Aquaculture Systems Research Articles

The impact of shade net use on total nitrogen removal by duckweed (Lemna perpusilla) at different levels of catfish farming effluent

Duckweed (Lemna perpusilla) has been shown to reduce nutrient levels in aquaculture effluent, particularly total nitrogen, which can be caused by a variety of organic contaminants in water. Duckweed biomass is an important source of bioenergy and phytoremediation in aquaculture. This aspect makes it a viable solution for sustainable integrated aquaculture, although appropriate duckweed biomass development is critical to its success and long-term survival. Duckweed growth, as an autotroph, is controlled by two factors: nutrition and sunlight. The aquaculture production cycle changes nutrient content in medium culture based on feed, fish age, and density, while weather influences solar radiation. The study aims to investigate duckweed growth response and phytoremediation capacity by analyzing changes in catfish farming waste-water quality grouped by fish age (L1: 2 months, L2: 3 months, and L3: 4 months) and shade net treatment at 25 % sunlight blocking (N25), 50 % (N50), and no shade net (N0). The experiment was carried out in triplicate in a semi-outdoor growth system placed in a greenhouse. It comprised of three series of duckweed culture containers filled with catfish farming wastewater, each with a working volume of 50 L. A total of 48 duckweed culture containers were floated inside a series of Recirculating Aquaculture System (RAS) tanks. Biomass harvesting and water quality monitoring were done every three days for a period of 18 days. N25 had the highest biomass weight, productivity, and average TN elimination efficiency, with values of 225.21 ± 140.04 g, 50.05 ± 10.06 g/(m2.d), and 61.94 ± 8.01 %, respectively (P < 0.05). The N0 values were 190.80 ± 117.52 g, 42.40 ± 9.29 g/(m2.d), and 55.61 ± 6.85 % (P < 0.05). The lowest values observed in N50 were 72.27 ± 55.70 g, 16.06 ± 4.90 g/(m2.d), and 51.67 ± 4.10 % (P < 0.05). This study proved the optimal duckweed growth and TN removal effectiveness with N25 under varying light intensity, allowing for the long-term use of duckweed in waste management and integrated aquaculture.

Hydrogel‐Based Capacitive Sensor Model for Ammonium Monitoring in Aquaculture

Monitoring aquaculture water quality, especially ammonium levels affecting fish health, is challenging due to limitations in traditional methods. This study presents an innovative capacitive sensor with an ionic hydrogel transducer for real‐time ammonium concentration monitoring. The sensor operates through ammonium‐induced dissociation in the hydrogel, causing osmotic pressure changes and altering electrode capacitance. Analytical formulations verified by finite element simulations demonstrate the sensor's ability to detect varying ammonium levels. Detailed analysis covers diffusion kinetics, swelling behavior, stress distributions, voltage variations, and ion equilibrium concentrations. The findings show a 20% increase in capacitance change within 200 s, even with a 3 μM ammonium concentration exposure. Additionally, the capacitance change plateau at ammonium levels exceeding 1 mM. The presented concept offers a promising and cost‐effective approach to addressing the limitations of traditional methods, paving the way for future research and development in real‐time water quality monitoring in aquaculture systems.

Assessment of dietary yeast-based additives for cultured catfish and tilapia health.

Channel catfish (Ictalurus punctatus) and Nile tilapia (Oreochromis niloticus) are two aquaculture species of great importance. Intensive production is often hindered by poor growth performance and disease mortality. The aim of this study was to evaluate the potential of a commercial fermented yeast product, DVAQUA, on channel catfish and Nile tilapia growth performance metrics and disease resistance. Channel catfish and Nile tilapia were fed practical diets supplemented with 0%, 0.1% or 0.4% of DVAQUA over approximately 2-month feeding periods in recirculation aquaculture systems. To assess the potential of the postbiotic against common aquaculture pathogens, juvenile catfish were subsequently challenged by immersion with Edwardsiella ictaluri S97-773 or virulent Aeromonas hydrophila ML09-119. Nile tilapia juveniles were challenged by injection with Streptococcus iniae ARS-98-60. Serum lysozyme activity, blood chemistry and growth metrics were measured at the end of the feeding period, but no differences were observed across the different metrics, except for survival. For the pathogen challenges, there were no differences in endpoint mortality for channel catfish with either pathogen (p > .05). In contrast, Nile tilapia survivability to S. iniae infection increased proportionally to the inclusion of DVAQUA (p = .005). Changes to sera lysozyme activity were also noted in the tilapia trial, with a reduction of activity in the fish fed the 0.4% DVAQUA diet compared to the control diet (p = .031). Expression profiles of proinflammatory genes and antibodies were also found to be modulated in channel catfish fed the postbiotic, indicating some degree of protective response. These results suggest that this postbiotic may be beneficial in protecting Nile tilapia against S. iniae infection by influencing immune parameters and additional research is needed to evaluate the potential of this DVAQUA for improving catfish health and disease control.

Evaluation of productivity and efficiency of a large-scale coupled or decoupled aquaponic system

Aquaponics, a sustainable agricultural method, is gaining attention for its closed-loop system's potential to address diverse environmental and economic challenges in traditional agriculture. The aim of this study was to fill knowledge gaps in scaling up lab-scale systems to larger-scale decoupled aquaponics, offering a comprehensive understanding of the system's productivity and water and fertiliser use efficiency. In coupled aquaponics (CAP), the aquaculture, and the hydroponic units are arranged in a single loop, and water flows continuously from the fish tanks to the plant unit and vice-versa. In decoupled aquaponics (DCAP), the aquaculture and hydroponics units are arranged in a multi-loop setup as separate functional units that can be controlled independently. This work compared coupled aquaponics, decoupled aquaponics and hydroponics (HP, in perlite slabs) under the same climatic conditions with a substrate grown crop in a pilot scale greenhouse. The evaluation of growth parameters, yield, water, and fertiliser use for basil, cucumber, parsley, and tomato cultivations co-cultivated with the tilapia recirculating aquaculture system (RAS) are presented. The highest yields were achieved by DCAP plants in all experiments (15% higher than HP and 19% than CAP for basil, 38% than CAP in cucumber, 17% and 72% than HP and CAP in parsley, and 8% and 55% for HP and CAP in tomato experiments). The CAP treatment that did not receive any fertilisers presented the highest water use efficiency compared to both HP and DCAP treatments. Also, compared to HP, the DCAP treatment presented higher water and fertilisers use efficiency. Consequently, the adoption of decoupled aquaponic systems is the key to aquaponic evolution in the future.

Genome sequencing and assembly of Indian major carp, Cirrhinus mrigala (Hamilton, 1822)

The freshwater aquaculture species, Cirrhinus mrigala, commonly known as mrigal, holds significance in the carp-dominated aquaculture system, globally. Despite constituting 1.08% of the total freshwater aquaculture production, mrigal is the third most important Indian major carp. However, its genome and associated information is not available. This study aims to address this gap by generation high quality genome assembly using PacBio long reads, Illumina short reads and Hi-C scaffolding. The characterization of assembled highly contiguous genome, 1.057 Gb in size, revealed 39,091 genes with functional annotations. The orthology analysis based on direct orthologs and single copy ortholgs places C. mrigala in a distinct position within the Otophysi clade. Additionally, the study delves into Hox gene clusters, identifying 38 Hox genes distributed in seven clusters. The present genomic information offers potential applications for sustainable aquaculture management, including selection programs for economic traits.

Mental models of aquaculture governance in Indonesia

Aquaculture stakeholders have mental models, which are the internal cognitive representations of how they understand and prioritize the different features of their aquaculture systems. Individuals and stakeholder groups are likely to have different mental models, with implications for making cooperative governance work and guiding the rapidly emerging sector’s sustainable development. We apply a participatory approach called fuzzy cognitive mapping to capture and compare the mental models of community-based coastal pond aquaculture stakeholders in Indonesia, including farmers, government managers, and researchers who need to work together to govern a rapidly expanding aquaculture sector which faces critical sustainability challenges. To conceptually structure our comparison, we use Elinor Ostrom’s social–ecological systems framework. Our results highlight important differences between stakeholder group mental models which represent potential conflicts of interest and barriers for collaborative governance. Fish farmer models emphasize resource system challenges relating to production instability and risk, while government managers emphasize increasing production intensity to meet sectoral growth targets. Researchers, in contrast, tend to focus on pond waste treatment and water quality management. Governance attributes were consistently perceived as less frequent and less influential compared to other social–ecological dimensions, reflecting perceptions of weak governance in the sector. We identify a critical need for programs aimed at strengthening community-level institutional arrangements for governing shared aquaculture resources, increasing technical knowledge capacity, and managing financial risk. By merging all stakeholder models into a single “community” model, we identify key consensus action situations across the three groups as potential focal points for aquaculture development which may serve as a starting point for actors to work together to identify context-appropriate institutional solutions to these sustainability challenges.

Safety Assessment on the Safety and Efficacy of an Additive of Dicopper Chloride Trihydroxide (IntelliBond® C) as a Feed Additive for Use in All Animal Species (RP812)

An application was submitted to the Foods Standard Agency in March 2021 from Trouw Nutrition GB (‘the Applicant’) for the renewal and modification of an additive (IntelliBond® C) containing dicopper chloride trihydroxide, under the category of ‘nutritional additives’ and functional group ‘compounds of trace elements’. The additive is proposed to be used in all animal species. The Advisory Committee on Animal Feedings (ACAF) was asked to review the dossier and the supplementary information submitted by the Applicant, and to advise the Food Standards Agency and Food Standards Scotland (FSA/FSS) in evaluating the dossier. The FSA/FSS concluded, based on the ACAF’s evidence, that the additive was fully identified and characterised, and no further concerns were raised for this section of the dossier. The use of the additive at recommended levels of incorporation into feed can continue to be considered safe for the target species and the consumer. Regarding user safety, the additive was determined to be non-corrosive and is not a skin sensitiser, however, is a skin irritant and should be regarded as a potential eye irritant. Following a request for a Phase I environmental risk assessment, the ACAF concluded that the additive poses an acceptable risk to the environment when used at the proposed levels for terrestrial species and land-based aquaculture systems. However, the safety of the additive for marine sediment when used in sea cages could not be concluded upon. It was concluded that the proposed minor modifications to the specifications and other provisions would not affect efficacy and therefore efficacy could be extrapolated from the original authorisation to the modified authorisation. The views of ACAF have been taken into account in this safety assessment which represents the opinion of the FSA/FSS.

A Review On Revolutionizing Waste Water Collection and Recycling Processes with IoT

This paper provides an extensive review of IoT-driven solutions addressing critical challenges in sectors like wastewater treatment, agriculture, waste management, e-waste recycling, and water quality monitoring. Innovative models leverage IoT technology for real-time monitoring, control, and optimization. Examples include an industrial IoT cloud-based model for wastewater treatment, sensor integration in aquaculture systems for improved resource management, and intelligent waste collection systems in smart cities. The review identifies gaps and opportunities for advancements, highlighting the importance of real-time data collection, cloud-based analytics, and machine learning for informed decision- making in environmental and resource management

Effects of yeast and willow extract in the diet on the survival and growth parameters of the crayfish (Cambarellus montezumae)

ABSTRACT The use of additives such as yeast or plant extracts in crayfish diets, even though are typically found in their natural habitats, has attracted recent attention due to the observed health, growth, and socio-economic benefits they offer. The presence of willow detritus in the stomach contents of free-living crayfish suggests its potential role in crayfish growth, even though it has not yet been demonstrated. This study aimed to evaluate the effect of yeast and willow extract as dietary additives on the growth of the crayfish Cambarellus montezumae. A total of 630 juvenile crayfish were collected, introduced into a recirculating aquaculture system, and randomly assigned to three treatment groups with three replicates each one (n = 70 per replicate): shrimp-balanced ration with yeast, shrimp-balanced ration with willow extract, and shrimp-balanced ration as the control. Throughout a 70-days period, the crayfish were weekly measured and weighed to assess various growth parameters and survival. Crayfish fed with the yeast ration showed improvements in weight, length, biomass, periodic absolute increase in weight and length, and relative growth rate in length compared with those in the willow and control groups. The incorporation of yeast into the ration demonstrates greater advantages to produce Cambarellus montezumae. The underlying mechanisms suggest efficient ration utilization and the potential for increased production which, has important implications for the aquaculture industry.

Removal of nutrients from aquaculture wastewater using cattail (Typha spp.) constructed wetlands.

The aquaculture industry is among the fastest growing food production sectors in the world. Land-based aquaculture systems continue to increase in popularity as they offer the benefits of controlling diseases, managing water quality, and minimizing threats to wild populations of fish. However, these systems discharge wastewater high in N and P. The ability of cattail (Typha spp.) constructed wetlands (CWs) to remove N and P from aquaculture wastewater (AWW) was examined here. Cattail CWs were established in mesocosms and had a gradient of AWW applied weekly for a total of 5 weeks. Total N and P loadings ranged from 13.7 to 209.2mg m-2 and 3.01 to 45.97mg m-2 over 28 days, respectively. Additions of AWW did not cause elevations in total dissolved N, total ammonia N, or nitrite N in CW water; however, concentrations of nitrate N and P in CW water were related to nutrient loading conditions. Elevations in P persisted for 3-4weeks among high nutrient loading treatments, providing an opportunity for eutrophic conditions to develop in CW systems. However, after 33 days of treatment,>95% total P concentration reduction was achieved in all mesocosms with final concentrations<0.05mg L-1, equivalent to reference conditions. High-loading treatments achieved greater P load reduction (856.8-955.0mg m-2year-1) than low-loading and reference treatments (591.7-792.7mg m-2year-1). This study demonstrates the effectiveness of cattail CWs to remove nutrients during AWW treatment and highlights the potential for end-of-season use in northern climates, providing insights regarding the operational timeline of such systems.

A Comparative Study on the Muscle and Gut Microbiota of Opsariichthys bidens from Rice Field and Pond Culture Breeding Modes.

To investigate difference in the quality of the different parts (back, tail muscles, and fish skin) of Opsariichthys bidens from pond and rice field cultures, a comparative study was conducted in terms of nutritional composition, volatile flavor profiles and gut microbiota. In detail, the texture, free amino acids, fatty acids were further assessed. The results suggested that the moisture content, crude protein and crude fat content in the skin of O. bidens are higher than those in the back and tail muscles, regardless of breeding modes. The fish cultured in the rice field had a higher protein content than those from the pond culture, while the fat content of the rice field-cultured fish was significantly low compared to the fish from the pond culture, especially in the back and tail parts. A total of 43 volatile components were detected by Gas Chromatography-Mass Spectrometry (GC-MS), with a maximum of 18 types of aldehydes and the highest concentration being nonanal. Compared to pond cultures, the fish from the rice field cultures showed more abundant flavor composition and odor-active compounds. The total content of DHA (Docosahexaenoic Acid) and EPA (Eicosapentaenoic Acid) in the rice field-cultured fish was higher than that of the pond group, while no significant disparity in amino acid composition was observed (p > 0.05). Comparative and clustering analyses of gut microbiota revealed notable discrepancies in the gut microbiota of O. bidens from two aquaculture systems. However, an inherent correlation between the gut microbiome and meat quality would be further emphasized in further studies. This study can offer a theoretical reference for the development of high-quality aquatic products by selecting the appropriate aquaculture models.

Physiological and Transcriptomic Analyses Provide Insights into Nitrite Stress Responses of the Swimming Crab Portunus trituberculatus.

Nitrite is a common environmental pollutant in intensive aquaculture systems. In this study, physiological and transcriptomic analyses were performed to investigate nitrite stress responses in the swimming crab Portunus trituberculatus, an important aquaculture species in China. The results revealed that nitrite can affect neurotransmitter signaling via the expression of neurotransmitter receptors such as octopamine receptor (OAR) and 5-hydroxytryptamine receptor (5-HTR), and depress ecdysteroid signaling by downregulating ecdysteroid receptor (EcR) as well as its downstream transcription factors in hepatopancreas. In addition, nitrite suppressed the expression of hemocyanins, the oxygen-transporting protein, which at least partly contributed to tissue hypoxia, resulting in a switchover of energy metabolism from aerobic to anaerobic pathway. To meet the energy demand, glycogens and lipids were mobilized and transported to the hemolymph, and the catabolism of amino acids and fatty acids was enhanced to provide energy for hepatopancreas. β-oxidation of fatty acids, the major process by which fatty acids are oxidized to generate energy, seems to occur mainly not in mitochondria but in peroxisomes. Although the cellular protective mechanisms, including antioxidant defense, heat shock response (HSR), unfolded protein response (UPR), and autophagy, were activated, nitrite-induced cellular stress overwhelmed the repairing capacity and caused significant increase in the levels of apoptosis. These results indicated that nitrite stress influences neurotransmitter and endocrine signaling, disturbs energy metabolism, damages cellular components, and induces apoptosis in P. trituberculatus. The findings of this study provide new insights into nitrite stress response in the swimming crab and provide valuable information for aquaculture management of this species.

Low-carbon wastewater treatment and resource recovery of recirculating aquaculture system by immobilized chlorella vulgaris based on machine learning optimization

Immobilized microalgae biotechnologies can conserve water and space by low-carbon wastewater treatment and resource recovery in a recirculating aquaculture system (RAS). However, technical process parameters have been unoptimized considering the mutual interaction between factors. In this study, machine learning optimized the parameters of alginate-immobilized Chlorella vulgaris (C. vulgaris), that is, 474 μmol/(m2·s) of light intensity, 23 × 106 cells/mL for initial cell number, and 2.07 mm particle size. Importantly, under continuous illumination, the immobilized C. vulgaris and microalgal-bacterial consortium improved water purification and biomass reutilization. Transcriptomics of C. vulgaris showed enhanced nitrogen removal by increasing pyridine nucleotide and lipid accumulation via enhanced triacylglycerol synthesis. Symbiotic bacteria upregulated genes for nitrate reduction and organic matter degradation, which stimulated biomass accumulation through CO2 fixation and starch synthesis. The recoverable microalgae (1.94 g/L biomass, 47 % protein, 26.23 % lipids), struvite (64.79 % phosphorus), and alginate (79.52 %) every two weeks demonstrates a low-carbon resource recovery in RAS.

Polyculture of pikeperch (Sander lucioperca) and Russian sturgeon (Acipenser gueldenstaedtii) using an artificial common pellet – Implications on feed to fish nutrient transfers in recirculating aquaculture system (RAS)

The purpose of this research was to investigate the effects of monoculture and polyculture on the utilization of an artificial common pellet to produce nutritious products, specifically pikeperch and Russian sturgeon, in a recirculating aquaculture system (RAS) for 84 days. The experiment was conducted under controlled conditions, with specific parameters for: water temperature (21.8±0.4 °C), initial weight of the fish (pikeperch: 18.17±2.65 g; sturgeon: 18.23±3.62 g), volume of the containers (working volume of 272 litres) and feeding rate (1.5 %). Five experimental groups were tested in triplicates, including monoculture groups (pikeperch: 63.46±18.49 g; sturgeon: 93.52±50.40 g) and three polyculture combinations [P90: 90 % pikeperch (68.63±13.79 g) + 10 % sturgeon (86.10±33.38 g); P80: 80 % pikeperch (76.88±18.06 g) + 20 % sturgeon (103.53±44.60 g); P70: 70 % pikeperch (81.51±19.24 g) + 30 % Russian sturgeon (94.48±33.25 g)]. The results indicated that the addition of Russian sturgeon to pikeperch tanks could lead to efficient transfer of feed lipid to fish biomass through sturgeons, but not pikeperch. Polycultures showed better lipid absorption (P70 lipid-ADC 96.06±1.96 %) from the common pellet than monocultures (pikeperch: lipid-ADC 91.93±6.37 %; sturgeon: lipid-ADC 97.08±2.07 %). Fillet lipid content of pikeperch remained unaltered across RAS monocultures and polycultures but changed positively in Russian sturgeon in polyculture (P70 2.64±0.71 % > P0 1.75±0.75 %). In both species, polyculture fillets accumulated 5–7 % higher MUFA (oleic acid, C18:1n-9) than monoculture fillets. The major conclusions drawn from this research are that polyculture group P90 had both fish species flesh with highest muscle reserves of glycine and proline. In polyculture, critically indispensable muscle lysine reserves depleted in pikeperch, but Russian sturgeon muscle amino acid profile was stable. Given the global constraints on land availability, the study proposes RAS polyculture as a potentially productive and nutritious aquaculture system of the future. The research also suggests that resilient species for RAS polyculture need to be identified, proposing Russian sturgeon as a possible candidate.

An automated lightweight approach for detecting dead fish in a recirculating aquaculture system

Accurate methods for detecting dead fish are of great significance for fisheries because of their potential to improve production and reduce water pollution. Small-scale fisheries typically apply manual observation, but this approach is labor-intensive and time-consuming, which limits its application on large-scale farms. Advances in computer vision tools have provided the foundation for revolutionary methods of automated identification of individual-animal behavior. However, computer vision systems often suffer from unstable accuracy, low efficiency, and limited detection capability. Thus, the aim of this study was to design a deep learning system, designated “Deadfish-YOLO”, to detect dead fish based solely on standard underwater camera images with no additional hardware. First, eight selected rearing tanks were monitored by a self-developed computer version system. From these tank images, a dataset containing 18,114 frames was built by manual labeling. Next, a lightweight backbone network was generated with YOLOv4 to ensure fast computations, and an attention mechanism was introduced into the model to suppress unimportant features. Finally, the ReLU-memristor-like activation function was adopted to improve neural-network performance. The accuracy and processing speed of Deadfish-YOLO were superior to those of other state-of-the-art single- and two-stage detection models; Deadfish-YOLO ran at 85 frames per second with a mean average precision of 0.946 and an average ratio of 0.924 between intersection and union. These results demonstrate that Deadfish-YOLO may be used to automatically monitor dead fish in real circulating aquaculture systems. In addition, the results of this study should facilitate the wider application of artificial-intelligence-based animal monitoring in aquaculture.

Increasing fish production in recirculating aquaculture system by integrating a biofloc-worm reactor for protein recovery

Aquaculture, producing half of global fish production, offers a high-quality protein source for humans. Improving nitrogen use efficiency (NUE) through microbial protein recovery is crucial for increasing fish production and reducing environmental footprint. However, the poor palatability and high moisture content of microbial protein make its utilization challenging. Here, a biofloc-worm reactor was integrated into a recirculating aquaculture system (BW_RAS) for the first time to convert microbial protein into Tubificidae (Oligochaeta) biomass, which was used as direct feed for culturing fish. Batch experiments indicated that an aeration rate of 0.132 m3L−1h−1 and a worm density of 0.3 g cm−2 on the carrier were optimal for microbial biomass growth and worm predation, respectively. Compared to the biofloc reactor-based recirculating aquaculture system (B_RAS), the BW_RAS improved water quality, NUE, and fish production by 17.1 % during a 120-day aquaculture period. The abundance of heterotrophic aerobic denitrifier Deinococcus in BW_RAS was one order of magnitude higher than in B_RAS, while heterotrophic bacteria Mycobacterium was more abundant in B_RAS. Denitrifiers cooperated with organic matter degraders and nitrogen assimilation bacteria for protein recovery and gaseous nitrogen loss while competing with predatory bacteria. Function prediction and qPCR indicated greater aerobic respiration, nitrate assimilation, nitrification (AOB-amoA), and denitrification (napA, nirK, nirS, nosZI), but lower fermentation in BWR compared to BR. This study demonstrated that BW_RAS increased microbial protein production and aerobic nitrogen cycling through ongoing worm predation, further enhancing fish production to a commercially viable level.

Ciliate diversity and growth rates in experimental recirculating aquaculture and aquaponics systems using microscopy

The function of recirculating aquaculture systems (RAS) relies on microbial communities, which convert toxic, fish-excreted ammonia into substances that can provide nutrients to plants as in the case of aquaponics systems. In the present study, heterotrophic protist communities of experimental sea water RAS and freshwater aquaponics systems were investigated using microscopy to characterize their diversity, natural abundance, and potential growth rates. Heterotrophic protist abundance was low (732 ± 21 to 5451 ± 118 ciliates L−1 and 58 ± 8 to 147 ± 18 nanoflagellates mL−1 in the aquaponics system and 78 ± 28 to 203 ± 48 ciliates L−1 in the RAS), which is in line with values typically reported for rivers. In the aquaponics system, ciliates grew faster in the fish rearing tanks (1.9 ± 0.01 to 1.21 ± 0.03 d−1 compared to 0.54 ± 0.03 to 0.79 ± 0.05 d−1 in the other compartments), while heterotrophic nanoflagellates grew slower in drain tanks downstream of the hydroponics compartment (0.5 ± 0.3 to 1.37 ± 0.05 d−1 and 4.09 ± 0.11 d−1 to 6.03 ± 0.34 d−1in the other compartments). Results indicated distinct niches and reduced microeukaryotic diversity at the end of the system’s operation cycle.

Study on recirculating aquaculture system (RAS) in organic fish production

Abstract The growth of conventional aquaculture has created environmental issues due to excessive feeding, low dissolved oxygen level etc into the water body. Organic aquaculture is a recent development as a solution to these issues. It is a clean alternative to reduce pollution and to produce safer consumable food. In the past few decades, recirculating aquaculture systems (RAS) were introduced to maintain pond water quality through lesser water exchange, by focusing on water reuse after treatment. In this study, the technical viability of RAS was analyzed for introduction in organic aquaculture systems. Indian major carps (IMCs) were cultured through conventional methods in the three tanks of conventional system, while the same species was grown organically in another three tanks in organic system. The stocking density and physical conditions were kept same for both cultured systems. The RAS consisted of fish culture tank with an average volume of each tank was 165 m3, a screen filter, foam fractionator and trickling filter. The various water quality parameters, i.e., solid size distribution in water, and removal efficiencies in biological treatment of both systems were compared. The present study, particle size distribution of solids in water body was measured by filtration, followed by weighing of dry residue solids. Pore sizes of 1000μ, 100μ, 20μ and 3μ were employed for filtration. For organic tanks, a majority of solids are of size between 1 mm and 100 μm. The larger sized particles (&gt; 30 μm) constitute nearly 70 % of the solids and the trait differs from the generalized conclusions of that a major part of sediments will be of sizes less than 20 μm. For the conventional tanks, majority of solids are of size between 3 mm and 20 μm and TAN shows higher removal efficiencies for effluents from organic system rather than conventional system. The results showed that organic aquaculture causes lesser pollution load per weight of fish. The particle size distribution of organic water was better compatible to screening and sedimentation than conventional water. Also the filtration efficiencies in nitrifying trickling filters of both water bodies were comparable, with that of organic water slightly on the higher side. Thus recirculating water treatment systems are introduced in organic aquaculture.

A comprehensive review of current practices, challenges, and future perspectives in Koi fish (Cyprinus carpio var. koi) cultivation.

The Koi fish (Cyprinus carpio var. koi) is an ornamental fish with a high selling value because of its attractive colors, color patterns, body shape, and swimming motion. Koi fish is extensively traded in the international fish market because of their popularity among hobbyists from numerous countries worldwide. This review discusses various aspects of Koi fish cultivation, including genetic involvement, selective breeding strategies, and management systems. By examining crucial factors such as water parameters, technological innovations, and evolving cultivation methods, this review explored their influence on the quality of Koi fish. Breakthrough technologies, such as ornamental fish warehousing and recirculation aquaculture systems, enhance breeding efficiency and profitability. Molecular sexing, feed optimization, and color enhancement strategies are central to pursuing superior Koi fish. Reproduction management, disease prevention, and risk reduction during transport underscore ongoing efforts to ensure their survival. Despite notable progress, several challenges remain, including limited genetic studies, gaps in disease research, and unexplored herbal alternatives. The active involvement of hobbyists and breeders in research initiatives is a pivotal force in unlocking the untapped potential. The holistic approaches to enhance production efficiency and improve care standards require further exploration, paving the way for a sustainable future in the evolving management of Koi fish cultivation.

The application of Global Burden of Animal Diseases methodology to aquatic animal production.

The Global Burden of Animal Diseases (GBADs) programme's key objective â€" to provide a systematic approach to determine the burden of animal disease â€" is as relevant to aquatic as to terrestrial animal production systems. However, to date GBADs methods have mainly been applied to terrestrial animal production systems. The challenges in applying GBADs methods, notably the Animal Health Loss Envelope (AHLE), vary considerably by production system. The authors demonstrate how the AHLE can be calculated for rainbow trout production in England and Wales and acknowledge that its application to other systems (e.g. hatchery production, polyculture and no-feed mollusc production) is more complex. For example, in small scale tropical fish production the impact of suboptimal nutrition on production would need to be addressed. Recirculating aquaculture systems have inherent high levels of biosecurity and disease control, and thus low levels of disease. Removing the capital and running costs associated with biosecurity fundamentally changes the system and invalidates the AHLE calculation. Lack of data from many systems, notably small-scale tropical finfish farming, means that expert opinion will be needed to support the application of GBADs methods. While calculation of the AHLE is the focus of this article, it should be noted that attribution to causes and value chain modelling are needed to generate data on the wider societal impact of aquatic animal diseases (and possible interventions), which governments require to support decision-making about resource allocation.