AbstractBased on a comprehensive review of the current status of mariculture and its seed industry in China, this study establishes an evaluation index system encompassing two dimensions, “available varieties” and “industrial development,” to assess the seed industry development level of 36 major mariculture species in China. The study examines the phenomenon of “available varieties but underdeveloped industry” in the marine seed industry, analyzes the underlying causes, and proposes targeted recommendations. Key findings include: (1) The overall level of China’s marine seed industry requires improvement, with significant disparities in development among species; 72% of assessed species fall into medium-to-low tiers, indicating pronounced polarization. (2) The seed industry for multiple specific species still requires accelerated revitalization. The number of species exhibiting issues of "available varieties but underdeveloped industry," "weak variety resources despite strong industrial development," and "weak variety resources with underdeveloped industry" are 4, 3, and 11, respectively. Combined, these categories account for 50% of surveyed species. (3) The primary constraining factors of the development level of the marine seed industry include an incomplete intellectual property protection system, immature business models in the marine seed industry, and misalignment between seed industry research and development and market demand. To address these issues, this study recommends implementing the guiding principles on seed industry revitalization proposed by the Central Committee of the Communist Party of China and the State Council, strictly enforcing the requirements outlined at the National Symposium on Seed Enterprises, and balancing short-term and long-term objectives, public and commercial interests, government oversight and market mechanisms, and staple and specialty species cultivation, thereby promoting marine seed industry advancement and supporting high-quality development of mariculture.

AbstractAquatic germplasm resources refer to genetic materials of aquatic animals and plants that possess actual or potential value, including species, subspecies, varieties, strains, etc. These resources hold significant economic, ecological, and scientific importance in the fields of fisheries and agriculture, serving as the foundation for aquaculture, genetic improvement, and biodiversity conservation. Aquatic germplasm resources encompass aquatic organisms such as fish, shrimp, shellfish, algae, and echinoderms, along with their genetic material. They are not only a core element supporting the sustainable development and international competitiveness of the aquaculture industry but also a strategic resource for safeguarding national food security, ecological security, and biodiversity. Building strengthened protection of aquatic germplasm resources, how to enhance the scientific utilization and innovative development of superior aquatic germplasm is both an urgent national need for biological and genetic diversity security and a pressing demand for high-quality, healthy aquatic products driven by growing public expectations. This review conducts a safety assessment from three perspectives: fundamental research on the utilization of aquatic germplasm resources, relevant technologies and platforms, and artificially cultivated and genetically improved germplasm. Based on a review of research progress in these areas, it analyzes existing problems within these three aspects and proposes recommendations for improving the utilization of aquatic germplasm resources. Future recommendations for enhancing the safety of aquatic germplasm resource utilization in China mainly include: strengthening the construction of a shared genomic resource platform for aquatic species based on China's independent intellectual property; increasing efforts to decipher the genetic mechanisms underlying economically important traits; advancing the development of low-cost, high-throughput, and intelligent technologies for precise phenotyping and genotyping, along with platforms for precise functional gene manipulation; and enhancing science popularization regarding transgenic and gene editing technologies while strengthening the protection of intellectual property rights for new varieties.

AbstractCoilia nasus, which can be migratory or sedentary, is a substantial economic fish in China and used to be an important anadromous fish in the Yellow River. It is a model organism for studying fish resource conservation. However, the C. nasus resources in Yellow River gradually depleted in the late 1980s because of river disconnection, water conservancy project construction, environmental pollution, and overfishing. With the promotion of the Yellow River water-sediment regulation and implementation of the Yellow River Fishing Ban period system, C. nasus has reappeared in the Yellow River basin. C. nasus has developed into a dominant population in Dongping Lake and Nansi Lake, but no large-scale population has been found in the channels and estuaries of the lower Yellow River. Some morphological differences can be observed between the samples from the Yellow River estuary and those from Dongping Lake and Nansi Lake. According to the relationship between age, body length, and weight, the samples from Dongping Lake and Nansi Lake collected in previous studies were basically 1+ age, and the proportion of 2⁺ age individuals was small, indicating miniaturization and younger age. Different geographical populations of C. nasus showed rich genetic diversity. Although the population of C. nasus in Dongping Lake appeared later than that in Nansi Lake, it was slightly more genetically diverse possibly owing to the unique geographical location of Dongping Lake. The convergence of the three major river systems, the Yellow River, the Wenhe River, and the Jinghang Canal, may be conducive to the reproduction and diffusion of C. nasus in Dongping Lake. Using mitochondrial control region (D-loop) gene sequencing, combined with the historical data and fishery monitoring results of Nansi Lake, we found that the C. nasus population in Nansi Lake was closely related to the population in the Yangtze River and Huaihe River. The C. nasus populations in Nansi Lake possibly originated from lakes in the Yangtze River by the urgent ecological water diversion in 2002. The population composition is not well understood because of the few samples in the main stream and estuary of the Yellow River. The habitat history of C. nasus in the Yellow River estuary is complicated. In history, the main migration channel of C. nasus in the Yellow River was the main stream of the Yellow River, the spawning ground was Dongping Lake, and the feeding and overwintering grounds were in the estuary of the Yellow River and offshore waters. Dongping Lake, as the only lake in the lower reaches of the Yellow River and once an important spawning ground for C. nasus, is still blocked by sluice at present. However, the water area of Pangkou Bay outside the sluice is in a significant position, and a certain amount of C. nasus resources already exist, which is the only habitat found at present. The resources of C. nasus in the Yellow River show a positive trend, but the resource amount and habitat conditions remain unclear. This review introduces the current research status of the biological characteristics, resource status, genetic diversity, and habitat history of C. nasus in the Yellow River and discusses the development trend and research direction. It may serve as a reference for the effective resource management, conservation efforts, and sustainable use of C. nasus in the Yellow River.

AbstractWith the ongoing rapid development of China’s mariculture industry, there has been a corresponding surge in the discharge of marine aquaculture tailwater, and the residual bait, feces, and other residues contained in this water have contributed to serious increases in the levels of nitrogen pollution. The wide geographical distribution of maricultural operations and the high concentrations of ions in tailwaters contribute to difficulties in the effective treatment and purification of this waste water, thereby seriously threatening the quality of the marine environment and the sustainable development of marine fishery resources. In this regard, microbial heterotrophic denitrification technology, which has the advantages of excellent nitrogen removal efficacy and less likelihood of contributing to secondary pollution, has increasingly become a focus of scholars engaged in research on mariculture tailwater purification. In this paper, we outline the mechanisms and advantages of heterotrophic denitrification and denitrification technology, summarize and assess the progress of research and the application of heterotrophic denitrification and denitrification technology in current mariculture tailwater treatment, and describe and evaluate the factors influencing the efficiency of denitrification, including the type of carbon source, hydraulic retention time, temperature, dissolved oxygen, and pH. On this basis of this information, we summarize the difficulties in applying denitrification technology to the commissioning of mariculture tailwater, assess potential solutions to the existing problems, and consider future research directions, with a view toward providing a theoretical basis and technical support for the application of denitrification technology in the efficient treatment of mariculture tailwater.

AbstractAntarctic krill (Euphausia superba) and its products have garnered increasing attention as valuable natural resources because of their rich nutritional profile, particularly that of their bioactive compounds such as proteins and phospholipids. These components offer significant health benefits, including antioxidant and anti-inflammatory properties, which have attracted consumers seeking nutritional supplements and functional foods. However, the safety and quality of Antarctic krill products are of critical concern, especially concerning the presence of elements such as arsenic (As) and fluoride (F) and the potential allergenic properties of krill proteins. This review provides a comprehensive analysis of the safety issues surrounding Antarctic krill and its products, addressing key concerns such as the presence of As, F, and allergenic proteins, and strategies to mitigate these risks. One of the primary food safety concerns of Antarctic krill is its potential to accumulate As through its diet of plankton and algae. Various forms of As exist in the natural environment; their toxicity depends on the chemical form. Inorganic arsenic, particularly arsenite (As(Ⅲ)) and arsenate (As(Ⅴ)), is highly toxic, whereas organic arsenic compounds, such as arsenobetaine (AsB), are considered nontoxic or of low toxicity. Studies have shown that Antarctic krill contain As primarily in the less harmful organic forms, with AsB accounting for a significant proportion of the total As content. The levels of inorganic As in Antarctic krill and its products are typically far below the regulatory limits set by food safety standards, such as the national standard of China (GB 2762-2022), which stipulates that the maximum allowable inorganic As content in aquatic products should not exceed 0.50 mg/kg. However, some krill oil samples exceeded the specific standard of 0.1 mg/kg for inorganic As in krill oil, highlighting the need for continued monitoring and control of As levels in these products. Another contaminant of concern in Antarctic krill is F; it naturally accumulates in marine organisms, particularly in the exoskeletons of crustaceans such as krill. Although F is an essential micronutrient at low concentrations, excessive F intake can lead to health issues such as skeletal fluorosis. Research has demonstrated that Antarctic krill and its products, especially krill meal and krill powder, contain elevated F levels because of the exoskeleton’s high F content. The presence of F limits the use of krill products in health supplements, but removing F remains a technical challenge. Current strategies for defluorination include physical and chemical treatments, such as enzymatic hydrolysis, calcium salt precipitation, and filtration. However, further research is required to improve the efficacy of these methods without compromising the nutritional quality of the products. The allergenic potential of Antarctic krill also poses a significant food safety issue. Krill contains proteins (e.g., tropomyosin) that are known allergens that can trigger immune responses in sensitive individuals, particularly those with shellfish allergies. Symptoms of krill protein allergies include skin reactions, respiratory issues, and gastrointestinal discomfort. Although there are no specific treatments for food allergies, several studies have explored methods to reduce the allergenicity of krill proteins. Techniques such as microwave treatment, ultrahigh-pressure processing, protease digestion, and electron beam irradiation have shown promising results in reducing the allergenic potential of tropomyosin and other proteins. For example, microwave and ultra-high-pressure treatments have been shown to reduce shrimp allergenicity, and protease digestion eliminates allergenic protein bands. Moreover, the Maillard reaction, commonly used in food processing, reduces the allergenicity of tropomyosin by altering its secondary structure. These findings offer potential solutions for rendering krill products safer for consumption by individuals with shellfish allergies. Given the growing demand for krill products in the food and nutraceutical markets, ensuring their safety and quality is essential. Future research should focus on understanding the mechanisms involved in As, F, and allergenic protein toxicity, developing more efficient methods for removing these harmful substances. Advances in processing technologies, such as improved defluorination techniques and novel methods for reducing protein allergenicity, are critical for enhancing the safety of krill products. In addition, regulatory frameworks must be strengthened to ensure that krill products meet food safety standards. This includes the use of advanced detection technologies for monitoring contaminants such as As and F and implementing strict labeling requirements for allergens. International cooperation is vital for sharing research findings and regulatory experiences, which can lead to the establishment of unified safety standards for krill products. Public education is another important aspect of ensuring consumer safety. Increasing awareness of the potential risks associated with krill consumption, including heavy metal contamination and allergenicity, can help consumers make informed decisions. Finally, ongoing policy development and establishing a comprehensive quality control system are crucial for protecting consumer health and ensuring the sustainable development of the Antarctic krill industry. In conclusion, Antarctic krill has immense potential as a sustainable and nutritious resource. However, ensuring the safety of its products is paramount. Through continued research, technological advancement, regulatory oversight, and public education, the krill industry can address safety concerns while meeting the growing consumer demand for healthy and functional foods.

AbstractChitosan is derived primarily from shrimp and crab shells. Expanding use of chitosan can promote the recycling of shrimp and crab shell waste while advancing green biotechnology. Chitosan and its derivatives exhibit a wide range of biological activities, including tissue repair, regeneration, and promoting coagulation and have antibacterial, anticancer, antioxidant, and absorption properties. Despite its excellent characteristics, chitosan has limitations, such as poor solubility and weak mechanical properties. The development of nanotechnology has provided a foundation for broadening the applications of chitosan. Chitosan-based nanocomposites are formed by introducing nanoscale inorganic or organic substances into chitosan, which serves as the matrix. Recently, chitosan-based nanocomposites have become the focus of research in various fields owing to their biocompatibility, degradability, and multifunctionality. In the medical field, chitosan nanocomposites can promote wound healing by enhancing epithelialization and collagen deposition in the dermis and are promising candidates for bone and cartilage regeneration. Furthermore, chitosan nanocomposites can deliver encapsulated drugs via various pathways; their nanoscale structure significantly improves the drugs’ bioavailability and targeting. Chitosan and its derivatives possess strong heavy metal adsorption capabilities in wastewater and pollutant treatment, owing to their multifunctional chemical groups, high hydrophilicity, high chemical reactivity, and flexible polymer structures. Chitosan nanocomposites can enhance these properties by improving their mechanical strength, stability, reusability, and adsorption capacity. In agriculture, chitosan nanocomposites are used as functional components in plant growth inducers, pesticide carriers, fertilizers, growth regulators, and stress inhibitors owing to their enhanced antimicrobial properties, targeting ability, and controlled release features. In the food industry, the antimicrobial, mechanical, and barrier properties of films and coatings can be improved by incorporating nanomaterials into chitosan, which enhances food quality and extends shelf life. In the fishery industry, chitosan nanocomposites serve as carriers, encapsulants, and immobilizers for bioactive ingredients, enabling the oral delivery of drugs, vitamins, nutrients, genes, and vaccines to the fish gastrointestinal tract. This paper systematically reviews the research progress and application potential of chitosan-based nanocomposites across the fields of medicine, agriculture, wastewater treatment, food, and fisheries to provide a comprehensive reference and foundation for expanding the applications of chitosan.

AbstractThe National Key Research and Development Plan "Blue Granary Science and Technology Innovation" key special project (hereinafter referred to as the Blue Granary Project) has made strategic arrangements in areas such as germplasm creation, healthy aquaculture, habitat restoration, environmentally friendly fishing, and green processing. This project has been implemented to promote modern fishery science and technology innovation in China, drive the transformation and upgrading of the fishery industry and green development, the establishment of a new fishery production system and its implementation. Based on bibliometrics, this study searched the publication of the Blue Granary Project in the SCIE database, and analyzed the research progress and focus of the project, including publication and citation situation of papers, research institutions, international collaboration, research directions, and high-frequency keywords, etc. The results show that since its launch in 2018 to November 7, 2023, the Blue Granary Project as the first funded project has published a total of 5,803 SCI papers, with a total citation frequency of 55,361, a total H index of 61, and ESI highly cited papers of 55, including 1 hot paper. A total of 47 nature index journal papers have been published, distributed over 15 journals, including top journals such as Nature Cell Biology, Nature Climate Change, Nature Genetics, Nature Communications, and PNAS. Shanghai Ocean University, Ocean University of China, Ningbo University, and other institutions had the most outstanding performance in terms of publication output; 951 of the papers were published by international collaboration with partners from 57 countries, with developed countries such as the United States and Australia having the highest output. The papers cover 78 research fields, mainly focusing on fishery, marine and freshwater biology, food science and technology, environmental science and ecology, chemistry, biochemistry and molecular biology, immunology, and veterinary medicine. The information retrieved from the papers shows that the Blue Granary Project has made significant progress in basic research, key core technology development, and typical application demonstration, providing theoretical support for high-quality development in aquaculture, aquaculture breeding, disease prevention and control, and aquatic product processing. The findings provide data-driven decision support for establishing a sustainable Blue Granary system, thereby advancing the high-quality development of the marine economy.

AbstractDNA methylation is an important epigenetic regulatory mechanism in organisms that regulates genome stability through chromosome and protein structures without altering gene sequences. DNA methylation has been applied in the fields of medicine, agriculture, forestry and animal husbandry, and has attracted great attention in the field of fish genetics and fish breeding. Methyl groups are transferred to cytosine residues by specific DNA methyltransferases in fish DNA molecules, such as DNMT3, and the existing DNA methylation cell patterns are maintained by the methylation maintenance enzyme, DNMT1. Finally, the methyl group is removed by the oxidation of ten-eleven translocation dioxygenase (Tet1/2/3). DNMT2 catalyzes the transfer of methyl groups from the cofactor S-adenosylmethionine (SAM) to carbon 5 of the cytosine residues of the cytoplasmic tRNA—SAM is also converted to S-adenosine homocysteine. These DNA methylated transferases are widely present in many cells and tissues and play an important role in fish. DNA methyltransferase catalyzes the transfer of methyl groups from SAM to biomolecules (DNA, RNA, proteins, and small molecules) in vivo. There are many species of fish DNA methyltransferases, including two homologous DNMT1 enzymes (DNMT1a and DNMT1b), one DNMT2 enzyme, and eight homologous DNA methyltransferase 3. The naming of DNA methyltransferase 3 homologous genes is complicated; however, they are all parologous genes of DNMT3a and DNMT3b. Demethylation refers to the demethylase-mediated removal of methyl groups from DNA, which plays a key role in gene expression regulation, cell differentiation, embryonic development, and disease occurrence and development. Demethylation refers to the removal of methyl groups from DNA by demethylases. DNA demethylation patterns can be divided into passive and active DNA demethylation patterns. In passive demethylation, methylated DNA undergoes demethylation in successive replication cycles by inactivation or nuclear rejection of DNA methylation transferases that maintain methylation patterns, as well as ubiquitin-like proteins containing PHD and RING finger domains1 (uhrf1). In active DNA demethylation, methylcytosine is first oxidized by TET1/2/3 and then excised by thymine DNA glycosylase. During this process, DNA 5-methylcytosine is oxidized to 5-hydroxymethylcytosine. These oxidation products act as intermediates in DNA demethylation and are replaced by unmodified cytosines to achieve demethylation. The biological function of DNA methylation in fish is similar to that observed in other organisms, such as mammals, and is involved in gene regulation and cell development. DNA methylation occurs in three C environments: CG, CHG, and CHH (where H is any basic group other than G). DNA methylation occurs primarily at the CG site and allows fish to precisely regulate gene expression and adapt to different environmental factors. Differential methylation—cytosine-phosphate-guanine sites—is involved in apoptosis, epigenetic regulation, autophagy, collagen metabolism, cell membrane function, and homeobox protein generation through gene expression regulation. DNA methylation leads to changes in DNA conformation and stability, and the manner in which DNA interacts with RNA (or proteins) to control gene expression. It can interact with its binding proteins to inhibit gene expression in fish. DNA methylation affects genome expression regulation by activating or inhibiting transcription at the transcriptional level. Methylation near the transcriptional initiation site blocks initiation, but in the gene body it does not block and may even stimulate transcriptional elongation. It plays an important role in fish biological functions—gene expression regulation, embryonic development, reproductive development, muscle growth, body color, disease, and evolution. It can also provide insights into how genes are regulated during development and how these patterns are passed on to future generations, contributing to the understanding of epigenetics. Fish are often used as model organisms in endocrine disruption studies because of their high sensitivity to environmental factors. Environmental factors—temperature, heavy metals, starvation stress, nutritional feed, and hormones—affect the regulation of DNA methylation in fish, affecting their growth, development, and overall health. Recently, DNA methylation has attracted increasing attention as an important epigenetic regulator. The pattern and biological function of DNA methylation in fish, as well as its relationship with important environmental factors, have been gradually recognized; however, knowledge of its depth and breadth are insufficient. For example: (1) because of the wide variety of fish species, their DNA methylation characteristics still need researching; (2) there are still many important epigenetic relationships between DNA methylation, and more genes associated with it need to be explored to improve the application efficiency of fish breeding; (3) the specific mechanisms of some important variations and DNA methylation levels are still unclear; (4) the genetic mechanism of DNA methylation levels in different generations is still unclear; and (5) the interaction of core regulators of DNA methylation and the regulation and differentiation mechanisms are not clear. Further studies of these scientific issues will reveal the mechanism of fish methylation regulation of growth and development and the environmental factor response mechanisms, enrich the theoretical system of fish epigenetics, and provide a theoretical basis for the application of genetic breeding.

AbstractPhosphorus is an essential element for plants, animals, and other living organisms. The lack of phosphorus in aquatic environments can restrict primary productivity, a concern that has increasingly attracted global attention. However, the high phosphorus concentration leads to the eutrophication of water bodies, impacting human activities, compromising water quality, and causing notable economic losses. Therefore, studies on phosphorus removal and the recovery of phosphorus resources are important. In 2023, 27.3% of China’s important fishery waters in inland rivers exceeded the total phosphorus standard. The area of marine natural important fishery waters that exceeded the standard for reactive phosphate was 27.0%, and the area of seawater key aquaculture areas that exceeded the standard for reactive phosphate was 28.2%,. Aquaculture development is particularly important in the context of the ‘Big Food Concept’. The China’s total aquatic product output in 2023 was 71.16 million tons, an increase of 4.39% year-on-year, of which aquaculture production accounted for 81.6%. From 2022 to 2024, China’s provinces and municipalities introduced the aquaculture tail water discharge standard. For example, Shandong Province has implemented DB37 4676-2023, which sets a total phosphorus primary discharge limit of 0.7 mg/L and a secondary discharge limit of 1.0 mg/L. Recently, the rapid development of aquaculture tailwater phosphorus removal technology and phosphorus recovery technology based on physical, chemical, biological and ecological methods has provided strong support for aquaculture tailwater phosphorus removal and recycling. The current aquaculture tailwater phosphorus removal technology has made some progress. However, the advanced removal of phosphorus from the tailwater and phosphorus recovery technology requires further investigation. Enhancing the advanced removal of aquaculture tailwater is essential to ensure the sustainable development of aquaculture. This study classified the phosphorus in the water, examined the principle and current status of aquaculture tailwater phosphorus removal technology, and reviewed the application of phosphorus removal in the tailwater of the current aquaculture model. The principles and current status of phosphorus removal technology in aquaculture tailwater were discussed in terms of physical, chemical, and biological methods of phosphorus removal. The study indicated that the physical method of phosphorus removal technology in aquaculture primarily relies on adsorption and membrane separation technology, in which the high adsorption saturation of adsorbent materials and renewable is the key to adsorption of phosphorus removal, and the physical principle of membrane separation technology is the selective permeability of the membrane. Pollutant retention is achieved through the concentration difference between the two sides of the membrane, hydraulic pressure difference, and potential difference. The current membrane separation technology research methods continue to innovate and generally combine the membrane separation technology and biological method applied to aquaculture tail water phosphorus removal technology. Chemical phosphorus removal technologies such as precipitation, electro-flocculation, crystallization and depth oxidation are important for aquaculture tailwater phosphorus removal technology. These technologies are notable in phosphorus resource recovery and should not be ignored. Biological phosphorus removal technology is a primary method for phosphorus removal in aquaculture tailwater and mainly includes biofilm reactor, Biofloc, microalgae biological purification, bacterial and algal synergistic reactor, artificial wetland and other technologies. Biofilm reactors and Biofloc mainly rely on the role of phosphate accumulating organisms (PAOs) and denitrifying phosphate accumulating organisms (DPAOs), both of which have different processing capacities and biological responses to phosphorus in aerobic, anaerobic and anoxic stages. PAOs absorb phosphorus in aerobic conditions and release phosphorus in anaerobic conditions; DPAOs release phosphorus in anaerobic conditions and absorb phosphorus in the anoxic stage. Microalgae biological purification technology mainly uses the photosynthesis of microalgae and microalgae growth to absorb and remove phosphorus from the water. The microalgae bioreactor is a bacterial-algae synergistic reactor formed by combining microalgae and biofilm reactors to remove phosphorus. Artificial wetlands are a comprehensive phosphorus management method that integrates physical, chemical, and biological methods. This approach is becoming prominent as a crucial technique for phosphorus management in aquaculture tailwater. Current aquaculture modes such as recirculating aquaculture system (RAS), pond aquaculture and other modes, in which RAS mostly use biofilm reactors, bacterial and algal synergistic bioreactors and multi-level integrated aquaculture systems and other treatment methods, and in recent years, artificial wetlands are also gradually applied in the treatment of phosphorus in RAS tailwater. Artificial wetlands are used with sediment and microbial fuel cells to remove phosphorus from aquaculture tailwater. In phosphorus treatment in recirculating aquaculture tailwater, the bioecological method is gradually being used as the main method to treat phosphorus in tailwater, supplemented by physicochemical methods. The pond aquaculture tailwater phosphorus management is also based on bioecological methods, such as ‘three ponds and two dams’, artificial wetlands, multi-level integrated aquaculture treatment system and other methods to remove phosphorus. This study analyzed the aquaculture tailwater phosphorus removal technology, which can provide new ideas for tailwater phosphorus treatment and phosphorus resource recovery and promote the green development of aquaculture.

AbstractAquaponics, which is widely considered as an efficient, ecological, and healthy aquaculture mode with notable implications for addressing issues such as aquaculture pollution, freshwater resource scarcity, and aquatic product quality, integrates the aquaculture and hydroponics. The definition of aquaponics remains controversial; however, the key lies in the symbiosis of aquatic animals and vegetables within a single system. Aquaponics encompasses various modes, such as the in situ mode combining pond aquaculture with ecological floating beds and the ex situ mode combining tank-based recirculating aquaculture and vegetable cultivation. Extensive research and discussion have been conducted on system design, aeration and filtration techniques, selection of plants and fish, nutrient balance, environmental control, disease management, and intelligent monitoring, providing technical support for constructing and operating aquaponic systems. Within the aquaponics system, microorganisms are crucial in nutrient transformation and the health of plants and animals, profoundly impacting the ecological balance of the system. Recently, with the rapid development of molecular biology and bioinformatics, genomic techniques such as amplicon-based high-throughput sequencing and qPCR have provided powerful support for analyzing the complex diversity, compositions, and functions of microbial communities in aquaponic systems. Regarding the diversity of microbial communities, studies have indicated higher bacterial community diversity in aquaponic systems than that in aquaculture systems. However, other studies have found no remarkable difference in bacterial diversity between aquaponic and aquaculture systems. Within the aquaponics system, notable differences were observed in the microbial community diversity among different microhabitats. Generally, the bacterial community diversity was the highest in the plant rhizosphere and biofilter and the lowest in the fish feces, with the bacterial diversity in the aquaculture water lying between the two. Various factors drive the spatial distribution of microbial diversity within the aquaponics system, profoundly impacting the functionality of microbial communities and system stability. Additionally, the composition of microbial communities in aquaponic systems are crucial in reflecting system characteristics and indicating the health and growth status of aquatic organisms. The composition of microbial communities in aquaponic systems differed from that in aquaculture and plant growth environments. Studies have identified core microbial taxa comprising bacteria belonging to the genus Bdellovibrio, Luteolibacter, Rhodobacter, and Nitrospira shared in different modes of aquaponic systems. Furthermore, research has shown that dominant bacterial groups vary between different functional units within the aquaponics system. In the biofilter, bacterial taxa belonging to the phylum Actinobacteria were enriched, whereas bacterial taxa belonging to the orders Sphingomonadales and Xanthomonadales inhabited the biofilm of the fish tank. The rhizosphere bacterial communities were dominated by taxa affiliated with the order Methylophilales. Generally, the presence of plants greatly influences the composition of bacterial communities in aquaponics systems. However, the effect of the presence of aquatic animals on plant-related microbial community compositions remains largely unexplored. Regarding microbial functions, nitrogen cycling is one of the most critical elemental cycling processes in aquaponics systems. Establishing efficient “nitrification” functional unit (i.e., biofilters) is a key aspect of system design and construction. The nitrifying microorganisms involved in the nitrification process are considered as beneficial microbial communities in the aquaponics system, typically colonizing the biofilter or the plant rhizosphere environment. For example, aerobic ammonia-oxidizing, anaerobic ammonia-oxidizing, nitrite-oxidizing, and complete ammonia-oxidizing microorganisms have all been detected in aquaponics systems. Additionally, denitrification, nitrogen fixation, and anaerobic reduction of nitrate to ammonium processes have also been identified in aquaponics systems. However, the existing research has primarily relied on taxonomic annotations of amplicon-based sequencing data according to the current database. Whether the nitrogen cycling microorganisms are functionally active and what the contributions of different nitrogen cycling processes are in the aquaponics system remain unclear. Furthermore, research on functional microorganisms involved in the cycling of other elements such as carbon, phosphorus, sulfur, and iron in the aquaponics system lacks, limiting our understanding of the operational mechanisms of aquaponics systems. In aquaponic systems, pathogenic microorganisms that pose risks to the health of fish and plants may be introduced during the construction and operation of the system. Their dispersal and colonization could be facilitated by the water flow in the aquaponics system. Therefore, the prevention and control of pathogenic microorganisms are crucial. One study has indicated that the aquaculture unit of the aquaponic system harbored microbes beneficial for plant health. However, whether these beneficial microorganisms could colonize the plant roots and consequently regulate plant health remain unclear. Additionally, the gut microbiota and rhizosphere microbial communities are key factors in promoting host health. Given the close correlation between the health of fish and plants in aquaponics systems, these host microorganisms interact. However, the interactions between these host microorganisms and host disease resistance in aquaponics systems remain unclear. The microbial communities in aquaponic systems exhibit dynamic characteristics, with their diversity and compositions being jointly influenced by multiple ecological processes. Drawing on microbial ecology theory of community assembly mechanisms and considering the unique features of aquaponic systems, we propose a framework for the formation of microbial communities within aquaponic systems. Abiotic environmental factors, biotic interactions, host selection, dispersal, speciation, and drift processes collectively govern the assembly of microbial communities in aquaponic systems; however, the relative contributions of these processes still require investigation. For a better understanding of the role of microbial communities in the stable and efficient operation of aquaponics systems the distribution characteristics and assembly mechanisms of the diversity, compositions, and functions of different microbial domains in aquaponics systems (e.g., eukaryotic microorganisms) must be systematically investigated. Additionally, the key microbial functional taxa in aquaponics systems and their impacts on the stability and efficiency of the system must be revealed, with the goal of potentially controlling aquaponic systems through microbial methods in the future.

AbstractWith the development of China's economic level and improving people's living standards, the state's supervision of food health and safety has increased. Consumer demand for many people has gradually changed from being satiated to eating well, and high-quality, environmentally friendly, and healthy aquatic products have become increasingly popular with consumers. However, intensive and high-density aquaculture causes the deterioration of water environmental conditions, the increase of anti-nutrient factors and nutritional imbalance caused by the replacement of animal protein with plant protein in feed, and changes in the growth, immunity, and digestive ability of aquatic animals caused by changes in feed nutrients, traditional processing methods, and transportation stress. The above situations encountered in aquaculture have a common impact on aquatic animals and inevitably cause a reduction in the muscle quality of aquatic animals. Therefore, improving the muscle quality of aquatic animals and the quality of aquatic products is an urgent problem with significant research value and potential. To improve aquatic quality, first, it is necessary to first identify the indicators of muscle quality in aquatic animals to improve aquatic quality. However, there is still a lack of a systematic muscle quality evaluation index system in the current aquaculture research. Therefore, this study reviewed the evaluation indices of muscle quality, including meat content, muscle nutrient composition, muscle fiber structure, muscle texture characteristics, and muscle physicochemical indices, to provide a reference for establishing scientific muscle quality evaluation indices. In addition, factors affecting muscle quality must be considered in studies aimed at improving the muscle quality of aquatic animals. Only by understanding the factors affecting muscle quality in aquatic animals can the key factors regulating muscle quality and their mechanisms be studied more comprehensively and scientifically. This study reviewed the factors affecting the muscle quality of aquatic animals, including feed nutrients, feed additives, and the culturing environment, and found that nutrients are key factors in improving the muscle quality of aquatic animals. Protein is an important nutrient, the main component of muscle, and an important indicator of muscle quality. Amino acids are the basic units of proteins and have a vital impact on muscle quality and flavor. Therefore, it is important to study the effects and mechanisms of action of amino acids on muscle quality in aquatic animals. Therefore, the effects of dietary amino acids on the muscle quality of aquatic animals were reviewed in this study, including the effects of amino acids on muscle nutrients, flavor, texture indices, and physical and chemical properties of aquatic animals. Furthermore, the effects of amino acids on muscle quality, including the promotion of protein synthesis, regulation of fat deposition, enhancement of antioxidant activity, and maintenance of intestinal health, were reviewed. In summary, this study summarized the influence of amino acids on the muscle quality of aquatic animals and its mechanism from the aspects of muscle quality evaluation indices, factors affecting meat quality, and the influence of amino acids on muscle quality, providing a reference for further research on the regulation of muscle quality by amino acids and the improvement of feed nutrients on the meat quality of aquatic animals.

AbstractWith the increase in global population, the demand for aquatic products rises annually. As a sustainable industry, aquaculture offers a promising solution to address the growing demand for fish products. Meanwhile, intensifying and expanding sustainable aquaculture is essential for achieving the United Nations’ global goal of the Decade of Action. Cage culture is a typical aquaculture method used globally. This culture method has the following advantages: (Ⅰ) Highly researched with a long history: cage culture has been in use since the 1970s. Cultivating high-value aquatic products through cage culture has become indispensable in aquaculture. (Ⅱ) The development prospects of cage culture are broad and include realization of the comprehensive breeding of different species. In the integrated multi-nutritive aquaculture (IMTA) system, cage culture enables a multi-species combination in which uneaten feed and nutrients from the excreted waste of one breeding species are used as food for other breeding species, thereby reducing nutrients released into the environment and increasing overall productivity. Net cage culture in shallow waters has grown exponentially in the past few decades. However, due to the limited space in nearshore areas and an increasing number of countries paying attention to the environmental problems caused by cage culture, the method has gradually shifted to deeper waters to ensure food security and safety. At the same time, alleviating environmental stress caused by nearshore cage culture and the expansion of the food production space are inevitable. Compared with nearshore aquaculture, the environmental conditions of offshore aquaculture are more complex, and the net cages are inevitably subjected to harsh sea conditions. To achieve the safe production of offshore aquaculture, it is crucial to study wind and wave resistance technology for use in culture net cages. As an essential part of net cages, the netting system is mainly used to maintain breeding space, protect the breeding species, prevent them from escaping, and protect them from predators. In the flow and wave field, the netting system bears most of the load on the farming facilities. Compared with other traditional marine structures, the nets have the mechanical characteristics of small scale and high flexibility. Under external force, the nets show large displacement and massive deformation, reducing breeding space and increasing the likelihood of damage to breeding species due to crowding. At the same time, the nets change the flow and wave field around the facility, affecting the distribution of the remaining bait, breeding species’ excrement, and dissolved oxygen in the water. Currently, the lack of analysis technology for nets is a limitation in offshore cage culture engineering, which restricts the large-scale development of offshore cages. Therefore, research on the hydrodynamic characteristics of nets is vital for developing offshore cage culture. This study introduced primary methods for calculating the netting hydrodynamic loads and their applicability. Simultaneously, the predominant modeling techniques in the numerical calculation of the netting dynamic response were summarized and analyzed. Furthermore, a systematic review of studies relating to the wave flow field around net mesh was conducted. Finally, the current hot topics in the research of netting hydrodynamic characteristics were reviewed to provide a reference for designing and optimizing cages. Considering the influence of various parameters on the hydrodynamic loads on the nets is an effective way to improve the prediction accuracy for the loads, which is also a critical area of research that requires further investment. In order to restore the real force characteristics of nets, a database of the netting hydrodynamic coefficients should be established through experiments. Intelligent algorithms, such as digital twin technology, are used to construct prediction models and generate mapping relationships between multiple factors and the hydrodynamic coefficients of the nets. Moreover, databases and algorithms should be updated regularly to improve the accuracy of calculating the netting hydrodynamic load. For the dynamic response of the nets, the fluid-structure coupling of the flexible nets should be studied intensively in the future, focusing on the two-way coupling between the nets and the fluid and exploring direct numerical simulation methods. Meanwhile, considering computational accuracy, suitable algorithms, such as the submerged boundary method, should be selected, and parallel computational methods should be developed to improve computational efficiency. In terms of the flow and wave field around the nets, further research should be conducted to determine the effects of extreme waves, biofouling, fouling density, cultured fish species, fish size, fish number, fish swimming speed, and fish swimming status on the flow field in the net cages, which will be conducive to monitoring the health of fish, reducing the risk of fish diseases, and ensuring the sustainable development of cage culture. This study provides a reference for developing net hydrodynamic analysis for digitalization and precision. It also provides more information for the sustainable development of aquaculture.

AbstractIn the context of global climate change, one central interest is an improved understanding of the global carbon cycle. A large number of studies have investigated carbon cycling and associated elements, mainly nitrogen and phosphorus. However, as an essential element for diatom growth, Si has been largely ignored. Si is the second most abundant element and is widely distributed on Earth. The chemical weathering of silicates on land and photosynthesis of diatoms in the ocean play an important role in atmospheric CO2 levels at various timescales. Diatoms are the primary producers in the ocean and account for as much as 40% of the annual ocean carbon fixation, which have an absolute requirement for Si to form siliceous cells. The main mechanism underlying ocean carbon sinks is a “biological pump.” The biological pump is driven by the biological Si pump to a large extent. Therefore, the biogeochemical process of Si has become one of the key research issues for global environmental change. Based on previous studies, the regulation and influence of the Si biogeochemical cycle on the carbon cycle are discussed in this review. The coupling effect and mechanism of the Si and carbon cycles in shellfish culture ecosystems were analyzed and the key research questions were explored. Chemical weathering of silicates and the cycling of their products form the basis of Si biogeochemistry. CO2 is consumed during weathering reactions. Therefore, silicate weathering on land represents an important sink for atmospheric CO2. Furthermore, at the geological timescale, primary silicate mineral weathering is the source of secondary silicate. Terrestrial plants absorb soluble silica through their root system during growth. Amorphous silica deposited in plant tissue after maturity is called phytolith. Phytoliths have excellent geochemical stability and occlude a certain amount of organic carbon during the formation process. The organic carbon occluded within phytolith is called phytolith-occluded carbon (PhytOC) and is buried in the soil. PhytOC is released into the soil with phytolith and may be preserved in soils for several thousands of years. As a consequence, PhytOC in terrestrial ecosystems could be significant potential carbon sinks globally due to the refractory phytolith. Primarily through river input, the dissolved silicate (DSi) is transported into the coastal ocean (approximately 84% of DSi input to the oceans). As the major primary producer, diatoms absorb DSi during growth and account for a large fraction of the total carbon fixation in the modern oceans. DSi is converted into biogenic silica via biological processes, is transported to the deep ocean, and is finally buried into sediments with organic carbon in the marine ecosystem. Thus, by controlling the contribution of diatoms to the total primary production, DSi can affect the carbon cycle in oceans. The carbon pump is driven by the Si pump. Mariculture has developed quickly in recent decades. Shellfish, which are dominated by filter-feeding species, are the main mariculture species. The filter-feeding shellfish consume particulate organic carbon as phytoplankton and use dissolved inorganic carbon to build their shell during growth. Filter-feeding shellfish are an import fishery carbon sink. As one of the important feed sources of filter-feeding shellfish, diatoms form fishery carbon sinks in coastal shellfish culture areas. Silicate is an essential salt for diatom growth. Consequently, the carbon sink of filter-feeding shellfish culture is connected with DSi through diatoms. Si could play an important role in driving the formation of carbon sinks in filter-feeding shellfish culture. Hence, it is necessary to consider all processes and coupling effects in the study of the Si biogeochemical cycle. It is important to understand its role in the carbon sinks of shellfish culture. Nowadays, in many systems, human perturbation has resulted in a decline in the ratio of Si:N to 1:1 or less, with severe impacts on the quality and structure of aquatic ecosystems. DSi limitation has been reported in many studies, in both coastal and marine waters. DSi limitation causes shifts from diatoms to non-siliceous algae and is supposedly related to the decreasing export of carbon. A shift from diatoms to other species would enhance the recycling of organic matter in the upper water column because diatoms are very effective in carbon sequestration. DSi limitation has also appeared in some aquaculture bays in China, such as Jiaozhou Bay and Laizhou Bay, in spring. Regarding future directions, it is suggested that more research be conducted on Si biogeochemistry in shellfish culture systems and coupling with the carbon cycle. The subsequent results could evaluate the role of Si in the carbon sink of filter-feeding shellfish culture. Future studies are expected to provide ideas for alleviating Si deficiency in the aquaculture bay and exploring the expansion path in shellfish farming.

AbstractThe Argentine shortfin squid Illex argentinus is a pelagic neritic cephalopod species found in the southwest Atlantic Ocean. The squid is characterized by a short lifespan, fast growth, and semelparous reproduction. The squid is one of most important targeted species in global cephalopod fisheries and plays a key role as transient “biological pumps” in the southwest Atlantic ecosystem. The squid is a highly migratory species and can migrate hundreds or even thousands of miles between its spawning and feeding ground to complete its life cycle. The squid adopts a mixed income-capital breeding strategy, where the reproduction is mainly supported by energy acquired and mobilized rapidly during the breeding season, coupled with using energy reserves when energy demands for reproduction are robust. The squid shows spatial differences in feeding habits and also shift diets as they grow, leading to different trophic niches. In general, the squid diet shifts from crustaceans to fish and cephalopods as they mature. Given the fact that species in a higher trophic position have greater energy content, a diet shift to fish and cephalopods is expected to meet the energy demands for reproduction. In the present review, we summarized the characteristics of energy accumulated in soma and reproductive systems for I. argentinus, which shows a dramatic increase in energy in the reproductive tissues when the squid reaches maturation. In addition, we compiled previous studies that focused on diet composition and trophic roles in the southwest Atlantic ecosystem, where the squid feeds voraciously on many prey species and plays a key role as prey item for many top predators, including marine mammals. Notably, squid changes diets in relation to energy demands and resource availability. However, future research is still needed to address the functional mechanisms of the shifting dietary habits with growth. To justify the mechanism, we suggest the following priorities in the near future studies: (1) evaluate the relationships between energy acquisition and migratory habits; (2) clarify feeding strategies that potentially maximize the energy gain; and (3) address the potential effect of the ongoing global climate change and fishery activity on the role of energy transfer in the southwest Atlantic ecosystem. Such research would advance our understanding of the species and support the sustainability of resource exploitation.

AbstractThe aquatic ecosystem is essential for human survival and development. Food web studies on aquatic ecosystems describe many key processes, such as material cycling and energy flow processes. The results are of great significance for protecting the diversity, stability, and functionality of biological and ecological systems. However, the extreme complexity of aquatic ecosystem food webs has puzzled ecological researchers. The development of stable isotope technology has contributed significantly to our understanding of intricate feeding relationships and structure of food webs. The carbon and nitrogen-stable isotope compositions of animal tissues are closely related to their food sources, reflecting the comprehensive characteristics of all food isotopic compositions assimilated over a period of time by animal tissues. The carbon isotope composition of animals can indicate their food source, while the nitrogen-stable isotope composition can reflect the trophic structure. However, the animal diet is not composed of a single food source, and the complexity and unpredictability of food sources complicate the interpretation of carbon and nitrogen-stable isotope data regarding the contribution of food sources. In recent years, the rapid development of stable isotope mixing models (SIMMs) has provided a powerful means to solve the complexity of aquatic food webs, particularly with regard to determining the contribution of food sources and comparing consumer niches. In this study, we reviewed the historical evolution of stable isotope models, the characteristics of the most prominent models, and factors to consider when utilizing such models. This study summarized the application prospects and limitations of stable isotope mixing models in the research field of aquatic ecosystem food webs in order to provide a reference and scientific basis for subsequent research. The development of stable isotope models can roughly be divided into three stages: the early initial stage (1976–2001), which mainly involved the development of linear models; the supplementary stage (2001–2008), during which numerous uncertain factors were added to the model analysis as a result of the advancement of computer technology; the Bayesian mixed model stage (2008–current). The mixed model stage is based on mass conservation, and the Bayesian framework greatly improves the accuracy and credibility of model analysis. Simmr, MixSIAR, and SIBER have become the primary isotope models used today. Stable isotope technology has a long history of development, and the emergence of various stable isotope models has expanded the application of isotope technology in the research field of food webs. These models have powerful analytical capabilities and provide researchers with a powerful means for analyzing the structure of the food web. However, owing to the limitations of isotope analysis and models, researchers should pay more attention to the relevant prerequisites and practical ecological significance when selecting models to analyze isotope data. Researchers should also devise reasonable field investigation and experimental treatment plans based on their own experimental conditions and economic capacity in order to avoid the error analysis and misuse of isotope models and reduce the uncertainty of model analysis results as much as possible. Based on the previous research progress, the authors share their experience and understanding of the application of isotope mixing models. The purpose of this study was to assist fellow researchers in quickly understanding the development process and matters requiring the attention of isotope models, as well as to provide fundamental data and theoretical support for related research.

AbstractBoth population and economic development are driving the rapid adoption of aquaculture development worldwide. The unique attributes of the intensive factory recirculating aquaculture system, including high density, low pollution, and high efficiency, have made this system an important avenue for aquaculture transformation and improvement, and this fits the current concept of green development in aquaculture. Flow patterns are an important environmental factor in the recirculating water aquaculture systems, with this parameter directly affecting the growth and welfare of fish within the system. However, it is also worth noting that the presence and movement of the fish also affect the construction of the system flow pattern. This study presents a comprehensive analysis of the effects of flow field conditions in recirculating aquaculture systems on different fish species, including the effects of flow rate on the growth and development, physiological indicators, and survival rates of commonly cultured fish, as well as the effects of other hydrodynamic conditions, such as circulating water and circulating water exchange rates, on fish behavior. The effects of fish and their locomotor behavior on hydrodynamic conditions and performance in culture ponds are also discussed, including the effects on turbulence intensity, flow-field flow patterns, and water mixing in these systems. The methods used to study the effect of fish movement on the flow field characteristics of any system can be broadly categorized into real measurement methods and numerical studies, where the real measurement methods include the visualization of research objects using the particle image velocimetry (PIV), acoustic Doppler velocimetry (ADV), and rhodamine water tracer fluorescence method. In contrast, numerical studies primarily rely on the application of the computational fluid dynamics (CFD) method. The advantages and disadvantages of both approaches are evaluated in this study. Our evaluations include a discussion of the common problems with the current system for constructing the circulating water aquaculture systems in industry, such as neglecting the flow field construction, lack of cross-disciplinary research, poor regularity, and repeatability of research, and suggest that a systematic experimental program should be established in combination with refined numerical simulation methods to facilitate the development of more accurate complex models. The aim of this study was to clarify the design of hydrodynamic conditions in these aquaculture systems in order to promote the development of better circulating water aquaculture systems for the industry in the hope of improving both the fish and water balance.

AbstractKnowledge of fish population ecology is fundamental for understanding population structure, habitat utilization, resource dynamics, and formulating conservation policy for natural fish resources. To date, various technologies have been used to better understand fish population ecology. Among them, otolith microchemistry analysis is one of the most important research approaches. Otoliths (ear bone) are biologically calcified structures in the inner ear of fish, which show continuous growth and are metabolically inert. They usually constitute three pairs of sagittae, lapilli, and asterisci in bony fish. As these hard tissues can record the habitat information that individual fish experience during their lifetime, otoliths are a useful resource for reconstructing the temporal and spatial histories of fish populations. The composition and content of otolith elements (like “fingerprints”) are mainly related to the bioavailability of macro and trace elements (including stable isotopes) in the ambient water and aquatic physical and chemical properties (especially salinity). Increasing scientific evidence has demonstrated that otolith microchemical analysis is a powerful tool to study fish population ecology, revealing the environmental conditions experienced by the organisms and tracing the key habitats (e.g., spawning site, nursery ground, and growing area) throughout their life cycle. Moreover, this approach offers significant advantages in assessing the formation mechanism and spatial structure dynamics of fish stocks. As the ratios of strontium to calcium (Sr/Ca) significantly differ between freshwater and seawater, and among different freshwater tributaries on a fine spatial scale, otolith Sr/Ca ratios are powerful markers for distinguishing freshwater, brackish water, and seawater habitats, and are widely used as a useful tool for revealing the habitat history related to spawning, hatchery, development, and migration of migratory fish. The combined analysis of otolith microchemistry (e.g., otolith line transects of elements) and microstructure (e.g., otolith increment of somatic growth) can be effectively used to quantify the duration and frequency of different habitat requirements by the target fish populations. Otolith microchemistry analysis also provides a good reference for studying population genetics. The core element characteristics of otoliths can separate the different fish sources originating from different spawning sites and obtain more accurate information on population structure. Notably, because of the small size of the fish at early life stages, electronic tags and telemetry technologies are almost impossible to use in life history studies. In contrast, the trace elements assimilated by fish during the ontogeny and growth process are stored in the otolith microstructure, and elemental profiles of the otoliths can indicate habitat clues of fish even at early life stages. The present review highlights the advances in studies on the characteristics of fish otolith elements and the application of otolith microchemistry analysis on fish population ecology, especially of natal origin reconstruction, habitat history inversion, population structure evaluation, and stock connectivity assessment. The limitations of otolith microchemistry analysis and possible solution routes are also discussed. Baseline investigations are suggested to enhance the robustness and interpretability of otolith microchemistry analysis, as several exogenous and endogenous factors may influence the spatio-temporal patterns of otolith chemistry. Additionally, building a multiyear database of otolith chemistry and water elemental signatures is recommended. It is noteworthy that the structure of otoliths in some cartilaginous fish is not suitable for microchemical analysis, and collecting otoliths from endangered or protected fish species is difficult. Alternative hard tissues (e.g., rays, scales, spines, and scutes) can be used to study fish population ecology as non-invasive substitutes of otolith samples. As mentioned, otolith microchemical analysis can accurately distinguish the ecological profiles of migratory fish; if combined analysis of otolith microchemistry and genetic markers is used to reveal the genetic structure and differentiation of fish populations, the results would become more reliable for developing and executing effective management and conservation strategies. At present, with improvements in the otolith microchemistry research, the analysis of otolith microchemistry has been extended to several new fields. The 87Sr/86Sr isotope ratio of otoliths has been utilized to investigate the life history of fish on a wider spatio-temporal scale. Furthermore, the approach of artificial otolith marking by macro and trace elements has strong applicability in the restocking of fisheries and will play a vital role in enhancing commercial and endangered fishery resource in the future.

AbstractAquatic products are a general term referring to marine and freshwater fishery organisms and their products. Such products mainly include fish, shrimp, crabs, shellfish, and seaweed. Aquatic products are rich in nutrients such as proteins, vitamins, fatty acids, and minerals. However, the recent illegal counterfeiting of the geographic origin label for aquatic products has become a major problem, receiving increasing attention worldwide. China is the largest producer of aquatic products globally, with a wide variety of aquatic species (especially fish, shrimp, crab, shellfish, sea cucumber, and microalgae). Several of these products are famous, exotic, high-quality, and new or endorsed by protected designations of origin. As an increasing number of consumers pursue better quality aquatic products, many well-known aquatic product brands and the protection of geographical indication products have been established. Consumers prefer aquatic products of well-known origins or famous brands, and are willing to pay higher prices for their quality. It is noteworthy that unscrupulous businessmen frequently fake shoddy products as real ones to earn profits. In addition to adulteration, the unclear origin identification and mislabeling are also rampant. Counterfeit activities inevitably harm the legitimate interests of consumers, producers, and the fishery industry. Using “bathed” Chinese mitten crab to counterfeit the native crabs cultured in the Yangcheng Lake of Jiangsu Province is a typical case of the above-mentioned activities. However, the establishment of traceability systems related to aquatic products remains unaccomplished in China. Thus, it is imperative to accelerate research on the origin traceability of aquatic products, and use scientific and objective methods to identify and confirm the origin of the products. Moreover, accurate and reliable analysis approaches are a prerequisite for effectively solving the adulteration and mislabeling of aquatic products and have special significance for implementing the national policy of rural revitalization. So far, biogeochemical approaches have especially advanced with a set of techniques for traceability of aquatic product origins. In particular, the corresponding mineral elements (e.g., Sr, Ba, Zn, Ca, Na, Cu, Mg, Al, As, Be, Co, Cr, Fe, K, Mn, Ni, P, Ti, and Zn) and stable isotopes (e.g., δ13C, δ15N, δ2H, δ18O, and 87Sr/86Sr) analyses have received increasing attention. The composition and content of mineral elements and ratios of stable isotopes in different habitats of aquatic organisms have individual characteristics and the mineral element/stable isotope “fingerprints” profiles in aquatic products must be different owing to various bioassimilation and bioaccumulation processes of the elements to the organisms from different geographical production regions of either natural or aquaculture water environments. Therefore, chemometric (especially, multivariate statistical authenticity analysis, e.g., discriminant analysis and principal component analysis) models based on the aforementioned “fingerprints” profiles (i.e., multi-elements, multi-stable isotopes, and the combination of multi-element and stable isotope) can be used to discriminate between aquatic products of wild or farmed origin, geographical origin, and species authenticity. This review summarizes the progress of the principles and applications of approaches to multi-mineral elements and stable isotopes traceability in aquatic products. Although the element uptake in fishery organisms may be influenced to some degree by water pollution and artificial diet, the availability of multi-elements/stable isotopes in ambient habitat waters and their bioassimilation/bioaccumulation are the most consistent and prominent factors influencing the biogeochemical “fingerprint” profiles in aquatic products. Advanced chemical analysis techniques can precisely and accurately reveal these profiles; for example, inductively coupled plasma (ICP) optical emission spectroscopy, ICP-atomic emission spectroscopy (ICP-AES), ICP-mass spectrometry (ICP-MS), laser ablation-ICP-MS, single collector quadrupole-ICP-MS, isotope ratio mass spectrometry, and multi-collector-ICP-MS. Successful studies of geographical origin traceability have already been reported in literature involving in many fishery species; e.g., Prochilodus lineatus, Genidens genidens, Eriocheir sinensis, Sepia officinalis, Dosidicus gigas, Ruditapes philippinarum, Mytilus edulis, Mytilus galloprovincialis, Patinopecten yessoensis, Chlamys farreri, Argopecten irradians, Pecten maximus, Salmo salar, Oncorhynchus mykiss, Salmo trutta, Oncorhynchus tshawytscha, Oncorhynchus kisutch, Ictalurus punctatus, Scomber japonicus, Larimichthys polyactis, Theragra chalcogramma, Apostichopus japonicus, Litopenaeus vannamei, Dicentrarchus labrax, Trichiurus haumela, tiger prawns, and several Cyprinidae species. The present article provides the most recent references and important theoretical bases for the development of more effective traceability and authenticity detection technologies for the famous, special, high-quality, and new aquatic products, promoting the implementation of national policies for rural revitalization. In addition, the establishment of local and national level databases is strongly suggested for effective geographical origin traceability of aquatic products in China.

AbstractIn recent years, there has been growing scientific and public interest in the protection of endangered aquatic animals, especially cetaceans. Chinese scientists have carried out numerous studies on marine mammals. However, only a few works have focused on the marine finless porpoise compared with the other two cetacean species/subspecies: Indo-Pacific humpback dolphins and Yangtze finless porpoises. Therefore, it is necessary to conduct systematic studies on marine finless porpoises. In this article, we reviewed the historical records, taxonomy, and studies on marine finless porpoises, particularly aspects such as the ecology, biology, conservation, genetics, acoustics, feeding, and breeding. In addition, further studies and conservation strategies are recommended accordingly, aiming to better understand and protect marine finless porpoise.

AbstractEchinodermata are important aquatic animals of commercial value in China. Enriched in proteins, amino acids, unsaturated fatty acids, and other physiologically active substances, they are considered healthy food with increasing consumer demand. Therefore, there is an urgent need to develop and industrialize echinoderm breeding. However, the high mortality rate, slow growth rate, and low nutritional quality during echinoderm breeding are the main bottlenecks limiting the development of the echinoderm industry. It is well known that marine animals require certain essential fatty acids, particularly n-3 and n-6 polyunsaturated fatty acids, for their normal growth, development, and immunity. Essential fatty acids can directly affect the development and survival of juvenile of echinoderms grown in aquaculture. To meet the nutritional needs of juveniles and adults, the supply of high-quality bait is essential to overcome these bottlenecks. Microalgae are rich in proteins, carbohydrates, vitamins, carotenoids, polyunsaturated fatty acids, and other nutrients, and have attracted increased attention in the development of new aquatic feed resources. Fresh bait for young animals is significantly better than artificial bait in promoting growth and improving survival rates. It is also widely used in breeding echinoderms. In this paper, the research progress on the application of microalgae and bioactive chemicals in typical commercial echinoderm (sea cucumber and sea urchin) farming and breeding were reviewed with respect to their effects on the growth, development, and impact on the larval growth. We have summarized the microalgae species commonly used in economic echinoderm breeding and the effects of microalgae on the fatty acid composition and immune status of sea cucumbers and sea urchins were analyzed. Furthermore, the challenges limiting the application of microalgae bait in echinoderm breeding and farming are discussed, and alternative solutions are offered for sea cucumber and sea urchin culture in China.

AbstractAlong with the development and innovations in genetic engineering and biotechnology, aquaculture breeding has expanded from traditional selective breeding and hybrid breeding to marker- assisted selective breeding, cell engineering breeding, genome-wide genotyping-based selective breeding, molecular design breeding, sex control breeding, gene transfer, gene editing, and other molecular marker-assisted breeding technologies. Although the aquaculture seed industry has advanced, several problems and challenges remain such as the low coverage rate of improved varieties and insufficient research depth. This review provides a detailed analysis of the main advances made in the field of aquaculture technology and summarizes the commercially valuable germplasm resources of echinoderms (sea cucumbers and sea urchins) and their applications. We also propose to the sea cucumber and sea urchin breeding industry to provide a reference for the development of germplasm resources for echinoderms of commercial value and promote the green development of the aquaculture industry.

AbstractEchinoderms hold the highest evolutionary status among the invertebrates and some species in the class Holothuroidea (sea cucumber) and Echinoidea (sea urchin) have very high economic and nutritional values. However, because of the impact of human activities, the number and biodiversity of several echinoderm species have severely declined, and germplasm degradation has been especially prominent in recent years, mainly manifesting as slow growth, frequent diseases, and low survival rates. Therefore, the preservation of germplasm resources is critical. Cryopreservation is an important method for the long-term preservation of germplasm resources. It has the advantages of breaking through geographical isolation, realizing distant hybridization, protecting germplasm resources, solving the problem of germplasm degradation, and protecting endangered species. This article reviews the progress in research on the cryopreservation of sperm of three major echinoderms (sea urchins, sea cucumbers, and starfish), and describes the various steps in sperm cryopreservation processes, such as sperm collection, extender and cryopreservation preparation, balance, cooling, thawing, and quality evaluation, to provide a ready reference for the future research and the industrial application of cryopreservation to echinoderm germplasm resources.

AbstractChina is one of the largest producers of cultivated mollusks and the production has increased steadily over the last 30 years. The aquaculture industry growing specific kinds of cultured mollusks in some localities or regions might suffer huge losses owing to infectious diseases. Mass mortalities of bivalves and small abalone (Haliotis diversicolor supertexta) associated with herpesviruses have frequently occurred since the 1990s, resulting in huge economic and social damages to related families and communities. Herpesvirus now represents the most destructive pathogen faced by mollusk aquaculture in China. Significant losses, which resulted from the epidemics associated with herpesvirus infection, have attracted enormous attentions in related sectors, including the scientific community. Epidemiological and etiological investigations showed that the herpesviruses infecting bivalves and abalone were Ostreid herpesvirus 1 (OsHV-1) and Haliotid herpesvirus 1 (HaHV-1). The outbreak of herpesvirus infection in mollusks not only happened in China but also in many other countries and regions around the world. Pacific oysters such as Crassostrea gigas were the most seriously affected bivalves. The significant loss associated with infectious diseases has attracted huge attentions from producers and researchers in the mollusk aquaculture sector around the world. To mitigate production loss associated with herpesvirus infection in mollusk aquaculture, researchers have investigated the characteristics of OsHV-1 and HaHV-1 viruses, their geographical distribution, susceptible hosts, epidemiological characteristics, and disease diagnosis and have tried to find ways to prevent and control them, including the use of disease resistance breeding. Large investments in scientific research has made OsHV-1 and HaHV-1 the most well studied viruses of mollusks. They also represented the only two mollusk viruses with clear classification status. In this study, we summarized the recent progress related to OsHV-1 and HaHV-1, with an emphasis on the occurrence, spread, damage, and disease control practices in China.

AbstractMarine biodiversity and its sustainable use are threatened by climate change and human activities, and research on this topic has drawn increasing interest worldwide. We used bibliometrics and knowledge mapping analysis to review information related to marine biodiversity indexed in the ISI Web of Science Core Collection database. We created descriptive statistics of the number of articles published annually, the journal frequency, and the country distributions. Then, the author, institution cooperation network, and keyword-based knowledge mapping and burst analysis were used to explore hotspots of marine biodiversity research. The descriptive statistics suggest that the number of studies has increased in recent decades, and scientific research influence and international attention are very high. Authors and institutions have formed frequent and stable cooperative networks. Author cooperation has formed core authorships, such as Miloslavich P., Danovaro R., and Mouillot D. Institutional cooperation has enabled extensive collaborations among James Cook University, the University of Tasmania, and the University of British Columbia. Ecology, biodiversity conservation, marine freshwater biology, and environmental sciences are the main disciplines of marine biodiversity. Burst analysis showed that current marine biodiversity research has five study frontiers: (1) the impacts of human activities and climate change on marine biodiversity, (2) the protection and sustainable utilization of marine biodiversity, (3) the establishment and management of marine protected areas beyond national jurisdictions, and the protection of ecologically or biologically significant marine areas, (4) the observation and evaluation of marine biodiversity and ecosystem change, and (5) marine genetic diversity and geographic variations in diversity.

AbstractReef fish are expensive, but owing to overdevelopment, environmental pollution, and global warming, reef fish resources are collapsing and their habitats are undergoing varying degrees of degradation. In order to solve the stress in the global marine ecological environment and its resources, the construction of marine ranching based on artificial reef and stock enhancement and release has become the main strategy for protecting aquatic organisms in coastal countries. By researching the behavioral ecology of reef fish, analyzing their reaction to reef structure and artificial habitat and the effect of artificial environments on fish, the fish release strategy will be optimized, survival rate will be increased, resources will be protected, and artificial reef constructions will be more scientific. Therefore, in this paper, research progress on the behavioral ecology of reef fish, both in China and abroad, was summarized, including habitat selection and foraging, aggression, territorial and defensive behaviors. Moreover, the importance of reef fish behavioral ecology on resource protection and development was analyzed. Meanwhile, existing problems in the behavioral ecology of reef fish were discussed, and suggestions put forward, to provide a more scientific theoretical basis and more efficient technical scheme for the development of marine ranching in China.

AbstractSalmon and trout are typical cold-water fishes with high economic values; they are among the most important economic fishes in the world. However, with increasing aquaculture density, the aquaculture environment is becoming increasingly degraded. The occurrence of salmon and trout parasitic diseases and corresponding damage to fishes are also increasing. These factors severely restrict the healthy development of the industry. Common and severe parasites of salmon and trout are Gyrodactylus, Caligus rogercresseyi, Neoparamoeba perurans, Myxobolus cerebralis, Tetracapsuloides bryosalmonae, and Kudoa spp. These parasites have simple life cycles and rapid reproduction rates. Most of them inhabit the skin and various organs of the fish body, thereby slowing growth and weakening the resistance of the fish. This effect damages the fish body and eventually kills the fish. Physical control methods and chemicals are used in combination for comprehensive prevention and control. This paper reviews the research progress and achievements in the field of the common parasitic diseases of salmon and trout to provide useful references for the research and control of such diseases.

AbstractIn this review, we have provided an overview of the current knowledge on the different molecular mechanisms of sex differentiation in major economic bivalves. The representative species of bivalves were introduced to understand the different mechanisms of sex differentiation or sex determination. The review provides a brief summary of the recent discoveries on sex differentiation in oysters, scallops, pearl oysters, and other common economically important bivalve species. The review highlights the various sex differentiation-associated molecular mechanisms by focusing on the involvement of nucleic acids, proteins, hormones, and so on. The current research trends on sex differentiation in bivalves have been discussed, which may help to advance our understanding of the sex differentiation and gonadal development of the Yesso scallop and other bivalves.

AbstractWith the development of fishery technology and people's improving living standards, the demand for aquatic organisms has gradually increased. Whether in terms of economic value, ornamental value and educational significance, aquatic organisms have gradually become an indispensable part of our lives. However, aquatic organisms especially fish still have a low level of welfare in the process of the breeding, transportation and display. Finding a suitable method to solve the problems of low welfare of aquatic organism has become an important issue for improving aquatic organism welfare. As one of the technical means to improve the welfare of captive animals, environmental enrichment can increase the living conditions and welfare of captive animals by adding some stimulating factors to the captive environment, so as to make the captive animals have normal psychological and physiological health and show their natural behaviors. At present, compared with foreign countries, domestic researches on environment enrichment of aquatic organisms is still in its infancy. Using environmental enrichment technology to improve the living conditions, ensure and enhance the level of welfare of aquatic organisms has become a research hotspot. Therefore, based on the review of the research progress and application of environmental enrichment technology in aquatic organisms at home and abroad, this paper divided the environmental enrichment technology of the aquatic organisms into four categories, discussed the existing problems of environmental enrichment technology and put forward some suggestions, in order to provide more scheme reference and theoretical basis for environmental enrichment technology of aquatic organisms.

AbstractSeagrass is a kind of higher angiosperm that originated as a terrestrial plant and over time became adapted to a marine environment. Seagrass beds have important ecological and economical value in that they provide habitats and feeding areas for diverse marine fauna, playing a key role in establishing a flourishing marine ecosystem. From 1993 to 2003, the seagrass acreage lost reached 2.6 × 106 hm2. The first estimated acreages of seagrass beds were recorded in 1879, and based on historical records, it is estimated that more than 5.1 × 106 hm2 of seagrass beds have completely disappeared. With the severe decline of seagrass beds and the public’s recent awareness of their ecological functions, seagrass bed ecological restoration has become one of the more important coastal, environmental engineering projects. Habitat enhancement is the main method utilized in seagrass bed restoration. Currently, seagrass bed restoration is in urgent need of well-organized planning, and large-scale artificial propagations have become vital to current habitat restoration. In order to significantly increase the quantity and efficiency with which seagrass is propagated, this study was to understand the characteristics of seagrass shoot clonal propagation, and determine what techniques would allow efficient plant propagation. In order to achieve highly efficient seagrass shoot propagation, it is necessary to: 1) Promote growth and propagation of key factors; 2) Construct and implement an artificial propagation platform; and 3) Disseminate the growth and propagation planting technique. In this study, the current state of research and knowledge of shoot propagation and planting of seagrasses was reviewed, the environmental factors affecting the growth and development of seagrass shoots was summarized, and the effect of planting space, planting time, and fertilization on the seagrass shoot growth and production was discussed. In addition, the key problems existing at present were summarized. Given the advances in research and public desire to restore damaged ecosystems, there is strong potential for large-scale restoration of damaged seagrass beds along the coast of China in the future, and the summaries provided here will hopefully be a useful reference to these projects.

AbstractAquatic products may be contaminated by microorganisms during storage and transportation, leading to product spoilage and quality deterioration. Aquatic products are prone to deterioration by decomposition, putrefaction, degradation of proteins and amino acids, and production of basic amines. Pretreatment by sterilization is required to reduce the effects of microorganisms on the quality and shelf life of aquatic products during processing and storage. The mechanisms, main advantages, and disadvantages of common water treatment methods, including electrolysis or ozonation of water and use of chlorine dioxide solution were compared and analyzed. The research focused on the application of ozonated water in the sterilization and preservation of aquatic products. Ozone exhibits strong oxidizability as well as bacteriostatic and bactericidal effects. In addition, treatment with ozonated water is convenient and plays an important role during storage and preservation by spraying, immersion, and flowing water treatment. Ozonated water is widely used to bleach and decolorize fish fillets and surimi products and to remove strong scents. Additionally, it is also used for product sterilization and preservation, and for cleaning and disinfection of processing equipment. However, ozonated water is associated with poor stability, which may affect its sterilization ability. Therefore, the combination of ozonated water with other preservation technologies may prolong the shelf life of aquatic products to a greater extent than that by ozonated water alone. The combination of ozone water with slurry ice, modified atmosphere packaging, and other freshness preservation methods were described. Researchers should consider using orthogonal experiments or response surface methodology to identify the optimal treatment concentration and duration, and to develop optimal process parameters based on the individual characteristics of different aquatic products.

AbstractWith the increase of fishing intensity, fish gradually evolve to adapt in response to fishing pressures to maintain the reproduction of the population. This process is called fishing-induced evolution (FIE). Nowadays, many fish in the world have evolved these biological characteristics. For example, Atlantic cod (Gadus morhua), small yellow croaker (Larimichthys polyactis) and other fish became smaller size and earlier mature. These lead to further the simplification of fish population structure, the decline of ecosystem stability and the reduction of fishing economic benefits, finally FIE seriously affects the sustainable development of fish resources in many countries. Therefore, it is essential to recognize the fishing-induced adaptive evolution and grasp the mechanism of fishing effects on fish resources, in order to formulate a scientific and rational strategy for recovery and management of fishing resources. Although FIE has caused wide concerns, the mechanisms underlying the impact of fishing on physiological, ecological and genetic characteristics of fish are not clear, especially in the dynamic environment of climate change and multi-species interactions. The role of FIE is more complex due to a number of influencing factors and the complex evolutionary process. The existing studies mainly focus on fishing-induced changes in fish biological traits, computer-simulated population resilience and fish resource management strategies, but rarely on the mechanisms of FIE. Here, we reviewed the main research methods of fish FIE including methods of field ecology, experimental ecology, numerical simulation, and genetics. We summarized the related research results that fishing affects fish body length, sexual maturity, behavior and other factors, by selecting the larger individuals caught by the most important kind of fishing, bottom trawling, and analyzed the effects on the fish population recovery and management of fish stocks. Finally, we concluded that the key scientific problems to be solved, in order to provide help for further FIE research and scientific management of fish resources.

AbstractMelanocortins are the products of the precursor protein proopiomelanocortin (POMC) with extensive localization in the central nervous system and peripheral tissues. Melanocortins play important roles in the skin, stress response, immune system, feeding behavior, and sexual function. In recent years, the -melanocyte stimulating hormone (-MSH) and melanocortin-4 receptor (MC4R) have received considerable attention for their regulation of energy homeostasis and reproduction. Previous studies have shown that POMC, -MSH, and MC4R regulate food intake and the reproductive system by mediating the secretion of hormones related to the hypothalamic-pituitary-gonadal (HPG) axis. In this review, we summarize the physiological functions of POMC, -MSH, and MC4R in energy homeostasis and reproduction. We also summarize the results of several studies reporting the pharmacological characteristics of teleost MC4R and discuss the potential commercial applications in aquaculture.

AbstractMarine plastic pollution has become a major global environmental issue combined with global climate change, ozone depletion, and ocean acidification. Microplastics (less than 5 mm in diameter), as emergent contaminants, are of great concern globally. Available studies show that microplastics are present in marine fisheries waters, and marine fishery organisms, an important source of high-quality protein for humans, have been contaminated by microplastics. Therefore, the study on microplastics pollution in marine fishery waters and their biological effects has attracted increased attention. In the present study, we summarized the main sources of microplastics in marine fishery waters and their pollution status, summed up the main toxic effects of microplastics on the marine fishery organisms and the corresponding toxicity mechanisms, discussed the transfer of microplastics along the marine food chain and their potential impact on the quality and safety of seafood, analyzed the current problems, and finally, provided the outlook for future work. This study provides a scientific basis for better evaluation of the effect of microplastics on the marine fisheries resources as well as seafood quality and safety.

AbstractMetabolic diseases, which are always characterized with abnormal lipid metabolism and severe fat deposition, have been commonly observed in farmed fish. However, the causes of the abnormal lipid metabolism in fish are complicated and difficult to be identified. In recent years, several studies have shown that environmental endocrine disrupting chemicals (EDCs), which are widely spread in the aquatic environment, not only have chronic toxic effects on fish development and reproduction, but also affect fish lipid metabolism and cause severe fat deposition, which would damage the quality and food safety of farmed fish. For the first time, this review systematically reviews the effects of EDCs on fish lipid metabolism. Persistent organic pollutants (POPs), heavy metals (Hg, Pb, Cd and Cu), environmental estrogens and artificially synthesized medicines (fibrates and antibiotics) are four major EDCs in water environment. In general, water or dietary exposure of these EDCs would disturb the biochemical activities and/or expressions of the enzyme proteins in the lipid metabolism pathways, including upregulating lipogenesis, inhibiting mitochondrial fatty acid β-oxidation, adipose tissue lipolysis and lipid transport cross tissues, and so on. The exposure of EDCs with high doses would also impair the functions of cellular organelles, such as mitochondria and peroxisome, which are important in the lipid metabolism. Recently, the disturbing effects of EDCs on some lipid metabolism-related nuclear receptors, such as peroxisome proliferators-activated receptors (PPARs) and sterol-regulatory element binding proteins (SREBPs), had also been found. However, it should be pointed out that among these EDCs, they also have specific mechanisms in affecting fish lipid metabolism and tissue deposition of fat. Even in the same EDC, different exposure method, duration and doses would also cause different effects in disturbing lipid metabolism in fish. In future research, more attentions should be paid on the endocrine disturbing effects of new environmental pollutants, combined effects of different EDCs, and the molecular mechanisms of EDCs effects. This review is helpful in studying EDCs in fish metabolism and also provides important theoretical supports for green and sustainable aquaculture development.

AbstractThe ovate pompano Trachinotus ovatus is a marine fish species with important economic value, whose culture was developed rapidly in recent years in China, and the annual cultured output has reached about 120,000 tons, which has become one of the most potential cultured marine fish in southern China. Up to now, there have been a lot of reports on its nutritional requirements and feed, however studies on some nutrients are still absent. This paper summarized the requirements of pompano on protein, amino acids, lipid, fatty acids, carbohydrates and micronutrient, dietary replacement of fish meal with other protein resources and fish oil with other lipid resources, as well as the application of functional feed additives. Available data showed that the optimum dietary requirements of juvenile golden pompano for protein, lipid and carbohydrate are 41%~49%, 6.5%~12% and 11.2%~16.8%, respectively. The optimal requirements for lysine, arginine, methionine, isoleucine, leucine, linolenic acid and arachidonic acid have also been determined. Preliminary studies on the replacement of dietary fish meal (FM) and fish oil (FO) with other protein or lipid resources have been conducted, and the results showed that the suitable substitution levels of FM by soybean meal (SBM) or fermented soybean meal (FSBM) are 20%~50%. When certain amount of FM was added in diet, it is feasible to replace FO with other animal or vegetable oils. The optimum dietary addition levels for soy isoflavone, chitosan and fermented product of Rhodotorula mucilaginosa are respectively 40 mg/kg, 4.0 g/kg and 500 mg/kg. However, studies on the requirements of vitamins and minerals are not reported. Besides, fewer studies were conducted on the nutritional requirements of fish during different growth stages or in different cultured patterns. We hope that this review can provide reference for the study of accurate nutrition and development of high-efficient, low cost and environment-friendly formula feed, and thus promote the healthy and sustainable development of T. ovatus aquaculture industry.

AbstractSaccharina japonica is one of the most economically important seaweeds in China. Because of both internal and external forces, S. japonica farming in offshore waters has begun to emerge in China. Focusing on offshore aquaculture of S. japonica, this paper contains a discussion of the definition of inshore and offshore aquaculture of S. japonica, compares the advantages and disadvantages of these two aquaculture methods, and analyzes the driving forces of S. japonica offshore aquaculture. We also summarized the current situation and problems involved in S. japonica offshore aquaculture and proposed the development of a strategy, with the hopes that the discussion herein will provide new ideas and concepts for the healthy and sustainable development of S. japonica offshore aquaculture.

AbstractThe tropical South China Sea has profound development potential for its wide sea area, excellent marine environment, high biodiversity, and abundant bio-resource species. Recently, under the background of coastal fishery resource degradation, it has become vital to speed up the protection and sustainable utilization of tropical island fishery resources in this area. Marine ranching is a new type of modern fishery, which combines habitat remediation, bio-resource restocking, leisure fishery, and landscape ecology. It can help to develop the marine economy together with effective protection of the ecological environment. The development of marine ranching in the wide, tropical South China Sea area has been slow. There are several advantages to carrying out marine ranching in the tropical South China Sea, such as in political, natural habitat, bio-resources, and industrial economy aspects, etc. Two appropriate marine ranching types were identified, including stock enhancement and tourism and leisure types. The progress of tropical coastal and offshore island marine ranching construction in Guangdong, Guangxi and Hainan provinces were reviewed, especially the first successful construction of island marine ranching around Wuzhizhou Island in Sanya and the first coral reef marine ranching at Lingyang reef in Sanshan. Several potential risks affecting tropical offshore island marine ranching development were also documented, such as extreme weather (typhoon), predators, poor basic living facilities on islands, long distance for transportation, application difficulty on the using right of the marine ranching construction area, expensive fees for use of the sea area, etc. Based on considerations above, we provide detailed suggestions, including scientifically selecting sites, optimizing artificial facility design, developing new anti-corrosion reef material, deployment protocols, and anti-wave mooring techniques. We also give suggestions for: development of predator prevention techniques (to increase the recapture rate of released animals); development of automatic operation, monitoring, and management systems; development of feasible investment and operation modes; and more policy support from the government.

AbstractToxins produced by harmful algae has been a global food safety issue in aquaculture industry. Unlike conventional phytoplankton and shellfish monitoring techniques, solid phase adsorption toxin tracking (SPATT) simulates the contamination of filter feeding bivalves and employed passive sampling of adsorption substrates. Combined with appropriate assays such as HPLC-MS/MS and ELISA that purify and analyze algal toxins, SPATT gives early warning of harmful algal blooms and the subsequent contamination of shellfish. In this review we discussed the progress and prognosis on studies of SPATT. We elaborated the advantage of SPATT in detecting marine toxins including diarrhetic shellfish poisoning, paralytic shellfish poisoning, amnesic shellfish poisoning, ciguatoxins, cyanotoxins, and homoanatoxins. We also summarized the function of different absorbent resins such as HP-20, SP-70, SP700, SP850, SP825L, XAD4, and L-493. SPATT is an inexpensive and convenient tool for fast detection of algal toxins.

AbstractThe inshore water areas are the major habitats and fishing grounds of many commercial species. Chinese inshore fisheries accounts for more than 90% of the total marine catches, and is an important resource of high-quality proteins for Chinese people. Currently the inshore fishery resources have been markedly declining due to the combination of overfishing and other excessive human activities (e.g. large-scale reclamation, pollution and mariculture). The sustainable production of many inshore fishery species has been impaired by adverse ecological change, such as the eutrophication-induced red tide and jellyfish bloom, and the fragmentation and defunctionalization of spawning and nursery grounds caused by the loss of wetlands. The recruitment of fishery populations is generally regulated by the interaction between the biological and physical processes in marine ecosystems which can be largely affected by the changes in environmental factors. To better understand the succession of marine ecosystem and sustainable yield of marine fishery populations, it is crucial to investigate how environmental changes affect the habitats and recruitment of fishery populations, especially at their early life stages. In this paper we reviewed literatures regarding these topics and analyzed the current situation of Chinese inshore fishery and the relevant problems of inshore ecosystems. We proposed and discussed four promising topics in future study: 1) fundamental and long-term changes in spawning and nursery grounds of fishery populations; 2) recruitment of fishery populations and the environmental driving forces; 3) adaptive strategies of fishery populations to environmental changes; and 4) evaluation of the effects of environmental changes on fishery population dynamics. These prospective studies are expected to provide essential knowledge that helps with the conservation of fishery habitats and resources as well as the improvement of sustainable development of inshore fisheries in China.

AbstractSea urchin embryo and larvae in the early developmental stages is an important model for research on marine ecological toxicology. Sea urchin dopaminergic (DA) nervous system develops earlier than the cholinergic system, and it starts to regulate the morphogenesis and swimming behaviors much earlier than the serotonergic system. Here we used sea urchin in the early developmental stages as a model and reviewed the development and the functions of the dopaminergic nervous system. The synthesis of dopamine and the receptors precedes the development of the dopaminergic nervous system. The dopaminergic neuron precursor cell period starts after the synthesis of DA and the receptors. In this period DA and DA receptor 1 (DRD1) appears in the form of granules of which the diameter is 1-2 μm (DA/DRD1-Gs), and they are also expressed on the surface of the embryo and larvae from the rotational blastula stage to the metamorphosis stage. After the aggregation of DA/DRD1-Gs, dopaminergic cells with the axon contacts begin to develop in the labial ganglion and the base of the back oral arms in the early four-wrist larval stage. The number of dopaminergic cells reached the maximum in the eight-wrist larval stage. Then the dopaminergic nervous system continues to develop until the maturity. The morphogenesis in the early developmental stage is regulated by several neurotransmitter systems together, and the swimming behaviors in different early periods can be regulated by either the dopaminergic nervous system alone or together with other systems. In the end, we assessed the prospective studies on issues, such as the factors affecting the development of the dopaminergic nervous system in the early developmental stages of sea urchin, the functions and the signaling pathway of DA receptors, the primary-secondary relationship and the mechanisms of the up-/down-regulation of the three important neurotransmitter systems in early morphogenesis and swimming behaviors, and the influences of neurotoxic substances on the development of the dopaminergic nervous system.

AbstractAquatic multi-trait integrated breeding system is an important selective breeding technology to improve economic traits of aquatic animals in China. It has been a vital issue how to select and mate the broodstock candidates to maximize the genetic gain at a defined rate of inbreeding in the breeding system. The optimum contribution theory (OC) has become an effective tool to establish equilibrium between the genetic gain and the inbreeding in the nucleus population. In this review we introduced the establishment and development of optimum contribution theory, the characteristics of different optimization algorithms, and its application in selective breeding of plants and animals. Three algorithms, Lagrange multipliers, Semidefinite programming and Differential evolution, have been used in the calculation of optimum genetic contribution. At equal rates of inbreeding, genetic gains calculated with Lagrange multipliers were 21%–60% greater than that with selection for BLUP-EBV. An improved algorithm based on Lagrange multipliers was invented for the calculation of optimal genetic contributions in the case of large number of candidates in the aquatic animal population. The additive relationship matrix between the selection candidates and the inverse of this matrix was replaced with the relationship matrix between the parents of the selection candidates and its inverse in the calculation of the optimal genetic contribution of the selection candidates to the next generation. Lagrange multipliers did not guarantee that the final solution is the global maximum; on the contrast the SDP method could always find the optimum solution that maximized the genetic gain using the interior point algorithms. The expected gains obtained from the Semidifinite programming were 1.5%–9% greater than that from Lagrange multipliers. Individual selection and mate allocation could be performed using Differential evolution algorithm. Many issues including genetic gain, diversity, progeny inbreeding, connections among farms, multi-stage selection, management of genetic marker, and various types of costs could be contained in the object function and be optimized. Genetic gain and the accuracy of optimum contribution could be increased using the pedigree and genomic information at predefined rate of inbreeding. The inbreeding level of selective breeding population was effectively controlled and genetic gains of object traits were 17%–30% greater than that of selection for BLUP-EBV in the livestock and forest breeding. New progress on the OC theory based on genomic information was also reviewed. The prospect of application of optimum contribution theory in aquatic selective breeding was analyzed in order to provide reference and guidance in aquatic animal breeding.

AbstractPhospholipid is the predominant polar lipid which plays a central role in growth performance, survival, salt-resistance, and temperature tolerance for fish, especially for the larvae. The biological characters of phospholipid, its digestion, absorption and transport in fish, its synthetic pathways, and the interactions between phospholipid and cholesterol were introduced in this review. Moreover, differences in the requirements of phospholipid between fish and crustacean were compared, in order to provide a theoretical guidance for the applications of phospholipid in fish culture.

AbstractFlow-through system for flatfish farming is transforming into industrialized Recirculation Aquaculture Systems in China,but development of the industry is greatly hampered by fish diseases. Currently, the main control methods against aquatic animal diseases include drug treatment, ecological prevention, and immunoprophylaxis. With the advantages of no pollution, no residue, and no drug tolerance, fishery vaccine possesses an overwhelming superiority, and its related research has attracted more and more attention. In this review, progresses and challenges on the study of fishery vaccine were summarized and analyzed to provide references for disease prevention and control in flatfish.

AbstractTurbot Scophthalmus maximus, a marine finfish with fast growth and strong tolerance to cold water temperature, is the most widely cultivated commercial flatfish around the world with the highest annual aquaculture production. From its introduction into China in 1992 to now, its aquaculture has developed into one of the dominant mariculture industries in China with an annual production of more than 60,000 tons. The progress and achievements on the industry development, seed production, selective breeding, culture modes, nutrition requirements and artificial feeds, disease prevention and control, processing and quality control, market and aquaculture economy during the past two decades, are reviewed. Further research and industry development priorities in turbot culture are also suggested. This paper also provides the necessary referential information for the development of turbot culture in China.

AbstractFish cell culture techniques are important and promising tools for biology studies. With the development of biological technology, an increasing number of fish cell lines have been established. Although the procedures for developing fish cell lines varied with cell sources, basic principles were similar. In this paper, the status of fish cell culture development, application and characteristics as well as culture techniques were reviewed, with emphasis on the perspectives for fish cell culture development.

AbstractDominant industry areas of sea cucumber Apostichopus japonicus Selenka aquaculture had been constructed in Shandong Province, which is one of the main sea cucumber producing areas in China. Yantai, Weihai and Qingdao constituted the major culture regions in Shandong Province, and they are the leaders in the development of sea cucumber aquaculture industry. Dongying and Binzhou areas are emerging industry belt for introduction and development of sea cucumber aquaculture, which indicated that it is feasible to culture sea cucumber in western area of Shandong Province. Rizhao and Laizhou areas are a new industry belt of sea cucumber culture representing deep water well greenhouse factory culture model, which is the new spotlight in sea cucumber aquaculture industry since 2007. In this paper, the problems and challenges in sea cucumber aquaculture industry are summarized and the corresponding strategies are proposed. It will be helpful for the healthy and sustainable development of sea cucumber aquaculture industry in Shandong Province, and in other areas of China, and it may provide theoretical and technical basis for decision making of relevant authorities.

AbstractThe Mugilidae family is an important fish group distributed throughout the world, inhabiting the fresh, estuarine and coastal waters. Mugil cephalus and Liza haematocheila are the two important economic species in Mugilidae family. Mugilidae are one of the most important foraging and detritivorous fishes. They feed by sucking silt or scraping rock and plant surfaces, acting as a scavenger and changes material cycle process in an aquaculture ecosystem. Mugilidae are an important fish for both fisheries and aquaculture purposes. The resources exploitation and ecological culture of Mugilidae not only improves the fishery structure, but also reduces the pollution of the cultured water, ensuring the sustained and healthy development of the aquaculture industry. The prospects of resources exploitation and ecological culture of Mugilidae in China are proposed in this paper.

AbstractCynoglossus semilaevis Günter, a deep water flat fish species, is a popular marine species in aquaculture with high market value and a good taste.Although techniques of large scale artificial breeding have made significant break through in recent years, which resulted in a successful seedling breeding of C. semilaevis, C. semilaevis culture was not successful due to a difficulty in feeding with pelleted diets under industrial conditions. To solve the problems, study of the sensory mechanisms of the tongue sole in feeding is of special significance. The feeding mechanisms of C. semilaevis were reported in this paper according to the late research. The author suppose that C. semilaevis has two possible feeding modes. For motile prey, fish use mainly lateral line and gustation in the oropharyngeal cavity for the detection and recognition of prey, and for still prey, olfactory organ and papillae on the abocular side of the head for the detection and recognition of prey. Based on these studies，the author confer that both stimulating the chemistry sense organ and stimulating the mechanism sense organ should be considered to improve the feeding.

AbstractPectenotoxins are a group of lipophilic toxins produced by dinoflagellates. There are 14 pectenotoxin analogues which have been confirmed. The profiles and the concentration of pectenotoxins are different in toxic algal and shellfish from different countries. The lethality of pectenotoxins by intra peritoneal injection is higher than by oral administration of mouse. At present, there are no internationally accepted criteria of maximum residue limits of pectenotoxins for shellfish. The total amount of pectenotoxins can be tested by mouse bioassay. The concentration levels of individual pectenotoxin can be analyzed by HPLC MS methods. The enzyme linked immuno sorbent assay(ELISA) method for determination of pectenotoxin is under development. In China, few studies on pectenotoxins have been carried out. The studies on profiles and metabolism of pectenotoxins in shellfish are recommended.

Abstract多溴联苯醚(PBDEs)作为阻燃剂被广泛用于电子电气设备和各种复合材料里。国内外研究证明，PBDEs是一种新型的全球性的环境污染物，会对生物肝脏、肾脏和神经系统的发育造成毒害，同时干扰甲状腺的内分泌,也会诱导有机体突变或致癌。检测结果显示，全球海洋环境中PBDEs污染是普遍的。本文概述了多溴联苯醚的特性及其对海洋污染状况，提出了遏制多溴联苯醚对海洋污染的应对措施。

AbstractA brief introduction to the research work and methodology of a number of foreign fisheries research institutes is reviewed in this paper, focusing on research fields such as the marine ecosystems, ecosystem restoration, sustainable use of marine resources, environmental monitoring, pollution monitoring and control, fishing technology optimizing, ecological and industrialized aquaculture, application of genetic technology for breeding improved species, the gene database of important species, the early development and sexual maturation of fish, etc. A brief comparison is made between research fields of China and foreign institutes.

AbstractThis paper reviewed the research progress of protein, lipid and vitamin requirement for marine fish larvae. Meanwhile, it introduced characteristics and production technology of microdiet. This review is expected to be a reference for the development of formulated diet of marine fish larvae.