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Recirculating Aquaculture System (RAS) is introduced in aquaculture farming industry to reduce water resource utilization, efficient the energy and land uses, and also help minimalize the water exchange. This system enables utilization of unsuitable land and promotes a sustainable environment in aquaculture industry. Furthermore, this technology has been established and proved efficient in monitoring the aquatic animal condition subsequently helps in maintaining the water quality and help remove solid particle wastes from the aquaculture treatment. As today, RAS has been developed with more effective technologies such as the use of UV irradiation, solid capture, protein skimmer and also provided with highly techno bio-filtration set. Basically, this system was applied for broodstock maturation, nursery phase, and grow-out production. In this review article, we provide an overview of RAS between the clear water, probiotic, and biofloc technology, and the advantages of its combination. Even though RAS and biofloc is two different parallel system, the application of the probiotic and biofloc in the semi-RAS application system is intense to be investigated. The synergistic effect of RAS using this combination towards high yield aquaculture production will be highlighted in this review paper. Expectantly this review paper will generate awareness and useful information on the RAS application in the aquaculture system operation with help in maximize the impact to the aquaculture yield production.

Simvastatin (SIM), a commonly prescribed drug for lowering serum-lipid, has been detected in many aquatic environments. Exposure to high concentrations of SIM in rats and aquatic organisms resulted in toxicity to hepatocytes and negative effects on development. However, there is a paucity of studies on the effects of long-term exposure to low concentrations of SIM on aquaculture species. This study aimed to analyze the effects of environmentally relevant concentrations (0.1 μg/L and 1 μg/L) of SIM exposure for two months on developing Mozambique tilapias. Surprisingly, the growth of male tilapias was enhanced after a 2-month SIM exposure. The analysis of testis histology revealed that after the SIM exposure, the development of the testis was delayed, and sperm production was reduced. Sequencing of testis transcriptomes showed that the exposure to SIM altered the expression of many genes related to the development of testes and spermatogenesis. These data suggest that a 2-month exposure to environmentally relevant concentrations of increases the growth of male tilapias by inhibiting sexual development of males.

Aquaculture, while offering significant contributions to global food security, generates substantial amounts of industrial waste, posing environmental and economic challenges. However, this waste also presents untapped potential for innovation in gastronomy. This paper explores the emerging trend of utilizing aquaculture industrial wastes in culinary practices, aiming to reduce waste, promote sustainability, and create novel gastronomic experiences. Through a review of literature and case studies, we examine various methods for repurposing aquaculture waste, including upcycling into new food products, incorporation into culinary dishes, and extraction of valuable components. Additionally, we highlight successful initiatives that have integrated aquaculture waste into gastronomy, emphasizing the benefits of waste reduction, sustainable food practices, and culinary innovation. Challenges such as food safety, taste, and consumer acceptance are acknowledged, with strategies proposed for addressing these issues. Finally, we discuss future directions for research and development in this field, identifying opportunities for collaboration between the aquaculture industry and the gastronomy sector. By exploring the utilization of aquaculture industrial wastes in gastronomy, this paper contributes to a deeper understanding of sustainable food practices and culinary creativity in the context of aquaculture waste management.

Kuhli loach (Pangio kuhlii) a popular ornamental freshwater fish species with economic potential, originating from Sumatra, Kalimantan, Java, and Malaysia. The kuhli loach's appeal lies in its vibrant colors and distinctive eel-like body. This study aims to explores the sexual primary and secondary characteristics of the kuhli loach. Conducted at Universitas Airlangga in Banyuwangi, Indonesia, the study involved a thorough analysis of 50 kuhli loaches, evenly split between males and females. Morphological observations revealed significant differences (p < 0.05), such as the elongated body and expanded abdominal region in females, suggesting adaptations for reproduction. Internal examinations, including peritoneal dissections and histological analysis, unveiled distinct stages of spermatogenesis in males and ovarian development in females, providing insights into the reproductive cycle. Meristic and morphometric analyses identified noteworthy differences in pectoral fin rays, suggesting potential roles in reproductive behavior, while other traits exhibited similarity between genders. This study contributes to the understanding of kuhli loach ecology and reproductive biology, highlighting the importance of addressing sustainability concerns arising from the continuous exploitation of wild populations. This study serves as a foundational step towards advancing reproductive improvement in fish and supports the conservation of this unique ornamental fish species, with implications for aquaculture practices and economic considerations.

The stress level of vannamei shrimp (Litopenaeus vannamei) is affected by increased density and several genes are expressed under the condition. This study aimed to determine the expression of genes encoding white shrimp stress after density treatment and the infectious myonecrosis virus (IMNV) challenge test. A completely randomized design (CRD) was carried out with 6 treatment groups, i.e. 3 different stocking density groups without IMNV infection (100, 200, and 400 shrimp/m2) and 3 different stocking density groups + IMNV infection (100, 200, and 400 shrimp/m2). In addition, a shrimp density of 400 shrimp/m2 reported the fastest rate of developing the IMNV virus as seen from the clinical symptoms. The lowest cumulative number of shrimp deaths was at a density of 100 shrimp/m2 and was caused by the IMNV virus confirmed through RT-PCR. Expression of stress-coding genes was divided into upregulated and downregulated characteristics. The upregulated genes were lectin and translationally controlled tumor protein (TCTP), while the downregulated gene was Toll Receptor. The results showed that the expression of genes related to immunity in L. vannamei was upregulated after pathogen challenges such as lectin and TCTP, meanwhile, the Toll receptor gene was downregulated. Further study should also be performed to measure the expression of the three genes in revealing the immune pathways.

The primary line of defense against pathogens from the environment is often fish epidermis tissue. Nevertheless, little is understood about the physiological mechanisms that underlie the non-specific and/or specific protection that these cells can offer. The exact nature of the relationship between the evolution of ostariophysan fish club cells and chemical warning signals is still unknown and controversial. Fish epidermis layer cells comprise mucus cells, lymphocytes, macrophage cells, cuboidal and squamous epithelial cells, and cells specific to certain fish species. Club cells, also called "alarm cells," are chemical alarms that sound in the event of a potentially hazardous scenario. These cells will burst in the presence of a predator, releasing pheromones that, if the skin is physically damaged, trigger an avoidance and terror reaction. In sturgeon larvae, mucus cells were visible in week 1, but club cells did not appear until week 4. Due to their later development during ontogenesis and after wounding, club cells may not have as much of a protective effect during wound healing as filament or mucus cells. Club cells are mostly found in the epidermis of the skin, and it is thought that when they work in tandem with mucus and goblet cells to fight infections, they serve as the body's first line of defense.

Fish productivity has long been the subject of studies using traditional Chinese medicine (TCM). To validate TCM's effectiveness on weight gain rate (WGR) and specific growth rate (SGR), a meta-analysis study was conducted. Of the 58 studies collected from PubMed, Scopus, and Cochrane Library, 4 eligible studies were analyzed quantitatively. The extracted data were then analyzed using Review Manager (RevMan) online to determine the standard mean difference (SMD), random effect, heterogeneity, and 95% confidence intervals (95% CI). As a result, TCM administration had a favorable effect on WGR (SMD = 8.33; p = 0.0001) and SGR (SMD = 8.12; p = 0.0004). In conclusion, this meta-analysis study emphasized the efficacy of TCM to improve fish production performance.

Fish farmers struggle with the problem of fish mortality due to climate change, poisoning, and bad water quality. Estimates on the mortality of fishes ranges from 60% to 80% depending on the type of fish. Traditional approaches in monitoring the quality of water such as observation or laboratory testing prove to be costly and time-consuming. This study aims to develop a portable water quality monitoring kit for fish farms. The device allows users to monitor the water's dissolved oxygen, nitrogen, total dissolved solids, turbidity, temperature, and pH level. It is powered by a rechargeable battery, uses an Arduino microcontroller, and has a real-time alert system. The device's limitations include the battery life and the sensors will need to be recalibrated at least monthly to ensure the accuracy of the readings. However, the results show that the implementation of the device garnered high acceptability in all parameters in the evaluation with a total mean rating of 4.66. This implies that the device can be used in monitoring the water quality in aquaculture sectors as corroborated by the respondent's evaluation. It is recommended to enhance the device by adding more water quality sensors and integrating Internet of Things (IoT) capabilities to further improve its functionality and reliability.

Purpose. To create a general bibliographic list of English-language scientific publications devoted to the peculiarities of pikeperch (Sander lucioperca Linnaeus, 1758) reproduction in natural and artificial conditions using various technologies as well as to briefly highlight English-language professional sources, in which the main attention is paid to the specifics of pikeperch development in the first stages of ontogenesis — starting from embryonic development and ending with the age-0+. Methodology. An interdisciplinary approach was used to create this thematic English-language bibliography. Its was based on the practical application of the principles of analytics and systematics. In turn, the limits of applicability of the latter were outlined by holistic and selective methods. The actual bibliographic core consists of sources that are found in the vast majority on the Internet, mostly with free access to the full texts. Findings. A thematic bibliography of 149 English-language sources is included. All of them are placed in alphabetical order by author or title and are drawn in accordance with the requirements of the State Standard of Ukraine (DSTU 8302:2015 “Information and documentation. Bibliographic reference. General provisions and rules of compilation” with amendments — UKND code 01.140.40) and the most common international standard (APA style). The absolute majority of the mentioned sources were published in the last 25 years in well-known international journals(«Aquaculture International», “Aquaculture Report”, “Aquatic Research”, “Biologia”, “Czech Journal of Animal Science”, “Ecology of Freshwater Fish”, “Fish Physiology and Biochemistry”, “Journal of Applied Ichthyology”, “Knowledge and Management of Aquatic Ecosystems”, “North American Journal of Aquaculture”, “Turkish Journal of Fisheries and Aquatic Sciences”, etc.). Practical Value. The presented thematic English-language bibliography can be used in educational, research, organizational and other types of activities related to the reproduction and preservation of aquatic living biological resources in Ukraine and in other countries of the world. The sources given in it will deepen and supplement the knowledge of scientists and producers regarding the peculiarities of reproduction and ontogenesis of pikeperch at the stages from gastrula to the age-0+.

Abstract Background The salmonid pathogen Flavobacterium psychrophilum poses a significant economic threat to global aquaculture, yet our understanding of its genetic and phenotypic diversity remains incomplete across much of its geographic range. In this study, we characterise the genetic and phenotypic diversity of 70 isolates collected from rainbow trout (Oncorhynchus mykiss) and brown trout (Salmo trutta m. fario) from fish farms in the Czech Republic between 2012 and 2019 to compare their genomic content with all draft or complete genomes present in the NCBI database (n = 187). Results The Czech isolates underwent comprehensive evaluation, including multiplex PCR-based serotyping, genetic analysis, antimicrobial resistance testing, and assessment of selected virulence factors. Multiplex PCR serotyping revealed 43 isolates as Type 1, 23 as Type 2, with sporadic cases of Types 3 and 4. Multi-locus sequence typing unveiled 12 sequence types (ST), including seven newly described ones. Notably, 24 isolates were identified as ST329, a novel sequence type, while 22 were classified as the globally-distributed ST2. Phylogenetic analysis demonstrated clonal distribution of ST329 in the Czech Republic, with these isolates lacking a phage sequence in their genomes. Antimicrobial susceptibility testing revealed a high proportion of isolates classified as non-wild type with reduced susceptibility to oxolinic acid, oxytetracycline, flumequine, and enrofloxacin, while most isolates were classified as wild type for florfenicol, sulfamethoxazole-trimethoprim, and erythromycin. However, 31 isolates classified as wild type for florfenicol exhibited minimum inhibitory concentrations at the susceptibility breakpoint. Conclusion The prevalence of the Czech F. psychrophilum serotypes has evolved over time, likely influenced by the introduction of new isolates through international trade. Thus, it is crucial to monitor F. psychrophilum clones within and across countries using advanced methods such as MLST, serotyping, and genome sequencing. Given the open nature of the pan-genome, further sequencing of strains promises exciting discoveries in F. psychrophilum genomics.

This study aimed to evaluate the effects of various plant-derived carotenoid extracts on growth parameters and skin coloration of golden trevally (Gnathanodon speciosus). Five groups of fish were fed diets containing carotenoid sources from the petal extracts of the leopard tree (Caesalpinia ferrea), wild sunflower (Tithonia diversifolia), marigold (Tagetes erecta), yellow bells (Tecoma stans), Wedelia chinensis (Wedelia chinensis), along with a control group, each diet had a carotenoid concentration of 0.25 g/kg feed. The diets were based on the same fundamental ingredients and administered for 56 days. Results showed significant differences in growth parameters among the different diets, with wild sunflower and marigold petal extracts proving most effective in enhancing the skin coloration of golden trevally. High yellow (CIE b*), ranging from 17.2 to 18.8, were observed (Minolta CR-400), compared to only 12.2 ± 0.34 in the control group. Additionally, the carotenoid content in the tissue of the various groups differed significantly (p < 0.05), with the highest level of carotenoids (71.2 ± 2.9 µg/g tissue) detected in the fish skin of the dietary marigold flower group (UV-visible spectrophotometry). It is suggested that the petals of wild sunflowers and marigolds can efficiently improve body pigmentation and growth performance in golden trevally, indicating that these plant-derived carotenoids may have potential applications in aquaculture.

Aquaculture and waste valorization have the potential to show solid achievements toward food security and improvements in the circularity of resources, which are crucial aspects of achieving a sustainable lifestyle in agreeance with Agenda 2030 goals. This study aims to optimize and simplify the decision-making processes for the valorization of marine wastes (natural and from aquaculture) as secondary raw materials to produce high-value-added market goods. However, significant concentrations of pollutants may be present within wastes, compromising overall quality, and social dynamics can hinder their usage further. Goro’s lagoon was chosen as a case study, where the relations between the ecosystem services, a thriving bivalve economy, and social dynamics are deeply rooted and intertwined. Therefore, in the manuscript cost–benefit and foresight analyses are conducted to determine the best usage for algal biomass considering pollution, social acceptance, and profitability. These analyses are virtually conducted on bio-refineries that could be operating in the case study’s area: briefly, for a thirty-year running bio-plant, the CBA indicates the two best alternatives with an income of 5 billion euros (NPV, with a 5% discount rate) for a biofuel-only production facility, and a half for a multiproduct one, leading to the conclusion that the first is the best alternative. The foresight, instead, suggests a more cautious approach by considering external factors such as the environment and local inhabitants. Hence, the main innovation of this work consists of the decision-maker’s holistic enlightenment toward the complexities and the hidden threats bound to this kind of closed-loop efficiency-boosting process, which eventually leads to optimized decision-making processes.

Abstract The present study aimed to determine the anaesthetic effectiveness, safety, and applicable concentrations of coriander (Coriandrum sativum) essential oils (CEO) for three-spotted tilapia (Oreochromis andersonii). For this purpose, CEO concentrations of 400, 500, and 600 µL/L were tested at two temperatures, 20.90 ± 1.19 °C and 30.60 ± 0.92 °C, on three different sizes (small, medium, and large) of the fish in duplicate glass aquaria with 200 mg/L of tricaine methanesulfonate (MS-222) served as the control. The sedative efficacy during simulated transportation experiments was also carried out. The results demonstrated that the induction and recovery time in O. andersonii anaesthetised with CEO were significantly influenced by concentration, water temperature, and fish size (P

This paper analyzes the factors influencing households’ resilience capacities to shocks within Kenya’s fisheries and aquaculture sectors and draws from primary data collected from 419 fish-dependent households across Kisumu, Busia, Mombasa, and Kilifi counties. The sample represents a total of 48,000 fishing households. The study adopted a quasi-longitudinal design and computed the household resilience capacity index (RCI) using the resilience index measurement and analysis (RIMA-II) model. The results indicate that male-headed households’ mean household RCI scores (mean = 45.07 ± 10.43) were statistically significant to that of female-headed households (mean = 38.15 ± 9.25), suggesting that female-headed households are associated with lower resilience capacities than male-headed households. Moreover, the study identifies differences in resilience levels across various occupations within the sector. For instance, RCI scores among fish traders (mean = 40.71 ± 9.97), a function performed mainly by women, statistically differed (p < 0.005) from male-dominated cage farming (mean = 48.60 ± 10.47), whereas RCI scores at the production level for fisher folks (mean = 44.89 ± 10.09) and pond farmers (mean = 44.04 ± 12.07) showed no statistical difference (0 > 0.05. Additionally, households with more income sources tend to have higher resilience capacities. Seasonality in fishing cycles limited households’ ability to recover from climate-induced shocks; the more months without fishing activity, the less the odds of recovery from shocks (OR = 0.532, 95% CI [0.163, 0.908], p = 0.022). Furthermore, households that lacked guaranteed market access and inputs during COVID-19 were less likely to recover during and after the shocks (OR = 0.401, 95% CI [0.161, 0.999], p = 0.05). Households organized in cooperatives with better access to credit showed a higher chance of recovery. The study recommends (a) adopting gender-sensitive approaches in fisheries and aquaculture interventions to empower women in trade, (b) strengthening policies to enhance access and adoption of climate-smart technologies such as cage fish farming, (c) promoting livelihood diversification to sustain households’ income during fishing off-seasons, and (d) enhancing market linkages in the fish value chain through coordinated producer organizations. Further research should explore the possibilities of introducing index-based weather insurance and other tested suitable safety nets for the fisheries and aquaculture sector.

This study compared the effects of three supplementary diets—egg yolk, Artemia, and commercial pellets with 48% crude protein—on the growth performance and survival rate of redbreast tilapia (Coptodon rendalli) under intensive culture conditions at the Kamutjonga Inland Fisheries Institute in the Kavango East region of Namibia. The study was conducted from December 2023 to January 2024 using a complete randomized design replicated thrice. Results showed that fish fed with commercial pellets exhibited the highest specific growth rate (1.39 ± 0.80%) compared to egg yolk (0.94 ± 0.54%) and Artemia (0.33 ± 0.19%). Commercial pellets also had the best survival rate (76.19 ± 43.099), compared to egg yolk and Artemia (70.47 ± 40.69; 33 ± 19.05), respectively. However, egg yolk had the best feed conversion ratio (0.20 ± 0.05) compared to the commercial pellets (0.22 ± 0.04) and Artemia (0.26 ± 0.07). Critical water quality parameters were maintained within acceptable survival ranges for C. rendalli across all treatments. These findings highlight the importance of dietary protein content in optimizing the growth and survival of C. rendalli under intensive culture conditions and provide insights for effective feeding strategies. However, commercial pellets are expensive and inaccessible to small-scale fish farmers. As an alternative, egg yolk emerged as a viable and affordable feed option, promoting fish growth and supporting the establishment of small-scale farming practices in the region.

This study evaluated the anaesthetic potential of clove basil (Ocimum gratissimum) essential oil (EO-OG) in the post-larvae (PLs) of M. rosenbergii. The PLs were individually transferred to aquariums (500 mL) containing 50, 100, 150, 200, or 300 μL L−1 EO-OG. A sixth group of PLs was exposed to freshwater only, and a seventh group was exposed to the highest concentration of ethanol used to dilute EO-OG. Upon reaching the anaesthesia stage, the PLs were transferred to aquariums (500 mL) with freshwater only to evaluate the recovery time. The shortest sedation times were observed at 200 (15.98 s) and 300 μL L−1 (25.85 s). The shortest anaesthesia time was observed at 200 μL L−1 (22.52 s). The longest recovery time was observed at 100 μL L−1 (1367.10 s); the shortest recovery time was observed at 150 μL L−1 (630.10 s). No mortality or adverse effects were observed in any experimental group. The concentration of 150 μL L−1 resulted in sedation (49.24 s), anaesthesia (80.10 s), and recovery (630.10 s) times within those suggested as adequate for freshwater prawn farming. This research demonstrated the sedative and anaesthetic properties of EO-OG and its potential application in prawn farming. This study recommends using 150 μL L−1 of EO-OG in M. rosenbergii PLs.

Tiger puffer is a commercially important fish cultured in high-density environments, and its accurate detection is indispensable for determining growth conditions and realizing accurate feeding. However, the detection precision and recall of farmed tiger puffer are low due to target blurring and occlusion in real farming environments. The farmed tiger puffer detection model, called knowledge aggregation YOLO (KAYOLO), fuses prior knowledge with improved YOLOv5 and was proposed to solve this problem. To alleviate feature loss caused by target blurring, we drew on the human practice of using prior knowledge for reasoning when recognizing blurred targets and used prior knowledge to strengthen the tiger puffer's features and improve detection precision. To address missed detection caused by mutual occlusion in high-density farming environments, a prediction box aggregation method, aggregating prediction boxes of the same object, was proposed to reduce the influence among different objects to improve detection recall. To validate the effectiveness of the proposed methods, ablation experiments, model performance experiments, and model robustness experiments were designed. The experimental results showed that KAYOLO's detection precision and recall results reached 94.92% and 92.21%, respectively. The two indices were improved by 1.29% and 1.35%, respectively, compared to those of YOLOv5. Compared with the recent state-of-the-art underwater object detection models, such as SWIPENet, RoIMix, FERNet, and SK-YOLOv5, KAYOLO achieved 2.09%, 1.63%, 1.13% and 0.85% higher precision and 1.2%, 0.18%, 1.74% and 0.39% higher recall, respectively. Experiments were conducted on different datasets to verify the model's robustness, and the precision and recall of KAYOLO were improved by approximately 1.3% compared to those of YOLOv5. The study showed that KAYOLO effectively enhanced farmed tiger puffer detection by reducing blurring and occlusion effects. Additionally, the model had a strong generalization ability on different datasets, indicating that the model can be adapted to different environments, and it has strong robustness.

Abstract In the past decade, the increasing distribution of pollutants in the aquatic environment has been observed, causing integrative effects on fish. Likewise, due to anthropogenic activities, the southern gulf of Lake Tana is an impacted region, and the production of Nile tilapia fish is reduced. For this reason, the aim of this study was to conduct a histopathological-based study of 48 Nile tilapia fishes’ health status at the southern gulf of Lake Tana and aquaculture using a cross-sectional study from February 2023 to May 2023. The study evaluated the histopathology of the gill, liver, gonads, and spleen organs using descriptive statistics accompanied by a 2 × 2 contingency table and t-test analysis. During the study, different histological alterations were detected, and the numbers of fish affected by a specific histological alteration were presented as percentage prevalence; hence, from the total fish examined, hyperplasia (54.15%), followed by pigment deposits (52%), hemorrhage (50%), and immune cell infiltration (50%), respectively, were the most frequently detected alterations. However, Nile tilapias from the southern gulf of Lake Tana were 1.4 (odds ratio) times more likely to show histopathological alterations than those from aquaculture, although statistically, was not significant (p > 0.05). In addition, the study found the mean value of the fish index (95.3) and regressive indices of the gill (13.6), liver (14.8), and gonad (12.3); moreover, the inflammatory indices of the spleen organ (11.3) and mean severity grade value of the gill (2.35) and gonad (1.7) organs, respectively, were obtained from the southern gulf of Lake Tana, and all those values were significantly higher (p

Abstract Background Livestock and aquaculture feed rely heavily on cereals, fish meal, and plant proteins, but these ingredients are not fully utilized by animals, and alternative protein sources are needed due to rising demand, unstable resources, and high prices. However, plant-based materials contain phytic acid or phytate, making phosphorus less available to monogastric animals. Bacterial phytases can effectively release phosphorus from phytate in the digestive system, making them cost-effective and a potential alternative to traditional sources of phosphorus. Probiotics are helpful bacteria that have long been employed in food production and health-related products. Bioengineered probiotics are utilized to express and transmit native or recombinant molecules to the digestive tract's mucosal surface, thereby improving feed efficiency and health. Therefore, this study aimed to use a biologically engineered probiotic supplement containing phytase enzyme-producing lactic acid bacteria as a feed additive for livestock, poultry, and fish to address this issue. Results The study involved multiple steps to engineer Lactobacillus lactis to produce the PHY protein for animal feed. These steps include identifying and designing primers for the phy gene, and phy gene was extracted from the pMNA1 plasmid by colony PCR and cloned in L. lactis, confirming the presence of the PHY protein through SDS-PAGE, and harvesting the product in granular form. The phy gene identified and isolated using PCR and inserted it into L. lactis, confirming the presence of the PHY protein through SDS-PAGE. The resulting product was harvested and used as animal feed for livestock, poultry, and fish. Conclusions The development of biologically engineered probiotic supplements containing phytase enzyme can enhance the nutritional value and sustainability of animal production. More research and development in this field can lead to more effective and sustainable animal production practices, benefiting both producers and consumers of animal products.

Abstract This study investigated a disease outbreak characterized by caligid copepod infestations and subsequent secondary bacterial infections in European seabass (Dicentrarchus labrax) and flathead grey mullet (Mugil cephalus) cultivated at a private facility in the Deeba Triangle region of Egypt. Moribund fish displayed brown spots on the skin, tongue, and gills, along with lethargy and excess mucus. The fish suffered severe infections, exhibiting external hemorrhages, ulcers, and ascites. The fish had pale, enlarged livers with hemorrhaging. Comprehensive parasitological, bacteriological, molecular, immunity and histopathological analyses were conducted to identify the etiological agents and pathological changes. Caligid copepod infestation was observed in wet mounts from the buccal and branchial cavities of all examined fish, and the caligids were identified as Caligus clemensi through COI gene sequencing and phylogenetic analysis. Vibrio alginolyticus was confirmed as a secondary bacterial infection through biochemical tests, recA gene sequencing, and phylogenetic analyses. Antibiotic susceptibility testing revealed resistance to β-lactams, aminoglycosides, and trimethoprim-sulfamethoxazole in V. alginolyticus isolates. Upregulation of the inflammatory marker IL-1β in gill and skin tissues indicated a robust cell-mediated immune response against the pathogens. Histopathological examination revealed severe tissue damage, hyperplasia, hemorrhage, and congestion in the gills, along with hepatocellular degeneration and steatosis in the liver, providing initial insights into this outbreak. A comprehensive therapeutic regimen was implemented, comprising prolonged hydrogen peroxide immersion baths, followed by the application of the nature-identical plant-based compound Lice-less and probiotic Sanolife Pro-W supplementation. This integrated approach effectively eliminated C. clemensi infestations, controlled secondary bacterial infections, and restored fish health, reducing morbidity and mortality rates to minimal levels.

Protein deficiency is a major difficulty for human needs in the past few decades, while different types of aquatic species are rich in high quality protein. Therefore, aquaculture is considered as the main developing food production sector globally. Bacterial infections are the main problem for aquaculture, and their outbreaks have a great impact on productivity, and previously indiscriminate use of antibiotics to control them. However, the emergence of multidrug-resistant pathogens might lead to sudden infectious disease outbreaks resulting in serious economic loss. Immunostimulants application is an effective technique to protect and enhance the immune system of aquatic animals and therefore improve aquaculture production. Nutrient immunostimulants such as essential fatty acids, amino acids, vitamins, and minerals are the most important responsibility to improve aquaculture production, as well as the cost of this method, which is effective, non-toxic, and environment friendly. These nutrient immunostimulants are supportive to increase the immune system, antioxidant, anti-inflammatory, and infection resistance of aquatic animals. In addition, nutritional feed additives improved feed palatability and the excellence of aquatic products and also enhance gut functions. Some information is available on nutrient immunostimulants in aquaculture applications, and this review provides information on different kinds of nutritional administration used in aquaculture to enhance positive impacts on aquatic animals’ health as well as feed quality development. This review will provide theoretical references for the application of nutrient immunostimulants in aquatic feeds.

The effects of different dietary lipid levels on lipid accumulation, inflammatory response, serum bio-chemical index and histological features of intestine and hepatopancreas of O. macrolepis was experimentally evaluated in an eight-weeks study. Fish (initial weight 50.11 ± 2.86 g) were fed with five iso-nitrogenous diets (around 390 g/kg protein) varying with lipid level (5%, 7%, 9%, 11%, 13%, being LL5, LL7, LL9, LL11, and LL13 respectively) in triplicates. Results showed that the content of crude lipid in carcass and hepatopancreas were not affected by dietary lipid levels (P > 0.05). Serum ALT, TP, HDL-c and MDA, etc., were not significantly affected by diets (P > 0.05), while serum total antioxidant capacity in LL9 and LL11 groups were significantly higher than the other groups (P 0.05), while the height of intestine villus showed the higher trend in LL9 compared with other groups. The relative expression of lipid metabolism related genes (ppar α, cpt-1α, fas, and hsl) and immune response related genes (tlr 22, nrf 2, tnfα, and il-γ) in the hepatopancreas of fish fed diets differing in their crude lipid levels were not significantly different (P > 0.05). The results suggested that a proper dietary lipid level of 9%–11% could maintain higher antioxidant and health status of adult O.macrolepis.

With the continuing development of the aquaculture industry, the stress associated with many environmental factors has severely restricted the growth of fish, reduced fish resistance to disease, and had a large negative impact on fishery production. Therefore, it is of great importance for the sustainable development of aquaculture to cultivate new fish varieties with strong stress resistance. Traditional hybridization and gynogenesis, selective breeding, modern breeding techniques such as molecular marker-assisted breeding and whole genome selection breeding can be used to develop efficient and accurate fish breeding strategies, and to cultivate new fish varieties with high stress resistance. This paper reviews the status of research on fish breeding for disease resistance, cold resistance, high temperature tolerance, hypoxia tolerance, salt tolerance, saline-alkali tolerance as well as non-specific stress resistance traits, analyzes trends in research on fish breeding for stress tolerance, and explores future development directions. Furthermore, this paper proposes new ideas for fish seed industry innovation to promote its continuous and sustainable development.

Seaweed aquaculture is becoming increasingly important as the global seaweed market is set to exceed £20 billion by 2030, leaving natural populations at risk of overexploitation. Fucoids, such as Fucus serratus, are intertidal seaweeds hand-harvested for their use in agricultural, pharmaceutical, and biomedical industries. Despite many aspects of the biology of fucoids being well researched, there have been very few studies on their aquaculture. In this study, we grew F. serratus biomass from gamete life stages in the Queen’s University Marine Laboratory for 8 months and monitored their growth, amino acid and phenolic contents in a subtidal field trial. Gametes of F. serratus were successfully fertilized in vitro and attached to substrata: Tiles (mesocosm) and Dyneema Twine (subtidal). The growth of F. serratus on each substrate was monitored for 6 months in the laboratory facility with juveniles reaching 2–4 mm in length. The juveniles on twine were then deployed at the Strangford Lough test site and growth was compared against the juveniles on tiles after an additional two months. Prior to field deployment, individuals grown on tiles were significantly longer (~17%) than those on twine growing to ~3 cm, however, after the two-month deployment, the twine thalli grew significantly longer than those on the tiles (~33%) reaching ~6 cm in length. Subtidal F. serratus grown on twine had significantly higher amino acid content, whereas the phenolic content was significantly lower (~62 mg PGE g−1) than seaweed grown on the tiles (~128 mgPGE g−1). Growing F. serratus successfully in subtidal areas is highly important for providing sustainably sourced biomass to reduce reliance on wild harvesting. Further, cultivating in the subtidal zone will help to avoid competition for space from other aquaculture industries operating in the intertidal zone.

Knowledge of amoxicillin (AMX) pharmacokinetics (PK) and tissue residues in fish, which is necessary for prudent drug use, remains limited. The study aimed to explore the PK characteristics of AMX in Nile tilapia (Oreochromis niloticus) reared at 25 and 30 °C as well as to determine optimal dosages and drug withdrawal time (WDT). In the PK investigation, the fish received a single dose of 40 mg/kg AMX via oral gavage, and the optimal dosage was determined by the pharmacokinetic-pharmacodynamic approach. In the tissue residue study, the fish were orally gavaged with 40 mg/kg/day AMX once daily for 5 days and the WDT was established by the linear regression analysis. The results revealed the temperature-dependent drug elimination; the clearance relative to bioavailability (CL/F) and elimination half-life at 30 °C (0.180 L/kg/h and 6.06 h, respectively) were about twice those at 25 °C (0.090 L/kg/h and 10.49 h, respectively). The optimal dosages at the minimum inhibitory concentration (MIC) of 2 μg/mL were 10.97 (25 °C) and 41.03 (30 °C) mg/kg/day, respectively. Finally, following the multiple oral administration, the muscle/skin residue of AMX on day 1 after the last dosing at 25 and 30 °C were 548 and 264 ng/g, respectively. The average tissue residues were depleted below the maximum residue limits (MRL) of 50 μg/kg on day 5 (25 °C) and 3 (30 °C), respectively, and the WDT were 6 and 4 days when rearing at 25 and 30 °C, respectively. This knowledge serves as a practical guideline for responsible use of AMX in treating bacterial diseases in Nile tilapia aquaculture.

ABSTRACTRussia’s full-scale war on Ukraine in early 2022 has brought geopolitics, particularly classical geopolitics, back into the political and economic discussions and decision-making. Discursive, as well as real-world change, has been rapid, as the turn of the 21st century was the time of globalisation and neoliberal ideology – the free movement of people, products, and services. However, in this paper, we argue that classical geopolitics has defined the development of Northern industries even before the war began in 2022. Our interview data (n = 60) collected in the advent of the Russian invasion of Ukraine reveal that the themes of state power; ‘hard’ security meaning military armament; the economy as a field of national interests; and spill-over effects of geopolitical tensions between superpowers have framed economic fortunes in the European Arctic. It is concluded that the state actors’ interests in the European Arctic’s physical space and natural assets will be increasingly expanding.

[Objective] This study aimed to evaluate the antimicrobial efficacy of essential oil (EO) from diverse chemotypes of Lippia graveolens against oxytetracycline-resistant Aeromonas hydrophila, which primarily affects the tilapia aquaculture (O. niloticus) in Guatemala. [Methodology] L. graveolens were collected in three departments in Guatemala. The EO was obtained by hydrodistillation and characterized using gas chromatography and mass spectrometry (GC/MS). Subsequently, an antimicrobial assay was conducted using disk and dilution susceptibility tests and evaluation of synergistic interactions among the chemotypes. Each test was performed in triplicate. [Results] The analysis revealed the presence of twenty-seven compounds in the EO obtained from the chemotypes, with the main class being monoterpenes. The major constituents identified were cis-Dihydro-β-terpineol (8.84%) in chemotype I, carvacrol (51.82%) in chemotype II, and thymol (79.62%) in chemotype III. All EO chemotypes of L. graveolens demonstrated the ability to inhibit the A. hydrophila growth. Thymol chemotype exhibited the strongest inhibitory effect against bacterial growth, with a minimum inhibitory concentration (MIC) of 92.4 µg/mL and a minimum bactericidal concentration (MBC) of 184.8 µg/mL. Furthermore, the results suggest that there is no synergistic or additive effect when combining different chemotypes of L. graveolens. [Conclusions] This is the first report of L. graveolens chemotypes exhibiting antimicrobial activity against oxytetracycline-resistant A. hydrophila. The findings suggest that the chemotype thymol could be a potential treatment for infections in the tilapia aquaculture in Guatemala.

Given the significance of fish farming as a promising sector of Ukraine’s agriculture, and the Mykolaiv, Odesa, and Kherson regions are characterised by a significant number of natural and artificial water bodies, the study of aquatic bioresource catching indicators in the south is both important and timely. The research aimed to determine trends in aquatic bioresource catching in southern Ukraine during the period 2018-2023 and to analyse the factors influencing the extraction of aquatic bioresources. This article presents overall catch statistics, as well as catch data for inland waters of the south and aquaculture conditions over the past six years. It has been established that the catch of aquatic biological resources in southern Ukraine has been declining each year from 2018 to 2023. The negative trends in aquatic bioresource catching, both in aquaculture and natural water bodies, are linked to several factors. In particular, the decline in catches has been influenced by: COVID-19; the unstable military and political situation in Ukraine, associated with Russian military aggression; outdated material and technical base of fishing enterprises; lack of government subsidies and foreign investment in the sector; imperfections in the systems of control and regulation of the extraction of aquatic bioresources; and irrational use of the bioproductive potential of water bodies in southern Ukraine. Based on a scientific analysis of the dynamics of aquatic bioresource extraction in southern Ukraine and the identification of key factors contributing to the decline in catches, a set of measures has been developed to positively impact the fishing industry. These measures include: attracting foreign investment in fish farming; improving the quality of monitoring, regulation, and control over aquatic bioresource catching at local, regional, and state levels; restoring critical fish farming infrastructure damaged by Russian aggression; ensuring sustainable fisheries management; and introducing EU best practices into Ukrainian fish farming. The scientific results obtained from this research can be used in practice to ensure the sustainable development of fisheries in southern Ukraine

As a precise and versatile tool for genome manipulation, the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) platform holds promise for modifying fish traits of interest. With the aim of reducing transgene introgression and controlling reproduction, upscaled disease resistance and reproductive intervention in catfish species have been studied to lower the potential environmental risks of the introgression of escapees as transgenic animals. Taking advantage of the CRISPR/Cas9-mediated system, we succeeded in integrating the cathelicidin gene (As-Cath) from an alligator (Alligator sinensis) into the target luteinizing hormone (lh) locus of channel catfish (Ictalurus punctatus) using two delivery systems assisted by double-stranded DNA (dsDNA) and single-stranded oligodeoxynucleotides (ssODNs), respectively. In this study, high knock in (KI) efficiency (22.38%, 64/286) but low on-target events was achieved using the ssODN strategy, whereas adopting a dsDNA as the donor template led to an efficient on-target KI (10.80%, 23/213). The on-target KI of As-Cath was instrumental in establishing the lh knockout (LH–_As-Cath+) catfish line, which displayed heightened disease resistance and reduced fecundity compared with the wild-type (WT) sibling fish. Furthermore, administration of human chorionic gonadotropin (HCG) and luteinizing hormone-releasing hormone analogue (LHRHa) can restore the reproduction of the transgenic fish line. Overall, we replaced the lh gene with an alligator cathelicidin transgene and then administered hormone therapy to move towards complete reproductive control of disease-resistant transgenic catfish in an environmentally responsible manner. This strategy not only effectively improves consumer-valued traits but also guards against unwanted introgression, providing a breakthrough in aquaculture genetics to confine fish reproduction and prevent the establishment of transgenic or domestic genotypes in the natural environment.

This study aims to analize the meaning, the decision making and the identification of fishery small entreprise investment. The study locates in Tuban Coastal–East Java Indonesia. It employs qualitative methods with case study. The data are collected through semi-structural interview, observation, and documentation. Techniques and time triangulation are used to check the validity of the data. CV. SAM is a fishery business on aquaculture of shrimp (vanname sp) and catfish (clarisas batracus sp), also makes probiotic and vitamins for fishes. The result shows that the entrepreneur interprets an investment as purchasing an asset to operation the entreprise. The owner decides on an investment for the purpose of expanding business and taking opportunity on the potential big market. Nevertheless, the enterprise identification several risks on their business. Firstly, operational risk; there are fish disease and increasing price of the feed and medicine on vanname that decreasing profit. Secondly, market risk; there are rejection or decline of selling price if the quality on low standart especilly for vanname on foreign markets. The entreprise anticipates operational risk by producing probiotics and vitamins for fish. On the market risks, the entrepreneur hasn’t any action to anticipate and to find solution especially for vanname. To develop the fishery small enterprise, the stakeholders need to support them in getting solution.

Technology of feed additive for fry feeding in fish farms is developed to provide both important nutrients (proteins, lipids, etc.) and optimal peptide composition of protein that is achieved using proteolysis of raw materials under certain conditions. For this purpose, enzymatic hydrolysis of substandard small-sized frozen pollock was used. The rational duration of the hydrolysis process was 60 min. that provided the degree of protein hydrolysis of 26–28 %. The experimental fermentolysate was concentrated to a water content of 3–4 % and presented as a feed additive TINRO-60. This product is compared with other feed additives (dried fermentolysates) produced in Russia from fish raw materials using bioconversion, such as Biomarin, Bioprom and Vakhob. General chemical composition of tested products was determined by standard methods of analytical chemistry; composition and content of fatty acids — by gas-liquid chromatography; microand macroelements, as well as toxic metals — by atomic absorption spectrophotometry; fractional composition of proteins and peptides — by high pressure gel permeation chromatography; amino acid composition — by ion exchange chromatography on a high-speed analyzer. All tested samples contain similar amount of the main feed component — protein substances. The quantitative ratio of peptide fractions is also comparable, the sum of the most active fractions (MW 0.1−10.0 kDa) in TINRO-60 and Biomarin is close to their level in tissues of Artemia, natural food for fish fry. The content of essential amino acids, EPA and DHA is significant in Biomarin, TINRO-60 and Bioprom, but almost twice lower in Vakhob. Analysis of mineral composition showed that bioconversion into dry fermentolysates does not cause concentration of toxic elements. High quality of the protein feed additive TINRO-60 produced by bioconversion of nonstandard fish raw materials under certain conditions is proved.

A plant and method of the sea cucumber cultivation have been developed and successfully tested. The technology allows to grow sea cucumber Apostichopus japonicus (Selenka, 1867) from juveniles of the current year to adults of commercial size on grounds in unprotected water areas and bottom landscapes unfavorable for habitat of this species. The plant consisted of 5 open-type cages with the size 20x20x1 m mounted on the sea bottom and occupied the area of 400 m2 each (2000 m2 in total). The tests were carried out from the fall of 2018 to late November 2023. After the first two years, only 20.5 % of initial number of resettled factory juveniles had survived, then the number of sea cucumbers stabilized and their distribution density was on average 2.7 ind./m2 (364.4 g/m2) by the end of the experiment. The stock in the cages was replenished annually by larvae from the natural larval pool that was estimated in 6.9 % per year. Monthly weight gains were on average 2.6 g in the last three years of cultivation, though sea cucumbers grew in 3−4 times slower in winter than in summer. The body weight of sea cucumbers by the end of the experiment was 143.9 g/ind., on average. After 5-year exposition, the portion of commercial-sized sea cucumbers (weight ≥ 130 grams) in the cages reached 58.5 % by number and 74.7 % by biomass; their average body weight was 183.6 g. The density of such sea cucumbers distribution in the bottom open-type cages of the plant was 1.5 ind./m2 (272.2 g/m2), on average. Total yield of commercial-sized sea cucumbers harvested from the plant in late November 2023 was 435 kg.

To study the chemical composition of four species of valuable fish reared in aquaculture conditions in South Vietnam.Individuals of Channa striata, Channa gachua, Oreochromis niloticus, a hybrid of Clarias gariepinus and Clarias macrocephalus were purchased in markets from farmers of cage farms and directly in the farms of Khanh Hoa province. The fish were measured, weighed, and then muscle tissue was dissected for chemical analysis. The water content in the tissue was determined by a two‐stage method for determining moisture, while lipids were determined by the fat‐free residue method in a Soxhlet apparatus. The amount of protein was obtained according to the principle of the Kjeldahl method, using a semi‐automatic distillation unit UDK 139 (Velp Scientifica, Italy, 2011); minerals were determined by the gravimetric method, and carbohydrates – by calculation. The index of physiological state was calculated according to the standard method.Hybrid catfish muscles are characterised as having the greatest nutritional value. In terms of lipid content, the individuals studied belonged to fish with a low fat content, Channa striata, which belongs to the category of lean fish. A high index of physiological state in Oreochromis niloticus was found to be associated with increased water content in muscle tissue. No significant differences were found between the biochemical parameters in the muscles of fish with an increase in body size, and only in Channa striata did the proportion of minerals increase. The data obtained can be used in the organisation of rational feeding and maintenance of aquacultural species.

Introduction: Polychaeta worms from the family Nereididae are widely used as live food to expedite sexual maturation and produce high-quality reproductive gonads in shrimp. This live feed, due to its high content of long-chain unsaturated fatty acids compared to commercial feeds, significantly impacts the gametogenesis process of marine shrimps, leading to increased production and hatching rates. The cultivation of native species presents a suitable solution for sustainable polychaete worm production. This type of production can meet various needs. Materials and Methods: This study aimed to identify and report species from the family Nereididae in the Persian Gulf within the coastal waters of Bushehr province over a period of one year. Polychaete samples were collected at each station using a Van Veen grab sampler. At each station, three sediment samples were taken for the separation and identification of polychaetes, which were immediately rinsed with sea water using a 500-micron sieve installed on board. To identify the species, larger organisms were initially separated using an unarmed eye and magnifying glass. The isolated samples were photographed using a stereomicroscope equipped with a camera and identified using relevant keys. Results: According to the results obtained in this study, 6 species including Perinereis heterodonta, P. nuntia, Perinereis sp., Ceratonereis sp.1, Ceratonereis sp.2 and Nicon sp. belonging to three genera—Perinereis, Ceratonereis, and Nicon—from the family Nereididae were identified in the Persian Gulf. Discussion: Given the vital role of polychaete worms in shrimp reproduction, identifying and utilizing native species from this family can enhance the performance of breeding centers and lead to sustainable development of the aquaculture industry.

Recent interest in scaling commercial kelp industries in Western cultures is juxtaposed by the apparent challenges in achieving more consistent and predictable yields. As such, site-level factors are a dominant and recurring conversation amongst stakeholders. The availability of seawater nitrogen (nitrate, ammonium, total N) can be highly variable across space and time and is often one of the top concerns for site selection and permitting. This study questions the relative importance of nitrogen availability on the yield of Saccharina latissima (sugar kelp) across five commercial farms on the U.S. East and West Coasts over two seasons, highlighting the relative influence of other interacting factors (i.e., farm design). We hypothesized that nitrate would strongly correlate with the harvested yield. Our results show significant spatial and annual variability in the kelp yield and ambient nutrients across and within farms, but with weak covariance. Standard linear regression suggests that seawater nitrogen is a poor explanatory factor for kelp yield, explaining 11.0% of the variation around the mean compared to the line spacing (explaining 26.1%) and the interaction between the total N and the line spacing (explaining 50.0%). Quartile regression, however, suggests that total N alone, is the strongest predictor of a lower threshold in terms of the yield (0.10 quartile, r2 = 0.431) relative to the median (0.50 quartile, r2 0.081). As such, seawater nitrogen may be a more useful metric in predicting baseline kelp yields rather than realized yields, and production above that baseline is likely more dependent on other factors that may or may not interact with seawater nitrogen.

Abstract Background Salmonid species have followed markedly divergent evolutionary trajectories in their interactions with sea lice. While sea lice parasitism poses significant economic, environmental, and animal welfare challenges for Atlantic salmon (Salmo salar) aquaculture, coho salmon (Oncorhynchus kisutch) exhibit near-complete resistance to sea lice, achieved through a potent epithelial hyperplasia response leading to rapid louse detachment. The molecular mechanisms underlying these divergent responses to sea lice are unknown. Results We characterized the cellular and molecular responses of Atlantic salmon and coho salmon to sea lice using single-nuclei RNA sequencing. Juvenile fish were exposed to copepodid sea lice (Lepeophtheirus salmonis), and lice-attached pelvic fin and skin samples were collected 12 h, 24 h, 36 h, 48 h, and 60 h after exposure, along with control samples. Comparative analysis of control and treatment samples revealed an immune and wound-healing response that was common to both species, but attenuated in Atlantic salmon, potentially reflecting greater sea louse immunomodulation. Our results revealed unique but complementary roles of three layers of keratinocytes in the epithelial hyperplasia response leading to rapid sea lice rejection in coho salmon. Our results suggest that basal keratinocytes direct the expansion and mobility of intermediate and, especially, superficial keratinocytes, which eventually encapsulate the parasite. Conclusions Our results highlight the key role of keratinocytes in coho salmon’s sea lice resistance and the diverged biological response of the two salmonid host species when interacting with this parasite. This study has identified key pathways and candidate genes that could be manipulated using various biotechnological solutions to improve Atlantic salmon sea lice resistance.

Abstract Several farmed fish species, including carps, tilapia, salmon, and catfish, have experienced significant economic losses in aquaculture due to motile Aeromonas septicemia caused by Aeromonas hydrophila. In the present study, a novel lytic bacteriophage infecting hypervirulent Aeromonas hydrophila (vAh) was isolated and characterized. This is the first report of a phage against vAh. Phage AhFM11 demonstrated lytic activity against both vAh strains and the A. hydrophila reference strain ATCC 35654. The AhFM11 genome was sequenced and assembled, comprising 168,243 bp with an average G + C content of 41.5%. The genome did not harbor any antibiotic resistance genes. Genomic information along with transmission electron microscopy revealed that phage AhFM11 belongs to the Straboviridae family. Therapeutic application of monophage AhFM11 in fish showed 100% survival in injection, 95% in immersion and 93% in oral feeding of phage top-coated feed. Fish and chicken meat spiked with A. hydrophila and phage showed significant reduction of A. hydrophila. These findings support that phage AhFM11 can be used as a biocontrol agent against vAh as an alternative to antibiotics.

Biofouling constitutes one of the main obstacles in the sector of shellfish farming. Under this perspective, it is of highly importance to critically combine the updated information regarding the invasive potential of ascidian species, together with the factors contributing toward these events. The biological features of each species in relation to the gathering of the main non-indigenous species in the Mediterranean basin represent the first step toward mitigation of negative effects of the phenomenon. Further, there are limited studies investigating the physiological changes of bivalves caused by biofouling while leading to an increase in stress biomarkers. In the present review, the major ascidian species negatively affecting bivalve culture in the Mediterranean Sea are presented, alongside monitoring of ascidians from four Greek mussel farming locations as typical mussel culture cases. Among the main ascidian species, Styela plicata, Clavelina oblonga, Ciona robusta, Aplidium sp., Didemnum sp., Botryllus schlosseri, and Didemnum drachi are included, with the last three being the most harmful for this aquaculture sector. Based on the existing literature and research conducted so far, future research directions are proposed, in an effort to effectively control or efficiently manage ascidian biofouling organisms. Overall, perspectives toward the way we manage the biofouling phenomenon, such as the use of ascidian’s by-products in feedstuffs, chemical and pharmaceutical industry, or their incorporation in bivalve co-culture and integrated multi-trophic aquaculture systems represent promising alternative approaches.

Protein kinases are enzymes involved in essential biological processes such as signal transduction, transcription, metabolism, and the cell cycle. Human kinases are targets for several drugs approved by the US Food and Drug Administration. Therefore, the identification and classification of kinases in other organisms, including pathogenic parasites, is an interesting subject of study. Monogeneans are platyhelminths, mainly ectoparasites, capable of causing health problems in farmed fish. Although some genomes and transcriptomes are available for monogenean species, their full repertoire of kinases is unknown. The aim of this study was to identify and classify the putative kinases in the transcriptomes of two monogeneans, Rhabdosynochus viridisi and Scutogyrus longicornis, and then to predict potential monogenean drug targets (MDTs) and selective inhibitor drugs using computational approaches. Monogenean kinases having orthologs in the lethal phenotype of C. elegans but not in fish or humans were considered MDTs. A total of 160 and 193 kinases were identified in R. viridisi and S. longicornis, respectively. Of these, 22 kinases, belonging mainly to the major groups CAMK, AGC, and TK, were classified as MDTs, five of which were evaluated further. Molecular docking analysis indicated that dihydroergotamine, ergotamine, and lomitapide have the highest affinity for the kinases BRSK and MEKK1. These well-known drugs could be evaluated in future studies for potential repurposing as anti-monogenean agents. The present study contributes valuable data for the development of new antiparasitic candidates for finfish aquaculture.

Abstract Total protein levels in fish are widely used in health and welfare studies, providing a simple and accessible measure. However, the multifaceted role of blood proteins makes it sometimes challenging to link total protein content to specific health issues, while specific protein fractions may offer more precise insights into fish biology and health, particularly in farmed fish species where such data is often lacking. Data were gathered from two experiments involving Dicentrarchus labrax and Sparus aurata, key species in European marine aquaculture. The aim was (1) to assess how different globulin fractions contribute to total protein content in blood and (2) how these contributions vary across different sampling times in healthy animals. In D. labrax, the beta1 globulin fraction emerged as the major contributor (34.16%), followed by albumin and alpha2 globulins (18.24% and 16.41%, respectively). In contrast, pre-albumins and alpha1 fractions had the least contribution (5.49% and 7.71%). S. aurata exhibited albumin as the primary contributor (23.39%), followed by beta1 and alpha2 globulins (19.71% and 19.15%, respectively), with gamma and alpha1 fractions contributing the least (5.34% and 8.63%). Notably, the study revealed relatively stable contributions of globulin fractions to total proteins within both species, albeit with minor variations over time, potentially linked to environmental and individual factors. Furthermore, larger fish displayed higher total protein levels. This research underscores the need for further investigation into the diverse factors influencing globulin contributions to total proteins, ultimately enhancing health and welfare monitoring for farmed fish species.

Abstract Each year, due to climate change, an increasing number of new pathogens are being discovered and studied, leading to an increase in the number of known diseases affecting various fish species in different regions of the world. Viruses from the family Iridoviridae, which consist of the genera Megalocytivirus, Lymphocystivirus, and Ranavirus, cause epizootic outbreaks in farmed and wild, marine, and freshwater fish species (including ornamental fish). Diseases caused by fish viruses of the family Iridoviridae have a significant economic impact, especially in the aquaculture sector. Consequently, vaccines have been developed in recent decades, and their administration methods have improved. To date, various types of vaccines are available to control and prevent Iridoviridae infections in fish populations. Notably, two vaccines, specifically targeting Red Sea bream iridoviral disease and iridoviruses (formalin-killed vaccine and AQUAVAC® IridoV, respectively), are commercially available. In addition to exploring these themes, this review examines the immune responses in fish following viral infections or vaccination procedures. In general, the evasion mechanisms observed in iridovirus infections are characterised by a systemic absence of inflammatory responses and a reduction in the expression of genes associated with the adaptive immune response. Finally, this review also explores prophylactic procedure trends in fish vaccination strategies, focusing on future advances in the field.

The purpose of this study is to evaluate the suitability of land/waters for seaweed farming activities, and analyze the sustainability status of grass business in the coastal area of West Kupang district. The method used in this study was a survey method; respondents were taken as many as 50 people from three sample villages, namely Tablolong, Tesabela and Oenaek villages, West Kupang District. Analysis of land/water suitability for aquaculture using two methods, namely land suitability matrix and weighting, while the sustainability of seaweed farming activities is analyzed statistically multivariate with Multidimensional Scaling (MDS) approach, and Rapid Assessment Techniques for Fisheries (RAPFISH) method. The results of the study found that the area suitable for seaweed cultivation in the study area was in the waters of West Kupang District with very suitable class criteria covering an area of 407.6 ha, appropriate class criteria covering an area of 856.93 ha and inappropriate class criteria covering an area of 2665.78 ha, in general the level of sustainability of seaweed cultivation activities in West Kupang District, Kupang Regency was in the category of quite sustainable, unless the technology dimension falls into the category of less sustainable. It is recommended that more in-depth research be carried out on assessment and addition of dimensions and attributes in the sustainability analysis of seaweed farming activities in order to provide input on more specific management recommendations.

Precision Livestock Farming (PLF) is a mechanism that manages a production system. This mechanism includes mathematical models and controllable inputs that can predict inputs with processes and results that can be monitored periodically. These parameters of PLF systems can improve resource use efficiency and reduce cultivation costs. Many situations, such as the behaviour of animals on farms, their nutrition, estrus cycles, and epidemics, can be monitored with wearable devices containing various sensors. However, real-time monitoring of the data collected by these devices is possible with Internet of Things (IoT) technology. IoT is a multi-layered network that enables sensors within the system to communicate with each other and implement certain decisions when necessary. Sensors and IoT devices extract information from the raw data they collect from the environment, which is then shared with other objects, devices, or servers via the internet. The real-time data collection, processing, and analysis provided by IoT enables improvements in the management of animal farms. This systematic review addresses IoT concepts and applications in the livestock sector from a systematic perspective for different animal farms.

Microplastics are an emerging pollutant of marine environments, affecting fish and other marine biota such as copepods and rotifers. The current study assesses the impact of plastic microbeads on the growth of roho (Labeo rohita) in a 4-month feeding experiment under laboratory conditions. Over a period of 120 days, roho fingerlings were exposed to different concentrations of plastic microbeads (50 mg to 200 mg/kg of feed) mixed into their feed. It was found that the ingestion of plastic microbeads negatively affected the growth of roho and that the concentration of the plastic microbeads directly influenced the growth rate of the fish.

The misuse of antibiotics and the emergence of antimicrobial resistance (AMR) is a concern in the aquaculture industry because it contributes to global health risks and impacts the environment. This study analyzed the AMR of sentinel bacteria associated with striped catfish (Pangasisanodon hypophthalmus) and giant snakehead (Channa micropeltes), the two main fish species reared in the pond culture in Cambodia. Phenotypic and genotypic characterization of the recovered isolates from fish, water, and sediment samples revealed the presence of bacteria, such as 22 species belonging to families Aeromonadaceae, Enterobacteriaceae, and Pseudomonadaceae. Among 48 isolates, Aeromonas caviae (n = 2), Aeromonas hydrophila (n = 2), Aeromonas ichthiosmia (n = 1), Aeromonas salmonicida (n = 4) were detected. A. salmonicida and A. hydrophilla are known as fish pathogens that occur worldwide in both fresh and marine water aquaculture. Antibiotic susceptibility testing revealed antibiotic resistance patterns of 24 (50 %) isolates among 48 isolates with higher multiple antibiotic resistance index (> 0.2). All the isolates of Enterobacteriaceae were susceptible to ciprofloxacin. Ciprofloxacin is a frontline antibiotic that is not recommended to use in aquaculture. Therefore, its use has to be strictly controlled. This study expands our knowledge of the AMR status in aquaculture farms which is very limited in Cambodia. HIGHLIGHTS Antibiotic resistance was found in enteric bacteria and Aeromonas spp. isolated from some Cambodian fish farms.; Some isolates were resistant to more than one antibiotic.; More extensive studies are required to ascertain the risks of antimicrobial resistance to Cambodian aquaculture and consumers.;

Probiotics play an essential role in fish nutrition, significantly contributing to their health and growth in aquaculture. By incorporating beneficial bacterial strains such as Lactobacillus and Bacillus subtilis into feed, the nutritional value of the feed is enhanced, enzymatic digestion is optimized, and pathogenic microorganisms are inhibited. Probiotics stimulate the immune response, increase intestinal microbial diversity, and have anti-mutagenic and anti-carcinogenic effects. Modern administration methods include bioencapsulation and the use of live foods, thus ensuring the probiotics' survival and effective colonization in the fish's digestive tract. Therefore, using probiotics in fish nutrition not only improves growth performance and health but also promotes sustainable and ecologically efficient aquaculture.

Interactions between various microbial pathogens including viruses, bacteria, fungi, oomycetes, and their plant hosts have traditionally been the focus of phytopathology. In recent years, a significant and growing interest in the study of eukaryotic microorganisms not classified among fungi or oomycetes has emerged. Many of these protists establish complex interactions with photosynthetic hosts, and understanding these interactions is crucial in understanding the dynamics of these parasites within traditional and emerging types of farming, including marine aquaculture. Many phytopathogenic protists are biotrophs with complex polyphasic life cycles, which makes them difficult or impossible to culture, a fact reflected in a wide gap in the availability of comprehensive genomic data when compared to fungal and oomycete plant pathogens. Furthermore, our ability to use available genomic resources for these protists is limited by the broad taxonomic distance that these organisms span, which makes comparisons with other genomic datasets difficult. The current rapid progress in genomics and computational tools for the prediction of protein functions and interactions is revolutionizing the landscape in plant pathology. This is also opening novel possibilities, specifically for a deeper understanding of protist effectors. Tools like AlphaFold2 enable structure-based function prediction of effector candidates with divergent protein sequences. In turn, this allows us to ask better biological questions and, coupled with innovative experimental strategies, will lead into a new era of effector research, especially for protists, to expand our knowledge on these elusive pathogens and their interactions with photosynthetic hosts. [Graphic: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

The protandric shrimp Hippolyte inermis is the only known marine invertebrate whose sex determination is strongly influenced by the composition of its food. In H. inermis, a sex reversal is triggered by the ingestion of diatoms of the genus Cocconeis associated with leaves of the seagrass Posidonia oceanica. These diatoms contain compounds that promote programmed cell death (PCD) in H. inermis and also in human cancer cells. Transcriptomic analyses suggested that ferroptosis is the primary trigger of the shrimp’s sex reversal, leading to the rapid destruction of the androgen gland (AG) followed by a chain of apoptotic events transforming the testes into ovaries. Here, we propose a molecular approach to detect the effects of compounds stimulating the PCD. An RNA extraction method, suitable for young shrimp post-larvae (five days after metamorphosis; PL5 stage), was established. In addition, six genes involved in apoptosis, four involved in ferroptosis, and seven involved in the AG switch were mined from the transcriptome, and their expression levels were followed using real-time qPCR in PL5 fed on Cocconeis spp., compared to PL5 fed on a basic control feed. Our molecular approach, which detected early signals of sex reversal, represents a powerful instrument for investigating physiological progression and patterns of PCD in marine invertebrates. It exemplifies the physiological changes that may start a few days after the settlement of post-larvae and determine the life destiny of an individual.

In aquaculture, co-culturing rice with fish may mitigate greenhouse-gas emissions. In this study, co-culture of four rice cultivars in a laboratory-scale rice–fish system reduced CH4 and N2O emissions relative to fish monoculture. Differences in CH4 and N2O emissions among rice cultivars primarily stem from the differential effects of rice plants on plant-mediated CH4 transport, CH4 oxidation and nitrogen absorption.

This study explored the impact of an active project-based, aquaculture constructivist-learning program, as perceived by high school students. The purpose of this case study was to discover if participation in the program influenced students’ interest, engagement, and future educational and career aspirations in science, technology, engineering, and mathematics (STEM) when integrating aquaculture in and outside the classroom. Likewise, the study also wanted to explore students’ knowledge about aquaculture and skill development after their participation in the program. The study employed a qualitative methods approach to explore students’ attitudes and experiences. Qualitative data were collected from post-student focus groups at three different public, rural high schools in Kentucky. Other qualitative data included teacher journal reflections (e.g., personal documents) and public newspaper articles (e.g., public documents). Four emergent themes were found: (1) Students show excitement and enthusiasm in the hands-on, aquaculture program; (2) students show attention to detail in the hands-on, aquaculture tasks, it sticks, and are more responsible; (3) students are collaboratively engaged with their peers; and (4) greater interest and confidence in STEM through practical application. Results demonstrated that the program engaged learners in real-world problem-solving and decision-making situations while working collaboratively in small works. It also appears that students gained an important life skill, responsibility, as well as self-confidence in STEM, after participating in the program.