Sustainable Development Of Aquaculture Research Articles

Changing circulations challenge the sustainability of cold water mass and associated ecosystem under climate change

Bottom cold water mass provides abundant nutrients and cool water in summer, playing a pivotal role in the productivity of marine ecosystem and sustainable aquaculture development. Located in the most densely populated region, the Yellow Sea cold water mass (YSCWM) is a unique one influencing hundreds of millions of people living in the rim of the Yellow Sea. As anthropogenic carbon emissions continue, how the YSCWM will be altered by climate change becomes a pressing issue, but remains elusive. Using an unprecedented set of climate models with high resolution and biogeochemical components, we find that the volume of the YSCWM will shrink by 48% to 2040–2050, along with the bottom temperature warming of 0.4 ± 0.1 °C dec−1 and the dissolved oxygen concentration declining of 0.09 ± 0.04 mg (L dec)−1. The significant destruction of the YSCWM is driven by the strengthened Yellow Sea Warm Current (YSWC). The reduced land-sea thermal contrast is the cause of the circulation change, by weakening the East Asian winter monsoon. Due to the resultant profound habitat reduction for marine life, predicting the change of the YSCWM will have far-reaching influences on the future policy-making for sustainable development of offshore aquaculture.

Assessment of Smallholder Fish Farming Enterprise in Argungu Local Government Kebbi State

This study aimed to assess the engagement and interest of rural people in fisheries activities in Argungu Local Government Area of Kebbi State. One hundred and fifty (150) questionnaires were randomly distributed in the three villages. The questionnaires consisted of socioeconomic Characteristics as well as the current engagement of the rural people in fisheries activities and their interest in fish farming. The data obtained from the questionnaires was analyzed using descriptive statistics. Results indicate that the majority (73.3%) of these fish farmers are male, compared to (26.7%) who are female. A large proportion of fish farmers have attained primary education (30.7%). Regarding marital status and income levels, (66%) of the fish farmers are married and (68%) of the fish farmers earn less than 10,000 Naira monthly. The results on engagement and interest of smallholder farmers in fish farming enterprises show that (52.7%) of the fish farmers are actively engaged in fish farming. Fish farming enterprises reveal that smoking is the most commonly used method, with (53.2%) of the respondents favoring it. The most prevalent constraints in fish farming enterprise indicate that (58%), is the poor marketing system and poor storage facilities, which affects (56.7%) of the smallholder fish farmers. Based on this, it is recommended that there is a need to assist in setting up small-scale fish farming projects in rural areas with proper monitoring and supervision and Small-scale fish farming policies and practices to significantly improve food security, rural incomes and sustainable aquaculture development.

Aquacultural source of nitrous oxide revealed by nitrogen isotopes

The rapid expansion of coastal aquaculture has led to an increase in the coverage of aquaculture ponds, where intense feed-derived nitrogen is causing significant emissions of nitrous oxide (N2O). Multiple N2O production pathways and the relative importance of water column vs. sedimentary production in aquaculture ponds remain uncertain. Clarifying these pathways is vital for sustainable aquaculture development. Using 15N-labeled dissolved inorganic nitrogen, the pathways and rates of N2O production in subtropical aquaculture ponds located in south China, cultivating whiteleg shrimp, Japanese seabass, and giant river prawn, were successfully characterized. Total N2O production rates ranged from 6 to 70 µmol-N m−2 d−1, with the shrimp pond exhibiting the highest total N2O production rates, followed by ponds for seabass and prawn. These differences are primarily due to varying feed amounts causing differences in dissolved nutrients in water column and sediment. Particularly, nutrient and organic matter accumulation at the surface sediment stimulated N2O production. The oxygenated sediment on a centimeter scale could produce substantially more N2O compared to the water column above on a meter scale. Partial denitrification, i.e., nitrate and nitrite reduction to N2O, was more important (> 60 %) for N2O production in aquaculture ponds. The availability of nitrite is likely a major factor driving partial denitrification for both sedimentary and water column N2O production.

Decoding the fish genome opens a new era in important trait research and molecular breeding in China.

Aquaculture represents the fastest-growing global food production sector, as it has become an essential component of the global food supply. China has the world's largest aquaculture industry in terms of production volume. However, the sustainable development of fish culture is hindered by several concerns, including germplasm degradation and disease outbreaks. The practice of genomic breeding, which relies heavily on genome information and genotypephenotype relationships, has significant potential for increasing the efficiency of aquaculture production. In 2014, the completion of the genome sequencing and annotation of the Chinese tongue sole signified the beginning of the fish genomics era in China. Since then, domestic researchers have made dramatic progress in functional genomic studies. To date, the genomes of more than 60 species of fish in China have been assembled and annotated. Based on these reference genomes, evolutionary, comparative, and functional genomic studies have revolutionized our understanding of a wide range of biologically and economically important traits of fishes, including growth and development, sex determination, disease resistance, metamorphosis, and pigmentation. Furthermore, genomic tools and breeding techniques such as SNP arrays, genomic selection, and genome editing have greatly accelerated genetic improvement through the incorporation of functional genomic information into breeding activities. This review aims to summarize the current status, advances, and perspectives of the genome resources, genomic study of important traits, and genomic breeding techniques of fish in China. The review will provide aquaculture researchers, fish breeders, and farmers with updated information concerning fish genomic research and breeding technology. The summary will help to promote the genetic improvement of production traits and thus will support the sustainable development of fish aquaculture.

Modelling and mapping carbon capture potential of farmed blue mussels in the Baltic Sea region

This study applies a regional Dynamic Energy Budget (DEB) model, enhanced to include biocalcification processes, to evaluate the carbon capture potential of farmed blue mussels (Mytilus edulis/trossulus) in the Baltic Sea. The research emphasises the long-term capture of carbon associated with shell formation, crucial for mitigating global warming effects. The model was built using a comprehensive pan-Baltic dataset that includes information on mussel growth, filtration and biodeposition rates, and nutrient content. The study also examined salinity, temperature, and chlorophyll a as key environmental factors influencing carbon capture in farmed mussels. Our findings revealed significant spatial and temporal variability in carbon dynamics under current and future environmental conditions. The tested future predictions are grounded in current scientific understanding and projections of climate change effects on the Baltic Sea. Notably, the outer Baltic Sea subbasins exhibited the highest carbon capture capacity with an average of 55 t (in the present scenario) and 65 t (under future environmental conditions) of carbon sequestrated per farm (0.25 ha) over a cultivation cycle – 17 months. Salinity was the main driver of predicted regional changes in carbon capture, while temperature and chlorophyll a had more pronounced local effects. This research advances our understanding of the role low trophic aquaculture plays in mitigating climate change. It highlights the importance of developing location-specific strategies for mussel farming that consider both local and regional environmental conditions. The results contribute to the wider discourse on sustainable aquaculture development and environmental conservation.

Polyculture of Genetically Improved Farmed Tilapia (GIF tilapia) and Penaeus vannamei Using Biofloc Technology – A Review

According to Food and Agriculture Organization of the United Nations (FAO), aquaculture has grown faster and its expansion aimed at meeting the increase of world fish demand, and preserving natural fish stocks. Currently, to produce fish in quantity and quality requires reduction of the environmental impact from aquaculture, through the improvement of culture systems. Disease is the major factor affecting the development and expansion in aquaculture. Losses due to disease in shrimp farming are high. Various approaches to minimize the impact of disease on production are possible. Another approach to keep the pathogen pressure low is polyculture of shrimp and finfish. This practice makes shrimp farming more sustainable by reducing the environmental impact and the incidence of shrimp disease. Antimicrobial peptides in the fish skin kill shrimp pathogens, keeping pathogen pressure of bacteria and viruses low. In polyculture, shrimps can eat tilapia faeces and unused fish feed, while tilapia filter phytoplankton, reducing the risk of low dissolved oxygen levels at night. In addition, shrimp bioturbation at the pond bottom returns nutrients to the water column, enhancing phytoplankton production and consequently the natural feed available for the tilapia. Biofloc technology (BFT) is one of the most applicable and promising systems for sustainable aquaculture development. This technology is essentially based on the recycling of nutrients via microorganisms, primarily (i) heterotrophic bacteria, which convert nitrogen compounds into microbial biomass, in addition to serves as a source of food for aquatic organisms, and (ii) chemoautotrophic bacteria, which convert ammonia to nitrite and nitrate.

Analysis of temporal and spatial dynamics and driving factors in the aquaculture industry of Fuding City, China

BackgroundThe sustainable development of aquaculture is a crucial determinant of food security, the well-being of aquaculture practitioners, and economic growth within coastal regions. Considering the existing gap in research regarding spatial and temporal development of aquaculture, this study investigates the progression of aquaculture practices over time and across various locations in Fuding City, China. MethodsWe retrospectively collected temporal and spatial data on aquaculture, as well as demographic, social, and economic data for Fuding City from 2010 to 2020. By employing 3D kernel density analysis, we illustrated the temporal and spatial changes in aquaculture. Furthermore, we utilized Ordinary Least Squares regression to investigate the driving factors behind the spatial changes in the aquaculture industry. ResultsOver the past decades, we observed that in Fuding City, both the number of fishing rafts and aquaculture households initially decreased and then increased. The spatial distribution of aquaculture experienced a shift from the west (inner bay area) to the east (coastal area). Additionally, the type of fishing rafts also varied by region, with traditional rafts dominating the western inner bay and plastic rafts prevalent in the eastern offshore areas. Analysis of driving factors revealed that at least six factors have a significant positive correlation with the eastward shift of the aquaculture industry's center, including the proportion of migrant population, proportion of aquaculture to total fishery output, average temperature, investment in aquaculture technology, total fish sales, and GDP of Fuding City. ConclusionThis study examines the spatial and temporal dynamics of aquaculture in Fuding City from 2010 to 2020, proposing an innovative approach to spatial optimization that integrates both horizontal and vertical strategies. These insights aim to guide the development of coastal aquaculture policies and support sustainable regional development, fostering a balanced coexistence between human activities and marine environments.

Catechol compounds as dual-targeting agents for fish protection against Ichthyophthirius multifiliis infections

Aquaculture is one of the fastest growing sectors in global food production, recognized as a significant contributor to poverty alleviation, food security, and income generation. However, the frequent occurrence of diseases caused by pathogen infections result in reduced yields and economic losses, posing a substantial constraint to the sustainable development of aquaculture. Here, our study identified that four catechol compounds, quercetin, luteolin, caffeic acid, and chlorogenic acid, exhibited potent antiparasitic effects against Ichthyophthirius multifiliis in both, in vitro and in vivo. The parasite is recognized as one of the most pathogenic to fish worldwide. Using a combination of in silico methods, the dipeptidyl peptidase (DPP) was identified as a critical target for catechol compounds. The two hydroxyl radicals of the catechol group were essential for its binding to and interacting with the DPP protein. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses indicated that catechol compounds disrupt pathways associated with the metabolism and growth of I. multifiliis, thereby exerting antiparasitic effects. Furthermore, these compounds attenuated the expression of proinflammatory cytokines in vivo in fish and promoted macrophage polarization toward M2 phenotype by inhibiting the STAT1 signaling pathway. The dual activity of catechol compounds, acting as both direct antiparasitic and anti-inflammatory agents in fish, offers a promising therapeutic approach for combating I. multifiliis infections in aquaculture.

A long-term multivariate time series prediction model for dissolved oxygen

Accurate and efficient long-term prediction of marine dissolved oxygen (DO) is crucial for the sustainable development of aquaculture. However, the multidimensional time dependency and lag effects of marine chemical variables present significant challenges when handling multiple inputs in univariate long-term prediction tasks. To address these issues, we designed a multivariate time-series long-term prediction model (LMFormer) based on the Transformer architecture. The proposed multivariate time-series decomposition strategy effectively leverages the feature information of prediction variables at different scales, thereby reducing the loss of critical information. Additionally, a dynamic variable selection strategy based on a gating mechanism was designed to optimize the collinearity problem in the multivariate data feature extraction process. Finally, an efficient two-stage attention architecture is proposed to effectively capture the long-range dependencies between dynamic features. This study conducted high-precision 7-day advance DO long-term predictions in two case studies, the environmentally stable Shandong Peninsula in China and the San Juan Islands in the United States, which are affected by extreme conditions such as ocean currents. The experimental results demonstrate the superior prediction performance and generalizability of the designed model. In the Shandong Peninsula case, the mean absolute error (MAE), root mean square error (RMSE), coefficient of determination (R2), and Kling–Gupta efficiency (KGE) reached 0.0159, 0.126, 0.9743, and 0.9625, respectively. In the San Juan Islands case, the MAE was reduced by an average of 42.34% compared to that of the baseline model, the RMSE was reduced by an average of 24.57%, the R2 increased by 22.54%, and the KGE improved by an average of 12.04%. Overall, the proposed prediction model effectively achieves long-term prediction of multivariate marine chemical data, providing valuable references for sustainable management and decision-making in aquaculture.

Assessment of the Proximate and Mineral Compositions of Moringa Oleifera Leaf Extracts, the Carcass and Eggs of African Clariid Catfish, Heterobranchus bidorsalis

The need to optimize feed efficiency, feed digestibility and improve metabolism, growth, and reproductive performance of fish has necessitated the use of phytogenic feed additives in aquaculture. A Study was carried out to assess the Proximate and mineral compositions of aqueous and ethanolic Moringa oleifera leave extracts (AMOLE and EMOLE respectively) according to standard procedures. Consequently, these two extracts were used to formulate test diets containing 0.00/100g (control), 1.0g/100g, 2.0g/100g and 3.0g/100g inclusion levels. H. bidorsalis samples (n=216; 800.00+150.00g; 37.50±1.5cm) were randomly distributed in triplicate into 24 concrete tanks of size 6m x 4m x1.3m in a completely randomized 2x4 factorial design and fed at 5% body weight twice daily for 16 weeks. The proximate and mineral compositions of the diets was determined while the carcass and the eggs nutrients compositions were subsequently assessed. The proximate composition of the eggs were significantly higher in crude protein contents than the CP in the MOLE (34.14±0.05), AMOLE (38.84±0.17) and EMOLE (38.44±0.07) diets and the Carcass (37.46±0.28) with range (72.32±0.41 (control) - 78.78±0.58 % (3.0/100g)) while the ash (1.44±0.10 (3g/100g - 2.41±0.10% (control)) and ether (2.88±0.09 (3.0/100g) - 3.25±0.9% (control) ) contents where significantly lower than the highest contents of ash (20.01±0.27%) recorded in fish fed 2.0/100g AMOLE diet and (7.94±0.05%) ether recorded in the control diet. Aqueous extraction method had the highest significant (P<0.05) retention of mineral concentrations: Ca (21.04), P (14.89), Mg (16.40), Na (23.33), K (65.57), Fe (10.67), Cu (6.48) and Zn (5.55) compare to ethanolic extraction method: Ca (2.87), P (12.65), Mg (7.65), Na (19.24), K (13.76), Fe (9.07), Cu (2.40) and Zn (2.32). For the carcass, only Manganese, Iron and Copper compositions were significant (P<0.05) among all treatment groups and the control. These findings have far reaching nutritional importance in the healthcare system and will help to address undernutrition in fish broodstock management in a cost effective manner. Thus, the use of M. oleifera leaves extracts as phytogenic feed additives and nutrients booster should be encouraged and sustained towards sustainable aquaculture development.

Dynamics changes of coastal aquaculture ponds based on the Google Earth Engine in Jiangsu Province, China

Monitoring the spatiotemporal variation in coastal aquaculture zones is essential to providing a scientific basis for formulating scientifically reasonable land management policies. This study uses the Google Earth Engine (GEE) remote sensing cloud platform to extract aquaculture information based on Landsat series and Sentinel-2 images for the six years of 1984 to 2021 (1984, 1990, 2000, 2010, 2016 and 2021), so as to analyze the changes in the coastal aquaculture pond area, along with its spatiotemporal characteristics, of Jiangsu Province. The overall area of coastal aquaculture ponds in Jiangsu shows an increasing trend in the early period and a decreasing trend in the later period. Over the past 37 years, the area of coastal aquaculture ponds has increased by a total of 54,639.73 ha. This study can provide basic data for the sustainable development of coastal aquaculture in Jiangsu, and a reference for related studies in other regions.

Therapeutic effects of white poplar (Populus alba) leave extract on hepatorenal, stress, and antioxidant-immune parameters of Oreochromis niloticus challenged with Aeromonas veronii

Herbal plants have gained enormous interest due to their immune, antioxidant, and antibacterial activities. The present study proposed that white poplar (Populus alba) leave extract (WPE) might provide a promising alternative to traditional antibiotics to treat Aeromonas veronii infection in Nile tilapia (Oreochromis niloticus). WPE showed an in vitro antibacterial activity [22 ± 0.45 mm inhibition zone, with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of 60 µg/mL] against A. veronii. For the in-vivo study, a factorial (2 × 2) design was used to investigate the therapeutic effects of WPE on the antioxidant/immune status and blood biochemical parameters of Nile tilapia challenged with A. veronii. One-hundred sixty fish (33 ± 1.5 g) were assigned into four experimental groups, each with four replicates (4 glass tanks/group, 40 fish/group, 10 fish/tank) for 10 days. In the first (1st) and 2nd groups, 0 and 1.5 mg/L WPE were applied in tank water, respectively, without fish being challenged. In the 3rd and 4th groups, 0 and 1.5 mg/L WPE were applied in tank water, respectively, with fish intraperitoneal inoculated with 0.2 mL of A. veronii (0.5 × 107 CFU). Aeromonas veronii infection significantly diminished the survivability, hepatic catalase, lysozyme activity, nitric oxide, immunoglobulin M, phagocytic %, total protein, albumin, and globulin. Moreover, a significant rise in the hepatic malondialdehyde, serum hepatorenal function indicators, cortisol, and glucose levels were consequences of A. veronii challenge. Interestingly, the interaction between bacterial challenge and WPE application increased the survivability, antioxidant activity, and immune responses and reduced ALT levels of fish treated with WPE during the bacterial challenge. The serum creatinine, cortisol, and glucose levels were decreased in fish treated with WPE during the infection but still higher than in the non-infected fish either treated or not treated with WPE. In conclusion, WPE (1.5 mg/L) can be used as an antibacterial substance in fish farming to alleviate the detrimental impacts of A. veronii infection by enhancing the antioxidant/immune status of the infected fish. These outcomes could help reduce antibiotic usage in fish farms, which is conducive to the sustainable development of aquaculture.

Vegetable omega-3 and omega-6 fatty acids differentially modulate the antiviral and antibacterial immune responses of Atlantic salmon

The immunomodulatory effects of omega-3 and omega-6 fatty acids are a crucial subject of investigation for sustainable fish aquaculture, as fish oil is increasingly replaced by terrestrial vegetable oils in aquafeeds. Unlike previous research focusing on fish oil replacement with vegetable alternatives, our study explored how the omega-6 to omega-3 polyunsaturated fatty acid (PUFA) ratio in low-fish oil aquafeeds influences Atlantic salmon's antiviral and antibacterial immune responses. Atlantic salmon were fed aquafeeds rich in soy oil (high in omega-6) or linseed oil (high in omega-3) for 12 weeks and then challenged with bacterial (formalin-killed Aeromonas salmonicida) or viral-like (polyriboinosinic polyribocytidylic acid) antigens. The head kidneys of salmon fed high dietary omega-3 levels exhibited a more anti-inflammatory fatty acid profile and a restrained induction of pro-inflammatory and neutrophil-related genes during the immune challenges. The high-omega-3 diet also promoted a higher expression of genes associated with the interferon-mediated signaling pathway, potentially enhancing antiviral immunity. This research highlights the capacity of vegetable oils with different omega-6 to omega-3 PUFA ratios to modulate specific components of fish immune responses, offering insights for future research on the intricate lipid nutrition-immunity interplay and the development of novel sustainable low-fish oil clinical aquaculture feeds.

Effect of Dietary Supplementation on the Growth and Immunity of Fish and Shellfish

With the rapid development of aquaculture, the shortage of high-quality dietary ingredients has become a critical problem limiting the sustainable development of aquaculture [...]

Effects of feeding chicken egg yolk antibodies on intestinal cell apoptosis, oxidative stress and microbial flora of tilapia (Oreochromis niloticus) infected with Streptococcus agalactiae

Streptococcosis, the most common bacterial disease of fish in recent years, is highly infectious and lethal, and has become an important factor hindering the healthy and sustainable development of aquaculture. Chicken egg yolk antibody (IgY) has the advantages of high antigen specificity, inexpensive and easy to obtain, simple preparation, no toxic side effects, and in line with animal welfare, which is a green and safe alternative to antibiotics. In this study, the potential of specific IgY in the treatment of gastrointestinal pathogens was explored by observing the effects of specific IgY on intestinal flora, pathological tissue, apoptosis, oxidative stress, and inflammatory response of tilapia. We used the specific IgY prepared in the early stage to feed tilapia for 10 days, and then the tilapia was challenged with Streptococcus agalactiae. The results showed that feeding IgY before challenge had a small effect on the intestinal flora, and after challenge specific IgY decreased the proportion of Streptococcus and increased the diversity of the intestinal flora; in histopathology, specific IgY decreased tissue damage and maintained the integrity of tissue structure.Further study found that specific IgY can reduce intestinal epithelial cell apoptosis and reduce caspase activity; at the same time, the content of MDA was decreased, and the activities of SOD, CAT, GSH-Px and GR were increased. In addition, specific IgY can down-regulate the expression levels of IL-8 and TNF-α genes and up-regulate the expression levels of IL-10 and TGF-β. The results of this study showed that specific IgY could improve the intestinal flora of tilapia infected with Streptococcus agalactiae, reduce intestinal cell apoptosis, oxidative stress injury and inflammatory response, thereby reducing tissue damage and protecting the health of tilapia. Overall, specific IgY can be further explored as a potential antibiotic alternative for gastrointestinal pathogen infections.

Trained immunity: Perspectives for disease control strategy in marine mollusc aquaculture

AbstractRecent evidence has demonstrated the unique properties of the innate immune system, known as innate immune memory, immune priming, or trained immunity. These properties have been described as the ability of the innate immune system to learn from previous microbial experiences, which improves survival after subsequent infection. In this review, we present the state of knowledge on trained immunity in invertebrates and provide a comprehensive overview of these capabilities in cultured marine molluscs, which are currently threatened by recurrent diseases. Studies have shown that exposure to environmental microbiota, pathogens, or derived elements, can provide a stronger response and protection against future infections. These studies highlight common and distinct features of protection, mechanisms, specificity, and duration that vary with immune markers, and methods of stimulation. While the cellular and molecular basis of these responses is only partially understood, effects on phagocytosis, haemocyte populations, apoptosis, oxidative stress, and immune gene expression have been suggested. Finally, we propose a framework for future research to go beyond the current evidence and address potential limitations in the implementation of trained immunity‐based strategies to control disease. Immune training may provide a unique opportunity to promote the sustainable development of marine mollusc aquaculture.

Sustainable Development of Fisheries and Aquaculture in North Africa: Current Status and Future Prospects

This paper delves into the fisheries and aquaculture sectors of five North African countries—Morocco, Algeria, Tunisia, Libya, and Egypt—highlighting their critical roles in economic stability and food security amid increasing regional demands for animal protein. Despite the rich marine ecosystems and substantial contributions to national economies and employment, most of these regions face several challenges in fisheries management due to limited knowledge, weak institutional frameworks, and insufficient international cooperation. The paper emphasizes the necessity of transitioning towards sustainable aquaculture practices to preserve natural fish stocks and augment food production capacities. Although legal and sustainable capture fisheries remain vital, the focal point of this review is the potential for aquaculture to meet the growing population's needs without exacerbating the pressures on marine ecosystems. The paper evaluates the current state of fisheries management, identifies challenges in scaling aquaculture, and discusses innovative practices that could lead to more sustainable and productive outcomes. The study calls for improved management strategies, enhanced research and training, and more significant investment in aquaculture to ensure sustainable development of the fisheries sector, ultimately contributing to food security, economic growth, and conservation of marine biodiversity.

Exploring the optimal integrated multi-trophic aquaculture (IMTA) patterns benefiting culture animals and natural water environment

Despite bringing various benefits, rapid developments in aquaculture have contributed to the eutrophication of natural water environments. Therefore, it is imperative to mitigate nutrient load in natural water bodies while ensuring sustainable development of aquaculture. On the basis, we proposed an integrated multi-trophic aquaculture (IMTA) system, which considered a perfect solution and constructed an optimised IMTA pattern. Silver and bighead carps and freshwater pearl mussels were used as purification organisms. Six experimental groups were established for a land-based enclosure experiment: giant freshwater prawn monoculture group (G); giant freshwater prawn and freshwater pearl mussel polyculture group (GH2); giant freshwater prawn and silver and bighead carp polyculture group (GSB); giant freshwater prawn, freshwater pearl mussel and silver and bighead carp polyculture groups (GSBH1, GSBH2 and GSBH3) in different densities of freshwater pearl mussels. Each group had four replicates. Control of cyanobacterial blooms, productivity index, outputs of total nitrogen and total phosphorus and microbial community composition were studied and compared in different culturing patterns. Results showed that the GSBH1 group had the most obvious comprehensive advantages in the above four aspects (no cyanobacterial bloom occurred; the best comprehensive productivity index of giant freshwater prawn; the abundance of beneficial microorganisms in sediments was the highest; reduced phosphorus emissions in tailwater by 60.34%; the utilisation rates of nitrogen and phosphorus increased by 10.99% and 13.05%, respectively). Even so, however, the GSBH1 group might not be the most optimal IMTA pattern in practice because the mortality rate of the mussels reached 12.33% and the weight gain was −3.66%. Additionally, the presence of freshwater pearl mussel at its lowest density in this experiment had exhibited detrimental impacts on the growth of silver and bighead carps. Therefore, the most optimal IMTA pattern needs to be determined by further research.

Evaluating the Effects and Mechanisms of the Eco–Substrate in Aquaculture Environment Restoration from an Ecosystem Perspective via the Ecopath Model

Aquaculture supplies high-quality and healthy proteins. With the increasing human demand for aquaculture production, intensive pond aquaculture developed rapidly and results in environmental deterioration. To solve this problem, the eco-substrate (ES), which is the biofilm carrier, has been utilized in aquaculture ponds. Studying the ecological mechanisms of ES from the perspective of the ecosystem may be conducive to the sustainable development of aquaculture. In this study, it was evaluated how ES makes a difference to the trophic structure, energy flow, and system characteristics of two different aquaculture pond ecosystems via the ecopath model. Three aquaculture ponds with ES were designed as the treatment ecosystem and three aquaculture ponds without ES were designed as the control ecosystem. There were 13 and 14 functional groups in the control and treatment ecosystems, respectively. The results showed that (1) the macrozooplankton and microzooplankton showed strong effects on the ecosystem in the keystoneness index; (2) energy transfer pathways in the treatment system with ES increased by 26.23% compared to the control system; (3) the ES improved the utilization rate of detritus, which was 14.91% higher than that of the control ecosystem; (4) the material and energy flow index and network information characteristics demonstrated the ES enhanced the complexity and stability of the treatment system. To improve the energy utilization efficiency, filter feeders can be introduced to ES ponds. Overall, the ES can alter the trophic structure, improve the energy utilization efficiency, and enhance the stability and maturity of aquaculture ecosystems, representing a sustainable practice. Considering the total area of aquaculture ponds on the earth reaching more than 5 million hectares, the application prospect of ES is broad.

THE ROLE OF FISHING PORTS IN THE SUSTAINABLE BLUE ECONOMY

Fisheries and aquaculture play an important economic, environmental and social role. The development of fisheries and aquaculture depends on many factors, including adequately equipped ports and landing sites. The aim of this paper is to highlight the roleof fishing ports in the sustainable blue economy. Fishing ports support the sustainable development of fisheries and aquaculture by promoting best practises for environmental protection, maintaining food quality, creating fair prices, supporting workers' rights, integrating local communities and ports, and more. The Food and Aquaculture (FAO)Blue Ports Initiative aims to strengthen the role of ports as drivers of sustainable development in coastal communities and promote the achievement of several key Sustainable Development Goals (SDGs), including SDG 1 (No Poverty), SDG 2 (Zero Hunger), SDG3 (Good Health and Well-being), SDG 5 (Gender Equality), and SDG 14 (Life Below Water). However, ports are also encouraged to adopt a blue economy approach to management to achieve long-term benefits for local communities. Port management, in collaboration with scientists, policy makers, the private sector, and civil society, should focus on inclusivity, competitiveness, greening, and process efficiency, and support collaborative actions to improve the quality of life of local communities. KEYWORDS:fishery and aquaculture; ports; sustainability; blue economy; marine environment