Search Results (17)

The large yellow croaker (Larimichthys crocea) is one of China’s most economically important marine fish species, with its cage culture production leading the nation for many years. However, the rapid expansion of aquaculture has brought challenges such as germplasm degradation, reduced disease resistance, inconsistent product quality, and low adoption of improved strains, which have hindered the sustainable development of the industry. The primary objective of this review is to summarize the current practices and challenges in seedling selection for L. crocea. The secondary objectives include discussing the influence of genetic, physiological, and environmental factors on growth performance and proposing future research directions for sustainable breeding programs. This review covers key topics including morphological screening, growth performance evaluation, genetic diversity conservation, disease resistance improvement, and adaptation to environmental stress. It also explores the application of modern technologies such as marker-assisted selection, intelligent monitoring, environmental control, precision feeding, and disease prevention. Moreover, it highlights core issues in current breeding practices, such as over-reliance on single-trait selection and insufficient integration of environmental adaptability and disease resistance. Finally, future trends are discussed, emphasizing the integration of genomic tools with artificial intelligence to promote intelligent, precise, and sustainable breeding approaches. These insights aim to enhance aquaculture productivity while supporting long-term ecological balance and industry sustainability. Full article

This study evaluated the effects of different lipid sources—fish oil (FO), soybean oil, rapeseed oil, and palm oil—on the growth and muscle quality of golden pompano (Trachinotus ovatus) cultured in offshore cages for 10 weeks. Three diets (D1–D3) were formulated: D1 used only fish oil, D2 blended fish, rapeseed oil, and palm oil, and D3 combined fish and soybean oils. Fish in the D1 group showed the highest weight gain, specific growth rate, and muscle protein content, significantly outperforming D3. No significant differences in muscle lipid content or edible quality were found between groups. D1 had the highest levels of long-chain and n-3 polyunsaturated fatty acids (PUFA), while D3 had higher n-6 PUFA. Saturated and monounsaturated fatty acids were higher in D1 and D2 than in D3. Muscle volatiles like aldehydes and amines were elevated in D1, with more pleasant flavors compared to D2 and D3. Muscle texture was superior in D2. These results suggest that rapeseed and palm oils can enhance growth, flavor, and texture in fish on low FO diets, offering a sustainable alternative to reduce reliance on marine-based feed in aquaculture. Full article

Photobacterium damselae subsp. Piscicida (PDP), a marine bacterium, has been reported to infect a variety of economically important marine species worldwide. Understanding the occurrence and pathogenicity of PDP is crucial for effective disease control and ensuring the success of aquaculture operations. In late August 2023, an epidemic outbreak of P. damselae subsp. piscicida DQ-SS1, accompanied by significant mortality, was recorded in cage-cultured black rockfish (Sebastes schlegelii) located on Daqin Island for the first time. Genomic analysis revealed that DQ-SS1 possesses 2 chromosomes, with a total size of 4,510,445 bp and 3923 predicted CDSs. Pathogenic genes analysis identified 573 and 314 genes related to pathogen–host interactions and virulence, respectively. Additionally, DQ-SS1 displayed susceptibility to 15 antimicrobials, was resistant to 11 antimicrobials, and was intermediately sensitive to four antibiotics. Meanwhile, the in vitro assay revealed that the extracellular products (ECP) of DQ-SS1 were lethal to macrophages and exhibited hemolysin, lipase, and amylase activities. Moreover, DQ-SS1 also demonstrated the ability to survive in fish serum and resist complement-mediated killing. The in vivo assay showed that the infected fish exhibited severe histopathological alterations, such as the infiltration of inflammatory cells, cellular degeneration and necrosis, and loose cell aggregation. Lastly, the in vivo infection assays revealed the LD₅₀ of DQ-SS1 was 1.7 × 10³ CFU/g. This is the first study to elucidate the pathogenicity and genomic characteristics of multidrug-resistant PDP in cage-cultured S. schlegelii, which contributes to the advancement of diagnostic and preventative strategies for this disease in marine-cultured fishes and provides information for an in-depth study of the pathogenic mechanism of PDP. Full article

Aquaculture and tourism can both be important industries for economic development, particularly in isolated geographies endowed with natural beauty. However, spatial conflict can arise, particularly along scenic coastlines, such as that in Oban, Scotland. This area is notable for the frequent overlap between marine tours and cage culture sites, with tours passing by or near these aquaculture locations. This study aims to understand whether tourists who encounter aquaculture operations during these tours have positive attitudes toward aquaculture–tourism integration, which refers to the favourable perception and acceptance of the coexistence of aquaculture and tourism activities, and whether this exposure influences their intention to consume locally farmed aquatic products. A face-to-face survey was conducted to recruit 200 tourists who experienced marine tours in Oban, Scotland. Hierarchical cluster analysis identified three types of tourists based on tourism motivation: (1) Multiple motivations, (2) “Relaxers”, and (3) “Outgoing nature enthusiasts”. Among the three tourist segments, the “Relaxers” were particularly unfamiliar with the concept of farming aquatic food. In general, the majority of tourists were positive about being exposed to aquaculture during marine tours. The results of the structural equation modelling analysis indicated that attitudes towards being exposed to aquaculture during marine tours mediate the relationship between attitudes towards aquaculture and the intention to eat locally farmed aquatic food. Motivational tourism factors, socialisation, and learning positively and significantly influenced attitudes towards being exposed to aquaculture during marine tours. Compared to age, gender, education, income, and travel frequency, only tourists’ dietary patterns significantly influenced behavioural intention. The findings suggest that aquaculture might serve as a potential site for social knowledge exchange, which might be crucial not only for tourism to be successful but also for promoting aquaculture’s social acceptability. The results can be used to inform policymakers, marketers, and aquaculture/tourism practitioners to promote sustainable aquaculture tourism in Scotland or similar sites where tourism and aquaculture coexist. Full article

This study examined the survival rates of Anadara broughtonii and Chlamys farreri with varying heights throughout winter and summer aquaculture periods under varying ratios of mixed-culture conditions in marine environments. The aim was to assess the viability and economic advantages of mixed-culture practices among different bivalve species. Results indicate that the winter (from December to February of the following year) mortality rate for A. broughtonii in mixed culture ranges from 12.04% to 16.85%, markedly lower than in single-species cultures. Mixed-culture A. broughtonii measuring 2.5–4.0 cm exhibit a significantly reduced summer (from July to September) mortality rate compared to those in single-species cultures (p < 0.05). No significant mortality difference was observed between the monoculture and polyculture of C. farreri. Growth rates of C. farreri and A. broughtonii showed no significant differences between monoculture and polyculture conditions. The optimal size for combining two different species of bivalves is 2.5 cm, with a 1:1 ratio being the most effective. An equal number of seedlings were cultivated across various seawater aquaculture systems for a period of one year. The survival rates of monoculture seedlings of Anadara broughtonii and Chlamys farreri were 60.34% and 86.55%, respectively. In contrast, polyculture seedlings exhibited higher survival rates after one year of mariculture, with Anadara broughtonii at 73.36% and Chlamys farreri at 89.74%. The polyculture of A. broughtonii and C. farreri in suspension cages demonstrates a favorable input–output ratio of 1:2.02. This approach effectively reduces winter and summer mortality rates of A. broughtonii, representing an efficient new method for marine bivalve aquaculture. Full article

The cage method for the cultivation of the seaside scallop Mizuhopecten yessoensis is the most developed and popular method at sea farms in Primorsky Krai (Sea of Japan). However, this method of mollusk cultivation requires the careful planning of farming activities. Recently, mariculture farms in different countries have often encountered the mass mortality of cultured hydrobionts. The causes of such diseases are not quite clear, and often their identification requires a large amount of time and financial expenditure. Therefore, the use of predictive mechanisms based on biomarkers can help identify hidden threats in cultured scallop organisms that lead to mass mortality. In this study, we propose a rapid diagnostic method for predicting the distant mass mortality of M. yessoensis cultured in cages using biomarkers. The assessment of the pathological state of cultured mollusks at earlier developmental stages using the DNA comet method and oxidative stress markers (malondialdehyde) will allow the diagnosis and prediction of significant losses of marketable individuals in marine farms. In this study, we evaluated different age groups of mollusks cultured in the different water areas of Peter the Great Bay (Sea of Japan). During the study, we found that the death of cultured mollusks increased with increasing DNA damage and the active accumulation of malondialdehyde in tissues. It was observed that in scallops aged 1+ cultured in Severnaya Bay, high levels of DNA molecule damage and malondialdehyde were registered in the digestive glands and gills, which subsequently led to the death of almost all marketable individuals aged 3+. Therefore, the work is of significant value in assisting the aquaculture industry in solving the emerging problems of scallop farming and preserving marketable products. The proposed markers effectively reflect the condition of molluscs under extreme conditions caused by various factors, making them highly suitable for monitoring studies and forecasts on aquaculture farms. Full article

Red seabream iridovirus (RSIV) is a major cause of marine fish mortality in Korea, with no effective vaccine available since its first occurrence in the 1990s. This study evaluated the efficacy of a formalin-killed vaccine against RSIV in rock bream under laboratory and field conditions. For the field trial, a total of 103,200 rock bream from two commercial marine cage-cultured farms in Southern Korea were vaccinated. Farm A vaccinated 31,100 fish in July 2020 and monitored them for 18 weeks, while farm B vaccinated 30,700 fish in August 2020 and monitored them for 12 weeks. At farm A, where there was no RSIV infection, the vaccine efficacy was assessed in the lab, showing a relative percentage of survival (RPS) ranging from 40% to 80%. At farm B, where natural RSIV infections occurred, cumulative mortality rates were 36.43% in the vaccinated group and 80.32% in the control group, resulting in an RPS of 54.67%. The RSIV-infectious status and neutralizing antibody titers in serum mirrored the cumulative mortality results. This study demonstrates that the formalin-killed vaccine effectively prevents RSIV in cage-cultured rock bream under both laboratory and field conditions. Full article

Spotted sea bass (Lateolabrax maculatus) is a high-economic-value aquacultural fish widely distributed in the coastal and estuarine areas of East Asia. In August 2020, a sudden outbreak of disease accompanied by significant mortality was documented in L. maculatus reared in marine cage cultures located in Nanhuang island, Yantai, China. Two coinfected bacterial strains, namely, NH-LM1 and NH-LM2, were isolated from the diseased L. maculatus for the first time. Through phylogenetic tree analysis, biochemical characterization, and genomic investigation, the isolated bacterial strains were identified as Vibrio harveyi and Photobacterium damselae subsp. piscicida, respectively. The genomic analysis revealed that V. harveyi possesses two circular chromosomes and six plasmids, while P. damselae subsp. piscicida possesses two circular chromosomes and two plasmids. Furthermore, pathogenic genes analysis identified 587 and 484 genes in V. harveyi and P. damselae subsp. piscicida, respectively. Additionally, drug-sensitivity testing demonstrated both V. harveyi and P. damselae subsp. piscicida exhibited sensitivity to chloramphenicol, ciprofloxacin, ofloxacin, orfloxacin, minocycline, doxycycline, tetracycline, and ceftriaxone. Moreover, antibiotic resistance genes were detected in the plasmids of both strains. Extracellular product (ECP) analysis demonstrated that both V. harveyi and P. damselae subsp. piscicida can produce hemolysin and amylase, while V. harveyi additionally can produce caseinase and esterase. Furthermore, infected fish displayed severe histopathological alterations, including infiltration of lymphocytes, cellular degeneration and necrosis, and loose aggregation of cells. Artificial infection assays determined that the LD₅₀ of P. damselae subsp. piscicida was 3 × 10⁵ CFU/g, while the LD₅₀ of V. harveyi was too low to be accurately evaluated. Furthermore, the dual infection of V. harveyi and P. damselae subsp. piscicida elicits a more rapid and pronounced mortality rate compared to single challenge, thereby potentially exacerbating the severity of the disease through synergistic effects. Ultimately, our findings offer compelling evidence for the occurrence of coinfections involving V. harveyi and P. damselae subsp. piscicida in L. maculatus, thereby contributing to the advancement of diagnostic and preventative measures for the associated disease. Full article

Mariculture offers enormous potential for providing sustainable food, playing a key role in achieving nutrition security, employment, and Blue Growth. This is particularly true in geographical areas where the dependence of local economies on fishery products is high and yet access to sustainable landings is hindered by environmental drawbacks. One such area is represented by the Black Sea, which offers different degrees of suitability for aquaculture development. While the southern and eastern shores are sheltered enough to allow for the development of large aquaculture activities, the north-western shoreline is characterized by wide environmental fluctuations and the strong influence of the Danube. This study aimed at investigating the suitability of a selected area of the Romanian coast (Mangalia) for finfish cage farming by adapting an internationally endorsed methodology for determining its Degree of Compatibility (DC). The development and expansion of finfish aquaculture depends on the availability of space, so designating Allocated Zones for Aquaculture (AZAs) is essential. The result obtained (DC = 80) indicates that the Mangalia area is suitable for finfish aquaculture activities: there is no major interference with other uses of the maritime space, no conflicts with nature conservation, and the environmental conditions are appropriate for fish culture in floating cages. The novel information provided by this study can be the building block for authorities to settle the governance gap that has so far impeded the development of marine aquaculture in Romania. At a larger scale, this study can serve as a good practice example at the regional Black Sea level. Full article

Vibrio spp. are important aquaculture pathogens that cause vibriosis, affecting large numbers of marine fish species. This study determines the field efficacy of a feed-based inactivated vaccine against vibriosis in cage-cultured Asian seabass. A total of 4800 Asian seabass, kept in a field environment, were separated equally into two groups (vaccinated and non-vaccinated) in duplicate. Fish of Group 1 were orally administered the feed-based vaccine on weeks 0 (prime vaccination), 2 (booster), and 6 (second booster) at 4% body weight, while the non-vaccinated fish of Group 2 were fed with a commercial formulated pellet without the vaccine. Fish gut, mucus, and serum were collected, the length and weight of the fish were noted, while the mortality was recorded at 2-week intervals for a period of 16 weeks. The non-specific lysozyme activities were significantly (p < 0.05) higher in the fish of Group 1 than the non-vaccinated fish of Group 2. Similarly, the specific IgM antibody levels in serum and mucus were significantly (p < 0.05) higher in Group 1 than in Group 2, as seen in the second week, with the highest level 8 weeks after primary immunization. At week 16, the growth performance was significantly (p < 0.05) better in Group 1 and showed lower bacterial isolation in the gut than Group 2. Despite the statistical insignificance (p > 0.05), the survival rate was slightly higher in Group 1 (71.3%) than Group 2 (67.7%). This study revealed that feed-based vaccination improves growth performance, stimulates innate and adaptive immune responses, and increases protection of cultured Asian seabass, L. calcarifer, against vibriosis. Full article

Iridoviruses are an important pathogen of ectothermic vertebrates and are considered a significant threat to aquacultural fish production. Recently, one of the most economically important marine species in China, the large yellow croaker (Larimichthys crocea), has been increasingly reported to be the victim of iridovirus disease. In this study, we isolated and identified a novel iridovirus, LYCIV-ZS-2020, from cage-cultured large yellow croaker farms in Zhoushan island, China. Genome sequencing and subsequent phylogenetic analyses showed that LYCIV-ZS-2020 belongs to the genus Megalocytivirus and is closely related to the Pompano iridoviruses isolated in the Dominican Republic. LYCIV-ZS-2020 enriched from selected tissues of naturally infected large yellow croaker was used in an artificial infection trial and the results proved its pathogenicity in large yellow croaker. This is the first systematic research on the genetic and pathogenic characterization of iridovirus in large yellow croakers, which expanded our knowledge of the iridovirus. Full article

Fish consumption is on the increase due to the increase in growth of the global population. Therefore, taking advantage of new methods such as marine aquaculture can be a reliable source for the production of fish in the world. It is necessary to allocate suitable sites from environmental, economic, and social points of view in the decision-making process. In this study, in order to specify suitable areas for marine aquaculture by the Ordered Weighted Averaging (OWA) methodology in the Caspian Sea (Iran), efforts were made to incorporate the concept of risk into the GIS-based analysis. By using the OWA-based method, a model was provided which can generate marine aquaculture maps with various pessimistic or optimistic strategies. Eighteen modeling criteria (14 factors and 4 constraints) were considered to determine the appropriate areas for marine aquaculture. This was done in 6 scenarios using multi-criteria evaluation (MCE) and ordered weighted average (OWA) methodologies. The results of the sensitivity analysis showed that most of the parameters affecting the marine aquaculture location in the region were as follows: Social-Economic, Water Quality, and Physical–Environmental parameters. In addition, based on Cramer’s V coefficient values for each parameter, bathymetry and distance from the coastline with the most effective and maximum temperature had the least impact on site selection of marine aquaculture. Finally, the final aggregated suitability image (FASI) of weighted linear combination (WLC) scenario was compared with existing sites for cage culture on the southern part of the Caspian Sea and the ROC (Relative Operating Characteristics) value turned out to be equal to 0.69. Although the existing sites (9 farms) were almost compatible with the results of the study, their locations can be transferred to more favorable areas with less risk and the mapping risk level can be controlled and low- or high-risk sites for marine aquaculture could be determined by using the OWA method. Full article

The fatty acid compositions of the fish muscle and liver are substantially affected by rearing environment. However, the mechanisms underlying this effect have not been thoroughly described. In this study, we investigated the effects of different culture patterns, i.e., marine cage culture and freshwater pond culture, on long-chain polyunsaturated fatty acids (LC-PUFA) biosynthesis in an aquaculturally important fish, the Japanese sea bass (Lateolabrax japonicus). Fish were obtained from two commercial farms in the Guangdong province, one of which raises Japanese sea bass in freshwater, while the other cultures sea bass in marine cages. Fish were fed the same commercial diet. We found that omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA) levels in the livers and muscles of the marine cage cultured fish were significantly higher than those in the livers and muscles of the freshwater pond cultured fish. Quantitative real-time PCRs indicated that fatty acid desaturase 2 (FADS2) transcript abundance was significantly lower in the livers of the marine cage reared fish as compared to the freshwater pond reared fish, but that fatty acid elongase 5 (Elovl5) transcript abundance was significantly higher. Consistent with this, two of the 28 CpG loci in the FADS2 promoter region were heavily methylated in the marine cage cultured fish, but were only slightly methylated in freshwater pond cultured fish (n = 5 per group). Although the Elovl5 promoter was less methylated in the marine cage reared fish as compared to the freshwater pond reared fish, this difference was not significant. Thus, our results might indicate that Elovl5, not FADS2, plays an important role in the enhancing LC-PUFA synthesis in marine cage cultures. Full article

In the rapid development of marine aquaculture, the water quality of aquatic environments is regarded as a main limiting factor. Therefore, it is necessary to assess the water quality and environmental conditions in marine aquaculture areas and find out the main influencing factors regarding damage to the water quality environment. In the present research, pond aquaculture and cage aquaculture areas were sampled in May, August and November in 2018. Nine water quality indicators were detected, including pH, temperature, salinity, dissolved oxygen, molybdate-reactive phosphorus, chemical oxygen demand, chlorophyll a, inorganic nitrogen and antibiotic resistance genes (ARGs). Principal component analysis (PCA) was used to analyze the water quality conditions, spatial–temporal changes, and the driving factors in pond and cage aquaculture areas. The results showed that three main components were extracted from the pond aquaculture area, which explained 66.82% of the results, the most relevant factors are salinity, dissolved oxygen and ARGs. For the cage aquaculture area, three main components were extracted which can account for 72.99% of the results, the most relevant factors are chlorophyll a, salinity and dissolved oxygen. The comprehensive scores of the principal components indicated that the heaviest polluted months in pond and aquaculture areas were August and November, respectively. The water quality of the pond aquaculture area is mainly limited by the volume of the pond, while aquaculture activities and seasonality are the main factors for cage aquaculture. ARGs in cage culture areas showed more variety and frequency compared with pond culture areas, which indicated that terrestrial input might be one of the sources for ARGs occurrence. The results would be helpful for the relevant authorities to select water quality monitoring parameters in marine aquaculture areas. Full article

Coastal zones support fisheries that provide food for humans and feed for animals. The decline of fisheries worldwide has fostered the development of aquaculture. Recent research has shown that extracellular polymeric substances (EPS) synthesized by microorganisms contribute to sustainable aquaculture production, providing feed to the cultured species, removing waste and contributing to the hygiene of closed systems. As ubiquitous components of coastal microbial habitats at the air–seawater and seawater–sediment interfaces as well as of biofilms and microbial aggregates, EPS mediate deleterious processes that affect the performance and productivity of aquaculture facilities, including biofouling of marine cages, bioaccumulation and transport of pollutants. These biomolecules may also contribute to the persistence of harmful algal blooms (HABs) and their impact on cultured species. EPS may also exert a positive influence on aquaculture activity by enhancing the settling of aquaculturally valuable larvae and treating wastes in bioflocculation processes. EPS display properties that may have biotechnological applications in the aquaculture industry as antiviral agents and immunostimulants and as a novel source of antifouling bioproducts. Full article