Fish recognition is essential for fisheries management and ecosystem protection measures due to provide a variety of information on the aquatic ecosystem, especially the abundance of fish resources and aquatic health. Time consuming, laborious and subjective manual fish recognition will lead to fish stress reaction after artificial contact, and is extremely unfavorable to the growth of fish. The traditional machine learning method avoids the adverse effects caused by contact with the fish directly, and still needs to manually extract the features and design the image vectorization method according to the recognition problem. However, deep learning known as end to end learning, different from the above recognition methods, is capable of obtaining high level features from the input data and mining the distribution patterns of the data, can free the labor, circumvent the tendency of subjective recognition, and minimize the stress reaction of fish, which is a positive contribution to the development of smart fisheries and precision aquaculture. The application of deep learning in fish recognition is described, and uniform recognition standard is proposed to clarify future research directions. Also, the level of applied research should be continuously improved to enhance practicability and intelligence. Addressing the interface compatibility between equipment and models is also recommended to increase flexibility for researchers in choosing tools, aiming to provide reference for researchers working on fish recognition using deep learning methods.

The rapid advancement of artificial intelligence (AI) has provided novel pathways for the intelligent transformation of the fisheries industry.This paper explores the application and development prospects of DeepSeek in fisheries.As a representative domestically developed open source large model,DeepSeek demonstrates high adaptability across multiple fisheries scenarios by leveraging its multimodal integration,dynamic reasoning,and knowledge graph construction capabilities.By constructing a DeepSeek-based fisheries intelligent agent,a new paradigm can be established for core production processes,including precision aquaculture management,breeding optimization,disease prevention,and resource stock assessment.Through interdisciplinary collaborative innovation,the co-construction of an “AI cooperative” ecosystem,technology scenario validation,and algorithm iteration,this study addresses critical challenges such as multisource data governance bottlenecks,industrial collaboration barriers,tacit knowledge conversion obstacles,and spatiotemporal decision making adaptation challenges.These efforts aim to achieve comprehensive integration of AI and fisheries practices,ultimately building a sustainable ecosystem for the intelligent evolution of the fisheries industry.

To elucidate the impacts of water environment of Dafeng River in Beihai, Guangxi, on health status of Hong Kong oyster(Crassostrea hongkongensis) cultured therein, the physicochemical factors in water quality, planktonic microalgae, bacterial abundance, and energy reserve and oxidative stress of Hong Kong oysters were surveyed in the main Hong Kong oyster farming area of Beihai Sea of Guangzhou, the mouth of the Dafeng River and the upper waters(108°52′49″E, 21°38′26″N; 108°51′30″E, 21°46′22″N) in September and October 2023. The results showed that, the estuarine water temperature was 28.1 ℃, with a salinity of 20.89, total bacterial abundance of 7.22×108 cells/L and Vibrio abundance of 1.49×107 cells/L in September. Diatom abundance was found to be approximately 1.3×107 cells/L, with the dominant species of Skeletonema costatum. The malondialdehyde (MDA) content of 9.60 nmol/mg protein was observed in the gill of cultivated Hong Kong oysters, with glycogen content of 6.18 mg/g and glucose content of 2.59 μmol/g in the adductor muscle. In October,however, the estuarine water temperature was decreased to 25.7 ℃, accompanied by an increase in salinity to 25.50, with bacterial abundance decreased to 4.97×107 cells/L and Vibrio abundance to 1.40×104 cells/L and diatom abundance decreased to 4.3×105 cells/L in the water. MDA content was 1.02 nmol/mg protein in the gill of cultivated Hong Kong oyster, and glycogen and glucose content in the adductor muscle was decreased to 2.49 mg/g and 1.94 μmol/g, respectively. The water temperature and total bacterial abundance were similar to those in the estuarine waters in the upstream waters in October. However, salinity and Vibrio abundance were relatively low, with high diatom abundance. The glycogen and glucose contents in adductor muscle were increased in cultivated Hong Kong oysters. In summary, Hong Kong oysters cultured in the Dafeng River estuary faced multiple environmental stressors, including high temperature, elevated bacterial and Vibrio abundances in September, leading to increased oxidative stress. In October, these oysters primarily encountered a single environmental pressure, high salinity, and improved oxidative stress status. The decrease in algal food led to decline in glycogen content and resistance to environmental changes in October, and there were lower salinity, higher diatom abundance, and relatively healthier conditions for Hong Kong oyster cultivation in upstream waters in the Dafeng River.

The golden pompano(Trachinotus ovatus) is a popular fish variety for marine cage culture and large-scale offshore aquaculture facilities.Successive breakthroughs in key technologies for breeding and cultivating golden pompano have promoted the rapid development of its industrial aquaculture in China.However,issues such as the decline in farming performance,caused by relatively weak fundamental biological and genetic breeding research,have become bottlenecks for sustainable development of this industry.We describe the current state of research and development in the industry and review the biological characteristics of T. ovatus,including resource distribution,habitat,morphological traits,and reproductive biology.We also summarize recent research achievements in artificial breeding,aquaculture,physiological ecology,and genetics.In light of the development,conservation,and the future potential of golden pompano resource,we propose future research directions,including selective breeding,basic genetic mechanisms,gonadal development regulation,and new strain development,to provide references for the future stable development of golden pompano aquaculture sector.

Large models, characterized by their extensive parameters and complex structures, are foundational to machine learning and are increasingly becoming a significant direction for future technological development.This paper elucidates the core technologies employed in large models and discusses the basic conditions necessary for their operation.It also explores the utilization of large models in assisting with disease prevention and control in aquaculture, including disease prevention and management, collaborative monitoring of aquaculture environments, aquatic drug research and development, and the application of genomics techniques in breeding disease resistance in aquatic species.Future prospects encompass data acquisition, processing, model adaptability, generalization, computational needs, training costs, privacy &security, model interpretability, multi-task learning, priority management, cross-regional data sharing, and knowledge graph-enhanced large model integration.The aim is to provide robust support for further applications of large models in the field of disease prevention and control in aquaculture, thereby promoting the development of the aquaculture industry towards greater efficiency and sustainability.

The deep-sea environment is characterized by high pressure, low temperature and high salinity, and the absorption and scattering of water molecules and suspended particles will have an impact on the light environment in the deep-sea domain, posing requirements and challenges to the design and application of deep-sea lighting technology. The stable energy supply, reliability and durability of deep-sea lighting equipment are prerequisites for the sustainable development of deep-sea lighting technology at this stage. The current status of research and application of deep-sea lighting technology is summarized, including light source technology, pressure-resistant technology, sealing and anticorrosion technology, through comparison, analysis, and summary of existing deep-sea lighting technologies.The future research is suggested to be focused on enhancing anticorrosion materials, improving heat dissipation performance, developing pressure-resistant materials, and advancing light source technology. The aim is to provide more reliable and efficient lighting solutions for scientific research, marine resource development, and engineering operations in deep-sea environments, thereby promoting the continuous development and exploration of the deep-sea field.

Fish as the oldest vertebrate have excellent underwater swimming ability after long-term natural evolution. Research of the swimming mechanism of fish including its movement characteristics, stress and interaction with water is not only helpful to deeply understand the evolution process of fish, but also provides scientific reference and innovative ideas for environmental protection, bionic design, agriculture and aquaculture. Fish have two modes of swimming: body/tail fin (BCF) and intermediate fin/opposing fin (MPF). The research progress of fish swimming mechanism are summarized from three aspects: theoretical research, experimental research and numerical research. In view of the existing problems in the research of fish swimming mechanism, it is proposed that further research should be carried out in the aspects of biological fish propulsion system, bionic fish application and multi-robot fish synergy in the future, so as to provide reference for marine fishery and marine industry development.

In order to explore the low-temperature preservation and transportation technology of freshwater fish, serum biochemical indices and contents antioxidant index were detected in grass carp (Ctenopharyngodon idellus) with body weight of (1 200±100) g at water temperature from 23-25 ℃ (control group) to 24, 20, 18, 16, 14, and 12 ℃ at cooling rate of 3 ℃/h at >25 ℃, 10 ℃ at ≤ 25 ℃, and 2 ℃/h at ≤ 10 ℃ and at salinity of 0.5-5 for 48 h and total ammonia nitrogen concentration in water was determined. The results showed that the grass carp had critical temperature of 6-8 ℃, and semi-dormant temperature of 16 ℃ at salinity of less than 3. The grass carp with delayed stress at 16 ℃ and lower concentration of ammonia and nitrogen in the water column had the maximal survival rate, lower serum levels of AST, ALT, COR and GLU at 48 h of preservation, whereas the maximal enzyme activities of SOD, CAT, and GSH-Px were found, with significantly lower content of MDA than that in other groups (P<0.05). Lower ammonia nitrogen concentrations in the water column, the maximal survival rate of grass carp, generally lower levels of the biochemical indicators in the serum of grass carp, higher activities of antioxidant enzymes and lower levels of MDA were observed at salinity from 1 to 2 for 48 h of preservation.The Pearson and Mantle tests revealed that the effects of temperature on COR, GLU and GSH-Px, and salinity on ALT, AST, COR, GLU and SOD were more significant. The water quality was improved and long-distance transport of grass carp with water was facilitated at water temperature of 16 ℃ and appropriate salinity. The key parameters of the transient conditions of grass carp in this experiment provide technical support for the live transport of bulk freshwater fishes and reference for the development of relevant transient and transport.

To understand the population dynamics of rockfish (Sebastes schlegelii) and determine the strategy of sustainable utilization,based on the surveyed data from 2011 to 2019 in Dachangshan Island waters,the relationship between body length and body weight was analyzed, the body length growth equation and body weight growth equation were established, and the resources of this species were evaluated in Dachangshan Island waters. The changes in eggs production per recruitment (EPR) and spawner biomass per recruition (SBR) of Sebastes schlegelii were simulatively analyzed under different management strategies. The results showed that the length-weight formula was described as W=4×10-5L2.934 4(R2=0.918 9,n=204). There were asymptotic body length(L∞)of 425 mm, the asymptotic body weight(W∞) of 2 064.5 g, growth curvature K of 0.23 a-1 and the theoretical initial age t0 of -0.58 a, and the inflection age of body weight growth of 4.1 a, with the total mortality(Z)of 1.34 a -1, the natural mortality(M)of 0.208 9 a-1 and the fishing mortality(F) of 1.311 1 a-1. The critical age was found to be 5.7 a, and the biomass to be 1 084.68 t. It would be more reasonable to set the closed fishing period from March to May, when EPR values return to 67.54% and SBR values to 85.35% during the unfished period. It is found that the resources of S. schlegelii are overfished, the population is seriously juvenile, and the spawner biomass is seriously insufficient in waters of Dachangshan Island, with urgent need of scientific management. The findings are expected to provide a reference for the rational use of population of S. schlegelii in Dachangshan Island.

With the development of artificial intelligence, automatic collision avoidance, and unmanned navigation technologies, unmanned vessels are being used more and more widely, especially in the fishery field, which plays an increasingly important role. The key technologies of unmanned vessels are introduced, mainly including environment sensing, path planning, target analysis and formation control technology, and main applications of unmanned vessels in the fishery field are analyzed. Unmanned vessel technology is also challenged by many problems including difficulty in release and recovery, poor environmental adaptability, limited longrange detection and high cost, although unmanned vessel technology shows great potential. Finally, the future development trend and research direction of unmanned vessels are discussed. With technological progress, unmanned vessels are expected to become an important tool for fishery resources investigation and management.

In order to explore the composition and diversity distribution of fish in important estuaries in the Bohai Sea and the North Yellow Sea from molecular technology, fish community diversity was surveyed and investigated in 12 important estuaries in Bohai Sea and North Yellow Sea (121°18′～124°19′E, 39°10′～40°54′N) by environmental DNA metabarcoding technique. The results showed that 74 fish species were found in Bohai Sea, belonging to 2 classes, 19 orders, 41 families and 57 genera, with the maximal proportion of species in Perciformes (45%). A total of 76 fish species were detected in the Northern Yellow Sea, belonging to 2 classes, 19 orders, 42 families and 59 genera, with the maximal proportion of species in Perciformes (42%). There was the similar variation trend of diversity index in Bohai Sea to that in the Northern Yellow Sea, with lower diversity index in the Bohai Sea than that in the Northern Yellow Sea, indicating the rich fish diversity in the Northern Yellow Sea. NMDS analysis and ANOSIM test based on Bray-curtis distance showed that the difference between fish communities was larger in Bohai Sea and Northern Yellow Sea than the difference within the groups (P=0.001). Environmental DNA metabarcoding survey was found to be featured by significant advantages in sensitivity, non-destructiveness and cost-effectiveness, compared with traditional fish diversity survey methods, and thus suitable for fish diversity survey. The findings demonstrated that eDNA metabarcoding technology supplemented the results of fishery resources investigation and had a wide range of business application prospects in fish diversity investigation.

Computational fluid dynamics as an important numerical simulation method in reaearch of the hydrodynamic properties of bionic fish has been widely used in many fields such as bionics and oceanography. The type of literature, journal distribution, trend of publication volume, authors, research institutions, and highly cited literature were analyzed in 146 English literature and 201 Chinese literature retrieved using CNKI Chinese database and Web of Science core collection database, and bibliometric analysis based on Cite Space software by combining with keyword network knowledge mapping and keyword clustering mapping to explore the research hotspots and future development trends of computational fluid dynamics in the field of bionic machine fish. The results of the analysis showed that the number of Chinese and foreign literature in the field of bionic fish was increased year by year, with high impact factor and citation frequency of bionic journals and literature. The research disciplines involved in many interdisciplinary disciplines including engineering, robotics, mechanics and material science, with the hot spots and key directions of the dynamics model, 3D flow simulation, design and fabrication. To address the current limitations in research, future investigations are suggested to focus on rigorous exploration of aquatic swarm behavior simulation, the mechanisms behind fish lateral line sensation, and hydrodynamic testing of bionic robotic fish. Such comprehensive research is essential for promoting interdisciplinary collaboration and offering a solid scientific foundation to overcome obstacles and chart a clear path forward in the development of robotic fish technologies.

In order to address the existing issues of suboptimal global and local solutions in current path planning algorithms, an optimization function PathOptimization and IsClear were incorporated into the Bidirectional A* algorithm, aiming to eliminate redundant turning points and to shortening the global path distance. Additionally, a discretization step function, repulsive force threshold, and temporary endpoint were introduced to avoid local optimal solutions and oscillation problems based on the artificial potential field method. A hybrid algorithm, termed Bidirectional A*-APF algorithm, was implemented by integrating these two approaches. Comparative simulation experiments were conducted on identical grid maps using MATLAB to assess the algorithm’s performance before and after the improvements. The results showed that the hybrid algorithm reduced the average number of redundant turning points by approximately 50%, decreased the average algorithm search time by 47.5%, and shortened the average path distance by around 7%. Moreover, it safely avoided dynamic and static obstacles. The findings indicate that the Bidirectional A*-APF algorithm effectively addresses issues related to suboptimal global and local solutions.

The increase in fishery resources via artificial propagation and releasing is a crucial method for replenishing biological resources and ensuring the sustainable development of fisheries, and developed rapidly in China in past decades. However, the high mortality of artificially bred seedlings after release led to the failure in most artificial proliferation and releasing of fish without the expected results, thereby affecting the benefits of fishery resource proliferation. One of the effective methods to improve the quality and survival rate of released seedlings is to conduct wild training through various methods before release, which plays an important role in enhancing the overall benefits of proliferation and release. The current situation of the proliferation and release of fishery resources in China was reviewed, focusing on scientific issues of concern in the research of proliferation and release. The reasons for the low survival rate of fish after release and the research progress of fish wild training were evaluated from several aspectsincluding food cognition, predator information, environmental complexity, and fish swimming ability. It is suggested to carry out genetic improvement, test sperm and egg quality, count injury rates,mortality rates and practice of analyzing blood biochemical indicators, controlling feeding space, improving the complexity of aquaculture environment, implanting chips and biological tracking for fish wild training, improving the quality of life of breeding and releasing species in the future, in order to provide reference basis for promoting water ecological restoration and sustainable development of the fisheries.

In order to probe the role of CgPOU3F4L gene in the response to high-temperature stress in Pacific oyster (Crassostrea gigas), the composition and evolutionary features of POU family genes and the involvement of CgPOU3F4L gene in the regulation of haemocyte apoptosis were investigated in 2 year old Pacific oyster exposed to water temperature of 28 ℃ for 72 h. The results revealed that the Pacific oyster genome contained four POU family genes, namely CgPOU2F1, CgPOU3F4, CgPOU3F4L, and CgPOU4F3. The CgPOU3F4L possessed a unique amino acid sequence, the unclear functional differentiation characteristics of which are not yet clear. There were significantly higher mRNA expression levels of CgPOU3F4L in mantle, adductor muscle and haemocyte than that in hepatopancreas, as high 91.32, 19.24 and 7.92 fold as that in hepatopancreas (P<0.05), as high 2.63 fold at 12 h, 3.05 fold at 24 h and 3.62 fold at 36 h in the Pacific oyster exposed tp high-temperature stress as that in the control group (15 ℃) (P<0.05). POU transcription binding sites were found at 1 197-1 207 and 1 286-1 297 bp in the promoter region of apoptosis-related genes CgBcl-2 and CgCaspase3, respectively. RNAi method was applied to inhibit the expression of CgPOU3F4L, and the mRNA expression of CgBcl-2 in CgPOU3F4L-RNAi group was shown to be increased significantly, which was 7.49-fold of that in the control group (P<0.001). Conversely, the mRNA expression level of CgCaspase3 was found to be decreased significantly, which was 0.57-fold of that in the control group (P<0.05). Additionally, the apoptosis rate of haemocytes (16.53%) was significantly lower than that in the control group (45.90%, P<0.001). It is approved that CgPOU3F4L gene regulates the apoptosis of haemocytes through the transcription regulation of CgBcl-2 and CgCaspase3 after high-temperature stress. These findings provide theoretical basis and reference for further understanding of the evolutionary characteristics of POU family and the mechanism of environmental stress response in oyster.

To optimize the fermentation process of sea lettuce (Ulva lactuca) fermented diet and explore the effects of fermented sea lettuce diet on the growth and digestion of sea cucumber (Apostichopus japonicus), the fermentation conditions of sea lettuce were optimized by single factor experiment including temperature (20, 25, 30, 35, and 40 ℃), moisture (30%, 40%, 50%, 60%, and 70%), and inoculation dose (1×106, 2×106, 3×106, 4×106, and 5×106 CFU/g (dry matter) )and response surface methodology with Bacillus tequilensis as the fermentation agent and contents of reducing sugar, free amino acids and peptides in the fermentation products as the evaluation indices. Sea cucumber with body weight of (6. 48 g±0. 84 g) were reared in 9 plastic tanks of each 40 cm×30 cm×25 cm and fed fermented sea lettuce, unfermented sea lettuce dry powder and commercial diet for 30 days at water temperature of 15-17 ℃ and salinity of 25-35.The results showed that the best fermentation of the sea lettuce was observed under the optimal conditions of temperature of 33 ℃, inoculum quantity of 4.4×106 CFU/g and 50% water content, with increase in free amino acids from 3.6 mg/g to 45.0 mg/g, peptides from 30.1 mg/g to 96.0 mg/g, and reducing sugars from 1.3 mg/g to 20.8 mg/g for 7 days fermentation. Feeding trail showed that there was higher diet conversion efficiency and digestive enzyme activity in the sea cucumber fed the fermented sea lettuce diet than those fed the unfermented dry powder diet and commercial diet (P<0.05), without significant difference in the weight gain rate from that in commercial diet group (P>0.05), significantly higher than that in unfermented dry sea lettuce powder group (P<0.05) and without significant difference in the food ingesting rate of sea cucumber in the three groups (P>0.05). The findings indicate that fermented U.lactuca can replace commercial diet, improve the weight gain rate and digestive enzyme activity of sea cucumber, which provides wide range of raw material resources for sea cucumber diet.

In order to explore the quality characteristics of grass carp (Ctenopharyngodon idella) cultured in low salinity water, the differences in composition and contents of nutrients (moisture, ash, fat, protein, amino acids and fatty acids), volatile flavor compounds, and textural characteristics were analyzed in the grass carp with body weight of (1.83±0.13)kg and (1.37±0.21)kg cultured in salinity of 0.1 (fresh water) and 3-5 (low salinity) from June to October 2022 to evaluate the qualities of the flesh between the two kinds of culture modes. The results showed that there were very significantly higher contents of protein, fat, total essential amino acid, total polyunsaturated fatty acids, and EPA+DHA in the grass carp cultured in low salinity water (LS group), with high nutritional value, higher than that in the grass carp cultured in fresh water (FS group) (P<0.01). The content of 1-octene-3-alcohol was found to be the most contribution to the flavor to the grass carp in the two groups, with significantly lower amount of 1-octene-3-alcohol, octane aldehyde, (E, E)-2, 4-decadienal in the LS group than those in the FS group, showing a better flavor (P<0.05). The grass carp in the muscle in LS group had significantly higher hardness and chewiness than the one in FS group did (P<0.05), indicating that the fish in LS group had better taste compared with that in FS group. Therefore, the grass carp cultured in low salinity water had higher edible value compared with the grass carp cultured in fresh water.

In order to probe the potential harm of microplastic pollution to fish in coastal waters in China, 286 samples of fish were collected in Lüsi fishing ground,the differences in microplastics pollution characteristics among fish species and the relationship between abundance of microplastic and length (weight) of fish and trophic position (via stable isotopes) were analyzed by detection of abundance of microplastic, shape, color, particle size and polymer type in stomach of fish via improved alkaline method for extraction of microplastics. The results showed that all fish samples contained primarily blue fibers microplastics, with an average abundance of (2.46±1.42) pieces/fish and an average particle size of (2.18±0.43)mm, with main polymer type of polyethylene terephthalate (83.9%). In addition, there was no significant correlation between the abundance of microplastics and the length (weight) and trophic position of fish (P>0.05), without biomagnification in the abundance of microplastics. The findings indicate that microplastics are widespread in the coastal waters, and the intake of microplastics significantly depends on body shape, feeding habits and habitat water layer of fish.

Proteins functional properties can be significantly enhanced by physical, biological and chemical methods to alter or maintain protein structural stability. The structures, functional properties and modification methods are summarized based on the most recent research developments of the optimization strategies of aquatic animal myofibrillar protein properties. Future main tasks of further deeply developing new method are suggested to identify protein modification sites and their regulatory mechanisms of aquatic animal myofibrillar proteins, strengthening the development and application of physical and physically combined methods in aquatic animal myofibrillar proteins, and more efforts should be paid to depth understand the possible relationship between modified protein food and sensory characteristics. This review aims to offer research ideas for the deep processing and utilization of aquatic animal proteins.

In order to adsorption removal of phosphate and ammonia nitrogen in water, oyster shell powder and kaolin were mixed in the ratio of 3∶1, and the modified oyster shell powder with the best adsorption effect was prepared and screened out under different conditions of MgO addition of 0%, 2%, 4%, 8%, and 12%; temperatures of 0, 600, 700, 800, 900, and 1 000 ℃ by scanning electron microscopy, and Fourier infrared spectrometry. The characteristics of the modified oyster shell powder was analyzed by scanning electron microscope, Fourier infrared spectrometer, specific surface and porosity analyser and X-ray diffractometer. The adsorption process was fitted by kinetic model and isothermal adsorption model, and the effects of initial pH and adsorption column on the adsorption of phosphate and ammonia nitrogen by modified oyster shell powder were analyzed. The results showed that the best adsorption performance of modified oyster shell powder was observed at 8% MgO addition and 800 ℃ calcination temperature, with the phosphate removal rates of 91.7% (seawater) and 82.25% (freshwater), and the ammonia nitrogen removal rates of 36.67% (seawater)and 47.71%(freshwater). The adsorption of phosphate by modified oyster shell powder conformed to the quasi-secondary kinetic model and the Freundlich model, and the maximum The adsorption of phosphate by modified oyster shell powder conformed to the quasi-secondary kinetic model and Freundlich model, with the maximum adsorption of 108.37 (seawater) and 101.99 (freshwater) mg/g, and the adsorption of ammonia nitrogen conformed to the Langmuir model, with the maximum adsorption of ammonia nitrogen of 0.27 (seawater) and 0.38 (freshwater) mg/g. The adsorption of ammonia nitrogen and phosphate by the modified oyster shell powder in the adsorption columns was facilitated by the acidic conditions, and the adsorption of ammonia nitrogen was more favorable by the neutral conditions. The adsorption amounts of modified oyster shell powder on ammonia nitrogen and phosphate were found to be 0.12, 78.95 mg/g (seawater) and 0.17, 70.34 mg/g (freshwater) in the adsorption column. In the application in the sewage into the sea, the effluent reached the standards of a class of water with the removal rate of 96.83% for phosphate, and ammonia nitrogen for 9.7%. The findings indicate that the low cost modified oyster shell powder has the potential to be applied to remove phosphate and ammonia nitrogen from water efficiently.

The Manila clam,Ruditapes philippinarum,is an economically important bivalve shellfish whose survival is affected by a variety of environmental factors,temperature being a key factor affecting its normal activities.Much attention has been given to the response of shellfish to high temperature,while fewer studies have been conducted on their response to low temperature.Considering the increasing occurrence of extreme weather,such as extreme cold,research is required on the adaptation of shellfish to low temperatures.In this study,R. philippinarum was exposed to low temperature for 60 days.Its immune indicators were systematically measured and analyzed,and the differentially expressed genes (DEGs) obtained were analyzed by using the GO/KEGG enrichment databases.A total of 8 344 and 2 674 DEGs were found in the gill tissues of R. philippinarum after 20 and 60 days of cold exposure,respectively.Enrichment analysis of these DEGs revealed that R. philippinarum has potential low temperature coping strategies in biological processes such as protein processing,substance metabolism,antioxidant,immune and anti-apoptosis.Regarding protein processing,the expression of the SAR1B,HSP20,HSP70,TRX,and SEC61G genes were up-regulated during protein processing,suggesting that R. philippinarum may maintain cellular stability at low temperatures by enhancing protein synthesis.Phosphatidylcholine (PC) is a key component of cell membranes,and the up-regulated expression of PC synthesis-related genes in this study suggests that R. philippinarum may maintain cell membrane stability under cold exposure by enhancing PC synthesis.In this study,the expression of the SOD,CYP450,GST,and GPX genes were up-regulated,and the MDA content decreased when the SOD activity increased during the late stage of cold exposure,suggesting that hypothermia induces SOD to scavenge excessive ROS in the organism,thus protecting it from hypothermic injury.In addition,the immune and anti-apoptosis related genes were also significantly activated at low temperature.These results provide basic data for furtherstudy on the mechanism of low-temperature tolerance in R. philippinarum and provide theoretical support for the selection and breeding of low-temperature tolerant shellfish varieties.

With an attempt to screen bacteria with potential probiotic effects on Manila clam (Ruditapes philippinarum), culturable bacteria were first isolated from the intestinal tract of the healthy clam and then subject to enzyme-producing ability examination by in vitro plate experiment. Those enzyme-producing strains were, morphologically observed and molecularly identified by plate counting method and the standard curve between the absorbance value and the bacterial cell number. The bacterium was examined for acid and bile salt tolerance, and the safety of the enzyme-producing bacterium on R.philippinarum larvae by challenging test. The Manila clam juveniles were reared to examine growth promoting effects. The results showed that a bacterial strain isolated from the intestinal tract of healthy clams designated as C26 produced amylase, protease and lipase was gram-negative and belonged to the genus of Pseudoalteromonas, with tolerabce to pH value of higher than 4.5 and a bile salts concentration ranging from 0 g/100 mL to 0.1 g/100 mL. In addition, Strain C26 had no pathogenicity to R.philippinarum and significantly improved the weight gain rate of the juveniles (P<0.05). To sum up, a safe Pseudoalteromonas strain C26 was screened and had probiotic effects on Manila clam larvae, which provides foundation for enrichment of the Manila clam probiotic strain resources.

To investigate the correlation between morphological traits and body weight in male and female pear-shaped ringed edge snail Bellamya purificata, 11 traits including body weight, shell width and shell height were measured in 1007 snail samples collected from Guangxi Nanfan Aquatic Breeding Base after sex identification and the correlation among the morphological traits was analyzed by trail analysis and multiple regression analysis. The results showed that there was significant correlation between each morphological trait and each quality trait (P<0.05). The body weight of both male and female snails was mainly affected by shell height, with a flux coefficient of 0.927. The soft body weight was primarily affected by shell height (0.904) in male snail, and by shell width (0.899) in females. Muscle weight was found to be largely influenced by the height of the body snail layer (0.899) in male snails, and by the combined effect of shell width, aperture width, body whorl height, and the spiral height in females. The maximal individual coefficient of determination for body weight of female (0.489) and male (0.281) and soft body weight of male (0.561) was observed in shell height. There were the maximal individual coefficient of determination for soft weight (0.190) and muscle weight (0.080) in female snails in shell width. In summmary, the body weight, soft weight, and muscle weight of male and female snails were shown to have good potential for selection. Shell height should be selected as a key auxiliary selection trait when selecting for higher body weight and soft weight. When muscle weight is used as a selection target, body snail layer height should be used as the main selection trait in male snails, while the effects of shell width, aperture width, and body whorl height should be considered in female snails. In this study, a better equation was established by stepwise multiple regression for body weight, soft body weight, and muscle weight of male and female snails, which provides an important reference basis for the subsequent selection of good pear-shaped ringed edge snail.

In order to alleviate the working pressure of law enforcement officers in fishing ports in the statistics of fishing vessels entering and leaving the port, a target detection and statistical model YOLOv8n-Bi-FPN-EMA for ships entering and leaving in a fishing port was proposed based on the improved YOLOv8n model. In the model YOLOv8n-Bi-FPN-EMA, the weighted bidirectional feature pyramid network structure (Bi-FPN) and the efficient multi-scale attention module (EMA) were adopted to improve the accuracy and stability of target detection, and the statistics of the entry and exit of various types of ships in the fishing port were realized through BoT-SORT. Compared with the YOLOv8n model, the accuracy of the YOLOv8n-Bi-FPN-EMA model was increased by 5.0%, mAP@0.5 improved by 0.2%, the recognition accuracy for law enforcement vessels, tugboats,and fishing vessels increased by 9.9%, 4.9%, and 0.3%, respectively.With the identification accuracy for fishing vessels of 99.1%,a recall rate of 84.4% and an mAP@0.5 of 97.8%.Research indicates that the YOLOv8n-Bi-FPN-EMA model has good performance in fishing vessel identification, and can be used for auxiliary work of fishing vessel identification and port entry and exit statistics.

In order to elucidate the molecular mechanism of GDH gene (glutamate dehydrogenase, GDH) expression and function regulated by the transcription factor HIF-1α gene in sea urchins (Strongylocentrotus intermedius), the promoter sequence of GDH gene and its structural characteristics were cloned and analyze by genome walking, luciferase reporter assay and RNA interference techniques and the binding site and regulatory relationship between HIF-1α gene and the promoter region of GDH gene were verified in S. intermedius. The effect of HIF-1α gene regulation on the expression of GDH gene on the energy production of coelomocytes and gonads of S. intermedius was investigated. The results showed that the total length of GDH gene promoter was found to be 1 067 bp, containing 12 promoter elements, 14 different transcription factor binding sites and 1 CpG island, with core promoter region ranging from -984 to -363 bp. There were two binding sites between HIF-1α gene and GDH gene promoter region (-683 to -649 bp; -280 to -264 bp), with a positive regulatory relationship between the two. The relative expression of GDH (mRNA and protein levels) and the activity of relative total GDH in coelomocytes and gonads were shown to be a downward trend, accompanied by a significant decrease in the relative content of ATP in S. intermedius exposed to inhibition of HIF-1α gene expression. These findings suggest that HIF-1α gene in sea urchin can affect the expression of GDH gene by positively regulating its transcriptional activity, and ultimately affect the ATP level in different tissues of the sea urchin.

To explore the regulatory mechanism of sperm motility in the yellow sea urchin (Glyptocidaris crenularis) during cryopreservation and resuscitation,RNA-Seq was used to analyze the gene transcription level of sperm after cryopreservation and seawater resuscitation.The results showed that 5.92-6.99 Gb of data were obtained for every group of sea urchin by high throughput sequencing,and that 113 728 transcripts and 73 814 Unigenes were assembled.And 15 333 Unigene annotations were made to the Kyoto Encyclopedia of Genes and Genomes database and classified into 290 pathways.The results of differentially expressed gene enrichment showed that low temperature treatment inhibited cell gap connection communication,oxidative phosphorylation and other pathways; and enhanced carbohydrate catabolism,pentose phosphate signaling,NADPH regeneration,glucose 6 phosphate metabolism,and other pathways after seawater resuscitation.The expression levels of differentially expressed genes Spe 8,Spe 12,CatSper2,and NKAa1,which are related to the regulation of sperm motility,were verified by fluorescence quantitative PCR.Their expression levels were significantly downregulated after low temperature silencing but significantly increased after seawater resuscitation.These results provide a theoretical basis and new clues for further research on the effects of cryopreservation and resuscitation on the regulatory mechanism of yellow sea urchin sperm.

To investigate the stability of an oscillating water column (OWC) perforated floating breakwater, the RAO (Response amplitude operator) for the motion of the floating breakwater was simulated using ANSYS AQWA software. The effects of several factors on breakwater stability were discussed including spacing between double-body structures of the breakwater, wave incident angle, width of OWC opening, draft depth, and length of anchor chain dragging. Results showed that the spacing change between double-body structures had little effect on mooring stability; an increase in wave incident angle led to reduce longitudinal sway motion amplitude and increase the stability; widening the OWC opening led to increased motion amplitude of the breakwater; increasing draft depth or reducing anchor chain length led to increase heave and roll direction motion amplitude while decreasing pitching direction motion and increasing natural period. The finding indicates that the mooring stability of OWC-perforated floating breakwater can be adjusted by changing the opening width, draft depth, length of anchor chain dragging, and wave direction in actual engineering.

To explore developmental characteristics of the female and male reproductive systems of limpet (Neptune cumingii), the gonadal and germ cell development was continuously observed in limpet with body weight of (58.09 g±10.70 g)cultured in Sishili gulf, Yantai, by histological technique, and the relationship between gonadal development and environmental conditions was analyzed in combination with the local water temperature. The results showed that the limpet was gonochorism, with ratio of female and male of 2.45∶1 in the samples, which deviated from the expected value. The male reproductive system was mainly composed of mating port, petasma, vas deferens, seminal receptacle and testis. The seminiferous lobulis were the tissues for spermatogenesis in the testis. The female reproductive system was primarily composed of the ovipositor, glandular vesicles as the tissue for oogenesis seminal vesicles, fallopian tubes, and ovaries. The development of both testis and ovary was divided into four stages: multiplication, growth, maturity and releasing, and degradation. The spermatogenesis was divided into 5 stages: spermatogonium, primary spermatocyte, secondary spermatocyte, spermatid and mature sperms. The oogenesis was divided into 4 stages: oogonium, small growing oocyte, large growing oocyte and mature oocyte. In the same individual, the maturation and releasing of different male reproductive cells were in batches, while the maturation and emission of different female reproductive cells were synchronous. It was found that both female and male gonads developed rapidly in the period of lower water temperature, and male matured 1 to 4 months earlier than females did. The development stages of gonads among different individuals are relatively close under the artificial culture conditions, and the spawning period was concentrated from May to June, which provides conditions for large scale artificial breeding of N.cumingii.

In order to evaluate the transport and transformation of antibiotics in marine fish and evaluate the ecological risk of antibiotics, the bioconcentration pattern and metabolic pathway of sulfamethazine(SMZ) were detected in rockfish Sebastes schlegelii reared in a 30 L container and exposed to 0(control group), 10, and 100 μg/L SMZ at water temperature of (20±0.5)℃ by liquid chromatography tandem mass spectrometry quantitative analysis and high-resolution mass spectrometry detection and analysis. The results showed that the maximal enrichment concentration of SMZ was observed in the fish exposed to SMZ in the third day during the whole exposure period, without significant difference between the maximum concentration of SMZ and the high and low concentrations of SMZ in fish. During the optimal enrichment period, the enrichment trend of SMZ in the fish was described as gill >muscle >liver. Metabolic analysis showed that the metabolites of SMZ in the test fish were N4-acetylated SMZ and 2-amino-4,6-dimethylpyrimidine. The main metabolic pathways were SMZ acetylation addition and N-S bond cleavage linked to 2-amino-4,6-dimethylpyrimidine. In conclusion, sulfonamides antibiotics can migrate to the main tissues and organs of marine fish, and the main metabolic pathways of SMZ in Sebastes schlegelii are acetylation addition and N-S bond breakage.

In order to investigate the effects of dietary Chinese herbal medicine (Scutellaria baicalensis Georgi) on growth performance, antioxidant and non-specific immunity capacity of channel catfish Ictalurus punctatus, juvenile channel catfish with body weight of (4.68±0.02) g were reared in net cages of each 1.0 m× 1.0 m× 1.2 m and fed isonitrogen and isolipid basic diet containing 0 (control group), 5, 10 and 15 g/kg S. baicalensis for 60 days with 3 replicates per group and 30 individuals per replicate. Then the growth performance, serum non-specific immune capacity and antioxidant capacity in liver were determined, and the histological structure was observed in the liver of the channel catfish. The results showed that there were increase in final body weight, weight gain rate and specific growth rate in 5 g/kg and 10 g/kg Chinese herbal medicine groups, without significant difference (P>0.05) compared with those in the control group. The food conversion ratio, however, was found to be significantly decreased by the supplementation of 10 g/kg Chinese herbal medicine (P<0.05). The supplementation of 5 g/kg and 10 g/kg Chinese herbal medicine led to significantly increase the levels of lysozyme acid phosphatase, total protein in serum and the levels of total antioxidant capacity, catalase, and superoxide dismutase in liver (P<0.05), and to decrease the levels of alanine aminotransferase, aspartate aminotransferase, and total cholesterol content in serum and malondialdehyde content in liver (P<0.05), with low vacuolation rate of liver. The findings indicate that the supplementation of S. baicalensis in diets can improve the feed utilization efficiency and enhance the antioxidant activity of channel catfish, with the appropriate supplemental amount of S.baicalensis of 10 g/kg under the experimental conditions.

In order to probe the differentially expressed proteins (DEPs) of plasma and their associated signaling pathways from Nile tilapia (GIFT) Oreochromis niloticus before and after infection with Streptococcus agalactiae, the plasma DEPs were analyzed in the plasma collected from the tilapia with body weight of (150 g±10 g) intraperitoneally injected with 100 μL of S.agalactiae WC1535 suspension at concentration of 5×107 CFU/mL in the experimental group and 100 μL sterile PBS in the control group in via proteomics after 6 h of challenge via proteomics. Furthermore, GO and KEGG enrichment was performed for the DEPs. The results showed that 751 proteins were identified in the tilapia plasma, with 34 significantly different proteins including 9 proteins significantly up-regulated and 25 proteins significantly down-regulated. GO functional annotation showed that these DEPs were mainly involved in binding, motility and catalysis functions. KEGG pathway enrichment analysis revealed that the DEPs were significantly enriched in regulation of actin cytoskeleton, MAPK signaling pathway, central carbon metabolism in cancer, and proteoglycans in cancer. It was found that the DEPs from the tilapia infected with S.agalactiae were mainly enriched in the pathways related to energy metabolism, cellular motility and immune regulation. The findings provided basic data for further research on the molecular mechanisms of S.agalactiae infection in tilapia.

In order to understand the pathogenicity and drug resistance of Bacillus paranthracis from a genetic perspective, whole genome sequencing, in vivo bacterial virulence testing, and antibiotic sensitivity testing were conducted in the pathogenic bacterium B. paranthracis designated as strain BC006 isolated from viscera of diseased bluntnose black bream (Megalobrama amblycephala). The results showed that, the genome of B.paranthracis strain BC006 consisted of 5 457 931 bp, including 1 chromosome (GenBank ID CP119629) and 7 plasmids (GenBank ID CP119630～CP119636), containing 5 539 coding genes,with the maximal degree of collinearity with B. paranthracis strain 1710 from bovine. The LD50 induced by intraperitoneal injection of BC006 was found to be 4.68×105 CFU/g in bluntnose black bream and 4.22×105 CFU/g in mice. The B. paranthracis strain BC006 carried 43 virulence genes, including alo encoding the hemolysin I component, hly Ⅲ encoding the hemolysin Ⅲ component, nheA/B/C encoding the non hemolytic enterotoxin (Nhe), and sph encoding sphingomyelinase (SMase), whose virulence genes were associated with β- hemolysis and enteritis by BC006. BC006 carried 16 resistance genes. Tet (45) and tetB (P) were shown to be involved in the resistance to tetracycline and doxycycline, and MPhL was involved in the resistance to erythromycin. Both Bc Ⅰ and Bc Ⅱ were involved in the resistance to cefotaxime and penicillin G. QacJ was involved in the resistance to metronidazole, trimethoprim, rifampicin, norfloxacin, enrofloxacin, ciprofloxacin, ofloxacin, and compound sulfamethoxazole. The findings indicate that Bacillus subtilis BC006 is a multidrug-resistant bacterium carrying multiple virulence factors, and a newly discovered pathogenic bacterium to bluntnose black bream. It is recommended to use fluophenicol and neomycin sulfate sensitive to this bacterium in national standard fishing medicines.

To ensure equilibrium of aquaculture ecosystem and health of aquatic animals, a pH prediction method for aquaculture water quality, designated as PCA-ES-LSTM-BSO-XGBoost (PELBX), was established. In the PELBX, principal component analysis (PCA) was firstly applied to reduce the dimensionality of water quality data, simplifying parameter complexity and enhancing the efficiency and accuracy of model training. Subsequently, the Long Short-Term Memory (LSTM) network was utilized to capture the dynamic changes in water quality parameters over time, employing early stopping to prevent overfitting and to ensure high prediction accuracy for unseen data. Moreover, the parameters of the XGBoost model in parallel were optimized by the BSO algorithm to improve the precision of pH predictions. Finally, the predictions from the LSTM and XGBoost models were weighted and combined, effectively integrating the advantages of time series analysis and nonlinear learning, significantly enhancing prediction accuracy. Experimental results showed that the PELBX model outperformed in pH prediction with a root mean square error of 0.115, mean absolute error of 0.088, mean absolute percentage error of 1.066%, and a coefficient of determination of 0.747. Compared to the best-performing PCA-LSTM-BSO-XGBoost model in ablation studies, the performance parameters above were improved by 8.73%, 8.33%, 8.26%, and 7.64% respectively; and relative to the best model in the field, BiLSTM-GRU, performances were improved by 10.16%, 1.12%, 0.56%, and 8.73% respectively. The finding demonstrates that the PELBX model significantly enhances the accuracy and stability of water pH value prediction, validating the effectiveness and feasibility of the proposed method.

In order to investigate the functionality of microbial communities in body of Antarctic fish, microorganisms were screened and cultured on the body fluids and intestinal contents of Trematomus bernacchii, a representative fish species angled from the vicinity of the Zhongshan Station in Antarctica (69°22.505 5′ S,76°21.574 0′ E). Representative strains were analyzed for physiological characterization and validation of secondary metabolite functions, and for initial functional explorations in live specimens to observe their impact on the host under low-temperature conditions. The results showed that the isolated strains were predominantly distributed in the phyla Proteobacteria and Firmicutes. Sequence alignment of the 16S rDNA gene revealed that the strain Ignatzschineria sp.LJ11 represented a potential new species. Significant antibacterial effects against Bacillus subtilis, Aeromonas hydrophila, and Staphylococcus aureus were observed in crude extracts from the bacterial cultures of Ignatzschineria genus and Bacillus genus. Zebrafish fed the strain Ignatzschineria sp.LJ11 and Bacillus sp.hb117 showed prolonged survival compared to the control group at low-temperature. Analysis of the gut microbiota diversity indicated that the bacterial composition in the Bacillus sp.hb117 group was dominated by the genus Aeromonas (over 60%), while Vibrio was the dominant genus in the gut microbiota of zebrafish in the Ignatzschineria sp.LJ11 group. It was found that the strains isolated under low-temperature conditions and using different types of culture media mainly belonged to the phyla Proteobacteria and Actinobacteria, and that showed potential for novel antibiotic production and the capability to enhance host cold tolerance. These findings provide new insights for further exploration of the functionalities of polar microbial strains.

Squid is an important energy carrier for marine ecosystems, and the Loliginidae species quickly adapt to the dynamic changes of coastal ecosystems due to their plastic life history characteristics. It was found that males use different reproductive strategies to mate with females, and the size of female eggs is negatively correlated with fecundity. The asymptotic growth of individuals depends on the size of paralarva, and growth strategies of hatching in warm- and cold-water periods were featured by growth responses to seasonal changes of habitat. The food items are changed from low trophic to high trophic levels with growth, with important prey organisms of larvae and juveniles fish. In the context of global climate change, Loliginidae species are better able to adapt to environmental variations. In the future, some research should be conducted on the population structure, migratory routes, growth sensitivity, reproductive strategies and ecological characteristics of Loliginidae species, in order to provide reference for the rational development and scientific management of Loliginidae species.

Different methods of age identification for different shellfish species result in low efficiency, large errors, and low repeatability in specific research and practical processes due to the lack of unified standards and significant differences in morphological structures and lifestyles in shellfish species. In this article, the key development history of shellfish age identification technology, principles, characteristics, and application effects of different age identification techniques for shellfish are reviewed based on related literature on shellfish age identification at home and abroad. Suggestions are made regarding the verification of shellfish growth line formation cycles, optimal selection of suitable methods, and standardization process, aiming to provide references for research and innovative utilization of shellfish growth and age identification methods.

In order to develop commercial feed for white-spotted conger (Conger myriaster), the white-spotted conger with body weight of (53.98 g±1.23 g)were reared in 600 L buckets in indoor breeding workshop at stocking density of 15 fish and fed commercial feed for Japanese eel (Anguilla japonica) supplemented with 3% of shrimp bran+14% of fishmeal (diet 1), A.japonica commercial feed (diet 2), trash fish Ammodytes personatus (diet 3), Enedras fangi (diet 4), and mixture of A.personatus+E.fangi (diet 5) at water temperature of 25.6-27.4 ℃ for 40 days to investigate effects of different diets on the growth performance, feed utilization, body composition and digestive enzyme activities. The results showed that the fish fed diet 1 and diet 2 had significantly low specific growth rate and weight gain rate compared to the fish fed diet 3 and diet 5 (P<0.05). There was significantly higher feed conversion ratio in diet 1 and diet 2 groups than that in diet 3, diet 4, and diet 5 groups (P<0.05), with significantly low apparent digestibility and absorption rate of dry matter, crude protein and crude fat in fish fed diet 1, and diet 2 compared to fish fed diet 3, diet 4 and diet 5 (P<0.05). With the increase in dietary crude fat and total sugar levels, the crude fat and total sugar contents in the fish showed an upward trend, with significantly low crude fat levels in the fish fed diet 1 and diet 2 compared to those in diet 3 and diet 5 groups (P<0.05). The fish total sugar content was shown to be significantly higher in diet 1 and diet 2 groups than in diet 4 and diet 5 groups (P<0.05). There was significantly lower trypsin activity in the stomach, foregut, midgut and hindgut in diet 1 and diet 2 groups than those in diet 4 group (P<0.05), with significantly lower lipase activity in foregut and midgut in the fish fed diet 1 and diet 2 than that in diet 3 and diet 5 groups (P<0.05). The significantly higher amylase activity in stomach, foregut, midgut and hindgut was observed in diet 1 and diet 2 groups than that in diet 3, diet 4 and diet 5 groups (P<0.05). In conclusion, the significantly better growth performance, feed coefficient, feed apparent dry matter, rude protein, and crude lipid digestibility, trypsin activity and lipase activity were observed in the fish fed A.personatus, E.fangi and A.personatus+E.fangi mixed than the fish fed A.japonica commercial feed treatment group and A.japonica commercial feed, with the best feeding effect in A.personatus group. It is recommended to develop an ideal practical feed formulation for C.myriaster based on the nutrient characteristics of A.personatus.

In this review, the research progress on Noctiluca scintillans was summarized, including basic biology, ecology, and red tide governance. Furthermore, future researches were proposed focusing on feeding, reproduction, physiology, biochemistry, and early warning and control of N. scintillans considering the challenges present in the current research on this species, aiming to offer theoretical perspectives on the mechanisms involved in bloom formation and prevention of red tides caused by N.scintillans.

Recirculating aquaculture systems (RAS) are widely acknowledged as pivotal in developing future improved aquaculture practices because of their ability to rear a large number of aquatic organisms in a small space,conserve resources,and maintain environmental sustainability.Nevertheless,the buildup of solid waste in RAS presents a danger to the health of aquaculture species and has detrimental impacts on the functioning and productivity of a system.Efficient management and disposal of solid waste in RAS is crucial for maintaining optimum system operation.This study examines the categorization,origins,and potential consequences of solid waste in the RAS,and also explores methods to enhance waste transportation efficiency.Significant improvements in solid waste removal efficiency can be achieved by optimizing the design of aquaculture tanks,upgrading intake and drainage structures,modifying tank bottom gradients,utilizing diversion devices,and enhancing feed quality.These improvements will guarantee the consistent and effective functioning of a RAS.

To explore transient receptor potential ankyrin 1b (trpa1b) gene on zebrafish(Danio rerio) under high temperature conditions, zebrafish model with trpa1b gene deletion was constructed by CRISPR/Cas9 gene knockout technology. Survival, tissue apoptosis and other related gene expression changes were investigated in Trpa1b knockout (trpa1b-/-) zebrafish and wild-type (WT) zebrafish exposed to water temperature from 28 °C to 40 °C at a warming rate of 1 °C/h per hour by histological and transcriptome methods. Zebrafish tissues of different genotypes were sampled at 40 ℃. It was found that the overall survival time of trpa1b-/-homozygotes was shorter under high temperature. TUNEL staining showed that there was significantly higher apoptosis in gill and brain of trpa1b -/- homozygotes than that in wild-type zebrafish(P<0.05). Transcriptome sequencing analysis for gill tissues of different genotypes under normal temperature (28 ℃) and high temperature (38 ℃ and 40 ℃) revealed that the expression level of hspa1b and hsp90aa1.1 in trpa1b-/- homozygotes was significantly down regulated under high temperature (P<0.001), and that the expression level of intracellular calcium ions, ubiquitin protein transferase, lysosome and ribosome related genes were changed, which impaired their viability under heat stimulation. The findings indicate that Trpa1b deletion will lead to more obvious high-temperature intolerance in zebrafish due to the fact that trpa1b gene is an important gene required to maintain high temperature tolerance in zebrafish, which provides reference for further research on the mechanism of high temperature tolerance in fish.

Amyloodiniosis, commonly referred to as “marine velvet”, velvet disease, is a parasitological disease caused by one of the most common and important parasitic dinoflagellates Amyloodinium ocellatum. The A.ocellatum infects a wide range of fish species in different habitats including tropical and subtropical geographical locations, and has a direct life cycle that comprises three stages: trophont, tomont, and dinospores, which can be completed in less than a week dependent on favorable environmental factors. The disease is characterized by rapid onset and high mortality, which seriously hinders the healthy development of China’s marine fish industrial farming and semi-intensive pond farming, leading to huge economic losses. The typical symptoms of amyloodiniosis are changes in fish behavior, decreased appetite, faster breathing, and swimming at the water surface or gathering at the areas with higher dissolved oxygen concentrations. Fish mortalities are usually attributed to hypoxia, inflammation, severe gill hyperplasia, hemorrhage, and necrosis in heavy infestations. This review summarizes the current situation and the latest researches progress on the life cycle of A.ocellatum, the prevalence, detection methods, and preventive and control measures of amyloodiniosis. It is proposed to strengthen the future research of pathogenic detection of the farming environment, low-temperature preservation, vaccine development, aiming to provide references for the scientific prevention and treatment of marine fish amyloodiniosis in fisheries production.

In order to solve the problem of low accuracy of fish detection caused by underwater imaging blur and distortion in actual aquaculture environment, a fish detection method(SK-YOLOv5)combining visual attention mechanism SKNet(selective kernel networks)and YOLOv5(you only look once)is proposed.In this method, UNet(convolutional networks for biomedical image segmentation)is firstly used to preprocess images to obtain clear fish images, and then SKNet is fused to Backbone end of YOLOv5 to form feature extraction network focusing on pixel-level information to strengthen the recognition ability of fuzzy fish.In this study, ablation test and model comparison test were carried out on underwater fuzzy fish swarming image data se to verify the effectiveness of SK-YOLOv5.The results showed that SK-YOLOv5 was effective in fish swarm detection task, and had recognition accuracy of 98.86% and recall rate of 96.64%, 2.14% higher and 2.29% higher compared with YOLOv5, respectively.Compared with XFishHmMp and FERNet with the maximal detection accuracy underwater target detection model, SK-YOLOv5 had the best detection effect, 5.39% higher in recognition accuracy, and 5.66% higher recall rate, and compared with FERNet, the recognition accuracy was improved by 3.59% and recall rate by 3.77%.The findings indicated that the fish detection of fusing SKNet and YOLOv5 can effectively enhence the identification ability of fuzzy fish, and improve the overall effect of fish detection and recognition.

 To construct a polar ratio fluorescent probe for accurate detection of biological microenvironment, the probe IA based on naphthalene ring fluorophore was firstly synthesized by introducing malononitrile and N, N-dimethyl group on acenaphthene ketone, and then the polarity responsive ratio fluorescent probe IAN was synthesized by condensation reaction of IA amino group into heterocycle. The molecular structure and mass of probes IA and IAN were characterized by 1H NMR, 13C NMR and HRMS, and then the absorption and fluorescence spectra of probes IA and IAN in different polarity solvents were examined and compared by UV-Vis and fluorescence spectrophotometer. The results showed that IA exhibited single absorption and fluorescence emission peaks and fluorescence intensity of IA was gradually enhanced with solvent polarity increasing. Differently, double absorption and fluorescence emission peaks of IAN were simultaneously detected in solvents (λem=474 nm, and 552 nm), and the fluorescence intensity ratio I474 nm/I552 nm produced a sensitive Boltzmann function response to solvent polarity changes. Compared with IA, IAN was able to respond accurately to environmental polarity changes as a ratio fluorescent probe. The fluorescence intensity of the lesions was shown to be significantly lower than those of the healthy tissues by using IAN on mice with breast cancer and grouper hybrid Epinephelus fuscoguttatus♀×E.lanceolatus♂ with hepatobiliary syndrome. These findings indicated that amino group undergoing a condensation reaction to generate a heterocycle containing nitrogen atom increased the conjugation degree of lone pair electrons of the nitrogen atom to the π system, so that the probe IAN produced n→π* and π→π* molecular transition at the same time, and then enabled the construction of a ratio fluorescent probe responding sensitively to polarity changes.

Artificial reef is an artificial facility used to restore and optimize the marine ecological environment and to build a habitat for marine aquatic organisms.It is also a basic ecological project in the construction of marine ranching.The selection and use of reef materials are directly related to the effect of artificial reef.From the six main categories of reef materials and the durability, environmental adaptability, biological affinity and economy considered in the use of materials, this paper summarizes the development status of materials used in the construction of artificial reefs at home and abroad, arranges and analyzes the characteristics and application effects of various reef materials of artificial reefs, and future development suggestions are put forward in the research, development and application of eco-friendly materials, new materials for resource recycling, carbon sequestration functional materials under double carbon goals and new artificial reef materials based on intelligent materials.It is expected to provide scientific reference for the selection of reef materials and the research and development of new materials.

This paper summarizes the progress on principle and technology of high - density rotifer in mass culture method in Japan. There are at least 100 times more efficient in Japanese mass rotifer culture method with less cost for production than that in the conventional method. Firstly, condensed freshwater Chlorella is employed as new food for rotifers instead of bakery yeast and Nannochloropsis. Secondly, cultures were generally supplied with constant O2 to avoid oxygen deficiency. Thirdly, pH was adjusted to 7 by automatic addition of HCl to promote the dissociation of NH3 to NH4^＋ and OH^-. Fourth, the excess suspended organic matter can be efficiently romoved by a nylon filtration mat. Fifth, addition of a defoamer substance can prevent the culture water from loss and from rotifer attachment to the foam. Using these techniques, the rotifer culture density increases to 20 000 ind. /mL. Recently a novel culture system using a continuous membrane filtration unit （CMFU） for ultra -high -density culture is developed in Japan. In this culture system NH4^＋ and soluble organic substances are removed by the culture liquid, with rotifer density of 160 000 ind. /mL.

In order to improve the accuracy of marine ship recognition in multiple targets and foggy environments, a marine ship recognition model SE-NMS-YOLOv5 is proposed based on improved YOLOv5 deep learning. The model is combined with Dark channel defogging algorithm, SE(squeeze-and-congestion) attention mechanism module and improved non-maximum suppression model for training and testing of ship data sets. The results showed that in the ship recognition task, there was the accuracy of 90.6%, recall rate of 89.9% and SE-NMS-YOLOv5 F1 value of 90.5%, and compared with YOLOv5 model, the detection effect is improved by 6.3%, 4.8% and 5.8%. Compared with YOLOv4, the model improved 19.1%, 19.0% and 19.3%. In foggy conditions, the accuracy, recall rate and F1 value of SE-NMS-YOLOv5-Dark channel model were 88.1%, 87.2% and 87.6%, compared with SE-NMS-YOLOv5 model, the detection results are improved by 13.8%, 13.3% and 13.5%, respectively. The findings indicate that the marine ship recognition method based on SE-NMS-YOLOv5 effectively solves the problem of low accuracy of marine ship detection on multiple targets and foggy conditions, and improve the overall effect of ship detection and recognition.

A edge detection algorithm of biologic image based on dynamic and mathematical morphology, which can solve the affection of noise and blurring effect in image edge detection,is presented in this paper. The dynamic binary method was used firstly to define binary image threshold in transforming gray image to binary image. Secondly, the Erosion algorithm of mathematical morphology and de - empty method were used to eliminate noise of binary image. Finally the skeleton detection was used to detect image edge. The numerical experimental showsed that this algorithm reduced the effect of noise in image edge detection, and realized were accurately edge orientation, and hold adequately image detail. This algorithm is a good edge detection method in biologic image.

In this paper we reviewed the physical and chemical nature, detection methods for tetrodotoxin and its derivatives, distribution among the species of organisms,and abilities of microorganisms which produce tetrodotoxin and its derivatives. The objective of present paper is to provide more necessary information about mechanism of toxic organisms accumulate toxins.

Sargassum pallidum as a typical representative of brown seaweed is widely distributed in the coastal areas of China including the Yellow Sea and the Bohai Sea, and is one of the earliest Marine Traditional Chinese medicines. Brown seaweed S.pallidum has several effects including resolving phlegm, softening and firmness, eliminating galls and nodules, promoting diuresis and detumescence, and has been used in the treatment of phlegm edema, gall, beriberi, adverse urination and other diseases. In recent years, there have been a lot of research on the methods of extraction and purification of polysaccharides from S.pallidum, as well as the biological activities of antioxidant, hypoglycemic, antitumor, antibacterial, hypolipidemic and immunomodulatory. The purified polysaccharide of S.pallidum was primarily composed of fucose, galactose, xylose, glucose, mannose and arabinose. In this paper, the extraction, separation and purification of polysaccharides from S.pallidum, as well as pharmacological activities are reviewed. Given of the problems existing in the research, suggestions for the future development of the optimization of the method of extraction and purification of the polysaccharide, the research and development of the polysaccharide preparation, and in-depth research on the fine structure of the polysaccharide are put forward, so as to make some contributions to further development and utilization of S.pallidum.

This paper presents basic principle and structure including the advantages,and disadvantages of the optic fibre gyro compass.The developing process of the fiber optic gyro compass was described and the forecast to the future application prospect was carried out.Meanwhile the errors and the precision factors affecting the optical fiber gyro compass were analyzed.The measurement to decrease the errors was put forward.

The full-length cDNA sequence of the growth regulator PTEN was cloned by homologous cloning and rapid amplification of cDNA ends (RACE),and temporal and spatial expression of PTEN mRNA was analyzed in goldstriped amberjack Seriola aureovittata by quantitative PCR (qPCR) to explore the molecular mechanism of PTEN in the growth and development of goldstriped amberjack.The results showed that the PTEN cDNA sequence was 1575 bp in length and the ORF was 1287 bp, encoding 428 amino acids.PTEN has the common feature of vertebrate PTEN and contains PTP (PTPc motif) and PTEN-C2 domain.Sequence alignment analysis revealed that both goldstriped amberjack and greater amberjack Seriola dumerili had a high homology(95%).The phylogenetic tree indicated that goldstriped amberjack PTEN was clustered into one branch with the PTEN Perciformes and Pleuronectiformes.By qPCR analysis, the maximal relative expression of PTEN was observed in the heart of goldstriped amberjack (P<0.05), followed by in the spleen, head kidney, kidney, stomach, intestine, gill and pituitary, indicating that the PTEN is involved in the regulation of a variety of physiological processes in various tissues due to high expression of PTEN mRNA.It was found that PTEN was continuously expressed in early embryonic development(embryonic stage, larvae and juvenile), with significantly higher expression level from early blastula stage (38 hours post fertilization, hpf) (P<0.05) with the maximal expression level in freshly hatched larvae (P<0.05).The expression level of PTEN mRNA was gradually decreased during the postlarvae and juvenile (P<0.05).The expression level of PTEN was found to be gradually decreased, significantly and constantly low at 35 days old.The findings indicate that PTEN plays an important regulatory role in the development of embryos and juveniles, which provides a theoretical basis with research of the regulation mechanism and culture during the early growth and development stages in goldstriped amberjack.

The sushi-grade evaluation technology and indicators are constantly developing, and the establishment of scientific and efficient evaluation methods is more and more urgent with the continuous improvement of the demand for high seafood.This paper focuses on fresh products, and systematically reviews the development of seafood quality evaluation from two aspects: indicators and methods.Firstly, the scientific origin of freshness evaluation and the construction process of traditional fishery product evaluation technology system are reviewed systematically from sensory evaluation and non-sensory evaluation methods, and the research progress of live product quality evaluation in recent years is described.Then, systematic analysis and emerging technologies and their corresponding indicators are discussed with modern analytical techniques as the focus.The analysis and summary centering on the evaluation system of traceability, varieties and sushi-grade are analyzed through modern analytical techniques such as chromatography, mass spectrum and spectrum, combined with Omics technology.Finally, from basic theory research on raw material to learn, the defects of the traditional consumption mode, and upgrade the existing domestic consumption and demand three aspects, the sushi-grade for the study of the importance and necessity of breakthrough point and the corresponding quality index and key real-time analysis technology is put forward to provide some reference for the application and development of fresh seafood evaluation indices and methods to promote fishery product-processing industry upgrading.

In the plant-derived materials used as a substitute for fishmeal in fish culture,there are a wide variety of antinutritional substances including factors affecting protein, mineral, vitamin, energy and other utilization. Protein inhibitors, phytates, lectins, goitrogens and antivitamins are heat labile factors, whereas saponins, non-starch polysaccharides, antigenic proteins, estrogens and some phenolic compounds are heat-resistance. These antinutrients make an effect on fish metabolism via enzyme inhibition, toxicity and production of combined compounds. The deleterious effects of the antinutrients can be removed from the materials by physical (heat, pressure and light), chemical (drugs) and biological methods.

Tuna (Thunnus spp.) as pelagic fish with fast swimming are widely distributed throughout the temperate and tropical epipelagic waters of the world’s oceans. They require a large amount of oxygen supply to generate energy for fast swimming via gills as the oxygen supply organ. Focusing on the morphology and function characteristics of the gills during rapid swimming in tuna, this review descries the morphological structure of gills, gills surface area, oblique blood flow pattern and thin water blood barrier thickness structure and oxygen supply characteristics of related research. Further, to elucidate the structural adaptation (gill fusion, calcification, lamellar arrangement of gills) of tuna gills to high-speed water impact and the characteristics of gills countercurrent exchange. The morphological structure and problems in the field of oxygen supply for tuna gills are discussed and some progresses are suggested including the early tissue development of tuna gills, function of gills cells, mechanism of adaptive evolution of gills by bioinformatics and the relationship between tuna gills physiological processes and environmental factors to provide theoretical reference for further studied on the molecular mechanisms of tuna gills.

Fish behaviors as well as feeding, reproduction and respiration include other acts including evading predators, migration, clustering and are affected by some environmental factors such as tide and water temperature. This paper summarizes the main fish behavior research methods, and application in fishing as the future main developmental trend is based on the characteristics of different fishes and development of highly efficient energy - saving and environment- friendly fishing gears. Thereby, we can maintain the fishery resources in a sustainable utilization.

Hormones and their dosages are crucial in fish industrialized artificial propagation. In order to provide reference with economically important main fishes farming in China, we summarized the types and dosage of hormones used in induction to spawn in economically important main fishes (116 species in 12 orders) in China and the mechanism of artificial propagation and the methods and rules of hormone injection are discussed. Also, we probe into the research future on optimal hormones used in new variety farming, microencapsulation slow release technology and gene expression regulation.

Fish eggs could be classified into three categories: adhesive, weakly adhesive and non-adhesive, depending on degree of egg adhesiveness. Many commercially important fish spawn as adhesive eggs, and upon contact with water, the outer layer of the chorionic membrane becomes hydrated, and the adhesive substance subsequently becomes activated and sticky. The adhesiveness of eggs is a huge challenge to artificial incubation and breeding technology, and thus the researches on the characteristics and the mechanisms of adhesive eggs are of great significance to the artificial reproduction of fish. Here we reviewed the latest research progress and developments on characteristics and mechanisms of adhesive eggs, and we also compared the effects of various reproduction methods in different fishes. Furthermore, the future and multiple potentials of artificial incubation and reproduction technologies in fishes that produce adhesive eggs are discussed to provide reference for the artificial breeding of adhesive eggs-spawning fishes.

With an attempt to screen sea grass Suaeda salsa plant growth promoting bacteria, six strains of culturable endophytic bacteria were isolated from the plant leaves and then subject to preliminary molecular identification and in vitro plating experiments to examine the abilities of dissolving phosphorus, decomposing potassium, fixing nitrogen, producing iron carriers and generating ACC deaminase.Colonization experiments using hydroponically grown seedlings were also performed to validate the plant growth promoting abilities of those bacteria.The results showed that through continuous plate streaking using 2216E agar plates, 6 strains of culturable bacteria were isolated from the plant leaves, among which 4 strains had the ability of producing iron carriers(labeled as JY21, JY24, BJY223 and BJY323, respectively)and 2 strains had the ability of generating ACC deaminase(labeled as JY32 and BJY323, respectively).A potential plant growth promoting bacterium(labeled as BJY223)was screened through colonization experiments, which could very significantly promote root elongation as well as stem growth of the hydroponically grown the seedlings(P<0.01).A BLASTn search against the NCBI nucleotide collection using the full sequence of the 16S rRNA gene of BJY223 was carried out to dig out its homologous bacteria, based on which a phylogenetic tree was plotted.BJY223 was therefore identified as being most closely related to bacteria of genus Pseudoalteromonas.The in vitro plating experiments as well as in vivo seedling colonization experiments revealed that a potential plant growth promoting bacterium was isolated from the S.salsa leaves, which will help to enrich the resources of potential S.salsa growth promoting bacteria.

Cellular and humoral immunity of crustacean are reviewed based on the data that have been issued in domestic and overseas journals. Hemocyte is the major immune factor and the reaction depends mainly on the hemocyte phagocytosis and encapsulation, but it is uncertain that the differentiation of the hemocytes and the roles are played by the hemocytes. The humoral immunity of crustacean is unspecialized. Some enzymes and regulatory factors in hemolymph, such as prophenoloxidase activating system, hemolysin, agglutinins,lysozyme and protease inhibitor are involved in humoral immunity of crustacean.

Histopathological, haematological and toxicological effects of malachite green （MG） on various animals, and the biotransformation of malachite green （MG） and its matabolites, leucomalachite green （LMG） were summarized. The recent research advances on determination of malachite green and leueomalachite green were dewed abroad. Alternative disinfectants to malachite green were advised. An approach to remove excess malachite green from treatment water should be explored.

Since low temperature is one of the main environmental factors affecting production and survival of shellfish, the research of mechanisms and tolerance to low temperature in shellfish has very important role in shellfish breeding industry. In this review, we summarize the progress in the field of the resistance and tolerance to cold stress in shellfish in recent years, focusing on research results of shellfish responding to low temperature stress, and effects of low temperature on physiological and biochemical characteristics of shellfish, including changes in energy budget, body composition and enzyme activities of shellfish under low temperature. The response of cold responsive genes in shellfish to low temperature is described, including the expression changes in cold shock proteins gene, heat shock proteins gene and antioxidant enzyme gene under low temperature stress. On this basis, the prevention and control measures of shellfish in response to low temperature environment are discussed and new perspectives and information on future research and practice in this field is put forward.

To preliminarily clarify the anti-tumor effects of crude protein from the mucus of the whelk Volutharpa ampullacea Perryi, the effects of crude protein from the mucus of the whelk on the proliferation of human hepatoma Hep-G2 cell and tumor growth of H22 tumor-bearing mice were analyzed and compared in vitro and in vivo experiments using microscopic observation, flow cytometry and qRT-PCR techniques. The results showed that the morphology of Hep-G2 cells in the group treated with 0.66 g/L crude protein from the mucus of the whelk showed severe deformation, nuclear condensation and blurring of nuclear membrane, vacuolation of cytoplasm, swelling of mitochondria and significant reduction of microvilli on the cell surface compared with the untreated control group (as control). The proportion of G2/M stage cells in Hep-G2 cells in the group treated with 0.66 g/L crude protein from the mucus of the whelk was significantly higher than that in the untreated group (P<0.05). The transcript levels of cell cycle protein CCNB1 and cell cycle protein-dependent kinase CDK1 in the Hep-G2 cells were shown to be significantly lower in the crude protein-treated group than those in the control group (P<0.05). The mean tumor weights of the tumor-bearing mice were significantly lower in the crude protein-injected groups (the injection dose of prevention group and the treatment group was 30 mg/kg) than those in the model control group (P<0.01). The findings indicate that crude protein from the mucus of the whelk has anti-hepatocellular carcinoma effects both in vitro and in vivo, showing the potential to be developed as an anti-hepatocellular carcinoma drug of marine origin.

In recent years, aquaculture activities cause severely impair to health of water body in nature as the rapid development of intensive aquaculture. During the aquaculture, fish faeces fail to be a properly handled and become the main contaminant which can destroy the water environment in aquaculture. The hazards coming from fish faeces to water body and farmed animals are summarized, the factors influencing fecal production and particles size under the condition of aquaculture are described, and several kinds of commonly measures from abroad and at home to prevent and control the hazards are discussed. The problems in management of water pollution in China, and a new outlook in the content of future research on faeces are presented.

Astaxanthin of Antarctic krill as a huge bioresource, still deeply undeveloped and unutilized marine living resources is a natural antioxidant with great antioxidant activities, and particularly, plays an important role in the body color change and the improvement of immunity of fish. In this article, the advances of preparation methods (solvent extraction method, enzymatic hydrolysis method, and supercritical carbon dioxide extraction), structure characteristics, bioactivities, detection methods (ultraviolet spectrophotometry, thin-layer chromatography, laser Raman spectrometry, high efficiency liquid chromatography and high performance liquid chromatography -tandem mass spectrometry) of astaxanthin from Antarctic krill are reviewed, and future suggestions on mechanism researches, key technologies and product developments of Antarctic krill astaxanthin are put forward. It is anticipated that contribute the deep research and utilization of Antarctic krill astaxanthin in the future.

The sustainable use of fishery resources is a key issue in the sustainable development of fisheries, so in order to ensure the maximum sustainable use of fishery resources, it is necessary to evaluate the development potential of fishery resources. The research on evaluation of the sustainable use of fishery resources is systematically organized and analyzed by using the Core Collection of Web of Science and the CNKI database to retrieve 229 and 238 documents, respectively, internationally and domestically, using the documentary econometric analysis method based on citespace software, and combined with keyword network knowledge map and mutation detection, the sustainable use of fishery resources evaluation of research hot spots and future trends are explored. The overall fluctuation of the research volume of sustainable use of fishery resources showed an upward trend, with more research in this field in the United States, China and Canada. At present, the research hot spots include the evaluation methods and strategies of sustainable use of fishery resources, the impact of climate change on fishery resources, the evaluation of sustainable use of fishery resources based on ecosystem management, and the management system of sustainable use of fishery resources. The key research directions are put forward in the future including the problems in the study of sustainable utilization of fishery resources, such as the improvement and unification of evaluation methods and the supervision and perfection of management systems.

The biological characteristics of bacterium Flavobacterium columnare were studied by Gram stain,colorimetry and agar diffusion methods.The bacterium cultured in broth Shieh meddium for 24 hours was showed different shape in the appearance including arch shape,U form,V form or S form and so on.Some of Flavobacterium columnare cultured for 72 hours appeared as branched cells and more granular involution form than that for 48 hours.The extracellular products（ECP） were found to be positive in the protease,lipoidase and lecithinase,but negative in amylase,gelatinase and urease.

Planktonic community features in a hatchery water system for short - necked clam, Ruditapes philippina rum were investigated at Haiyang village of Zhuanghe, Dalian, Liaoning Province in China from May to November in 2005. Totally, sixty - two taxa （most diatom）of phytoplankton （the biomass of 2.90 -30. 91 mg/L） were found in the water, with the predominant species of Nitzschia closterium, Chaetoceros lorenzianas, Nitzschia sp. , Phaeodactylum tricornutum, Navicula sp. , Chroomonas acuta, Chlorella vulgaris, and Euglena viridis, and the maximum mean biomass （16.78 mg/L） at the exit of a deposit pond, followed by in the entrance station, and the minimum at the exit of the purifier pools. There were forty - five taxa of zooplankton comprised of eopepods and its nauplius or copepodite, Leprotinnus nordquisti, Chilodonella vorax, Strobilidium gyrans, Brachionus plicatilis, Epiphanes senta, Paracalanus parvus, Corycaeus affinis and Cypris subglobosa being the predominant species. The mean density of the zooplankton varied from 5.5 ind./L to 118 ind./L, with mean biomass of 0.01 mg/L to 5.97 mg/L, the maximum biomass （2.48 mg/L） in the shallow area, and the minimum in the purifier pool.

In order to investigate the mechanism of the response of scalloped spiny lobster Panulirus homarus to nitrite stress, the transcriptomics were comparatively analyzed in hepatopancreas of scalloped spiny lobster with body weight of (39.00±5.31)g exposed to under normal conditions  <0.01 mg/L, control group)and to 80 mg/L nitrite stress prepared by NaNO2 for 7 d by a transcriptomic sequencing approach. The results showed that 264 differentially related genes were screened, with up-regulated 86 and down-regulated 178. GO functional annotation results showed that the annotated differential genes were primarily involved in functions including binding, catalysis and metabolism, and KEGG pathway enrichment analysis showed that the differentially expressed genes were significantly enriched in focal adhesion, leukocyte transendothelial migration, insulin resistance, tight junctions, and starch and sucrose metabolism pathways. Nine differential genes were randomly selected for qRT-PCR validation, and the fluorescence quantification results were found to be in general agreement with the sequencing results. The findings will provide substantial reference for the research of gene functions in energy metabolism, growth and immunity in scalloped spiny lobster under nitrite stress.

According to the trend of worldwide environment protection, the paper discusses the end using time of some refrigerants, refrigerant replacement and transition, and recycling of prohibited refrigerants. Some proposals for refrigerant replacement in China are also given in the paper.

In order to solve the using limitation of non - continuous lines among AutoCAD standard lines for ship graphing, some lines＇definition, like phantom and other non -continuous lines, are introduced in this article. The multi -line （five -line） definition way of trajectory is described in drawing for a boat.

Protease activities were determined in different parts of digestive organs in largemouth bass （Micropterus salraoides） at different temperature, pH and casein concentration by means of enzymological analysis. The results showed that the protease activities in different parts of digestive organs were arranged in a descent order as： stomach 〉 pyloric caeca 〉 foregut 〉 midgut 〉 hindgut. The protease activities changed with variations in temperature, pH and casein concentration in different organs. The optimum temperatures and pH were （40℃, 2.4 ） for stomach, （55℃ ,7.6） for pyloric caeca（45℃ ,8.0） for gut. The optimum temperature for protease activity was higher than that in the fish body. The highest activity of protease occurred in strong acidic condition in stomach, but in neutral or weak alkaline condition in pyloric caeca and gut. The activity of the protease also changed with concentrations of the casein, the optimum casein concentration of 20 g/L for stomach. 20 g/L for pyloric caeca, and 10 g/L for gut.

The effects of fourweaning foods including soybeanmilk,egg yolk,fairy shrimp and rotifers enriched by green algaChlorella vulgarison growth performance and body composition of larval bulatmai barbelBarbus capitowere investigated in order to explore the optimalweaning food of bulatmaibarbel larvae.The results showed that the fish had increase in body weight and body length since 14 days post hatching(DPH)with the best growth in the fish fed rotiferswhich showed higher survival rate,bodyweight,and body length than those in the fish fed the other foods on 14 DPH,19 DPH and 24 DPH.There were 16.45％of protein and 8.79％of fat in the fish fed rotifers. The fish fed fairy shrimp had body weightof1545.2mg,body length of22.509mm and survival rate of88.7％on 24 DPH,significantly higher than those in the fish fed egg yolk and soybean milk.The larvae had good growth by 14 DPH,and seldom grew later when they fed egg yolk.Theminimal growth and survival rates were found in the fish fed soybeanmilk.The findings indicated that rotifers enriched byChlorella vulgariswasmost suitable as aweaning food,and that the key point for initial feedingwas of14 DPH in bulatmaibarbell larvae,egg yolk being used as a supplement food before 14 DPH.

The species composition and distribution status of crabs were evaluated based on the data of four seasonal fishery resources surveys in the northern continental shelf of South China Sea from 2006 to 2007. The results showed that there were 51 species belonging to 10 families and 24 genera in the area, most of which were tropical warm - water species belonging to South China - Southeast Asia subregion of Indian - western Pacific fauna. Depending on their adaptability, all crab species were categorized into three ecological groups： tropical euryhaline group, eurythermic euryhaline group, and tropical halophile group, with predominant tropical euryhaline species including Portunus argentatus , P. sanguinolentus , P. tweediei , Charybdis feriatus , Charybdis hongkongensis , Calappa philargius,and Charybdis miles, C. truncata, by Pinkas. The catching rate of the predominant species （2.99 kg/h） was around 81.69% in total catching rate of crab species（3.66 kg/h）. The economic crab species Portunus sanguinolentus , P. trituberculatus , P. haanii, P. pelagicus , Charybdis feriatus , C. miles, and C. japonica belonging to Portunidae（2.37 kg/h） had the catching rate of around 64.75% of total catch rate （3.66 kg/h）. The crabs were stocked at a density of 97.47 kg/km2, including the economic crabs at stocking density of 63.20 kg/km2. The maximal distribution area of the crabs were found in the transect D （ 125.60 kg/km2） and the minimal in the transect C（70.93 kg/km2）. The maximal biomass of the crabs were observed in autumn（ 181.60 kg/km2） and the minimal in winter（50.13 kg/km2）. The most aggregation of crabs species were mainly distributed in depths of 10 -60 m with the peak （222.13 kg/km2） in depth of near 10 m, negative relation with the water depths.

The phytoplankton community structure including species composition, density, biomass dominance and biodiversity of phytoplankton was surveyed in 5 sampling sites in Moguhu Reservoir in wet season (April), normal level season (July) and dry season (November) in 2016 in order to understand the phytoplankton in Moguhu Reservoir and current eutrophication in waters in Moguhu Reservoir.There were 90 species (genera) of phytoplankton were identified including 12 dominant species, with good phytoplankton diversity and relatively stable community structurein Moguhu Reservoir.The phytoplankton community structure was dominated by blue-green algae and green algae throughout the year, with average density of phytoplankton was (817 ±982)×104 cells/L, and the biomass was(6.72±5.88)mg/L.The significantly seasonal changes in phytoplankton biomass and density were found(P<0.05), the maximum in July (summer) and the minimal in April (early spring), indicating that the water quality in Moguhu Reservoir is under V class water standand in the year.The CANOCO software analysis revealed that the main environmental factors affecting the dominant species of phytoplankton are temperature, nitrate nitrogen and nitrite nitrogen levels, Moguhu Reservoir is currently under eutrophication pollution, with significant correlation between temperature and density and biomass of phytoplankton.

The theory of the optimal stocking time of fish fry is developed from regular pattern of water quality and plankton development, especially rotifera peak period, after disinfection of a pond, and organ development of fry related to initial feeding, and includes two aspects: physiological optimal stocking time and ecological optimal stocking time. The physiological optimal stocking time indicates fry organ development gradually adapts to start feeding in terms of structure and function, and the ecological optimal stocking time indicates to provide the pond with initial feeding, suitable density and good external ecological environment conditions in the ponds. We review the development process of the theory of the optimal stocking time of fish fry and divided suitable initial weaning diets into nine types: rotifer, Artemia nauplii, Cladocera, Limnodrilus，bait fish fry, phytoplankton，body surface mucus, compound initial feed, and microparticle feed according to the research status of suitable initial feeding for main economically important fishes. “Timely” in this theory needs to be more accurate under different conditions. It is necessary to make a systematic study on the series of diets from initial feeding “mouth opening” (postlarvae) to juvenile stage in order to improve the survival rate of fry and ecological breeding.

In order to reveal that enzymatic peptide and protease replace 5% fish meal in the diet of Pacific white shrimp Litopenaeus vannamei, the effects of partial fish meal substitution by enzymatic peptide and protease on the growth, digestive indices and intestinal flora of Pacific white shrimp was investigated. Pacific white shrimp juveniles with initial body weight of (0.32±0.01)g were reared in an aquarium (40 cm×50 cm×60 cm)and fed basic diet (control group), and diet containing 5% fish meal replaced by 5% peptide (group EP) and by 0.3% protease (group PR) at water temperature of 28 ℃ for 56 d with three repetitions. The results showed that there were higher final body weight and weight gain rate in the shrimp in EP and PR groups than those in the control group, with significant differences in hepato-somatic ratio and dressing rate (P<0.05). The plasma glucose, total cholesterol and triglyceride levels were shown to be significantly higher in EP and PR groups than those in control group (P<0.05). The shrimp in EP and PR groups had higher activities of lipase, pepsin and protease than the shrimp in control group did (P<0.05). Shannon index in enzymatic peptide and protease groups was higher than that in control group, Simpson index in protease group was significantly lower than that in control group, and that in peptide group was significantly lower than that in protease group (P<0.05). At the phylum level, the number of Proteobacteria and Actinobacteria in group enzymatic peptide was higher than that in control group and protease group. At the class level, in enzymatic peptide and protease groups the Alphaproteobacteria of Proteus was lower than that in control group, and Gammaproteobacteria in enzymatic peptide and protease groups were higher than in control group and enzymatic peptide group, and Verrucomicrobiae was higher than in control group and protease group. At the genus level, it can be seen that the proportion of Rhodobacteraceae_unclassified in enzymatic peptide and protease groups was higher than that in the control group, with the large difference, and little difference among Flavobacterium_unclassified groups. The findings indicated that the addition of enzymatic peptide and protease in the diet improved the growth performance of Pacific white shrimp, with positive impact on digestive indices and intestinal structure, and that enzymatic peptide and protease were used as a new resource to reduce the addition of fish meal in shrimp formula feed.

Mechanisms of sex determination in fish are complex and changeable procedures,and usually depend on interactions between genetic and environmental factors.Great progress in identification and characterization of fish sex determination and differentiation related genes has been made with the development of molecular biotechnology. It has been shown that sex determination and differentiation are influenced by environmental factors including temperature,photoperiod,pH,hypoxia,and water pressure in most fishes.Types of sex determination and differentiation,genetic sex-determination(GSD)and temperature-dependent sex determination(TSD),are proposed.Sex determination and differentiation is largely affected by temperature.The current advances on molecular players are reviewed,including Sox9,Dmrt 1,Amh,Foxl2,and aromatase genes,which are involved in sex determination and differentiation in fish temperature-dependent sex determination and differentiation,including temperature-dependent sex determination and genetic sex-determination plus temperature effects are emphasized.The influence of temperature on sex ratio of fish is discussed to provide valuable insights for elucidation of mechanisms of sex determination and differentiation in fish and for design of better fish breeding and reproduction programs in farmed fish.

Based on a number of compaction tests, the compaction behaviour of heterogeneous soil is investigated in this paper. Then an empirical formula for assessing the maximum dry density of heterogeneous soil is proposed. It is shown that the proposed formula is practically applicable.

Effects of different levels of sodium citrate, EDTA - Na2, HEPES, and sodium oxalate on anticoag-ulation of coelomocytes were studied in sea cumcumber Stichopus japonicus. The results showed that the coelomocytes were morphologically kept activity at 1.0 - 1.5 mg/mL EDTA - Na2, 3.8 mg/mL sodium citrate, 0.2 - 0.6 mg/mL HEPES, and 1.0 - 1.5 mg/mL sodium oxalate, EDTA - Na2 being the best anticoagulant.

In order to probe into the effects of low temperature stress on the survival and fatty acid metabolism related genes of Manila clam Ruditapes philippinarum zebra clam No.2, the survival differences and three genes related to fatty acid metabolisms including stearoyl coenzyme A desaturase (SCD), fatty acid desaturase (FAD) and acetyl coenzyme A carboxylase (ACC) in gill tissues were investigated in three populations including zebra clam No.2, Dalian in Liaoning Province and Beihai in Guangxi under low temperature stress of -1 (in a refrigerator)， 4 (in a recirculating tank)， and 12 ℃ (room temperature) by qRT-PCR. The results showed that after acute low temperature (-1, 4 ℃) stress for 9 d, the order of the survival rates of Manila clam populations was expressed as zebra clam No.2 > Dalian population in Liaoning > Beihai population in Guangxi. The expression of three fatty acid metabolism related genes in gill tissues was significantly affected by temperature (P<0.05 ).With the temperature decreasing from 12 ℃ to -1 ℃, the expression level of the three genes were increased under 4 ℃ or -1 ℃ cold stress. Compared with 0 h, the expression levels of SCD and FAD genes in gill tissues of zebra clam No.2, Beihai population and Dalian population were significantly up-regulated from 12 to 72 h(P<0.05). The expression levels of ACC genes in the three populations were significantly up-regulated at different time, and the up-regulation range of the three genes in the gills of zebra clam No.2 was significantly higher than that in Beihai population and Dalian population (P<0.05). The results demonstrated that the survival rate and low temperature tolerance of zebra clam No.2 at -1 ℃ were apparently higher than Dalian, Liaoning and Beihai, Guangxi. In addition, the high expression level of SCD, FAD and ACC genes of zebra clam No.2 might be related to its strong tolerance and high resistance to low temperature.