Abstract:

Abstract:The biological indices of Coilia mystus were studied based on samples collected from May to July 2018 and May and August 2019 in the Yangtze Estuary. The results showed that the average condition factor (K) of female C.mystus was 0.32%, and that of male C.mystus was 0.37%. The average gonadosomatic index(GSI) of female was 18.58%, and that of male was 7.47%. In 2018 and 2019, the egg diameter of C.mystus in the Yangtze Estuary was 0.68 mm and 0.70 mm, respectively. Compared with previous studies, the egg diameter of C.mystus tended to be smaller. The average absolute fecundity of C.mystus in 2018 and 2019 were 11 621 and 6 131, respectively. The difference in absolute fecundity between 2018 and 2019 may be caused by the fecundity difference between different generations. The absolute fecundity and body length relative fecundity of C.mystus were positively correlated with body length, body mass, net body mass and gonad mass, and the body mass relative fecundity (F_W) was significantly correlated with gonad mass and gonadosomatic index. Individual fecundity is most closely related to gonadosomatic index. Stepwise regression showed that the relationship between absolute fertility and biological indices was as follows:F=5 059.50W₁+1 009.00(R²=0.73); F_L=22.77W₁+27.71 (R²=0.76); F_W=2 614.35I_GSI-40.67W₁+412.41(R²=0.60).The spawning fraction of C.mystus in 2018 and 2019 were 0.26 and 0.24 by migratory nucleus method. The difference in sampling time may have caused the annual difference in spawning fraction. The study on the individual fecundity and the spawning fraction of C.mystus in the Yangtze Estuary could provide a key parameter for assessing the spawning stocks biomass of C.mystus in the Yangtze estuary by using the daily egg production method. It provides some reference for the evaluation of restoration effect of C.mystus resources in the Yangtze Estuary in the future.

Abstract:The Northern Mauxia Shrimp Acetes chinensis is widely distributed in the offshore of waters Northwest Pacific Ocean, especially being abundant in coastal waters of the Bohai Sea, the Yellow Sea, and the East China Sea. A. chinensis accounts for a great proportion of total shrimp catch in China, South Korea, and Japan. Moreover, it plays a pivotal role in the marine ecosystem as a primary consumer in the offshore marine food web and as the main bait for economic fish. This review presents a comprehensive account of the history and current knowledge on the growth development, reproduction, feeding, and migration of A. chinensis. We take the opportunity of A. chinensis in Haizhou Bay under the pilot of marine fisheries total allowable catches (TACs) and A. chinensis in the adjacent waters of Daya Bay Nuclear Power Station causing disasters to discuss how to utilize and control it under different circumstances. And, based on the summary and analysis of existing research results, we have drawn a sketch map of alternation of generation and migratory routes between spawning and overwintering grounds to gain further insight into the sustainable exploitation and ecological safety of A. chinensis.

Abstract:During a survey of freshwater diatoms from Dongzhen reservoir in Putian City, Fujian Province, China, a newly recorded diatom, Navicula gondwana Lange-Bertalot was discovered. This species was first reported in Australia, but the original scanning electron microscope (SEM) images of the external valve were limited, and the internal valve SEM images were not provided. Based on the application of light microscope (LM) and SEM, the morphological characteristics of the population of Navicula gondwana Lange-Bertalot collected from Fujian were observed and described, and compared with the morphological characteristics of its holotype species and other similar species. The results show that:(1) Navicula gondwana Lange-Bertalot valves are narrowly lanceolate and the ends are rounded. (2) The raphe fissures are simply straight, the proximal raphe end is slightly enlarged and inclined to the valve side, the terminal raphe end extends into a strong hook shape, and two ends' orientation is the same as the proximal raphe end. (3) The axial area is narrowly linear and the central area is irregularly circular. (4) The striae of valves are composed of uniseriate short-lineate areolae, which are arranged radially in the middle and gather at both ends, and there are 11~14 striae within 10 μm. The results of this study are consistent with the morphological and lineal characteristics of Navicula gondwana Lange-Bertalot, so it was identified as Navicula gondwana Lange-Bertalot, which is the first report from the freshwater area in China.

Abstract:Acute hypoxia in water has always been a thorny problem in aquaculture, and iron metabolism plays an important role in hypoxic stress in fish. To explore the effect of iron concentration on hypoxic stress in fish, Ammonium ferric citrate (FAC) and Deferoxamine (DFO) were used to supplement exogenous iron and remove endogenous and exogenous iron in ZFL cells, so as to compare the response of ZFL cells to hypoxic stress at different iron concentrations. The results showed that hypoxic stress significantly reduced the proliferation ability and survival rate of ZFL cells and the expression of iron metabolism-related genes, while supplementation of exogenous iron significantly enhanced the proliferation ability and survival rate of ZFL cells under hypoxic stress compared with the control group and the group of scavenging of endogenous and exogenous iron. Meanwhile, the mRNA expression levels of iron absorption (tfa), iron storage (fthl27, fthl28, fthl31) and iron output (fpn) were significantly increased, when ZFL cells under hypoxic stress were supplemented with exogenous iron. Furthermore, the detection of reactive oxygen species (ROS) levels in ZFL cells under hypoxic stress showed that supplemental exogenous iron could restore ROS levels in ZFL cells to a certain extent, indicating that the increase of intracellular ROS level in a certain range is beneficial to the resistance of ZFL cells to hypoxic stress. In conclusion, this study found that when ZFL cells were in acute hypoxia, supplemental exogenous iron ions could increase intracellular iron level, thus producing certain beneficial ROS and contributing to improving their survival rate in hypoxia environment.

Abstract:Voltage-gated sodium channels (VGSC) play an important role in the initiation and propagation of action potentials in vertebrate cranial nerves. To investigate the role of zebrafish voltage-gated sodium channel member scn1Laa in cranial nerves, the CRISPR/Cas9 approach was used to establish a stable hereditary scn1Laa-deficient (scn1Laa^-/-) zebrafish without significant effect on growth. Compared with wild-type siblings, there were more GABAergic neurons (inhibitory neurons) in scn1Laa-deficient larvae at 5 dpf (5 days post-fertilization), while glutamatergic (excitatory neurons) and mature neurons were significantly reduced. Besides, cell proliferation in the brain was also reduced at 5 dpf. The movement of scn1Laa-deficient zebrafish at 5 or 90 dpf was more active than that of wild-type siblings at the same time, and the burst movement of scn1Laa-deficient zebrafish was observed at 90 dpf. These results showed that loss of scn1laa made excitatory neurons (glutamatergic neurons) decrease and reduced cell proliferation of cranial nerve, which affected the discharge of peripheral nerve, causing motor nerve dysfunction and abnormal motor behavior. Above all, the voltage-gated sodium channel scn1Laa participates in the development and functional maintenance of the zebrafish cranial nerve and indirectly participates in the regulating behavior with limited influence on body growth. At the same time, this research also lays the foundation for further exploration of voltage-gated sodium channels in the cranial nerves.

Abstract:Invading virus is recognized by one of pattern recognition receptors, RIG-I-like receptor (RLR), to activate antiviral RLR signaling pathway. Abnormal activation of PRRs will lead to chronic inflammation, immune organ damage, and even autoimmune diseases. In order to prevent the premature or excessive activation of antiviral signals, the body has established a perfect regulatory system to prevent the disorder of signal transduction process. Post-translational modification (PTM) of proteins is a key mechanism for regulating the stability and activity of pattern recognition receptors and their downstream signaling proteins, while ubiquitination (UB) is an important part of protein post-translational modification in antiviral signaling pathways and has extensively studied. Of these, K48- and K63-linked ubiquitination is the most common:K48-linked ubiquitin chains can cause degradation of target proteins via the proteasomal pathway, while K63-linked ubiquitin chains can promote protein activation and cell signaling. RIG-I, MAVS, TBK1 and TRAF family member proteins are the signaling molecules of RLR signaling, and the ubiquitination mechanism of these proteins has also been studied. This paper discusses the research progress of K48 and K63 ubiquitination in antiviral immune signaling pathways, especially the ubiquitination modification of proteins in signaling pathways triggered by RIG-I-like receptors.

Abstract:Interleukin-34 (IL-34) is a multifunctional cytokine that plays an important role in innate immunity and inflammation. Quantitative real-time PCR was used to analyze the expression of IL-34 after bacterial and viral infection. The results showed that IL-34 was constitutively expressed in the tissues of healthy zebrafish and during embryogenesis. The expression of IL-34 was up-regulated in the spleen at 48 and 72 h after intraperitoneal (i.p.) injection with lipopolysaccharide (LPS) or Polyinosinic acid-polycytidylic acid[Poly (I:C)]. The expression of IL-34 was also significantly increased in the intestine (except for the decrease after 24 h LPS stimulation). Infection with Edwardsiella tarda (E. tarda) resulted in increased expression in the intestine at 3, 9 and 24 h post infection, while it was inhibited in the spleen at 6, 9 and 72 h. The IL-34 expression was upregulated in the spleen at 1, 3, 5 and 7d and intestine at 1 and 3 d after i.p. injection with spring viremia of carp virus (SVCV). In ZF4 cells SVCV infection and LPS stimulation enhanced the expression of IL-34. Besides, LPS, IL-1β and IFNφ1 induced the expression of IL-34 in the primary splenic cells. The results suggest that IL-34 is involved in immune defenses against bacterial and viral infection.

Abstract:Single nucleotide polymorphism (SNP) is one of the commonly used molecular marker-assisted breeding tools. In this study, based on the high-density linkage map and QTL mapping results of black carp (Mylopharyngodon piceus) in previous study, two SNP molecular markers at the body weight QTL interval were used to verify in three populations. The purpose of this study was to verify whether the SNP from previous study exists and can be applied to other geographic groups. Two SNP molecular markers flanking sequences were analysed by using performing genotype composition analysis, genetic diversity analysis and neutrality test in three geographic groups. The results of genetic diversity showed that the haplotype diversity (H_d) of the extended fragment of snp8107 was 0.782, 0.515 and 0.497 in Hanjiang population, Xiangjiang population and Shishou population, respectively; the observed heterozygosity (H₀) of each locus was from 0.067 to 0.533; The expected heterozygosity (H_e) ranged from 0.127 to 0.506, with an average of 0.306, and the polymorphic information content (PIC) ranged from 0.117 to 0.374, with an average of 0.246. The neutral test for three populations showed that the bottleneck effect may have occurred in history which led to loss of the rare alleles. Combined with the results of genetic diversity, we speculated that the Hanjiang population retained more rare alleles after experiencing the bottleneck effect. It was concluded that the Hanjiang population was the best variety suitable for genetic improvement.

Abstract:To compare the effects of supplemental yeast hydrolysates and small peptides in the feed of juvenile largemouth bass (Micropterus salmoides), the fish were fed with basal diet, diet supplemented with 1% yeast hydrolysates(YH) or 1% small peptides(SP) respectively to conduct 56-day feeding trial. Then the growth performance, liver-intestine health and anti-infection ability were investigated. The results showed that 1% yeast hydrolysates and small peptides had no significant effect on growth performance of juvenile largemouth bass. However the YH significantly reduced the amylase activity of mid- and hindgut, and increased the lipase activity of fore- and hindgut, while the SP significantly reduced the amylase activity of fore- and hindgut, and increased the lipase and protease activity of fore-, mid- and hindgut. In the SP group, the intestinal structure was smoother and clearer, and the cells on the surface of brush border were closely arranged, then the cup-shaped cells were more clearly visible. As for the serum biochemical indexes, the albumin content in YH and SP groups was significantly lower than the control group, and the alanine aminotransferase content was significantly higher than the control group. Also the lowest cholesterol and triglyceride content was observed in SP group. There was the strongest total antioxidant capacity and catalase activity of the liver in YH group. The strongest lysozyme activity of the head kidney and the lowest cumulative mortality rate after infection with Aeromonas hydrophila were shown in SP group. In summary, the addition of both 1% SP and 1% YH could improve liver and intestinal health and anti-infection ability, but each had its own advantages. SP had significant advantages in promoting the intestinal health and the immune protection of largemouth bass. While YH was more prominent in enhancing the antioxidant capacity of the liver. Consequently, it would be more beneficial to the overall health of juvenile largemouth bass when YH and SP were added in the feed selectively.

Abstract:In order to understand the operating effects of the nitrification and heterotrophic biofloc culture systems, the experiment was conducted to culture GIFT Oreochromis niloticus juveniles in the nitrification group and the heterotrophic group for 51 days, and to compare the growth performance and non-specific immune enzyme activity, digestive enzyme activity of tilapia, and community structure of water and intestinal microorganisms. The results showed that there was no significant difference in the growth performance indicators such as survival rate and weight gain rate of the two groups of tilapia. The non-specific immune enzyme activity of the heterotrophic group tilapia was significantly higher than that of the nitrification group. The activities of amylase and lipase in the intestine of tilapia in the nitrification group were significantly higher than those in the heterotrophic group, and the protease in the heterotrophic group was significantly higher than that in the nitrification group. The top 5 dominant phyla of tilapia intestines are Proteobacteria, Actinobacteria, Chloroflexi, Firmicutes and Chlamydiae. Among them, the Proteobacteria phylum is the most important flora in each group. The top 4 dominant phyla in the water of the nitrification group are Proteobacteria, Chloroflexus, Bacteroidetes, and Planctomycetes; the top 4 dominant phyla in the water of the heterotrophic group are Proteobacteria, Chloroflexus, Bacteroides, and Actinomycetes. Mycobacterium is the most important potential pathogenic bacteria in water and intestinal tract, while Diplorickettsiaceae and Plesiomonas maintained at a low level. Except for Clostridium, other potential pathogenic bacteria such as Aeromonas and Flavobacterium in the water and intestines were higher in the nitrifying group than in the heterotrophic group.Through the comparison of the cultivation effect, fish biochemical indexes and intestinal microorganisms, it was found that heterotrophic bioflocs were more beneficial to the cultivation of juvenile tilapia.

Abstract:In order to understand the impact of Litopenaeus vannamei culture on the community structure of metazooplankton in ponds, 16 surveys were conducted in an aquaculture farm and its outer channels in Fengxian District, Shanghai from early May to early October in 2021. Metazooplankton species composition and dominant species, density, biomass and biodiversity were analyzed. A total of 33 metazooplankton species (including 23 species of Rotifers, 6 species of Cladoceras, and 4 species of Copepods) were identified in the study. Among them, Polyarthra trigla and Mesocyclops leuckarti were the common dominant species in both aquaculture ponds and outer channels. Jaccard similarity analysis indicated that the species composition of metazooplankton in aquaculture ponds and outer channels were moderately similar. Generally speaking, the density, biomass, dominant species and diversity index of metazooplankton were higher in aquaculture ponds than those in outer channels. The mean values of Shannon-Wiener diversity index H' were 1.56±0.48 and 1.55±0.34 in aquaculture ponds and outer channels, respectively, which showed moderate pollution, and the mean values of Gleason-Margalef species richness index D were 0.81±0.32 and 0.76±0.33, respectively, which showed heavy pollution; Aquaculture ponds were at middle eutrophic level, while outer channels were at light eutrophic level. Pearson correlation analysis showed that the metazooplankton community structure in aquaculture ponds was significantly correlated with Water Temperature(WT), Total Nitrogen(TN), Total Phosphorus(TP), Permanganate index(COD)and phytoplankton(Cryptophyta),while the outer channels metazooplankton community distribution were significantly correlated with WT, Dissolved Oxygen(DO), Chlorophylla(Chl.a), COD, Suspended Solids(SS)and phytoplankton(Cryptophyta, Euglena and Dinophyta)Correlation. Redundancy analysis(RDA)showed that TP and COD were the key factors affecting the metazooplankton community structure in Litopenaeus vannamei aquaculture ponds. Phytoplankton(Cryptoplankton), DO, and TN were the main environmental factors that affected the metazooplankton community in outer channels. The results show that the environmental factors in Litopenaeus vannamei aquaculture ponds have significant impacts on the community structure of metazooplankton, which is obviously different from the influence of environmental factors on the community structure of metazooplankton in outer channels. It reveals that the shrimp aquaculture production will significantly change the community structure of metazooplankton in aquaculture ponds compared to natural water, which is of great significance to the ecological aquaculture of Litopenaeus vannamei and the regulation of water quality.

Abstract:In the present study, attapulgite pellets with a diameter of 2 mm were selected as inorganic carriers, and the native microorganisms screened from culture pond were immobilized using the adsorption method to create immobilized microbial pellets. The characteristics and performance of these pellets on removal of COD_Mn and ammonia from aquaculture wastewater were investigated. The results indicate that immobilized microbial pellets have good mechanical strength. The number of bacteria released into water can be maintained at 1.5×10⁶ CFU/mL, and the sustained release performance can be maintained under different environmental conditions. The immobilized microbial pellets can efficiently degrade COD_Mn and ammonia, and the degradation kinetics fit the Monod model very well. The effect of environmental conditions on the degradation performance of immobilized microbial pellets showed that neutral conditions are suitable for the degradation of COD_Mn, while neutral and alkaline conditions for ammonia. There is no significant difference in the degradation of COD_Mn with different gas flow rates (P>0.05). The higher the dissolved oxygen in the water is[DO=(8.600±0.028) mg/L], the higher the ammonia removal rate is. As the initial concentration of pollutants increase, the first-order rate constants of COD_Mn and ammonia gradually increase (except the too high ammonia concentration). Within 10~35℃, the higher the temperature is, the first-order rate constants of COD_Mn and ammonia is.

Abstract:In order to treat the low-temperature temporary aquaculture water of marine products, realize the synchronous power generation and desalination of the system and harvest algae biomass energy, a three-chamber biocathode macroalgae new microbial desalination fuel cell (MDC) was constructed. The power generation performance, desalination efficiency, denitrification effect and algae growth and COD degradation rate of macroalgae MDC in the treatment of temporary aquaculture water of marine products at different temperatures were experimentally studied. The results showed that in terms of power generation performance:under the load of 1 000 Ω external resistance, there was no significant difference in the voltage peak value of the system at 8 and 25℃, but there was great difference in the single power generation cycle and voltage stability time. The single power generation cycle was 228 and 158 h respectively, and the voltage stability time was 36 h and 84 h respectively; To achieve the same desalination rate, the time required at 8℃ was longer than that at 25℃. At low temperature, prolonging the operation time of the reactor can improve the desalination rate of MDC system. At low temperature, the removal rates of COD, NH₄⁺-N, NO₃^--N and TN in seafood temporary culture water could reach more than 60%. The macroalgae Ulra prolifera in MDC system grew slowly at low temperature, the net growth was low, and it still remained normal, and the photosynthetic efficiency F_v/F_m was 0.4-0.5. Low temperature affects the power generation and desalination performance of macroalgae MDC. However, the high COD degradation rate and denitrification effect show that the constructed macroalgae MDC can be used to treat low-temperature temporary aquaculture water of seafood.

Abstract:Marine macroalgae are enriched in heavy metals, and the enrichment of heavy metals by macroalgae is driven by concentration differences, binding of heavy metals to the cell surface of algae, and active uptake of heavy metals by algae. The enrichment of heavy metals by algae is affected by a variety of environmental factors including pH, temperature, salinity, etc., in addition to the type and concentration of heavy metals and the type of algae. Based on the investigation of heavy metal content in seaweeds by domestic and foreign scholars, this review summarizes the environmental effects of heavy metal-enriched seaweeds. On the one hand, the biomagnification of heavy metals along the food chain may cause ecological hazards and human health threats. On the other hand, the use of macroalgae as indicator organisms for heavy metal pollution in seawater or bioremediation materials for heavy metal pollution in water bodies has received increasingly widespread attention by taking advantage of the differences in the enrichment of heavy metals by seaweeds.

Abstract:In order to explore the development process of fisheries resources science, we analyzed the research hot spots, concerned problems and variation trends in each research periods, and provided reference for the development of fishery resources science in China. The methods of bibliometric analysis and Citespace software were used to review the document related to the study on fisheries resource science and indexed ISI Web of Science Core Collection database. We first created descriptive statistics of the number of articles published annually and frequency distribution. Then, the methods of key words based on knowledge mapping and burst analysis were used to explore the research hotspots and recent frontiers. The results showed that the overall studies on fisheries resource science increased steadily in the past decades, especially the number of documents has shown a rapid growth trend since 2017. The most hotspots in fisheries resource science include attaching importance to the research on the fisheries resources assessment, paying attention to the research on fishery management methods, practice and the impact of management on fishery, studying fishery biology and ecology of the bony Osteichthyes, the cartilaginous and economic Cephalopods, and studying impacts of climate changes or human activities on fishery resources or fishes. The study found that the future research of fishery resources should focus on the following work:(1) finding out the biological characteristics of important economic species and key species through interdisciplinary innovation of new techniques and methods in fishery biology; (2) innovating new techniques in fishery resources assessment to realize the accurate estimation of the amount of important economic species resources and the allowable catch; (3) innovating new methods in fishery resources management and conservation to realize the sustainable development of fishery resources; (4) applying new techniques such as artificial intelligence and big data in fishery resources research. With the development of understanding and research on fish stocks, and the development of research means and methods, and the research on fishery resources in the future will be expanded to a more detailed, broader and deeper level, and the people and natural fishery resources will be considered as a whole system, from the traditional single-species-multi-species-ecosystem, to the eco-socio-economic system, to achieve the optimal output of fishery resources in the human-natural system, as well as the long-term sustainable utilization of fishery resources.

Abstract:Geometric morphometrics is a shape statistical analysis method based on Cartesian landmarks. This approach can retain comprehensive shape information of original sample, and analyze shape data along with mathematic and statistical techniques, and is therefore widely used in many fields, including fish ecology. In this review, the development, important concepts, research methods of geometric morphometrics and its research progress of application in fish ecology are briefly described. The application of this approach in the field of fish ecology can be summarized as three aspects, i.e., the effect of environments on individual development, adaptive radiation, and functional form and ecology. The results show that, in the ecological study, geometric morphometrics can reflect explicitly morphological difference and fit the subsequent data analysis, however, the theoretical research and technology development need to be improved. The approach has promising prospects in reflecting functional form and combining ontogenesis, and multi-aspect and three-dimensional shape analysis.

Abstract:South Pacific albacore (Thunnus alalunga) is the main species of Chinese tuna longline fishery, and it is also an important temperate tuna species in the western and central Pacific Ocean.In 2019, the total catch of the south Pacific albacore in the western and central Pacific Ocean was 85 050 metric tons, of which 96% was caught by longline fishing vessels. Catch of Chinese longline fishing vessels accounts for one third of the total, ranking first in the fishing of south Pacific albacore.In 2005, the western and central Pacific Fisheries Commission (WCPFC) adopted the south Pacific albacore conservation management measures which limits the fishing effort in the area of south of 20°S in the Convention area. This paper analyses the management objectives of southern albacore tuna including maintaining the stock of the south Pacific albacore above the interim target reference point, adopting the management road map of the south Pacific albacore and amending the new conservation and management measures of the south Pacific albacore, and suggests abolishing the 20°S, expanding the operating area, and actively developing the fishing mechanism of long-term lease arrangement with Pacific island countries.This paper also discusses the formulation and revision process of the south Pacifica lbacore conservation and management measures of WCPFC, and projects the impact of the zone-based fishery management system proposed by the south Pacific island countries on Chinese tuna longline fishery targeting south Pacific albacore, which provided scientific reference for the adjustment direction and countermeasures of Chinese south Pacific albacore fishery in the future.

Abstract:According to the samples of Chinese squid (Uroteuthis chinensis) collected in the Northern South China Sea from April to June 2016, using the gradient forest method to screen the key environmental factors which affect individual growth, the relationship between daily increment of statolith and key environmental factors was established through the generalized additive model to analyze the impact of environmental factors on individual growth. The results showed that the squids hatched from October 2015 to January 2016, and the hatching peak was from November to December; sea surface temperature(SST),temperature of 25 m(T₂₅) and sea surface salinity(SSS) are the key environmental variables affecting the spawning population of the squids (November to December).When SST changed in the range of 23 to 28℃, the daily increment width of statolith decreased with the increase of SST. When T₂₅ changed in the range of 23 to 28℃, the daily increment width of statolith showed a gradual downward trend with the increase of T₂₅. When SSS changed in the range of 33.2 to 33.8, the daily increment of statolith decreased gradually with the increase of SSS. It can be inferred from the results that water temperature and salinity have significant effects on the growth of squids.

Abstract:The WTO fishery subsidies negotiations that restarted in 2018 are underway, in which the prohibition on subsidies to IUU fishing are widely agreed on by WTO members. However, there are still divergences in matters such as the determination of IUU fishing, the implementation of the prohibition, how to deal with territorial and maritime jurisdiction disputes, and special and differential treatment for developing countries. This paper analyzes the important matters related to the prohibition on subsidies to IUU fishing, and suggests that the definition in FAO International Action Plan against IUU Fishing should be explicitly quoted in the future agreement; coastal Members, flag States Members, RFMO/A, port States Members and subsidizing Members can make determination of IUU fishing according to international law, but when the determining Member is not the subsidizing Member, a procedure for IUU fishing determination confirmation or verification by subsidizing Member should be set up. Applying such prohibition should follow the principle of "whoever receives subsidies will be abolished", and the seriousness of IUU fishing should be considered, and the legal relief for damage caused by subsidies prohibition triggered by improper determination of IUU fishing should be stipulated; Territorial and maritime jurisdiction disputes should be completely excluded from WTO fishery subsidy agreement; Prohibition on subsidies to unreported and unregulated fishing should be exempted for developing countries from non-large industrial fisheries in waters on the landward side of the outer boundary of territorial sea. In addition, it is suggested that China should firmly maintain its status as a developing country, further strengthen the elimination of subsidies to IUU fishing, revise the Fisheries Law as soon as possible to improve the provisions against IUU fishing, and join the Agreement on Port State Measures as soon as possible.

Abstract:Due to the territorial characteristics and swimming ability, the production links such as bait in shrimp and crab pond breeding are "moving" and shrimp and crab are relatively "motionless", which is more difficult to mechanize compared with the fish pond with "moving" fish and "fixed" equipment. By sorting out the mechanization research progress of bait casting, grass cutting, fishing, and water quality management in shrimp and crab ponds at home and abroad, from the difficult point of view brought by the mobility difference demand of shrimp and crab pond mechanical equipment compared with fish pond equipment, the complexity of the currently developed equipment and its reduced reliability and use friendliness are analyzed. This paper points out the current problems in maturity, environmental adaptability, accurate feedback and other aspects of shrimp and crab pond breeding equipment. In view of these problems, the integration of mechanical equipment and green ecological breeding mode, standardization and reliability, operator adaptation and other solutions are discussed. The development prospect of unmanned shrimp and crab farm is also discussed.

Abstract:Fish has been the important study object of biologists and bionics researchers for a long time for their efficient and flexible swimming ability. This paper selects the fish in the swimming mode of caudal fin propulsion as the study object, and the geometric model and motion control model of biomimetic fish were constructed. The Computational Fluid Dynamics (CFD) method together with dynamic grid technology was used to simulate their swimming behavior numerically and analyze the propulsion mechanism of the caudal fin swing. On this basis, by changing the parameters such as the tail beat frequency, swing amplitude, body wave length and body shape, combined with biological characteristics such as fish's dash movement, swimming style and body shape evolution, the influence on the swimming ability of fish under different parameters was explored.The results show that the reverse Kármán vortex street generated in the tail flow field when they move is the main cause of the propulsion force. With the increase of tail beat frequency and swing amplitude, fish can get a higher dash speed in a short time. When λ=0.75 L, a(x)_max=0.1, in order to obtain the swimming speed of 1.0 L/s, the tail beat frequency should reach about 2 Hz. The change of body wave length (λ) will change their swimming mode. When the wave length reaches about 0.75 L, the fish can swim forward at a speed of 0.5 L/s, and the propulsion increases with the increase of body wave length. Compared with fish with large head and small body, fish with slender body have less pressure difference resistance when swimming, so they can obtain greater thrust in the same caudal fin propulsion mode. The research results of this paper can provide some reference for the optimization design of the bionic underwater vehicle.

Abstract:The hadal zone remains one of the least-explored marine biospheres on Earth. Accumulated evidence suggests the existence of abundant microbial communities and active microbial carbon turnover in the sediment of hadal trenches, making the hadal biosphere a "hotspot" of organic carbon degradation in the deep ocean. However, little is known about the composition and metabolic potentials of hadal microbial communities. In this study, we utilized metagenomic sequencing and in-depth bioinformatic analysis to study the composition and functional capacities of microbial communities in the surface sediments of the "Challenger Deep", the Mariana Trench (water depth 10 853 m). The ultimate goal was to reveal the potential mechanism of hadal microorganisms to drive the biogeochemical cycles in the deep ocean and the consequential ecological effects. The results showed that Proteobacteria (Gammaproteobacteria, Alphaproteobacteria, Betaproteobacteria, Deltaproteobacteria), Thaumarchaeota, Bacteroidetes, Actinobacteria, and Planctomycetes were the dominant taxa in the surface sediments of the Mariana Trench. Functional annotation with particular focus on the metabolism related to carbon, nitrogen, and sulfur cycles showed that the studied microbial communities in the Mariana Trench dominated by heterotrophic processes, with the capability to degrade a wide range of organic carbon (OC) compounds, including some recalcitrant OC, such as phthalate or other aromatic compounds. The findings suggest a strong capability of the analyzed microbial communities for degradation of organic carbon compound, supporting their active roles in processes of organic matter degradation. In addition to the heterotrophic metabolism, the results also showed that autotrophic metabolic processes such as ammonia oxidation may occupy an important position in the analyzed microbial community, suggesting that the microbially fixed carbon may be an important source of organic carbon in the hadal sediment of the Mariana Trench.

Abstract:After being caught and landed, marine fish often die within a short time due to environmental incompatibility. Due to its delicious taste and rich nutrition, marine fish will enter the spoilage process rapidly after death and have a short shelf life, so the development of marine fish preservation technology is important. This paper analyzed the spoilage factors due to enzymatic autolysis, microorganism and lipid oxidation of different marine fishes after death, summarized the endogenous enzymes in the cold storage process of marine fish and their effects on the quality of marine fish, and also summarized specific spoilage organisms and their spoilage compounds during low temperature storage of some marine fishes. This paper focused on the research progress of traditional and emerging preservation technologies in the food industry, compared the preservation principles and effects of the above technologies, and also looked into the future development of marine fish preservation technologies. This review aimed to provide references for further development and optimization of seawater fish preservation technologies for application in food industry.

Abstract:As a filter feeding bivalve marine organism, oyster is easy to accumulate microorganisms due to its living habits. In this study, oysters from four coastal areas of China were selected as the research objects. The microbie diversity in different samples and the distribution of antibiotic and heavy metal resistance genes in intestinal, gill and muscle were analyzed. Finally, the correlation between resistance genes was compared by correlation analysis. The results showed that:(1) The top five bacteria with microbial content are uncultured Bacteroides, unclassified Bacillus cohn, unclassified Pseudomonas, Vibrio fluvialis and Arcobacter skirrowii, including two types of spoilage bacteria and one type of pathogenic bacteria; (2) In terms of resistance gene types, the detection rate of aminoglycoside args is the highest (84.1%), β-lactam args and quinolone args were the lowest (57.1%). Detected by different tissues and organs of oyster, the detection rate in muscle (65.6%) > gill (59.1%) > intestine (58.4%). Detected from different sample sources, the overall detection rate of GXBH samples is the highest (72.7%), and the overall detection rate of SDWH1 is the lowest (54.5%), and the samples from different sources have no significant difference in the type and abundance of resistance genes. After PCA analysis, it is found that the same sample can be significantly normalized and classified, indicating that the resistance genes in different tissues and organs of the same sample are highly correlated. (3) From the correlation analysis of different resistance genes ARGs and HTGs, CARB and qnrS have the highest correlation, chrR has a great correlation with sulA and mecA, and copA has a certain correlation with all kinds of ARGs, indicating that different types of resistance genes have the possibility of sharing a gene box. From the correlation analysis of samples from different sources, it basically follows the normalized classification of samples from different places of origin. It shows that the breeding environment can affect the distribution of resistance genes in oysters. Through the above studies, the dominant microbial groups in oysters were analyzed, and the correlation between resistance genes and varieties, places of origin, tissues and organs was preliminarily compared, which laid a foundation for further research on the mechanism of resistance.

Abstract:The photovoltaic fishery breeding mode is a new environmental protection mode that combines pond aquaculture and photovoltaic power generation. The differences in basic nutrition composition, sensory evaluation, and taste quality in the meat of Chinese mitten crab (Eriocheir sinensis) between the common pond breeding mode and photovoltaic fishery breeding mode were compared in this study. The free amino acids and taste nucleotides in meat were determined, and the taste activity value was calculated. Taste activity value (TAV) and equivalent umami concentration (EUC) were associated with artificial and electronic senses to comprehensively analyze the taste quality. The results showed that the crude protein and crude lipid contents in meat of female crabs in group PM were significantly higher than those in group CM (P<0.05), but there were no differences in male crabs. The meat of female crab in group PM had strong umami and sweet taste intensity, while the meat of male crab in group CM had strong saltiness and umami taste intensity. The contents of total free amino acids and sweet free amino acids in group PM were significantly higher than those in group CM (P<0.05). The EUC in the meat of Chinese mitten crab in group PM was higher than that in group CM. The photovoltaic fishery breeding mode can make the enable of Chinese mitten crab to have better nutrition and umami and sweet taste.

Abstract:After the sea bass (Lateolabrax japonicus) is cut into small pieces, it has quality problems such as inability to cook, easy to fall apart, and poor integrity, which severely restricts the development of series of products. This research develops a quality improvement technology suitable for small pieces of sea bass. The effects of TG enzyme, gelatin, egg white powder and immersion time on the quality of fish flakes were studied by single factor, and the formula and process of compound quality improver were optimized by Box-Behnken response surface. The results showed that TG enzyme, gelatin and egg white powder could all improve the boiling resistance and integrity of sea bass small pieces. The best process was:TG enzyme addition amount 3.90%, gelatin addition amount 2.40%, egg white powder addition amount 6.00%, dipping temperature was 0-4℃, and the immersion time was 5.50 h. The processed sea bass slices had good boiling resistance, high integrity, white color, moderate elasticity, and strong aroma. The observation of the microstructure showed that it could make the tissue structure of the fish slices more compact. This research solved the "bottleneck" problem in the processing of sea bass cut into small pieces, and provided technical support for the production of hot pot, simple community dishes and other products.

Abstract:In this study, the extraction conditions of polysaccharides from Hippocampus mohnikei were optimized by single factor test and response surface test, and the monosaccharide composition and antioxidant activity of Hippocampus mohnikei polysaccharides were determined. The results showed that the optimum extraction condition were ultrasonic time 47 min, extraction temperature 87℃, and solvent-to-solid ratio of 23 mL/g. Under these conditions, the extraction yield of crude polysaccharide HP was 9.91%. Two kinds of polysaccharides, HP-1 and HP-2, were obtained after being purified by column chromatography. HP-1 was mainly composed of glucose, galactose, mannose in a molar ratio of 11.32:6.39:5.64, with a small amount of arabinose, xylose, fucose and rhamnose. HP-2 was mainly composed of glucosamine, glucuronic acid, galacturonic acid, galactose, glucose, mannose in a molar ratio of 29.03:18.18:8.48:6.30:4.88:2.70, with a small amount of fucose, and xylose. HP-1, HP-2 had the ability of scavenging DPPH free radical, among which HP-2 had the best effect. Furthermore, HP, HP-1 and HP-2 had reducing power, indicating that Hippocampus mohnikei polysaccharides had better antioxidant activity.

Abstract:Aquatic food is an essential source of animal protein, significantly contributing to food and nutritional security in China. With the rapid development of China's economy, demand and consumption of aquatic food in China are expected to increase further. In order to reduce the risk and raise the sustainability and robustness of aquatic food supply in China, the present study reviews the status and development trends of aquatic food production and consumption in China. The results show that aquaculture and capture fisheries are China's primary aquatic food sources, while imported aquatic food only accounts for less than 5% of the total aquatic food supply and consumption. China's aquaculture production is four times that of capture fisheries. Capture fisheries production has decreased while aquaculture production has kept increasing. However, China's aquaculture area and the number of practitioners have decreased in recent years, putting sustainable production and supply of aquatic food in China at risk. Due to the enormous production and consumption volume of aquatic food in China, the future aquatic food supply in China still needs to be based on domestic production. Aquaculture production needs to increase to meet China's increasing demand for aquatic food, and marine and inland catch production needs to stabilize, with aquatic food imports supplementing the supply. Aquaculture needs to improve yields per unit area and labor productivity while reducing the environmental impacts to achieve "sustainable intensification". The present study suggests strengthening aquatic food in the national food security framework, supporting sound policy formulation through better statistics, and more balanced resource investment in capture fisheries and aquaculture.

Abstract:Promoting the green development of mariculture is very important for the construction of maritime power, while the top priority is to handle the relationship between resources, environment, and economy in the process of industrial development properly so that Chinese mariculture industry may break relevant development bottleneck for a transformation from big mariculture country into mariculture power. In this study, a coupling coordination degree model was used to measure to what degree relevant development is coordinated based on a comprehensive resource-environment-economy evaluation system for Chinese mariculture industry. The results showed that from 2011 to 2018, for both mariculture resource and environment development indexes of China, there was a downward trend, while for the economic development index, there was an oscillatory upward trend. The complex system for Chinese mariculture was in a high coupling of intermediate coordination state at a low development level. For both resource-environment and environment-economy systems, the coordination degree showed an oscillatory downward trend on the verge of misalignment, while for the resource-economy system, the coordination degree showed an oscillatory upward trend. In terms of geographical distribution, the coordination degree for the complex system is high in the north and low in the south. It is suggested that all relevant regions should focus on the weak links in development, strengthen the innovation in aquaculture technology, and mainly support the resource-environment harmonious development, so as to promote the green sustainable development of mariculture industry.

Abstract:The 10-year fishing ban on the Yangtze River has raised an important issue for the protection and inheritance of the fishery culture of the Yangtze River.The fishing culture of the Yangtze River is one of the main sources of the culture of the Yangtze River,the culture of the Yangtze River is one of the important sources of Chinese culture.In the face of the ten-year fishing ban on the Yangtze River, the protection and inheritance of the fishing culture of the Yangtze River is urgent.This paper takes Chongming District as a case study to analyze the influence of the protection and inheritance of the fishing culture of the Yangtze River from the perspectives of the government, society and the people through questionnaires and on-the-spot interviews, the data collected were analyzed by statistics and SPSS 20.0 software to sum up the problems in the conservation and inheritance of fishery culture in the Yangtze River basin:The administrative functions of the relevant government departments are not properly performed, the local governments attach too much importance to economic interests and neglect the protection and inheritance of culture, and the People's awareness of the protection and inheritance of the fishery culture of the Yangtze River is weak.Finally, this paper puts forward some pertinent suggestions to solve these problems:We will improve the system, mechanisms, policies and regulations of the fishery culture of the Yangtze River, promote the building of multi-skilled personnel, strengthen the protection of the inheritors of the fishery culture of the Yangtze River, increase the publicity and popularization of the fishery culture of the Yangtze River, it provides reference for the protection and inheritance of the fishery culture in the Yangtze River basin.