIAN VETERINARY INSITUTE, Author
4. Sture, Merete Gåsvær, NORWEGIAN VETERINARY INSITUTE, Author
5. Sterud, Erik, Pure Salmon Tech, Author
6. Hess-Erga, Ole-Kristian, NIVA, Author
7. Larsen, Sondre Veberg, Akvaplan-niva, Author

The Heart of the Problem: Advancing electrocardiography as a diagnostic tool in farmed fish.

Despite significant efforts to enhance the health and welfare of farmed fish, cardiovascular diseases and disorders remain a major challenge in aquaculture. For example, the salmonid industry continues to experience high mortality rates, resulting in the annual loss of tens of millions of fish. This not only undermines financial returns but also threatens the environmental sustainability of fish farming. Although no single cause has been identified for these high mortalities, cardiovascular dysfunction likely plays a critical role. Many fish succumb during stressful handling procedures—when cardiac workload spikes—suggesting a reduced tolerance to stress due to underlying heart issues.

Unfortunately, effective tools for early diagnosis and timely intervention are currently limited. In human medicine, electrocardiography (ECG) is a standard first-line diagnostic tool for evaluating suspected cardiac conditions. While ECG has been used in aquaculture primarily to monitor heart rate as an indicator of stress, a more comprehensive analysis—including waveform morphology, durations, intervals, rhythms, and potential abnormalities—has yet to be widely adopted for diagnostic purposes in fish health.

This study investigates the potential of ECG as a screening tool for cardiovascular disease in farmed fish. Particular focus was given to the coronary artery in salmonid species, the main conduit for delivering oxygenated blood to the heart. This artery is also a common site for arteriosclerotic lesion development, which can lead to myocardial ischemia—reduced oxygen supply to the heart—thereby impairing cardiac function and diminishing the fish’s ability to cope with environmental stress. To examine this, we experimentally induced myocardial ischemia in rainbow trout by occluding the coronary artery (coronary ligation) and employed provocation maneuvers to modulate heart rate, enhancing the sensitivity of ECG in detecting cardiac abnormalities.

In parallel with the renewed growth of Atlantic cod farming in Norwegian aquaculture, it is becoming increasingly important to identify potential cardiac pathologies that could impact both productivity and fish welfare. In this context, we also explored the use of ECG to investigate abnormal heart morphology in cod, assessing its potential value as a diagnostic tool.

1. Zena, Lucas, NOFIMA – NORWEGIAN INSTITUTE OF FOOD, FISHERIES AND AQUACULTURE RESEARCH, Presenter
2. Mortensen, Heidi, FIRUM, Author
3. Andersen, Øivind, NOFIMA – NORWEGIAN INSTITUTE OF FOOD, FISHERIES AND AQUACULTURE RESEARCH, Author
4. Seljehaug Johansson, Gunhild, NOFIMA – NORWEGIAN INSTITUTE OF FOOD, FISHERIES AND AQUACULTURE RESEARCH, Author
5. Hansen, Miroslava, NOFIMA – NORWEGIAN INSTITUTE OF FOOD, FISHERIES AND AQUACULTURE RESEARCH, Author
6. Puvanendran, Velmurugu, NOFIMA – NORWEGIAN INSTITUTE OF FOOD, FISHERIES AND AQUACULTURE RESEARCH, Author
7. Hansen, Øyvind, NOFIMA – NORWEGIAN INSTITUTE OF FOOD, FISHERIES AND AQUACULTURE RESEARCH, Author
8. Noble, Chris, NOFIMA – NORWEGIAN INSTITUTE OF FOOD, FISHERIES AND AQUACULTURE RESEARCH, Author
9. Lazado, Carlo C., NOFIMA – NORWEGIAN INSTITUTE OF FOOD, FISHERIES AND AQUACULTURE RESEARCH, Author
10. Gräns, Albin, Swedish University of Agricultural Sciences, Author

The importance of Mx in the antiviral resistance of fish cell lines

Introduction Mx (myxovirus resistance) is a key antiviral effector. Mx genes, part of the Interferon Stimulated Genes (ISGs) encode IFN-inducible dynamin-like GTPases that have an antiviral effect against a wide array of RNA viruses as well as some DNA viruses. In salmonids, the mx genes reside in four distinct chromosomal loci, that cluster together into separate phylogenetic clades.

Methodology To understand the contribution of Mx to the innate antiviral resistance in fish, we knocked out mx1, mx2 and mx3 genes by CRISPR/Cas9 genome editing and generated triple mutant CHSE-derived cell lines. Single guide RNAS (sgRNAS) were designed within the first coding exon of mx1, mx2 and mx3 genes, using CRISPOR v5.01 web tool, synthetized in vitro, complexed with recombinant Cas9 and transfected into CHSE-EC cells by electroporation. Edited clones were isolated by FACS using the megfp transgene as a negative selection method. After genotyping by PCR and Sanger sequencing of clonal edited cell lines, homozygotes clones with null mutations were isolated by FACS, selected and expanded. The absence of Mx1/2/3 proteins in three clonal mx1^-/-mx2^-/-mx3^-/- mutant cell lines was confirmed by western blot. Differences in the cytopathic effect and replication kinetics between the wild-type and mutant cell lines were evaluated by infection with a panel of fish viruses.

Results and Conclusions Cytopathic effect was more pronounced in the mutant cell line lacking the Mx proteins when compared to the wild type cell line after infection with the rhabdoviruses Infectious hematopoietic necrosis virus (IHNV) and SnakeHead RhabdoVirus (SHRV) as well as the Salmon Alphavirus (SAV). In addition, rate of replication of another rhabdovirus, Viral Hemorrhagic Septicemia Virus (VHSV). This survey using viruses from different categories shed lights on the host-pathogen interactions in fish at the cellular level and inform on the potential viral evasion strategies. This triple mutant clonal cell line is a good candidate for viral production system.

1. CHAUMONT, LISE, INRAE, Author
2. PERUZZI, MATHILDE, INRAE, Author
3. HUETZ, FRANCOIS, INSTITUT PASTEUR, Author
4. RAFFY, CLAUDINE, VIRBAC, Author
5. LE HIR, JEROME, VIRBAC, Author
6. MINKE, JULES, VIRBAC, Author
7. BOUDINOT, PIERRE, INRAE, Author
8. COLLET, BERTRAND, INRAE, Presenter

The Dilemmas of Digital PCR: Technology Transfer for Fish Health Diagnostics

Introduction:

Viral myopathies of farmed Atlantic salmon threaten the aquaculture industry, resulting in economic losses and poor fish welfare. Rapid, sensitive and cost-effective detection of myocarditis-related viruses in farmed salmon is crucial for early interventions and appropriate mitigation for disease management.

Droplet digital polymerase chain reaction (ddPCR) is a relatively new evolution of PCR with the advantage of absolute nucleic acid quantification, unlike Real Time-PCR (qPCR), which provides relative quantification information. ddPCR is also reportedly better suited to multiplex assays due to reduced competitive effects.

This project aims to develop a multiplex ddPCR assay for three RNA myocarditis-related viruses. Three viruses significantly affecting Irish farmed salmon include Salmonid Alphavirus (SAV) initiating pancreas disease (PD), Piscine Orthoreovirus (PRV) causing Heart Skeletal Muscle Inflammation (HSMI) and Piscine Myocarditis Virus (PMCV), triggering Cardiomyopathy Syndrome (CMS).

Methodology:

This project planned to optimise qPCR molecular detection assays in singleplex, transfer these singleplex assays to ddPCR and subsequently develop a ddPCR multiplex assay.

Existing Taqman® probe-based qPCR assays for SAV, PRV and PMCV were optimised using the Applied Biosystem 7500 qPCR machine, then tested in singleplex using the Stilla Naica Prism 3 ddPCR machine. Two probe-based detection methods were tested using ddPCR: Hydrolysis probes (TaqMan®) and Universal Nucleic Acid Detection probes (Rainbow Technology – Pxlence).

Results:

Transfer of the specific qPCR assays to the Stilla Naica Prism 3 ddPCR system has been challenging. Technical issues include the availability of probe dyes compatible with both systems, the probe quencher types available with certain dyes and limitations multiplexing more than two minor groove binder (MGB) probes. In preparation for multiplex development, a combination of MGB and QSY (non-fluorescent quencher technology by Thermo Fisher Scientific) probes were tested. QSY probes had low fluorescence signal compared to MGB probes on ddPCR. To overcome these issues, Universal Nucleic Acid Detection probe technology (Rainbow) was trialed in singleplex.

Conclusions:

This project, while in early stages, has already shown that transferring molecular detection assays from a qPCR platform to a digital one may not be as straightforward as expected. Careful consideration of the digital platform and probe-based assay type is necessary, as probe dye and quencher compatibility are key factors for successfully multiplexed ddPCR assays. In this instance, extensive optimisation and redesign of key assay components was required to move viral RNA detection qPCR assays onto a ddPCR platform. Optimisation experiments remain ongoing.

1. LINEHAN, STEPHANIE, MARINE INSTITUTE, Presenter

Diversity and significance of Y. ruckeri isolates from German fish farms

Introduction:Yersiniaruckeri, the causative agent of (Enteritic Red Mouth Disease), causes acute and in some cases chronic chronic diseases in fish (especially salmonids: e.g. trout) and can lead to enormous economic losses in fish farms. In addition to specific diagnostics for pathogen detection, information about mobile genetic elements (e.g. plasmids), pathogen modification and control options are of interest.

Methodology: With the help of classical and sequence-based methods, an extensive Y. ruckeri collection (n=57) was characterised in detail. The isolates were collected between 2008 and 2023 from infection events of different fish species. They were first typed using mass spectrometry and ‘colourful series’ and then characterised by pulsed-field gel electrophoresis for their genetic diversity and plasmid content. In addition, agar diffusion tests were performed to analyse the antimicrobial resistance situation of the isolates. The data obtained were compared with the results from genome sequencing (WGS).

Results: The investigations revealed a high diversity among the isolates. A total of ten different NotI macrorestriction profiles were identified, some of which belong to different subclusters and the two biotypes 1 and 2. The determination of the minimum inhibitor concentration showed resistance to different classes of antibiotics (e.g. sulfonamides, quinolones), which could be traced back to specific, mostly plasmid-encoded genes using WGS. In addition, the WGS data showed very similar virulence factors for the isolates, which are exclusively associated with mobility, immune regulation and effector supply. Furthermore, different temperate prophage sequences were detected in the chromosome of the isolates, but their activation has not been experimentally possible so far.

Conclusion: In this presentation, the phenotypic and genotypic data are interpreted comparatively and statements are made on the significance of the isolates for animal health and food safety. In addition, starting points for possible control using bacteriophages are presented, with which Y. ruckeri could be reduced in aquacultures.

1. HAMMERL, JENS ANDRE, GERMAN FEDERAL INSTITUTE FOR RISK ASSESSMENT, Author
2. BARON, SANDRINE, ANSES, Author
3. LeDevendec, Laetitia, ANSES, Author
4. Goellner, Cornelia, GERMAN FEDERAL INSTITUTE FOR RISK ASSESSMENT, Author
5. Nekat, Jonas, GERMAN FEDERAL INSTITUTE FOR RISK ASSESSMENT, Author
6. Manta, Diana, GERMAN FEDERAL INSTITUTE FOR RISK ASSESSMENT, Author
7. JAECKEL, CLAUDIA, GERMAN FEDERAL INSTITUTE FOR RISK ASSESSMENT, Presenter

Are you really a Vibrio cholerae? Impact of V. cholerae-like species in the environment, aquacultures and food

Introduction: As environmental bacteria of aquatic ecosystems, vibrios can be of significant importance for animal and human health. Currently, for consumer protection and food safety, a focus is set on V. parahaemolyticus, V. vulnificus and V. cholerae, which are responsible for the majority of (extra)intestinal diseases in humans. With regard to the seasonal occurrence of these climate-associated indicator bacteria, an increasing significance of pathogenic vibrios is to be expected in the future.

Methodology: As part of monitoring studies on Louisiana crayfish in Italy, Vibrio spp. were obtained, which were classified as V. mimicus (n=3) and V. cholerae (n=15) using routine methods (e.g. API20E, MALDI-ToF, PCR). However, WGS indicate that 12 of 15 V. cholerae isolates could be assigned to the species V. tarriae and were thus further genetically studied in detail.

Results: To date, information about human pathogenicity of V. tarriae is scarce, although some of the isolates described have been associated with human infections. The genomes of all three species obtained from Louisiana crayfish revealed differences in virulence factor content and phylogenetic relationship. The available V. tarriae genomes were used to derive a species pangenome consisting of ~3,100 core genes. Further typing approaches for easy differentiation such as MALDI-TOF MS and FTIR were evaluated for its suitability.

Conclusion: Our data provide insights into the genetic diversity and possible human pathogenic potential of V. tarriae and highlight limitations in the detection of new Vibrio species in routine diagnostics.

1. HAMMERL, JENS ANDRE, GERMAN FEDERAL INSTITUTE FOR RISK ASSESSMENT, Author
2. BARON, SANDRINE, ANSES, Author
3. LeDevendec, Laetitia, ANSES, Author
4. Goellner, Cornelia, GERMAN FEDERAL INSTITUTE FOR RISK ASSESSMENT, Author
5. Nekat, Jonas, GERMAN FEDERAL INSTITUTE FOR RISK ASSESSMENT, Author
6. Manta, Diana, GERMAN FEDERAL INSTITUTE FOR RISK ASSESSMENT, Author
7. JAECKEL, CLAUDIA, GERMAN FEDERAL INSTITUTE FOR RISK ASSESSMENT, Presenter

RT-qPCR at ¨points-of-need¨ for rapid and reliable detection of Atlantic salmon (Salmo salar) cardiac viral infections

Myocardial infection in salmon with Piscine Myocarditis virus (PMCV), Piscine Orthoreovirus (PRV) and Salmonid alphavirus (SAV), pose challenges for the fish health and welfare and may have significant economic implications. Rapid and reliable viral detection is essential for timely and informed management decisions. Currently, detection relies on molecular methods (RT-qPCR) conducted in centralized laboratories. During the Covid-19 pandemic, compact equipment and user-friendly kits for the detection of the SARS-CoV-2 at ¨points-of-need¨ were developed. This study evaluates RT-qPCR assays based on similar technology for detecting PMCV, PRV and SAV by the local fish health services. The assays utilize robotic extraction and kits, developed by Schweitzer Biotech Company (SBC, Taiwan) and can yield results within two hours post-sampling, while minimizing contamination risks. Heart tissue samples collected by the local veterinary services were analyzed in parallel by using SBC kits at Aquamedic’s lab and standard protocols by central labs. Additionally, positive archive samples and reference test results were also included. We assessed the quality agreement (positive/negative results) between the SBC kits and the central lab. The agreement was almost excellent for SAV and PMCV and moderate for PRV according to Cohen’s kappa analysis. The samples for SAV come mainly from experimentally infected fish or from salmon farms outside the SAV-zone, thus further SAV-positive field samples will be recruited. The PMCV and PRV SBC kit detected a higher rate of positive results. Of note, the observed differences are mostly in specimens with low viral loads (Ct-values >32) originating from fish groups with no clinical signs of disease. We believe that these differences can be explained by methodological variations e.g. extraction method, equipment etc. among the labs. Additional data from tests performed directly by the local veterinary services will be incorporated into the results in the future. Nevertheless, the results so far support the local use of small-sized equipment and SBC kits for rapid detection and flexible monitoring of cardiac viruses in farmed Atlantic salmon. Adoption of such ¨point-of-need¨ diagnostics could reduce response time and drive targeted farming management in salmon aquaculture which may subsequently improve salmon health monitoring.

1. Spanos, Georgios, Aquamedic, Presenter
2. Midtlyng, Paul J., Aquamedic, Author