Fishes

Early detection and effective monitoring of aquatic environments are essential for detecting and mitigating potential ecological threats to aquatic organisms and for ensuring the sustainable management of freshwater ecosystems. Passive sampling is an emerging approach for environmental DNA (eDNA) collection in aquatic systems while active sampling involves controlled collection and filtration of water. This study evaluates active and passive sampling methods in a riverine system for detecting eDNA from Atlantic salmon (Salmo salar) and its lethal ectoparasite Gyrodactylus salaris. Sampling was conducted in the Sande River, Vestfold County, Norway. The loop-mediated isothermal amplification (LAMP) method was employed due to its high efficiency and specificity for amplifying target genes. The selected genetic markers were mitochondrial cytochrome B (Cyt B) DNA for S. salar and cytochrome c oxidase 1 (COX1) for G. salaris. The results indicate that host eDNA was readily detected using both sampling methods, whereas detection of G. salaris was more effective using active sampling. These findings provide valuable insight into optimizing eDNA detection protocols for both host and parasite, demonstrating specificity and sensitivity of LAMP in detecting the target organisms. This case study contributes to the development of conservation strategies aimed at preserving Atlantic salmon populations and freshwater biodiversity. Full article

To evaluate the potential of compound attractants in ameliorating diet-induced intestinal dysfunction in Siniperca chuatsi fed commercial compound feed, this study investigated their effects on intestinal metabolism and microbiota composition. In this study, four distinct diets are formulated: a control diet without attractants and three experimental diets supplemented with compound attractants A (nucleotides and L-glutamic acid), B (nucleotides, L-glutamic acid, and allicin), and C (nucleotides, L-glutamic acid, and betaine). Over a period of 8 weeks, groups of S. chuatsi were fed these diets, after which we assessed the intestinal microbiota and transcriptomic responses. KEGG pathway analysis of differentially expressed genes (DEGs) indicated that the A group exhibited significant changes predominantly in intestinal cholesterol homeostasis and inflammatory responses. The B group showed DEGs primarily associated with mucosal immune functions and pro-inflammatory cytokine signaling. Diversely, the C group revealed DEGs chiefly tied to immune and inflammatory response pathways. Furthermore, the intestinal microbiota exhibited beneficial modifications at both the phylum and genus levels in the A and B groups, while such beneficial shifts were not observed in the C group. These findings indicated that dietary supplementation with compound attractants A and B could positively influence both the intestinal transcriptomic landscape and microbiota composition in S. chuatsi, highlighting their potential as effective additives in compound feeds for aquaculture. Full article

Incorporating protein feed ingredients that exhibit strong attractiveness to the target fish species is an effective and sustainable feeding strategy to improve feed intake and enhance growth performance. An 8-week feeding experiment was performed to elucidate the manipulation impact of graded levels of jack mackerel meal (JMM) in diets replacing 10% fish meal (FM) with corn protein concentrate (CPC) on the growth, feed utilization, and blood chemistry of rockfish (Sebastes schlegeli), as well as to perform an economic analysis. A total of 450 fish were randomly assigned to 15 plastic tanks (30 juveniles/tank). Five experimental diets were formulated to be isoproteic (50.0% crude protein) and isolipidic (15.5% crude lipid). The control (Con) diet contained 55% FM. In the Con diet, 10% of the FM was substituted with CPC, and graded levels of JMM at 0%, 20%, 40%, and 60% were subsequently incorporated instead of the FM, referred to as CPCJ0, CPCJ20, CPCJ40, and CPCJ60, respectively. Triplicate groups of rockfish were carefully hand-fed the diets to satiation throughout the feeding experiment. The rockfish fed the CPCJ60 diet produced significantly higher weight gain (WG) (p < 0.002) and specific growth rate (SGR) (p < 0.003) than those fed the Con, CPCJ0, and CPCJ20 diets but showed no significant (p > 0.05) differences compared to those fed the CPCJ40 diet. Both the WG (Y = 0.9367X + 17.0500, p < 0.0001, Adjusted R² = 0.8468) and SGR (Y = 0.0005X + 0.0165, p < 0.0001, Adjusted R² = 0.8580) of the rockfish increased linearly with increased dietary JMM inclusion levels when 10% of the FM was replaced by CPC. The rockfish fed the CPCJ60 diet showed a significantly higher feed consumption (FC) (p < 0.03) compared to those fed the CPCJ0 diet. Among the dietary treatments, however, no significant (p > 0.05) differences were found in the feed utilization, proximate composition, amino and fatty acid profiles, and blood chemistry of the rockfish. The CPCJ60 diet resulted in the highest economic profit index (EPI) among the dietary treatments. Conclusively, JMM was found to be effective in improving the FC of rockfish fed the diets replacing 10% of the FM with CPC. Furthermore, the WG and SGR of the rockfish fed the diets replacing 10% of the FM with CPC improved linearly with elevated JMM inclusion. Thus, incorporating 60% of JMM into the diets substituting 10% of the FM with CPC was the most recommended strategy according to the growth performance and FC of the rockfish, providing the highest EPI for fish farmers. Full article

To assess the status of Coilia nasus resources in the Yangtze River Estuary and support evaluation of fishing ban effectiveness, this study integrated fishery resource survey data and environmental variables collected from 2023 to 2025. A generalized additive model (GAM) was applied to examine post-ban recovery patterns of C. nasus and the environmental drivers shaping its spatiotemporal distribution. The results revealed pronounced seasonal variation in biomass, with autumn (November) values significantly higher than those in spring and summer. Biomass peaked in autumn 2024, forming a persistent and highly concentrated aggregation. Spatial analyses further indicated that high-biomass areas were consistently distributed within the brackish-water mixing zone of the outer estuary, corresponding to migratory pathways and foraging requirements of the species. GAM results demonstrated that the spatiotemporal distribution of C. nasus was jointly regulated by multiple environmental factors. In spring, temperature, depth, transparency, pH, dissolved oxygen (DO), and chlorophyll-a (Chl-a) exerted significant effects; in summer, salinity and pH were the dominant drivers; and in autumn, temperature, pH, salinity, DO, ammonium (NH₄⁺–N), nitrate (NO₃⁻–N), and phosphate (PO₄³⁻–P) showed significant influences. This study provides scientific evidence to support the management of C. nasus resources, particularly in the brackish-water mixing zone of the outer Yangtze River Estuary, and to improve evaluation of fishing-ban effectiveness. Full article

Integrated multitrophic aquaculture (IMTA) emerges as a sustainable strategy to control the excess of solids and inorganic nutrients that tend to increase in the biofloc system (BFT) cycle, since the model integrates organisms from different trophic levels sharing the same system and nutrients. Thus, this study compared a Penaeus vannamei monoculture system with an integrated biofloc system including Mugil liza, Holothuria grisea, Crassostrea tulipa, and Salicornia neei, focusing on water quality and the performance of organisms and systems. This study consisted of three monoculture systems (16 m³; 375 shrimp m⁻³) and three IMTA systems, composed of a shrimp tank (16 m³), a mullet tank (4 m³; 30 ind m⁻³), a combined tank (3 m³) for oysters (45 ind m⁻³) and sea cucumbers (3 ind m⁻²), and a Salicornia neei bed (2.78 m²; 37 ind m⁻²). All IMTA systems operated in recirculation without water exchange, using 10% of the established biofloc inoculum. The IMTA system had half the hydrated lime use (2.13 vs. 4.29 kg), lower solids (299.56 vs. 373.33 mg L⁻¹), and reduced sludge production (9.37 vs. 15.87 kg). Shrimp growth was similar in both systems. Mullet grew adequately with a survival rate of 95.8%, but oysters showed a survival rate of 45.7%. Sea cucumber had a survival rate of 100% until day 28, when a marked decline appeared, strongly correlated with rising temperature (>28 °C; r = −0.71). This resulted in a significant increase in solids in the last weeks, suggesting that the population decline reduces solids control capacity. Furthermore, the biofloc in IMTA was dominated by coccoid forms, with lower proportions of filamentous and cyanobacterial forms. Full article

Understanding the chronic thermal acclimation capacity of chum salmon (Oncorhynchus keta) is essential for predicting species resilience and developing mitigation strategies under ocean warming. We investigated the upper limit of chronic thermal acclimation and its underlying molecular mechanisms in chum salmon smolts exposed to four constant temperatures (10, 14, 18, and 22 °C) for 6 weeks. Transcriptional responses of genes related to cellular stress protection, endocrine feedback regulation, antioxidant defense, metabolic regulation (AMPKα and mTOR), and protein degradation were quantified in the liver, skeletal muscle, and brain. Chronic exposure to elevated temperature elicited tissue-specific molecular responses, with the most pronounced effects observed at 22 °C. At this temperature, all tissues showed marked induction of heat shock proteins and ubiquitin, accompanied by suppression of antioxidant defenses, glucocorticoid receptor signaling, and AMPKα–mTOR-mediated metabolic regulation, particularly in the liver and muscle. These responses were consistent with previously reported impairments in growth performance, lipid reserves, and hematological indices from the same growth trial. In contrast, smolts maintained at 18 °C exhibited molecular signatures indicative of effective physiological compensation without severe cellular stress. Collectively, these results indicate that chum salmon smolts can acclimate to chronic warming up to 18 °C, whereas exposure to 22 °C exceeds their acclimation capacity and induces a tertiary stress response. Full article

This study investigated the characterization and application of organoclay formulations in a chemoautotrophic biofloc system. Organoclays were produced using the calcination method and bentonite, chitosan, corn, and tapioca starches as ingredients. Thermogravimetric analysis confirmed the high thermal stability of bentonite, whereas biopolymers (tapioca, chitosan, and corn starch) exhibited greater thermal sensitivity and a lower residual mass. Scanning electron microscopy revealed that organoclays had increased porosity (4–21 µm) compared to bentonite, while energy-dispersive spectroscopy confirmed the retention of key chemical elements. X-ray diffraction and Fourier-transform infrared spectroscopy indicated structural modifications due to thermal processing. In aqueous conditions, bentonite and organoclays disaggregated into particles with sizes between 0.76 and 1.24 μm. Based on these physicochemical properties, three formulations were selected for nitrification trials due to their stability in water, O1 (bentonite + tapioca), O2 (bentonite + tapioca + chitosan), and O6 (bentonite + corn starch), along with a 100% bentonite treatment and a control group (C) supplemented with inorganic salts and artificial Needlona^® substrates. All treatments achieved full nitrification within 37 days, with O1 exhibiting the best performance by maintaining ammonia and nitrite levels within safe thresholds. These findings suggest that organoclays, particularly O1, can enhance nitrification stability, providing a promising strategy for water quality management in intensive aquaculture systems. Full article

Extreme natural disasters raise a fundamental question for biologically rigid food production systems: does post-disaster productivity recovery stem from technological change or from adaptive reorganization within existing constraints? In inland aquaculture, where biological processes, fixed production cycles, and capital requirements severely limit short-run technological upgrading, this distinction is particularly critical. Using two post-earthquake time points (2023 and 2025), the analysis documents productivity and efficiency patterns rather than causal recovery trajectories. Accordingly, the analysis is explicitly descriptive and does not attempt to identify causal recovery mechanisms or long-run productivity dynamics. Adaptive efficiency is not directly measured in this study; rather, the term is used as an interpretative construct to describe efficiency changes that are consistent with adaptive behavior under post-disaster constraints. This study examines productivity patterns observed during the post-earthquake period in inland trout aquaculture following the 6 February 2023 earthquake in Eastern Türkiye, with a particular focus on adaptive efficiency as a recovery-consistent mechanism. Using a balanced panel of 290 inland trout farms observed during the immediate post-earthquake adjustment period (2023) and a subsequent recovery phase (2025), the analysis integrates bias-corrected Data Envelopment Analysis, Malmquist productivity decomposition, and resilience-oriented truncated regression. Recovery dynamics are examined conditional on farm survival, allowing within-farm adaptive adjustment to be distinguished from exit-driven selection effects. The results indicate that productivity recovery was driven predominantly by improvements in technical efficiency, while technological change remained close to unity across provinces, suggesting short-run production frontier stability. This pattern is consistent with delayed or constrained investment behavior under heightened uncertainty rather than with technological stagnation. This interpretation is not unique and should be read as one plausible mechanism among several, rather than as a definitive explanation of observed frontier stability. Farms primarily restored performance through operational reorganization, input coordination, and scale adjustment within existing biological and technological constraints, rather than through innovation. Second-stage results further show that the coefficient on access to liquidity is positive, while higher mortality rates and greater distance to markets are systematically associated with weaker post-disaster adjustment. Overall, the findings indicate that short- to medium-term productivity patterns in biologically rigid inland aquaculture systems are governed primarily by efficiency changes consistent with adaptive efficiency rather than technological change. From a policy perspective, post-disaster aquaculture recovery strategies should prioritize liquidity support, biological continuity, and operational stability over premature technology-push interventions. The analysis is based on two post-disaster observation points (2023 and 2025), which allows identification of short- to medium-term recovery-consistent patterns but does not permit causal or long-run inference. Full article

Offshore aquaculture requires net cages that remain stable under strong currents and during submersion and emergence operations. In this study, we proposed a submersible net cage structure equipped with vertical buoyancy columns as an alternative to the conventional horizontal floating-frame cage and evaluated its stability using a net geometry and load analysis system (NaLA system). Model-scale cages were tested in a recirculating flume tank at two current velocities, and the three-dimensional cage geometry was reconstructed using the multicamera through direct linear transformation method to validate the simulated cage inclination. The NaLA system accurately reproduced the measured geometry and time-varying inclination. After validation, stability was compared over a range of current velocities by tracking the cage inclination during the emergence phase. When mooring lines were attached to the top of the cage, the conventional floating-frame cage exhibited a smaller inclination than the buoyancy-column cage. However, relocating the mooring attachment point on the columns significantly improved the stability; attaching the moorings near the bottom of the columns generated the smallest final inclination and yielded a higher stability than the conventional cage. The buoyancy columns can outperform those of conventional designs when paired with an appropriate mooring configuration, thus offering a promising structure for applications under harsh offshore conditions. Full article

Marine copepods are an essential live feed for the culture of many marine ornamental fish and other finfish species, yet their production is frequently constrained by contamination from free-living ciliates. To address this challenge, the efficacy of three disinfectants (sodium hypochlorite, iodine, and hydrogen peroxide) was evaluated for ciliate removal in cultures of two copepod species, Parvocalanus crassirostris and Oithona colcarva. Appropriate ranges of disinfectant concentrations and exposure durations were identified through a preliminary trial assessing the toxicity to Euplotes spp. over a 5-min period. Subsequent experiments tested three doses of each disinfectant to quantify ciliate removal success and egg hatch rates for each copepod species. Ciliate presence/absence showed no variation (100% in controls, 0% after disinfection), precluding statistical analysis except for one variable iodine trial, which was analyzed using Fisher’s Exact Test. Hatch and recovery rates were analyzed using binomial GLMMs with treatment as a fixed effect and replicate as a random effect, with Tukey-adjusted pairwise comparisons and α = 0.05. Sodium hypochlorite and hydrogen peroxide consistently removed all ciliates across tested concentrations, whereas iodine only achieved complete removal at the highest dose. The effects on hatch rate differed between species, with hydrogen peroxide producing the highest hatch rates in P. crassirostris (approximately 44 to 46% at 50–100 g/L for one minute) and sodium hypochlorite supporting the highest hatch in O. colcarva (up to 92% at 250 mg/L for one minute). These findings demonstrate that disinfectant performance is species-specific and that species-specific disinfection protocols are warranted to improve the reliability of copepod production in marine aquaculture. Full article

This study evaluated the effects of different frozen concentrated microalgal feeds and their mixtures on the growth, digestive enzyme activity, biochemical composition, and metabolomic profiles of adult Manila clams, Ruditapes philippinarum, aiming to optimize feeding strategies for clam aquaculture. Clams were fed four diets: single species of Chlorella pyrenoidosa, Isochrysis galbana 3011, or Chaetoceros muelleri, and a mixed combination. Results showed that clams fed with C. muelleri exhibited the highest specific growth rate (p < 0.05). Digestive enzyme activities varied significantly, with the highest lipase activity observed in the I. galbana group and the highest amylase activity in the C. muelleri group (p < 0.05). Biochemical composition analysis indicated that C. muelleri supported higher glycogen storage (p < 0.05), while I. galbana increased free fatty acid content (p < 0.05). Metabolomic profiling revealed that different microalgae influenced metabolic networks, particularly lipid, amino acid, and energy-related pathways. Under the experimental conditions, C. muelleri appeared to be a more effective single-species diet for supporting growth and nutritional status in adult clams, providing useful insights for developing practical bivalve feeding strategies. Full article

Investigating the impact of factor mobility (FM) on the economic efficiency of marine fisheries (EEMF) holds scientific reference value for promoting the high-quality development of the marine fisheries economy in China’s coastal regions. This study is based on panel data from 11 coastal provinces and municipalities in China, covering the period from 2008 to 2023. Utilizing Tobit models and mediation effect models, it empirically analyzes the direct and indirect impacts of FM on the EEMF, as well as the regional heterogeneity of these effects. Research findings indicate that (1) the level of FM and the EEMF in coastal regions both exhibit fluctuating upward trends, although regional variations exist across different provinces. (2) FM in coastal regions enhances the EEMF. For every additional unit of FM, the EEMF increases by 0.0825 units. (3) Technological innovation levels and industrial structure upgrading serve as key pathways through which FM influences the EEMF, acting as mediating variables. (4) This impact exhibits regional heterogeneity, with the Eastern Marine Economic Circle being the most significantly affected. The research findings expand the scope of studies on FM and the EEMF, providing practical advice for promoting the optimal allocation of factors in coastal regions and enhancing EEMF development. Full article

Bait costs constitute 40–50% of the total expenditure in river crab aquaculture, highlighting the critical need for accurately assessing crab growth and scientifically determining optimal feeding regimes across different farming stages. Current traditional methods rely on periodic manual sampling to monitor growth status and artificial feeding platforms to observe consumption and adjust bait input. These approaches are inefficient, disruptive to crab growth, and fail to provide comprehensive growth data. Therefore, this study proposes a machine vision-based monitoring system for river crab feeding platforms. Firstly, the Contrast Limited Adaptive Histogram Equalization (CLAHE) algorithm is applied to enhance underwater images of river crabs. Subsequently, an improved YOLOv11 (You Only Look Once) model is introduced and applied for multi-target detection and counting in crab ponds, enabling the extraction of information related to both river crabs and bait. Concurrently, underwater environmental parameters are monitored in real-time via an integrated environmental information sensing system. Finally, an information processing platform is established to facilitate data sharing under a “detection–processing–distribution” workflow. The real crab farm experimental results show that the river crab quality error rate was below 9.57%, while the detection rates for both corn and pellet baits consistently exceeded 90% across varying conditions. These results indicate that the proposed system significantly enhances farming efficiency, elevates the level of automation, and provides technological support for the river crab aquaculture industry. Full article

The bactericidal permeability-increasing protein (BPI) and lipopolysaccharide binding protein (LBP) are fundamental to innate immunity. However, their functional diversity and evolutionary conservation in ecologically crucial invertebrates, such as oysters, remain largely understudied. In this study, we identify and characterize a novel homolog of BPI/LBP, designated as ChBPI/LBP in the Hong Kong oyster (Crassostrea hongkongensis). Through structural and phylogenetic analysis, we identify ChBPI/LBP as a distinct member of the BPI protein family, with a high isoelectric point (pI of 9.26), indicating potent cationic BPI-like bactericidal function. We found that ChBPI/LBP is constitutively highly expressed at mucosal sites such as the gills and is rapidly upregulated in hemocytes following a challenge with Aeromonas hydrophila. Recombinant ChBPI/LBP demonstrated potent and specific bactericidal activity against Gram-negative pathogens. These findings suggest that ChBPI/LBP is an important antimicrobial peptide (AMP) effector in the oyster’s immune response. This work provides novel perspectives on the evolutionary mechanisms of innate immunity in bivalves and may have implications for disease management in aquaculture. Full article

This review examines the status, challenges, and future trajectories of global mussel aquaculture within the blue food system. Despite steady production growth, mussels’ relative contribution to total bivalve output has significantly declined over recent decades due to disproportionate expansion of oyster, clam, and scallop sectors. A major geographical production shift has occurred, with Asia, spearheaded by China, emerging as the dominant region, supplanting traditional European producers while the Americas rapidly ascend. China’s overwhelming dominance in overall bivalve production starkly contrasts with its underdeveloped mussel sector, where growth lags behind other bivalves despite substantial absolute increases, reflecting a fundamental restructuring of species composition. The industry faces interconnected sustainability constraints: persistent vulnerabilities in spat supply stemming from environmental variability, hatchery limitations, and disease transmission risks; escalating environmental stressors including climate change impacts, harmful algal blooms, pollution, and pathogens; structural flaws in value chains characterized by fragmented production, market volatility, and underutilized byproducts; and governance challenges related to spatial access and licensing inefficiencies. This review advocates for a comprehensive strategy to boost the mussel aquaculture. These encompass advancing hatchery technology and genetic breeding programs, implementing ecosystem-based management such as multi-trophic systems and AI-enhanced environmental monitoring, restructuring value chains through producer cooperation and high value product diversification, and establishing science-based spatial planning frameworks with streamlined governance. Addressing these challenges holistically is critical to position mussel farming as a resilient pillar of sustainable blue food production capable of reconciling ecological integrity with economic viability and social equity. Full article

Heavy metal contamination poses concerns for managing Twaite shad (Alosa fallax) populations, yet data remain sparse. Intermittent capture as bycatch, with negligible prospects for post-release survival and IUCN Red listing, provides a compelling case for investigation. Concentrations of six trace metals (As, Cd, Cr, Cu, Pb and Zn) in the dorsal muscle tissue of A. fallax from the Curonian Lagoon (Lithuania) and the Elbe Estuary (Germany) were analyzed to evaluate size-related patterns and compliance with international safety standards. Overall, metal levels were uniformly low, with Cd and Pb below EU limits. Cu exhibited a weak negative correlation with fish weight (ρ = −0.35; p < 0.05), while Zn tended to increase in larger individuals, reflecting its essential physiological role. Comparing both adult populations, Cr and Zn, which provide nutritional benefits, were higher in the Curonian Lagoon, whereas toxic As and Pb were higher in the Elbe Estuary. All concentrations complied with EU and FAO thresholds, indicating acceptable risk for human consumption. The findings provide baseline information for A. fallax as a potential bioindicator. Constraints on the number of A. fallax sampled, given its IUCN status, exclusion of Hg and lack of environmental parameters, limit conclusions, but would be mostly remediable by future research. Full article

The leopard coral grouper (Plectropomus leopardus), an economically important marine fish, is widely farmed in Hainan Province, China. However, intensive farming has led to frequent disease outbreaks, including viral nervous necrosis, vibriosis, and enteritis, with skin ulceration a widespread and significant concern. To identify the pathogen causing skin ulceration, we collected diseased fish from Hainan and conducted histopathological and ultrastructural analyses, parasite examination, viral metagenomic sequencing, and bacterial isolation and identification. The histopathological analysis and ultrastructural observation showed that the diseased P. leopardus displayed marked pathological alterations, with significant hepatic degeneration and necrosis and splenic structural disorganization. Parasites and viruses were both excluded from being the primary pathogen. A total of 79 bacterial strains were isolated from diseased P. leopardus liver tissue, including Vibrio harveyi (38 strains, 48.1%), Vibrio owensii (17 strains, 21.5%), Vibrio rotiferianus (16 strains, 20.3%), and Photobacterium damselae subsp. damselae (8 strains, 10.1%). Infection experiments suggested that all four bacterial species could induce skin ulceration. This study demonstrates that skin ulceration in P. leopardus is associated with multiple bacterial pathogens, refining the previous view that attributed the disease solely to V. harveyi. These findings provide a foundation for developing vaccines and disease-resistant breeding strategies. Full article

The development of effective vaccines is a critical step in effective disease management in aquaculture. This study introduces a novel Multiepitope Chimeric Vaccine (MCV) designed to enhance immunity in lumpfish against Vibrio anguillarum, Aeromonas salmonicida, Yersinia ruckeri, Moritella viscosa and Piscirickettsia salmonis. Epitopes from major toxins and virulence factors were selected to construct the MCV in silico. Structural validation showed 96.7% of residues in favored regions, confirming stability. Codon optimization yielded a G+C content of 54.61% and a Codon Adaptation Index (CAI) of 1, indicating strong expression potential in Escherichia coli. Immune simulations predicted robust B- and T-cell responses, suggesting induction of both humoral and cell-mediated immunity. Experimental vaccination of lumpfish (n = 35/group) with E. coli-expressed MCV led to significantly elevated IgM levels at four- and six-weeks post-vaccination (p ≤ 0.05, p ≤ 0.01, respectively). Upon pathogen challenge, vaccinated groups showed delayed mortality against V. anguillarum, A. salmonicida, and P. salmonis, though survival differences were not statistically significant across treatments. These results highlight the immunogenicity potential of the MCV and its capacity to elicit targeted immune responses. However, further optimization is necessary to improve protective efficacy and survival outcomes. This study lays a foundation for the application of multiepitope vaccines in lumpfish aquaculture and supports ongoing efforts toward sustainable disease control strategies. Full article