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  • Evaluation of low-salt tolerance of razor clams (Sinonovacula constricta) from different families and their physiological responses
    ZHAN Tianyu, ZHANG Na, YE Kai, BAI Zengqi, KANG Pengtian, NIU Donghong
    Journal of Dalian Fisheries University. 2025, 40(5): 780-788. https://doi.org/10.16535/j.cnki.dlhyxb.2025-068
    Abstract (4342) PDF (944) HTML (4)   Knowledge map   Save
    To evaluate low salt tolerance of different family lines of razor clam (Sinonovacula constricta), we exposed specimens from six razor clam family lines (8, 13, 14, 23, 24, and 28) to low salt (2 salinity) or control (20 salinity) conditions to carry out low salt stress experiments. Tissue damage, apoptosis, Na+/K+-ATPase (NKA) activity, and antioxidant enzyme activity were measured and compared among the specimens from the different families. The results showed that the mortality rates of razor clams from F8, F13, and F14 were >80% but the survival curves of all families were similar. The Pearson correlation between razor clam survival and shell width was highly significant (P<0.01), and the Spearman correlation between shell width and body weight was significant (P<0.05). Hematoxylin and eosin (HE) staining showed that clams from F8, F13, and F14 had normal gill tissue structure by 48 h, some gill filaments were swollen at 72 h, gill spacing was reduced, gill volume was enlarged, and the area of broken region was increased at 96 h. Clams from the F23 group had slight edema of localized gill filaments at 72 h, and their damage extent were not worse than those from F8, F13, and F14 by 96 h. F24 and F28 clams had intact gill filament structure at 96 h of the stress cycle. The level of apoptosis was observed by Hoechst 33342 staining, showing that the nuclei of F8, F13, and F14 cells displayed dense bright blue patches, with aggregates of apoptotic vesicles and more apoptosis. In clams from the F23 group, the proportion of apoptotic cells was reduced; and the proportions of apoptotic cells were lower in F24 and F28 clams, with occasional sporadic apoptotic vesicles. The activity of NKA of clams from all family lines decreased continuously during 12 h of low salt stress, and the enzyme activities of clams from the F23, F24, and F28 increased significantly by 24 h but then decreased.The NKA activity levels of F8 and F13 clams decreased continuously, and the value of F8 was always lower than that of F13.The antioxidant enzyme activity assay showed that the catalase activity of two lines (F13 and F14) was always lower than that of the other lines. The superoxide dismutase activity of clams in all families increased and then decreased, with the maximum value at 24 h. The malondialdehyde content of clams in the F8, F13, and F14 groups was higher than that of clams in the F23, F24, and F28 groups at the end of the low salt stress period. In conclusion, the six razor clam families had different tolerances to low salt conditions, and the F23, F24, and F28 clams were the most tolerant. The study results provide a reference for further breeding new low salt-tolerant razor clam lines.
  • The current development status and future prospects of smart fisheries technology:a review
    LIU Huang, LIU Shijing
    Journal of Dalian Fisheries University. 2025, 40(4): 541-551. https://doi.org/10.16535/j.cnki.dlhyxb.2025-183
    Abstract (4269) PDF (2182) HTML (4)   Knowledge map   Save
    Smart fisheries are an important means of improving fishery production efficiency and promoting the modernization and transformation of the fishery industry. By deeply integrating advanced technologies such as multisensing, the Internet of Things (IoT), big data, and artificial intelligence, smart fisheries have made significant progress in key areas such as breeding, aquaculture, fishing, and processing. However, the new trends in the high quality development of modern fisheries pose higher demands on the development of smart fisheries. This paper systematically reviews the major research progress in smart fisheries technologies from three dimensions: information sensing, transmission, and analysis and decision-making. It also outlines the technology development trends and summarizes the current applications of intelligent technologies in breeding, aquaculture, resources, fishing, and processing, in combination with the practical needs of the industry. The aim is to provide support for the transformation of China’s fisheries from a big fishery country to a strong fishery nation.
  • Optimization of cultivation conditions for the alga Isochrysis galbana in a pilot-scale tubular photobioreactor
    ZHANG Yao, FAN Chonghui, QIU Zhujun, ZHAO Wenyu, WANG Yuqing, ZHANG Tao, SUN Ziyi, SUN Yan, ZHANG Qian
    Journal of Dalian Fisheries University. 2025, 40(6): 1011-1017. https://doi.org/10.16535/j.cnki.dlhyxb.2025-119
    Abstract (4061) PDF (423) HTML (1)   Knowledge map   Save
    To overcome the shortcomings of traditional microalgae cultivation, such as low biomass concentration and susceptibility to weather conditions, we developed a controlled cultivation system using the alga Isochrysis galbana—a vital microalgal diet for marine aquaculture breeding—as the model species. We used a pilot-scale tubular photobioreactor to optimize light regimes, CO2 supplementation, and cultivation strategies. Regarding the light regime, we found that compared with natural light conditions, supplementary LED lighting at night significantly promoted the growth of I. galbana. Additionally, gradient light supplementation was more conducive to the growth of I. galbana, as we detected 0.38 g/L dry weight,an increase of 11% compared with constant light group after 7 days of cultivation. The average daily light intensity of 150 μmol/m2/s was the optimal condition and the dry weight reached 0.41 g/L. Regarding CO2 supplementation, a high aeration rate (400 mL/min) significantly enhanced growth of I. galbana. Under the same average aeration, the gradient aeration mode was beneficial to stability of the system’s pH. It significantly increased the dry alga yield of I. galbana by 9% compared with the constant light group after 7 days of cultivation. In the semi-continuous cultivation mode, the biomass yield with a 40% renewal rate was much higher than that with a 20% renewal rate. After 14 days of cultivation, 488.32 g of biomass was harvested, 20% higher than that of the 20% renewal rate group. These results show that gradient light regimes, gradient aeration, and semi-continuous cultivation with 40% renewal can significantly enhance the biomass production of I. galbana, thereby providing optimized specifications and technical guidance for industrial-scale microalgae cultivation.
  • DNA methylation in response to environmental stress in aquatic animals： a review
    LI Jin, NIE Hongtao
    Journal of Dalian Fisheries University. 2025, 40(6): 1053-1064. https://doi.org/10.16535/j.cnki.dlhyxb.2025-022
    Abstract (4012) PDF (521) HTML (1)   Knowledge map   Save
    Environmental stress has a significant impact on survival, growth, physiology, and innate immune response of aquatic animals. The innate immune defense system of aquatic animals can quickly respond to environmental stress and help organisms adapt to environmental changes. DNA methylation is an important epigenetic modification.It may dynamically regulate gene expression in aquatic animals facing biotic and abiotic environment stress, participate in metabolism, immunity, and resistance functions, and maintain body homeostasis. This article reviews environmental stress factors, including abiotic factors (temperature, salinity, low dissolved oxygen, pollutants) and biotic factors (viruses, bacteria, parasites); changes in DNA methylation, physiological and ecological effects, and DNA methylation regulation of gene expression in aquatic animals. It provides a scientific reference for a comprehensive understanding of how DNA methylation regulates immunity in the biological response to environmental stress and its potential role in variety breeding and ecological protection.
  • Gene sequence and expression pattern of hsd17b12a in large-scale loach (Paramisgurnus dabryanus)
    FANG Yutong, GUAN Xin, ZHANG Lei, SHI Mijuan, XIA Xiaoqin
    Journal of Dalian Fisheries University. 2025, 40(6): 907-915. https://doi.org/10.16535/j.cnki.dlhyxb.2025-089
    Abstract (3912) PDF (580) HTML (1)   Knowledge map   Save
    The hsd17b12a gene is a key regulator of sex steroid metabolism. To assess the functional mechanism of this gene in large-scale loach (Paramisgurnus dabryanus), we conducted protein prediction and evolutionary analysis based on the full-length coding sequence of hsd17b12a annotated in the genome. The gene's expression patterns were examined using quantitative real-time PCR across embryonic development stages, various adult tissues, and key time points of gonadal development. The results revealed that hsd17b12a has a 949 base pair coding sequence that encodes a 319 amino acid protein. During embryogenesis, its expression was significantly higher at the cleavage stage than that at other stages. The gene was broadly expressed in the heart, liver, spleen, muscle, intestine, gills, brain, and gonads of both sexes, with significantly higher expression in the ovary than that in the testis(P<0.05). These findings suggest that hsd17b12a is closely associated with gonadal development and differentiation in large-scale loach, potentially playing a crucial role in ovarian development while being partially suppressed during testicular development.
  • Mechanisms of high-temperature adaptation of Manila clams(Ruditapes philippinarum) during intermediate culture in northern ponds
    DU Zehua, SAIJI Zhuoma, DING Xiangming, ZHANG Guozhu, CHEN Yanyu, XU Yunrui, HUO Zhongming, WANG Hua
    Journal of Dalian Fisheries University. 2025, 40(6): 947-956. https://doi.org/10.16535/j.cnki.dlhyxb.2025-070
    Abstract (3859) PDF (401) HTML (1)   Knowledge map   Save
    The study was to assess the impact of dynamic environmental changes during the summer high-temperature period on physiological metabolism of Manila clams (Ruditapes philippinarum). To assess the metabolic-driven mechanisms underlying the high-temperature adaptation of Manila clams under water quality regulation in intermediate nursery ponds, we systematically monitored individual growth (shell length, wet weight), energy metabolism (oxygen consumption rate, ammonia excretion rate), and key water quality parameters. During the high-temperature window of 27 ℃ to 30 ℃, the clams exhibited significant growth advantages, with a monthly average shell length increase of (3.93 ± 0.21) mm (n= 300). The clams displayed active respiration and metabolism, with oxygen consumption rates ranging from 1.532 to 1.974 mg/(g·h) and ammonia excretion rates between 0.048 and 0.086 mg/(g·h). The oxygen to nitrogen ratio also showed significant temporal variation, indicating dynamic adjustments in metabolic substrate to achieve high-temperature adaptive growth. Additionally, the regular water exchange strategy implemented in the intermediate nursery ponds effectively maintained water quality stability (salinity: 20.6-24.4; dissolved oxygen: 4.72-8.78 mg/L; pH: 7.17-8.37; chlorophyll a: 3.66-16.86 μg/L), providing a suitable environment for clam cultivation. These results demonstrate a “high temperature-high metabolism-stable growth” aquaculture pattern for Manila clams in northern summer nursery ponds, offering technical support for water quality regulation and scientific management in such systems.
  • The effect of Cu2+ stress on the expression of genes related to the immune response and oxidative stress in the kidney of Gymnocypris eckloni
    WANG Lu, JIA Chunyan, LI Changzhong, MA Shuxiong, YAN Weiyi, LIU Zhenya, CHEN Yanxia, ZHANGCAIDAN Zhuoma, JIN Wenjie
    Journal of Dalian Fisheries University. 2025, 40(6): 926-938. https://doi.org/10.16535/j.cnki.dlhyxb.2025-097
    Abstract (3765) PDF (544) HTML (1)   Knowledge map   Save
    The study was to explore the effects of Cu2+ stress on expression of genes related to the immune response and oxidative stress in the kidney of Gymnocypris eckloni. Three-year-old fish were exposed to 0.01 mg/L CuSO4·5H2O for 0, 6, 36, and 72 h respectively. At each time point, the kidney samples were taken, and transcriptomic analysis of kidney tissues was conducted to measure the expression of genes related to immunity and oxidative stress. Six significantly altered immune-related genes (HIF1A, Golph3, Susd2, CXCL8, H2-Eb1, TOP2B) and two significantly altered stress-related genes (INIP and ATP8B2) were detected in the kidneys of G. eckloni under Cu2+ stress. Among them, the expression of HIF1A was significantly up-regulated at 6, 36, and 72 h of Cu2+ stress, but its expression remained stable in the K1, K2, and K3 experimental groups. Golph3 expression was rapidly up-regulated, suggesting that it might be a key early-warning sign of Cu2+ toxicity. Susd2 expression was significantly up-regulated under Cu2+ stress and activated the NF-κB pathway to help the kidney resist heavy metal damage. Expression of CXCL8 was up-regulated at the initial stage of stress, but its expression decreased over time. H2-Eb1 and TOP2B expressions were up-regulated at the early stage and down-regulated at the later stage, respectively. The expression of INIP was significantly down-regulated at the initial stage of Cu2+ stress and significantly up-regulated at 36 h. ATP8B2 expression was normal during the initial phase of stress but suppressed with prolonged stress duration. In conclusion, Cu2+ stress has complex and diverse effects on the expressions of genes related to the immune response and oxidative stress in the kidney of G. eckloni. The changes in the expressions of these genes reflect various adaptation mechanisms and possible damage as the kidney of G. eckloni copes with Cu2+ stress. The research results provide an important theoretical basis for further analysis of the molecular response mechanism of G. eckloni exposed to heavy metal stress and also provide scientific references for protecting this species and other aquatic organisms from heavy metal pollution.
  • Molecular cloning, expression profiling, and functional characterization of the caspase-8 gene in the sea urchin Strongylocentrotus intermedius
    TIAN Ye, LI Yuanxin , QUAN Zijiao, LIU Kexin, XU Haoyuan, LIU Jiaqi, FAN Yichen, HAN Bing, HAN Lingshu, DING Jun
    Journal of Dalian Fisheries University. 2025, 40(6): 897-906. https://doi.org/10.16535/j.cnki.dlhyxb.2025-058
    Abstract (3675) PDF (604) HTML (1)   Knowledge map   Save
    To investigate the role and expression characteristics of the apoptosis-related gene caspase-8 in the immune response of the sea urchin Strongylocentrotus intermedius, rapid amplification of cDNA ends technology, quantitative real-time PCR, and RNA interference were employed. The molecular features of caspase-8 and its encoded amino acids, expression patterns across developmental stages and different tissues, and its biological functions were examined. The full-length caspase-8 cDNA consisted of 3 107 base pairs, with a predicted open reading frame of 2 064 base pairs encoding 687 amino acids. The predicted molecular weight of the protein was 254 700, and the theoretical isoelectric point was 4.85. Caspase-8 exhibited conserved structural features, including two death effector domains(DED) and a cysteine-aspartic acid-specific catalytic domain(CASs). Among the various tissues, caspase-8 expression was highest in coelomocytes and lowest in the intestine. Expression was highest at the 8-cell stage of development and lowest at the gastrula stage. The expression levels of caspase-8 and caspase-3 were assessed following knockdown of caspase-8 with specific small interfering RNA, and the activities of key enzymes were measured before and after interference. Caspase-8 was most efficiently silenced in coelomocytes, and caspase-3 expression levels were significantly downregulated in both the intestine and coelomocytes (P< 0.05), indicating a regulatory relationship between the two genes. In addition, the activities of superoxide dismutase, catalase, peroxidase, and glutathione peroxidase were significantly reduced (P< 0.05), suggesting that silencing caspase-8 may suppress the immune response of sea urchins. This study demonstrates that caspase-8 plays a crucial role in the immune response of sea urchins and that a regulatory association exists between caspase-8 and caspase-3.
  • Dietary β-hydroxy-β-methylbutyrate supplementation affects growth performance, muscle quality, and glycolipid metabolism in Pacific white shrimp (Litopenaeus vannamei) fed a high carbohydrate diet
    JIANG Shuai, SHUAI Meiqi, XU YiHuan, ZHANG Lihan, FANG Xuedan, GUO Ran, CHEN Guang
    Journal of Dalian Fisheries University. 2025, 40(6): 989-1000. https://doi.org/10.16535/j.cnki.dlhyxb.2025-049
    Abstract (3455) PDF (316) HTML (1)   Knowledge map   Save
    The study was to investigate the effects of dietary supplementation with calcium β-hydroxy-β-methylbutyrate (HMB) in a high carbohydrate diet on growth performance, muscle quality, and glycose-lipid metabolism of Pacific white shrimp (Litopenaeus vannamei). We formulated six isonitrogenous and isoenergetic diets with a high carbohydrate concentration with graded HMB levels of 0, 0.25, 0.5, 1, 2, and 4 g/kg (HMB0, HMB0.25, HMB0.5, HMB1, HMB2, HMB4, respectively). These diets were fed to Pacific white shrimp (initial body weight, 0.28 g ± 0.01 g) for 56 days. Compared to the HMB0 group, the weight gain rate (WGR) and specific growth rate (SGR) of shrimp in the HMB2 and HMB4 groups were significantly higher, whereas the feed conversion ratio was significantly lower. Quadratic regression analysis of the WGR and FCR indices showed that the optimum levels of HMB were 2.58 g/kg and 2.71 g/kg, respectively. Pacific white shrimp in the HMB2 group showed upregulation of key genes in the PI3K/AKT/mTOR signaling pathway and myogenesis regulation in muscle, which improved muscle quality. In the HMB2 group, HMB also downregulated expression of the FoxO1 gene, leading to significant inhibition of gluconeogenesis and lipolysis in shrimp. This further activated glycolysis and enhanced glucose utilization. Furthermore, HMB inhibited lipid synthesis, thereby attenuating high carbohydrate diet-induced lipid deposition in shrimp. In conclusion, dietary supplementation of 2 g/kg HMB in a high carbohydrate diet synergistically improved growth performance, muscle quality, and glucose-lipid metabolism in Pacific white shrimp. These results provide novel insights for promoting the utilization of high carbohydrate diets in the culture of Pacific white shrimp.
  • Review of the effects of net cage biofouling on hydrodynamics in aquaculture environments
    DU Shupeng, LIU Ying, LU Shan, TIAN Zhenglin, REN Xiaozhong
    Journal of Dalian Fisheries University. 2025, 40(6): 1065. https://doi.org/10.16535/j.cnki.dlhyxb.2025-032
    Abstract (3310) PDF (318) HTML (1)   Knowledge map   Save
    As the aquaculture industry moves towards intensive facility-based development and the expansion of nearshore farming to offshore areas, the scale of cage farming continues to increase. In turn, the issue of net biofouling is having an increasingly prominent impact on production. Biofouling is one of the key factors affecting the hydrodynamic characteristics of offshore aquaculture cages. Biofouling organisms not only significantly influence the durability and service life of net structures, but they also play a crucial role in the hydrodynamics of aquaculture environments. This review focuses on the literature related to biofouling of offshore aquaculture nets, specifically on: 1) the impact of net materials on aquaculture environment hydrodynamics; 2) the effects of biofouling on aquaculture environment hydrodynamics, and 3) research methodologies for offshore net biofouling. Current challenges are summarized and future prospects are discussed, with the goal of providing scientific references for understanding biofouling mechanisms and promoting the development of the cage aquaculture industry.
  • The direct antibacterial function and mechanism of interleukin-8 in mandarin fish (Siniperca chuatsi)
    YANG Jie, MA Xiaojie, LI Chao, CHEN Shannan, NIE Pin, HUO Huijun
    Journal of Dalian Fisheries University. 2025, 40(6): 957-963. https://doi.org/10.16535/j.cnki.dlhyxb.2025-078
    Abstract (2702) PDF (483) HTML (1)   Knowledge map   Save
    To investigate the direct antibacterial function and mechanism of interleukin-8 (IL-8) obtained from mandarin fish (Siniperca chuatsi), we analyzed its molecular physicochemical properties and structural characteristics. The recombinant protein was prepared through prokaryotic expression, and its direct antibacterial effects on model pathogen strains and fish pathogenic bacteria were tested. To assess the antibacterial mechanism of IL-8, flow cytometry was used to detect changes in bacterial membrane permeability and membrane potential. The results showed that the net charge of the mature peptide region of mandarin fish IL-8 was +4.1, conferring cationic properties. The positively charged amino acids and hydrophobic residues on the molecular surface were clustered in distinct regions, endowing the molecule with amphipathicity. These cationic and amphipathic features provided the structural basis for the direct antibacterial activity of mandarin fish IL-8. The recombinant IL-8 protein also exhibited significant growth inhibitory effects against model strains such as Escherichia coli and Staphylococcus aureus and against fish pathogens like Aeromonas hydrophila, Aeromonas media, and Streptococcus agalactiae. Inhibitory effects were detected at 4 μmol/L and complete inhibition of bacterial growth occurred at 32 μmol/L, demonstrating direct antibacterial function. Flow cytometry revealed that bacteria treated with mandarin fish IL-8 showed significantly enhanced staining with the membrane impermeability probe and the membrane potential probe, indicating that mandarin fish IL-8 may increase membrane permeability and induce membrane depolarization, thereby having a direct destructive effect on bacterial membranes. These results suggest that mandarin fish IL-8 exerts its direct antibacterial function by disrupting bacterial membranes.
  • The inhibitory effect and mechanism of thymol against bacterium Aeromonas hydrophila
    LI Luning, LI Junyi, REN Xinyu, LIU Bingyu, ZHOU Jiachen, XU Dan, ZHANG Ye
    Journal of Dalian Fisheries University. 2025, 40(6): 964-972. https://doi.org/10.16535/j.cnki.dlhyxb.2025-023
    Abstract (2651) PDF (539) HTML (1)   Knowledge map   Save
    The study was to investigate the in vitro antibacterial effects of thymol against the bacterium Aeromonas hydrophila and to elucidate the potential mechanisms of action. We determined the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of thymol against A. hydrophila, plotted the bacterial growth curve, measured the fluorescence intensity of 1-N-phenylnaphthylamine(NPN) and propidium iodide(PI), observed bacterial morphology using scanning electron microscopy, quantified intracellular protein and DNA leakage, and assessed swarming motility. The MIC and MBC of thymol against A. hydrophila were 125 mg/L and 500 mg/L, respectively. At a concentration of 1 MIC, thymol completely inhibited the growth and reproduction of A. hydrophila within 24 h. Additionally, thymol effectively disrupted both the inner and outer membrane structures of A. hydrophila, leading to leakage of intracellular macromolecules. The extent of leakage was significantly and positively correlated with both the concentration of thymol and duration of exposure. Thymol also inhibited the swarming motility of A. hydrophila, thereby reducing the risk of biofilm formation and subsequent colonization on host surfaces. These results show that thymol possesses substantial antibacterial and bactericidal activities against A. hydrophila and that these effects are primarily achieved through the disruption of both the inner and outer membrane structures of A. hydrophila, leading to alterations in bacterial morphology, leakage of cellular contents, and bacterial death. They also contribute a critical theoretical foundation for investigating thymol as a potential alternative to antibiotics for controlling pathogenic bacterial infection.
  • The influence of hemoglobin residue on the frozen fish meat quality of fat greenling (Hexagrammos otakii)
    MAO Xiaocong, WU Fangbing, WANG Jiayan, SHI Feilong, TIAN Yuanyong, ZHAO Hui, LU Hang
    Journal of Dalian Fisheries University. 2025, 40(6): 1028-1039. https://doi.org/10.16535/j.cnki.dlhyxb.2025-064
    Abstract (2594) PDF (338) HTML (1)   Knowledge map   Save
    To explore the effect of hemoglobin residue on the meat quality of frozen fat greenling(Hexagrammos otakii), two groups of fish were killed respectively using brainstem bloodletting or fish head tapping. The hemoglobin residues in frozen fish meat were compared between two groups. The change of hemoglobin, meat quality, and oxidation of lipids and proteins in frozen fish meat at 4 ℃ were analyzed and compared. The results showed that the hemoglobin content was reduced approximately 30% in the frozen fish killed by brainstem bleeding, and that it gradually decomposed and its content continued to decrease. During the 5-day refrigeration process, the hemoglobin content of fish meat in the bleeding and non-bleeding groups decreased from 12.86% to 4.65% and from 16.96% to 5.98%, respectively. The content of heme, a decomposition product of hemoglobin, gradually increased over time and then degraded. The content of oxygenated hemoglobin in the fish meat of the bleeding and non-bleeding groups decreased from 14.76% to 0.65% and from 16.86% to 1.08%, respectively, while the content of methemoglobin increased from 9.81% to 23.22% and from 14.88% to 25.22%, respectively. This pattern indicates that oxygenated hemoglobin was transformed into methemoglobin. Compared with the meat from the bleeding fish, the contents of hemoglobin, heme, free iron, Fe2+ and Fe3+ in the meat of the non-bleeding fish were significantly higher. During the 5-day refrigeration storage, the brightness(L*) and redness(a*) values showed an upward trend, while the yellowness(b*) value showed a downward trend. Over time, the peroxide values(POV) of the bleeding and non-bleeding groups increased by 0.83 μg/100 g and 1.11 μg/100 g, respectively, and the mass fraction of malondialdehyde increased by 0.22 μg/100 g and 0.31 μg/100 g. The carbonyl content of fish meat from the two groups increased by 3.16 nmol/mg and 6.21 nmol/mg, respectively, and the thiol content decreased by 4.04 nmol/mg and 7.32 nmol/mg. In summary, bleeding killing method delayed the decline in meat quality and reduced the oxidation degree of lipids and proteins in frozen fish meat. Correlation analysis indicated that the oxidative degradation of hemoglobin in fish meat during refrigeration intensified the occurrence of lipid oxidation and protein oxidation, which in turn significantly affected the rate of deterioration of the frozen fish meat.
  • Influence of salinity on growth, blood biochemistry, tissue structure and antioxidantcapacity of juvenile Amur whitefish (Coregonus ussuriensis)
    ZHENG Hao, LIU Enhui, HUANG Tianqing, GU Wei, WANG Gaochao, GE Kaibo, FAN Peng, SUN Yunchao, LI Datian, WANG Xinyang, WANG Junwei, XU Gefeng
    Journal of Dalian Fisheries University. 2025, 40(6): 939-946. https://doi.org/10.16535/j.cnki.dlhyxb.2025-136
    Abstract (2546) PDF (551) HTML (1)   Knowledge map   Save
    The study was to investigate influence of different salinities on growth performance, blood physiological indicators, and antioxidant systems of Amur whitefish (Coregonus ussuriensis). Juveniles C. ussuriensis with an initial weight of 35.0 g± 1.5 g were divided into five groups： control (freshwater, salinity 0) and salinities of 8, 16, 24, and 36. The fish survival rates and growth indicators of each group were measured and compared. After 30 days of salinity acclimation, physiological index measurements and tissue structure observations were made to assess physiological responses of fish to different salinities. The fish cultured at salinities <24 showed good growth performance, and the survival rate significantly dropped to 21.4% of fish cultured at salinity 32. The plasma osmolality, blood glucose level, and concentrations of ions such as Na+, Cl-, and Mg2+ gradually increased with an increase in salinity and reached a significantly different level at salinity 32. Under the high salinity (32), the gill and liver tissues were severely damaged, as indicated by severe vacuolation. Superoxide dismutase(SOD), catalase(CAT), and glutathione peroxidase(GSH-Px) activities gradually and significantly increased with an increase in salinity. These results indicate that the suitable salinity for breeding and stocking C. ussuriensis is from 0 to 24. Beyond this range, salinity will have a significant negative impact on survival and physiological health of this species.
  • Comparative study on tissue indices and biochmemical composition between the normal Chinese mitten crabs (Eriocheir sinensis) and the abnormal crabs
    WU Yuting, ZHANG Dongdong, SU Qiling, SUN Qiufeng, WU Xugan
    Journal of Dalian Fisheries University. 2025, 40(6): 1001-1010. https://doi.org/10.16535/j.cnki.dlhyxb.2024-184
    Abstract (2444) PDF (346) HTML (1)   Knowledge map   Save
    We compared characteristics of healthy Chinese mitten crabs (Eriocheir sinensis) with abnormal crabs (shuibiezi crab) affected possibly by hepatopancreatic necrosis syndrome. Utilizing anatomical and biochemical analysis methods, we measured tissue indices, color parameters, carotenoid content, proximate composition, and fatty acid composition of the two groups of crabs. The hepatosomatic index (HSI), gonadosomatic index (GSI), muscle yield (MY), and total edible yield (TEY) of the abnormal group were significantly lower than those of the normal group (P< 0.01). The L*, a*, and b* values of the wet hepatopancreas samples from male and female abnormal crabs were significantly lower than those from normal crabs (P< 0.01). The contents of lutein and β-carotene in ovaries of female crabs from the diseased group were notably lower than those in the normal group. Similarly, the total carotenoid and β-carotene levels in the hepatopancreas of diseased male crabs were significantly lower than those in the normal male group (P< 0.05). The moisture contents in the hepatopancreas and gonads of the diseased group were significantly higher than those in the normal group. In contrast, the total lipid content of hepatopancreas was significantly lower in the diseased group compared with the normal group (P< 0.05). While the levels of C20:2n6 and C20:5n3 were notably higher in the hepatopancreas of the diseased group compared with the normal group, the C16:1n7 and DHA/EPA ratio were significantly lower in the diseased group (P< 0.05). In summary, shuibiezi crabs exhibited high moisture content in edible tissues, low muscle and gonadal protein content, an unbalanced fatty acid composition, and overall low nutritional value. Moving forward, enhancing nutritional regulation may be a crucial measure to prevent and control “shuibiezi” disease in Chinese mitten crabs.
  • Estimation of the carrying capacity of the marine area off Dongying City, Shandong Province for the Zebra Ⅱ strain of the Manila clam (Ruditapes philippinarum)
    LI Yunzhi, WANG Fan, LI Cuicui, QIN Lizhao, YANG Guojun, GU Jing, LI Zhengyuan, ZHANG Gang , YU Liangju, WANG Hua, HUO Zhongming, YANG Feng, YAN Xiwu
    Journal of Dalian Fisheries University. 2025, 40(5): 742-750. https://doi.org/10.16535/j.cnki.dlhyxb.2025-009
    Abstract (2246) PDF (302) HTML (0)   Knowledge map   Save
    To optimize large-scale cultivation of the Zebra Ⅱ strain of the Manila clam (Ruditapes philippinarum) in the intertidal zones and offshore area of Shandong Province, sampling stations were established in the Hekou shellfish farming region in Dongying City, Shandong Province. Based on an annual survey of indicators such as chlorophyll-a (Chl-a) and primary productivity (PP) in the survey area combined with laboratory-measured filtration rates and other relevant parameters, the carrying capacity of Zebra Ⅱ strain in this marine area was estimated. The annual average Chl-a concentration in the surveyed area was (3.55±0.27) mg/m3, with a range of 1.54 to 5.41 mg/m3. There was no significant difference in horizontal distribution between the intertidal zone and the offshore area (P>0.05). Seasonally, the intertidal zone exhibited greater fluctuations in Chl-a levels, while the offshore area remained relatively stable. Overall, the average Chl-a concentrations in the clam farming area during summer and autumn were significantly higher than those in winter and spring (P<0.05). The annual average PP in the marine area was (199.46 + 138.89) mg C/(m2·d), with a range of 35.6 to 597.81 mg C/(m2·d). The intertidal zone had significantly higher PP than the offshore area (P<0.05), and the average PP in summer was significantly higher than that in winter (P<0.05). Laboratory experiments demonstrated that under an average water temperature of 14.2 ℃, the average filtration rate of Zebra Ⅱ strain clams was 1.43 L/(g·h) (dry weight). Estimation with the Herman model revealed that under the nutrient conditions (Chl-a and PP) studied, the carrying capacity of the marine area was higher in summer and autumn than in winter and spring. A conservative estimate of average carrying capacity for this strain of Manila clam (with a shell length of 3 cm) based on summer and autumn averages was 258 ind./m2, with values of 55 ind./m2 in the intertidal zone and 461 ind./m2 in the offshore area. Relative to the Herman model values, the estimated carrying capacity estimated by using the food-limitation index (Dame’s method) was higher in the intertidal zone and lower in the offshore area. The results of this study suggest that in the intertidal zone of the Hekou coastal area of Dongying City, Shandong Province, the Zebra Ⅱ strain may be cultivated at densities moderately higher than 55 ind./m2, while densities should be kept moderately lower than 461 ind./m2 in the offshore area. Stocking densities should be dynamically adjusted based on the calm growth performance of the clams and the water quality conditions during cultivation, with the aim of maintaining high yields while ensuring the relative stability of the marine ecosystem and achieving sustainable development.
  • Isolation and application of a beneficial intestinal bacterium Bacillus flexus from Apostichopus japonicus
    ZHAO Xinyan, LIU Shang, LI Jiaxi, CHEN Yingxu, GUAN Hui, ZHAO Chenyang, LI Yongming, HUO Zhongming, FANG Lei
    Journal of Dalian Fisheries University. 2025, 40(4): 565-574. https://doi.org/10.16535/j.cnki.dlhyxb.2025-025
    Abstract (2240) PDF (435) HTML (0)   Knowledge map   Save
    Bacteria beneficial to the growth of the sea cucumber Apostichopus japonicus were isolated from the intestines of healthy individuals. Strains producing protease, lipase, and amylase were screened by using selective media, and their enzymatic activities were subsequently verified. Further evaluations included tests for antibiotic sensitivity and tolerance to acids and bile salts. The strains were identified based on morphological characteristics and full-length 16S rDNA sequencing. Safety and aquaculture experiments were conducted to assess their growth-promoting effects on A. japonicus. One strain, designated AC27 was successfully isolated and found to be capable of simultaneously producing protease, lipase, and amylase.AC27 exhibited no β-hemolytic activity, demonstrated high sensitivity to multiple antibiotics, and was able to grow under conditions of pH 3.0 and 0.7% bile salt concentration.Morphological and 16S rDNA sequencing analyses identified AC27 as Bacillus flexus. Pathogenicity tests confirmed that AC27 was non-pathogenic to A. japonicus. Immersion culture experiments demonstrated that it significantly enhanced the weight gain rate and specific growth rate of A. japonicus (P<0.05) while reducing the coefficient of variation in body weight. In conclusion, B. flexus AC27, isolated from the intestines of healthy A. japonicus, is safe, reliable, and exhibits significant growth-promoting effects.This study highlights the potential of B. flexus as a valuable candidate for developing probiotics tailored for A. japonicus.
  • Molecular cloning of lymphocyte cytosolic protein 1 (LCP1) gene in Nile Tilapia (Oreochromis niloticus) and its role in the immune response against Streptococcus agalactiae
    LI Weifu, YUAN Jiayi, ZHANG Xiangdong, WANG Zhiwen, XIA Hongli, LU Yishan
    Journal of Dalian Fisheries University. 2025, 40(5): 761-770. https://doi.org/10.16535/j.cnki.dlhyxb.2025-043
    Abstract (2233) PDF (283) HTML (0)   Knowledge map   Save
    To investigate molecular characteristics of the Nile tilapia (Oreochromis niloticus) lymphocyte cytosolic protein (LCP1) gene and its potential function in the immune response against Streptococcus agalactiae, the gene encoding LCP1 from Nile tilapia was successfully cloned (OnLCP1). Bioinformatics analysis was conducted on this gene, and its subcellular localization was determined. The expression pattern of OnLCP1 mRNA in various tissues after S. agalactiae stimulation was analyzed by using fluorescence quantitative PCR. A dual luciferase reporter gene assay was used to detect the impact of transcription factors such as NF-κβ, STAT1, ISRE, IFN-1, and IFN-3 on promoter activity of the LCP1 gene. The results showed that OnLCP1 consists of 1857 base pairs and encodes a 618-amino acid protein. The OnLCP1 protein contains an EF-hand domain (calcium binding domain) and two tandem actin binding domains(ABD), with each actin domain containing two calmodulin homology(CH) domains. OnLCP1 is an extracellular protein without the transmembrane region, and it shares a highly similar three-dimensional structure with the human LCP1 protein, suggesting that its function may be conserved. OnLCP1 was expressed in various tissues of healthy Nile tilapia, with the highest expression level in the spleen. After stimulation by inactivated S. agalactiae, the expression of the OnLCP1 gene in immune organs significantly increased, indicating its potential involvement in the immune response against pathogenic bacteria. The subcellular localization experiment showed that OnLCP1 was expressed in the cytoplasm of HEK-293T cells. The dual luciferase reporter gene experiment showed that the OnLCP1 gene significantly activates the NF-κβ signaling pathway (P<0.05), suggesting that OnLCP1 may mediate defense against S. agalactiae infection through this pathway. The results of this study provide a scientific ground for further research of LCP1 function in the innate immunity of fish.
  • Qualitycontrol and data lifecycle management for farmed fish datasets
    GU Xiaowei, ZHANG Shengmao, YANG Shenglong, WU Zuli
    Journal of Dalian Fisheries University. 2025, 40(5): 873-886. https://doi.org/10.16535/j.cnki.dlhyxb.2025-200
    Abstract (2206) PDF (380) HTML (0)   Knowledge map   Save
    Aquaculture industry is transformed towards artificial intelligence and high-qualtiy datasets are cornerstone to promote the development of digital intelligence fisheries.We systematically reviewed the construction pipeline, data types, key technologies, and quality control methodologies for farmed fish datasets.First, we summarized and analyzed the application characteristics and associated challenges of diverse data types, including images, videos, audio, 3D point clouds, and text, within intelligent aquaculture.Second, the technical frameworks for key processes, such as data acquisition, annotation, augmentation, and multi-modal fusion, were elaborated.Third, we constructed a full life cycle data quality control and standardization mechanism that addressed dimensions such as acquisition quality, annotation consistency, and structural standardization.Finally, the characteristics and limitations of typical open source datasets were summarized. Building upon cutting-edge technologies such as self-supervised learning, federated machine learning, and digital twins, we concluded by proposing future research directions for farmed fish datasets. The research result provides systematic data support and methodological references for both the research and practice of intelligent aquaculture.
  • Expression of the opa1 gene of medaka (Oryzias latipes) and its potential role in sex differentiation of male and female gonads
    LI Chenjie, QIAN Feng, CHEN Juan, YU Shiqi, GUAN Guijun
    Journal of Dalian Fisheries University. 2025, 40(6): 916-925. https://doi.org/10.16535/j.cnki.dlhyxb.2025-084
    Abstract (2131) PDF (503) HTML (1)   Knowledge map   Save
    To explore how the gonadal soma-derived factor (gsdf) affects dynamic changes in mitochondrial morphology and metabolism in medaka(Oryzias latipes), we applied transcriptomics and quantitative real-time PCR to analyze the differential expression of the optic atrophy gene 1 (opa1) in various tissues of male and female deletion of gsdf (gsdf-/-) and wild-type (gsdf+/+) medaka. Opa1 encodes an inner mitochondrial membrane fusion protein. Its expression in gsdf-/- testes was significantly elevated, whereas little difference in expression was detected between wild-type and gsdf-/- ovaries. Opa1 mRNA was widely expressed in multiple tissues of wild-type adult medaka, with the highest expression level in the testes. Proportional comparison of the long isoform of opa1 (L-opa1) in the gonads of gsdf+/+ and gsdf-/- medaka revealed that the level of its mRNA was significantly decreased in the testes of gsdf-/- medaka. This low expression in the testes of gsdf-/- medaka suggests that the gsdf signal may be involved in the stimulation of L-opa1 expression or L-opa1 mRNA maintenance, thereby maintaining normal mitochondrial cristae structure in germ cells. Transmission electron microscopy revealed that only some of the mitochondria had abnormal cristae structure in gsdf-/- male germ cells. Combined with the observation of altered L-opa1 mRNA proportion in gsdf-/- XX and XY gonads, these findings imply the presence of at least two types of mitochondria, namely those that are sensitive or insensitive to the gsdf signal. We hypothesize that dynamic changes in mitochondrial energy metabolism in germ cells may drive dynamic alterations in autosome-sex chromosome pairing and meiotic homologous recombination. Our results support the premise that dynamic changes in mitochondrial metabolism may be an important driving force promoting the differentiation and healthy development of male and female germ cells. They also show that the shaping of diversified sex chromosomes with different autosomal origins in various species accompanying species evolution may be a common result of germ cell fertility changes caused by mitochondrial oxidative phosphorylation metabolism.
  • Large scale artificial propagation technology and observations on the embryonic development of Pseudorasbora parva
    MO Yanfang, LUO Xiaonian, DUAN Youjian, LI Jiao, LI Jianqiao, KANG Junlong, DONG Ruixin, SUN Rongzhen
    Journal of Dalian Fisheries University. 2025, 40(4): 607-617. https://doi.org/10.16535/j.cnki.dlhyxb.2025-004
    Abstract (2123) PDF (634) HTML (0)   Knowledge map   Save
    To achieve the largescale production of Pseudorasbora parva, a comparative study of P. parva reproductive technologies was conducted at the Xingda Farm in Liaoyang County from 2023 to 2024. Oxytocin dosages, injection methods, interval of injections, optimum water temperature for estrus, changes in sperm motility of male fish injected with aphrodisiacs, and five methods to extract eggs and two methods of hatching management were assessed. The results showed that the peak breeding period of P. parva in the Liaoyang area, was from early April to early June. The maturity rate of the fish was 291.41%. When LHRH-A2 8 μg/kg+HCG 2 000 IU/kg was injected, the highest level of oxytocin was achieved, reaching 63.00%±5.77%. The highest level of oxytocinoccurred when the water temperature was 17 ℃, and the time between the two injections was 8 h, resulting in an effect time of 23-36 h. The time for sperm to move rapidly reached the maximum of (89.50±0.50) s at 16 h after P. parva males were injected with oxytocic drugs.At 24 h, the life-time of sperm reached its maximum of (132.00±15.04)s. Of the five artificial spawning substrates tested, sieve cloth achieved the highest egg adhesion rate of 98.00%±0.02%. Of the two hatching methods, incubation baskets significantly outperformed static aerated plastic basins (P<0.05). In 2024, three oxytocic production batches under the optimized conditions yielded 400 000 eggs and 255 000 fry. The elliptical yellowish adhesive eggs of were measured (1.08±0.23) mm pre-hydration, expanding to (1.68±0.13) mm post water-absorption. Embryonic development progressed through 27 stages across 7 phases (blastodisc formation, cleavage, blastula, gastrula, neurula, organogenesis, and hatching). At 18 ℃-21 ℃, hatching took 199 h 58 min with a total accumulated temperature of hatching of 3 811.62 ℃/h. The total length of newly hatched larvae was (5.01±0.32) mm, and horizontal swimming and readiness for releasing to pond was achieved within 3-4 days post-hatching. This study shows that large-scale artificial propagation of P. parva may be achieved by artificially controlling the type dosage and injection methods of oxytocic drugs.
  • Effects of compound Chinese herbal medicines on intestinal antioxidant capacity and immune-related gene expression of rainbow trout (Oncorhynchus mykiss)
    SUN Manqiang, HUANG Jinqiang, LI Yongjuan, WANG Qi, ZHAO Lu, GUO Zhijia, LIU Kangkang
    Journal of Dalian Fisheries University. 2025, 40(5): 809-820. https://doi.org/10.16535/j.cnki.dlhyxb.2024-284
    Abstract (2067) PDF (263) HTML (0)   Knowledge map   Save
    To investigate the effects of Chinese herbal compound medicines (CHMM) on the intestinal antioxidant capacity and expression of immune-related genes in rainbow trout (Oncorhynchus mykiss), ten Chinese herbal medicines, including Astragalus membranaceus, Angelica sinensis, Codonopsis pilosula, Ophiopogon japonicus, and Glycyrrhiza uralensis, were mixed in equal proportions and then added into the basal diet at mass ratios of 0 (control), 1%, 2%, and 3%. These diets were fed to rainbow trout with a body weight of 30.0 g± 0.5 g. The intestinal samples of fish were collected respectively after fed 7d, 21d, 35d.Additionally the samples were taken after 12d infected with infectious hematopoietic necrosis virus (IHNV).Antioxidant indicators and the expression of immune-related genes of fish were tested by using quantitative real-time PCR technology. The result showed that,compared with the control group, the total antioxidant capacity (T-AOC) and catalase (CAT), total superoxide dismutase (T-SOD), and acid phosphatase (ACP) activities in the intestines increased first and then decreased as the proportion of CHMM increased. The values peaked in the 2% group, at which point they were significantly higher than those of the control group (P<0.05). However, the activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and the content of malondialdehyde (MDA) first decreased and then increased, and the MDA content in the 2% group was significantly lower than that in the control group (P<0.05). After infected with IHNV, the T-AOC and activities of T-SOD, CAT, and ACP significantly increased, while the content of MDA and the activities of ALT and AST significantly decreased (P<0.05). The quantitative PCR analysis showed that before infected with IHNV, the fish in the 1% group had significantly upregulated the expression of jak1, myd88, and irf7 genes (P<0.05), while the expression levels of mx1 and mda5 were not significantly upregulated (P>0.05).In the 2% group, the expression level of immune-related gene il-8 was significantly upregulated (P<0.05), but the expression levels of il-1β, mx1, myd88, and mda5 were not significantly changed (P>0.05). After infected with IHNV, the fish in the 1% group had significantly upregulated expression levels of il-1β, mx1, mda5, lgp2, irf3, and irf7 (P<0.05). Overall, the experimental results show that the 2% addition of the CHMM could effectively improve the activity of antioxidant enzymes and regulate the expression of immune-related genes of rainbow trout. The CHMM addition also significantly enhanced the immunity and anti-IHNV ability of the fish. These findings lay the foundation for understanding the mechanisms that traditional Chinese herbal medicines enhance the natural immune response of rainbow trout to diseases and provide a helpful reference for the development and application of Chinese herbal medicine to prevent and control fish diseases in aquaculture.
  • Temporal and spatial distribution of macrozoobenthic communities and their relationship with environmental factors in Qiandao Lake, China
    SUN Qihao, ZHANG Jingwen, LIU Qigen, HU Zhongjun, SHAO Jianqiang, PAN Jiayong, HE Guangxi
    Journal of Dalian Fisheries University. 2025, 40(6): 1018-1027. https://doi.org/10.16535/j.cnki.dlhyxb.2024-218
    Abstract (1989) PDF (249) HTML (1)   Knowledge map   Save
    To investigate temporal and spatial distribution patterns of macrozoobenthic communities in Qiandao Lake, Zhejiang Province, China and to explore the key environmental factors influencing their distribution, macrobenthos were collected from 25 sampling stations from December 2020 to October 2021. Eighteen species of macrozoobenthos were identified and classified into three phyla and four classes. The most macrozoobenthos species in Qiandao Lake (88.89%) belonged to Oligochaeta and Insecta, with nine and seven species, respectively. Limnodrilus hoffmeisteri and Tubifex tubifex were the dominant species throughout the year. The annual average density and biomass of benthic macroinvertebrates were 611.1 ind./m2 and 1.45 g/m2, respectively. No significant seasonal differences in density and biomass were detected by two-way analysis of variance, but there were significant spatial differences. Correlation analysis showed that spatial differences were primarily positively correlated with pH, total dissolved solids (TDS), specific conductance (SPC), nitrite nitrogen  total nitrogen (TN), and/or the permanganate index (CODMn) and negatively correlated with water transparency. The explanatory variables for density and biomass varied along different flow directions. Redundancy analysis results indicated that soluble phosphate  water temperature (WT), TDS, TN, water depth (WD), CODMn, and pH were the key factors influencing the spatial and temporal distribution of benthic macroinvertebrate communities in Qiandao Lake (P<0.05). L. hoffmeisteri, Limnodrilus claparedeianus, and T. tubifex exhibited significant positive correlations with pH, CODMn,  TN, and WT. In contrast, the insect Procladius choreus and oligochaetes Branchiura sowerbyi and Aulodrilus pluriseta showed significant negative correlations with WT, TSD, and WD. The results also showed that primary productivity was a key driver of spatial variations in macrobenthic abundance in Qiandao Lake and that most of the Lake was in a lightly polluted state, with good water quality in general.
  • Fighting behavior of Chinese mitten crabs (Eriocheir sinensis) cultured under different carbonate alkalinities
    OUYANG Ningyuan, CHEN Yongjin, XUE Xue, XU Dongpo
    Journal of Dalian Fisheries University. 2025, 40(5): 789-797. https://doi.org/10.16535/j.cnki.dlhyxb.2024-233
    Abstract (1985) PDF (444) HTML (0)   Knowledge map   Save
    To investigate the influence of carbonate alkalinity on fighting behavior of crustaceans and to clarify the behavioral mechanism among the same crustacean species, we took the Chinese mitten crab (Eriocheir sinensis) as the experimental species. We used the behavior research methods in a limited space, did one-on-one crab fighting experiments and attack experiments of crabs rapped, and explored the characteristics of crab fighting and attack behavior under different carbonate alkalinity stress.The results showed that the duration of crab fighting, number of fights, fight scores and attack scores of crab rapped first increasedand then decreased as carbonate alkalinities went up.Fighting and attack behavior of crabs became moderate significantly at 60 mmol/L of carbonate alkalinity.The attack number of crab nylon-rod rapped also gradually decreased. The average duration of crab fighting at a high carbonate alkalinity was generally longer than that at a low carbonate alkalinity. Additionally, the average duration of fighting and number of fights between female crabs were slightly more than those between male crabs, but the fighting score between female crabs was slightly lower than that between male crabs. The number of attacks between male crabs rapped was slightly lower than that between female crabs, while the aggressiveness score for male crabs was slightly higher than that for female crabs. However, there was no significant difference in these two indicators for male crabs fighting and female crab fighting under different carbonate alkalinity stress. The experimental results showed slightly higher values of fighting duration, average fighting duration, and attacks score during the day than those at night, while the number of fights, fighting scores, and attack frequency were slightly lower during the day than those at night. But the A0 group with no alkalinity showed the attack frequency of rapped crabs was significantly lower during the day thanthat at night. The study primarily revealed the characteristics of fighting behavior of E. sinensis under carbonate alkalinity stress. It provided scientific references for E. sinensis cultivation in saline alkaline water, protection of wild crab population, and control of ecological invasion.
  • Microsatellite analysis of genetic diversity among five cultured populations of Leiocassis longirostris
    YU Aiqing, SHI Yonghai, XU Jiabo, LIU Yongshi, JIANG Fei, YUAN Xincheng
    Journal of Dalian Fisheries University. 2025, 40(4): 618-627. https://doi.org/10.16535/j.cnki.dlhyxb.2024-268
    Abstract (1867) PDF (488) HTML (0)   Knowledge map   Save
    We investigated the genetic diversity and genetic structural differences among different cultured populations of Leiocassis longirostris to enable the development of effective scientific strategies for the selection and breeding of superior varieties. Twenty fluorescently labeled EST-SSR primers were selected to evaluate the genetics of five cultured populations of L. longirostris from Shanghai Baoshan (BS), Jiangsu Changzhou (CZ), Sichuan Meishan (MS), Guangdong Shunde (SD), and Hubei Xiantao (XT). We detected a total of 219 alleles from 20 EST-SSR primers, with an average of 10.95 alleles per primer. The average number of effective alleles (Ne), observed heterozygosities (HO), expected heterozygosities (He) and polymorphism information contents (PIC) of the five cultured populations ranged from 3.03 to 4.13, from 0.708 3 to 0.813 3, from 0.624 3 to 0.727 6, and from 0.574 0 to 0.686 5, respectively. Hardy-Weinberg Equilibrium (HWE) tests indicated that out of the 100 population locus combinations analyzed, 45% significantly deviated from the HWE (P<0.05). A population genetic differentiation analysis showed that the BS population exhibited moderate genetic differentiation (0.05<Fst<0.15) while the MS, SD, and XT populations, showed weak genetic differentiation in pairwise tests (Fst<0.05). Molecular variance analysis results indicated that the majority of the genetic variation originated from differences among individuals within the populations (95.28%), with only 4.72% of the genetic variation stemming from differences between populations. Consistent results were obtained from an Unweighted Pair-Group Method with Arithmetic Mean analysis, a Principle Component analysis, and a Bayesian Structure Clustering analysis and revealed two major groups among the five cultured populations: the BS population formed a separate group, while the CZ, MS, SD, and XT populations clustered into a second group. This study showed that five cultured populations of L. longirostris had relatively high levels of genetic diversity and exhibited varying degrees of genetic difference. In particular, the BS population showed a relatively independent genetic structure.
  • Research progress on aquaculture biology of Phoxinus lagowskii：a review
    LUO Xiaonian, DUAN Youjian, BAI Xiaohui, WU Chen, LI Jiao, YANG Peimin, JIN Guanghai
    Journal of Dalian Fisheries University. 2025, 40(6): 1040-1052. https://doi.org/10.16535/j.cnki.dlhyxb.2025-056
    Abstract (1786) PDF (355) HTML (1)   Knowledge map   Save
    Phoxinus lagowskii is a sub-cool small fish that normally lives in low water temperature rivers. It is one of important freshwater economic fish species in China and has become a key aquaculture species in northern regions in recent years. Significant research progress has been made in the field of its aquaculture biology. This paper elaborates on the sysematics and morphological characteristics of Phoxinus lagowskii, and reviews the advances in studies on its biological traits, including reproductive capacity, sperm biology, oxygen consumption rate and asphyxiation point, molecular mechanisms of hypoxia tolerance, light preference, and temperature adaptability. It also summarizes key aspects of artificial breeding technology, embryonic development, juvenile development, fry cultivation, adult fish farming, feed nutritional requirements, disease prevention and control, as well as genetic characteristics. Based on the current status of Phoxinus lagowskii aquaculture, the paper explores future research directions in its aquaculture biology to provide a systematic theoretical foundation for optimizing large-scale farming technology, promoting genetic improvement and breeding, and fostering the healthy development of Phoxinus lagowskii aquaculture industry.
  • Degradation activity and structure analysis of the anaerobicmicrocystin-degrading bacterial community in a shrimp pond
    SHI Zecheng, WANG Xinyu, BI Xiangdong, DAI Wei, YANG Jinghua
    Journal of Dalian Fisheries University. 2025, 40(6): 982-988. https://doi.org/10.16535/j.cnki.dlhyxb.2024-006
    Abstract (1780) PDF (296) HTML (1)   Knowledge map   Save
    To understand the anaerobic degradation of microcystin (MCs) by microorganisms in anoxic environment of shrimp culture ponds in summer, samples of overlying water, sediment and shrimp were collected from a Litopenaeus vannamei culture pond. The accumulation of MCs in samples was analyzed. The anaerobic MCs-degrading bacterial communities in sediment and shrimp intestine were continuously enriched, and their community structures and degradation activities were analyzed. The results showed that there were soluble MCs in overlying water. MCs accumulation could be detected in pond sediment, hepatopancreas and muscle of shrimp. Anaerobic MCs-degrading bacterial community existed in both pond sediment and shrimp intestine. Kosakonia became the dominant bacteria after 4 times of enrichment in pond sediment and 2 times of enrichment in shrimp intestine. The degradation rate of MCs by anaerobic bacteria community increased with the increasing enrichment times. After continuous enrichment, community structures of anaerobic MCs-degrading bacteria in pond sediment and shrimp intestine were stable, and the compositions of bacteria community were highly similar. The study showed that anaerobic MCs-degrading bacteria existed in anoxic environment of shrimp ponds and had anaerobic degradation effects on the elimination of MCs. The study provide a scientific reference for reducing MCs pollution in shrimp ponds through anaerobic biodegradation.
  • Preparation and application of monoclonal antibodies to the VP2 protein of infectious pancreatic necrosis virus
    WU Min, SHAO Yizhi, LU Tongyan, ZHAO Jingzhuang, XU Liming
    Journal of Dalian Fisheries University. 2025, 40(4): 575-584. https://doi.org/10.16535/j.cnki.dlhyxb.2025-012
    Abstract (1378) PDF (254) HTML (0)   Knowledge map   Save
    We established a rapid diagnostic method for infectious pancreatic necrosis virus (IPNV) by predicting antigenic epitopes on the IPNV virus VP2 protein and screening two peptides with strong antigenicity and good conservation, located at positions 178-191, and 380-393 on the protein surface. Monoclonal antibodies VP2-178 and VP2-380 were prepared against these VP2 protein regions. The purified antibodies were labeled with HRP, and an antigen capture ELISA detection method for the IPNV virus VP2 protein was established. The results showed that the capture antibody VP2-178 had an optimal working concentration of 0.5 μg/per and the detection antibody VP2-380 had an optimal working concentration of 1∶2 000. After optimizing the detection conditions, the ELISA method was able to detect the prevalent type 1 and type 5 IPNV strains. However, it did not react with IHNV, SVCV, or VHSV, indicating broad spectrum applicability and high specificity. Sensitivity tests showed that the method's lowest detection limit for IPNV was 62.5 TCID50/mL. Repeatability results showed that the intra- and inter-batch variation coefficients were less than 7%. The results showed a 100% concordance rate when the antigen capture ELISA detection method established in this study was compared with the national standard method in 40 clinical samples, tested simultaneously. These results indicate that the ELISA detection method established in this study can provide technical support for the rapid clinical diagnosis of IPNV.
  • Accumulation and elimination dynamics of diazepam and its metabolites in grass carp (Ctenopharyngodon idella)
    LIU Haixin, TANG Shuifen, YU Ying, LUO Fangfang, CHEN Yufeng, WANG Lijuan, JIANG Linlin, CHEN Si, ZHENG Yiling
    Journal of Dalian Fisheries University. 2025, 40(5): 798-808. https://doi.org/10.16535/j.cnki.dlhyxb.2025-048
    Abstract (1323) PDF (452) HTML (0)   Knowledge map   Save
    To elucidate the pharmacokinetic characteristics of diazepam and its metabolites in fish, we treated grass carp (Ctenopharyngodon idella) with the test compounds using the drug bath exposure-clear water elimination model. The dynamic concentration changes of diazepam and its metabolites in plasma, muscle, and liver tissues were monitored by HPLC-MS/MS. Pharmacokinetic software was employed for model fitting and parameter analysis. During the absorption phase at (23±1)℃, the absorption half-lives (t1/2Ka) in muscle, blood, and liver were (0.786±0.010), (1.86 + 0.63), and (0.492 + 0.066)h, respectively, while the peak concentrations (Cmax) reached (447.5 + 11.6), (864.1 + 40.9), and (1 595.1 + 113.2)μg/kg, respectively. The elimination phase exhibited multiple peaks, with residence times of (298.90±3.31), (347.70±9.96), and (341.40±0.96)h in muscle, blood, and liver, respectively. The theoretical withdrawal period was estimated to be as long as 87 days based on pharmacokinetic modeling, which significantly exceeds that of conventional aquaculture drugs. These findings demonstrate that diazepam has strong accumulation capacity in the liver and a prolonged elimination time and that aquatic product residues primarily derive from direct exposure rather than environmental accumulation.
  • Tissue expression, intestinal localization, and functional analysis of the epidermal growth factor receptor (EGFR) gene in Nile Tilapia (Oreochromis niloticus)
    ZHU Weijuan, WANG Zhang, LIU Hong, TANG Chenglin, LIU Zhigang, YI Mengmeng, WANG Miao, CAO Jianmeng, KE Xiaoli
    Journal of Dalian Fisheries University. 2025, 40(5): 717-729. https://doi.org/10.16535/j.cnki.dlhyxb.2025-033
    Abstract (1314) PDF (341) HTML (2)   Knowledge map   Save
    To investigate the role of the epidermal growth factor receptor (EGFR) gene in Nile tilapia (Oreochromis niloticus) during Streptococcus agalactiae infection, real-time quantitative reverse transcription PCR (RT-qPCR) was employed to detect the expression levels of EGFR in various tissues of tilapia infected with S. agalactiae or stimulated with lipopolysaccharides (LPS) or polyinosinic polycytidylic acid (Poly I∶C).Immunofluorescence detection was also used to localize the expression of EGFR protein in the midgut tissue of tilapia before and after S. agalactiae infection.The results showed that the cDNA sequence of Nile tilapia egfr is 5 405 base pairs in length, with an open reading frame(ORF)of 3 621 base pairs that encode 1 206 amino acids.This gene has three different mRNA splice variants: EGFRX1, X2, and X3,and EGFRX2 contain one transmembrane domain, while EGFRX3 lacks a transmembrane domain. The protein sequence similarity between EGFRX1, EGFRX2, and EGFRX3 is 77.86%. After infection with S. agalactiae, the expression level in the spleen significantly decreased (P<0.05), while the expression levels in the intestine and liver significantly increased at 24 h (P<0.05). After Poly I:C stimulation, the expression level in the intestinal tissue significantly increased, reaching a peak at 8 h.The expression levels of EGFR in the gills and spleen showed an initial increase, followed by a decrease, and then another increase.EGFR protein was positively expressed in the serosa, mucosa, submucosa, and muscularis of the tilapia midgut.After infection with S. agalactiae, the distribution density and positive area ratio of EGFR protein in the intestinal serosa significantly increased (P<0.05), and the goblet cells in the mucosa layer significantly increased.These results suggest that different splice variants of Nile tilapia EGFR may have functional differences, the expression of egfr is related to the mucosal immune function of tilapia, and the EGFR protein may enhance the repair of the intestinal barrier by promoting mucus secretion. These findings provide a basis for further functional analysis of the tilapia EGFR gene.
  • Status of research on controlling aquatic pathogenic Vibrio biofilms by using natural products: a review
    ZOU Qian, SHI Junning, WANG Qiyao, CHOI Sangho, LI Yuanchenjing, ZHANG Yibei
    Journal of Dalian Fisheries University. 2025, 40(5): 887. https://doi.org/10.16535/j.cnki.dlhyxb.2025-029
    Abstract (1291) PDF (342) HTML (0)   Knowledge map   Save
    Biofilmis a collective defense system formed by bacteria to adapt to environmental stress, and its dynamic formation process is precisely regulated by multi-layered signaling networks. In an aquaculture system, formation of pathogenic Vibrio biofilms enhances bacterial resistance to antibiotics and host immunity, and exacerbates disease transmission through pathogen vectorization, thereby forming a critical bottleneck for sustainable industry development. Use of traditional antibiotic therapies faces challenges due to rising drug resistance and ecological concern about drug residue. Researchers have focused on unravelling the molecular mechanisms of biofilm formation and developing green, sustainable control strategies.This review systematically delineates the molecular regulatory networks underlying Vibrio biofilm formation, with a focus on the hierarchical interplay of quorum sensing (QS) systems, cyclic diguanylate (c-di-GMP) signaling pathways, flagella, pili, extracellular polymeric substances, and global transcriptional regulators. The current control strategies based on an “inhibition-eradication” framework primarily target key biofilm components through inhibitors, including antibiotics, chemical disinfectants, and natural products. Notably, some natural products exhibit unique advantages in addressing aquaculture pathogen resistance due to their multi-target action, low risk of resistance induction, and environmental compatibility. The paper reviews the recent research progresses in plant extracts, marine-derived bioactive compounds, and agents of animal origin,and elucidates the multi-mechanisms by which natural products disrupt biofilm formation, such as quorum sensing interference, inhibition of extracellular polymeric substance synthesis, and bacterial adhesion blockade.The findings provide novel insights into the development of eco-friendly technologies for aquaculture disease management.
  • Isolation and purification of germline stem cells from ricefield eel and preliminary transplantation
    ZHANG Yimin, LUO Tingting, ZHAN Yuanyuan, SUN Yuhua
    Journal of Dalian Fisheries University. 2025, 40(5): 771-779. https://doi.org/10.16535/j.cnki.dlhyxb.2025-083
    Abstract (1251) PDF (281) HTML (0)   Knowledge map   Save
    To optimize the isolation and purification method of ricefield eel (Monopterus albus) germline stem cells and the autologous transplantation procedure of germline stem cells, the gonads of ricefield eel at different ages were analyzed by gonadosomatic index comparison and histological observation. The Percoll density gradient method was used to separate gonadal cells, and the germline stem cells of ricefield eels were identified by methods such as flow cytometry, alkaline phosphatase staining, and differential expression analysis of stem cell marker genes, and germline stem cell transplantation was carried out. The results showed that the enrichment layer of ricefield eel germline stem cells was the 40% Percoll concentration layer, accounting for 72.52%; the optimal transplantation donor for autologous transplantation was 1 year old female fish, and the optimal transplantation recipient was 4-5 years old male fish; the combined treatment of busulfan and high temperature could basically deplete the endogenous germ cells in the recipient fish, and then the transplanted germline stem cells could colonize and proliferate in the recipient fish, with a success rate of 75%; the Percoll density gradient centrifugation method could isolate and purify ricefield eel germline stem cells in a relatively short time, and the obtained cells could be used for germline stem cell transplantation. The allogeneic transplantation success rate was relatively high, showing excellent transplantation potential. This study can provide a scientific reference for the establishment of an allogeneic transplantation system for ricefield eel germline stem cells.
  • Selection of the optimal carbon source for fermented feed for sea cucumbers and the effects of fermented feed on the growth and digestive physiology of the sea cucumber (Apostichopus japonicus)
    LI Qian, WANG Jiying, LI Baoshan, WANG Peifeng, WANG Xiaoyan, SUN Yongzhi, HUANG Bingshan
    Journal of Dalian Fisheries University. 2025, 40(4): 597-606. https://doi.org/10.16535/j.cnki.dlhyxb.2025-001
    Abstract (1243) PDF (517) HTML (0)   Knowledge map   Save
    This study examined the effects of various carbon sources on the fermentation of compound feed for Apostichopus japonicus and the effects of fermented feed on the growth, digestion, and non-specific immunity of A. japonicus. In the fermentation process, 2% of either glucose, sucrose, maltose, soluble starch, or fructooligosaccharides was added as a carbon source. The compound feed offering the optimal fermentation effect was selected as the complementary feed, and was added to the basic feed in different proportions to prepare six experimental diets with complementary fermentation feed contents of 0 (D1), 5% (D2), 10% (D3), 20% (D4), 30% (D5), and 40% (D6). The experimental A. japonicus had an initial average body weight of (27.03±0.12) g and were fed for eight weeks. The results showed that adding a carbon source significantly increased the acid-soluble protein and reduced the sugar contents of the experimental feeds. On days 1, 3, and 4 of fermentation, the fructooligosaccharide group contained significantly higher acid-soluble protein than the other groups. On days 2 and 4 of fermentation, the soluble starch group contained significantly lower acid-soluble protein than the other groups. On days 1 to 4 of fermentation, the soluble starch group had a significantly lower reducing sugar content than the other groups. Compared with the feed with no carbon source: the fermentation time was shortened from four days to three days; the acid-soluble protein content increased from 11.88% to 13.46%; and the reducing sugar content increased from 2.13% to 3.15%. As the fermented feed substitution ratio increased, the weight gain rate (WG) and specific growth rate of A. japonicus first increased and then decreased, with a maximum WG value of 78.93% in the D4 group. There were no significant differences in the moisture, crude protein, crude lipid, and crude ash contents in the body wall of A. japonicus in any of the experimental groups. The addition of fermented feed significantly improved the activity of intestinal digestive enzymes. The protease and amylase activities in the D2-D5 groups were significantly higher than those in the other two groups. The cellulase activities in the D4-D6 groups were significantly higher than those in the other groups. The height of the intestinal folds was the greatest in the D4 group. As the substitution ratio of fermented feed increased, the intestinal alkaline phosphatase and acid phosphatase activities first increased and then decreased, reaching their maximum values in the D5 and D4 group, respectively. The total superoxide dismutase activity in group D1 was significantly lower than that in the other groups. The malondialdehyde content decreased at first and then increased, and was lowest in the D4 group. In summary, fructooligosaccharides as a carbon source provided the best fermentation effect, and the fermentation effect of soluble starch was the worst. Taking WG as the evaluation indicator, a linear regression analysis showed that the optimal substitution ratio of fermented feed for A. japonicus of initial body weight 27.03 g, was 24.69%.
  • Accumulation of nutrients in the sediments of the “Two Dams and Three Zones” system for largemouth bass (Micropterus salmoides) aquaculture
    XU Chengpeng, AN Shuwei, ZHANG Hongfei, XU Huimin, MENG Shunlong, LIU Zhuping, LI Dandan, QIU Liping
    Journal of Dalian Fisheries University. 2026, 41(1): 67-74. https://doi.org/10.16535/j.cnki.dlhyxb.2025-103
    Abstract (1213) PDF (350) HTML (0)   Knowledge map   Save
    To clarify the impact of the widely adopted “Two Dams and Three Zones” tailwater treatment system on nutrient accumulation characteristics in sediments within largemouth bass (Micropterus salmoides) aquaculture areas, we selected typical fish farms in Suzhou City, Jiangsu Province and set sampling sites in three functional zones: culture pond (YZ), purification area (JH), and tailwater discharge area (PS). Sediment samples were collected in August (growth stage of largemouth bass), October (fattening stage), and December (harvest/drainage stage) and systematically analyzed to assess the accumulation patterns of nutrients and their influencing factors using one-way analysis of variance and Spearman correlation analysis. The results indicated that PS were the primary enrichment area for total nitrogen (TN), total phosphorus (TP), nitrate nitrogen , and ammonium nitrogen , with TN and TP concentrations peaking in winter (December).  is the main form of inorganic nitrogen, and it accumulated continuously with the aquaculture process in PS and YZ. The content of  in PS reached as high as (117.62±29.12) mg/kg in December, which was significantly higher than the values in YZ and JH. TN in JH sediments was lower than that in YZ pond in August but higher in October and December, reflecting cumulative effects of continuous tailwater input and sedimentation.  in JH sediments showed an initial increase followed by a decrease, suggesting ongoing nitrification and potential plant uptake. Spearman correlation analysis revealed significantly positive correlation between  and TP content, where  acted as an electron acceptor for Fe-P binding and Fe3+ served as the primary adsorption carrier for phosphorus, indicating critical roles of sulfate reduction and iron-bound phosphorus in sediment phosphorus cycling. High-flow drainage disturbances in December triggered resuspension and release of nutrients from sediments, leading to their redeposition in JH and PS and subsequent increases of TN and TP in PS and TN in JH during December. These results demonstrate that long-term reception of treated tailwater from YZ and JH establishes PS sediments as a major nutrient enrichment “hotspot”. As a key “nutrient intermediate pool” within the system, sediment nutrient accumulation patterns-particularly spatiotemporal enrichment and speciation transformation-are jointly driven by the culture cycle, drainage disturbance, and key environmental factors (temperature,  Fe3+). These findings provide a theoretical basis for optimizing system operation, scientifically identifying dredging areas and timing (especially dynamic winter dredging), and recovering nutrients through plant harvesting to achieve sediment resource-oriented utilization, which is crucial for advancing green and sustainable M. salmoides aquaculture.
  • Transcriptome analysis of Pacific white shrimp (Litopenaeus vannamei) co-infected with different amount of the microsporidian parasite Enterocytozoon hepatopenaei and infectious hypodermal and haematopoietic necrosis virus
    YUAN Ruqing, WEI Shuzhan, CHEN Caiyi, YAN Dongchun, CHANG Linrui
    Journal of Dalian Fisheries University. 2025, 40(6): 973-981. https://doi.org/10.16535/j.cnki.dlhyxb.2025-088
    Abstract (1187) PDF (351) HTML (1)   Knowledge map   Save
    The RNA sequencing was used to explore the immune mechanism of Pacific white shrimp (Litopenaeus vannamei) co-infected with the microsporidian parasite Enterocytozoon hepatopenaei (EHP) and infectious hypodermal and haematopoietic necrosis virus (IHHNV). Groups of L. vannamei were infected with different amount of the two pathogens： the IH group had more severe IHHNV infection, and the EH group had more severe EHP infection. Subsequently, the hepatopancreas RNA of the samples was sequenced. Relative to the IH group, the EH group had 619 significantly differentially expressed genes, including 243 up-regulated genes and 376 down-regulated genes. In total, 1672 single genes were annotated into the three Gene Ontology categories of biological process, cellular component, and molecular function. Genes related to immunity and metabolism in the EH group were most significantly affected, and most of them showed a downward trend. These results indicated that EHP posed a more prominent threat to the growth of L. vannamei compared to IHHNV. The findings provide a theoretical basis for further study on co-infection of aquatic animals and present new ideas and perspectives for the prevention and control of IHHNV and EHP.
  • Identification of chitin synthase genes in Crassostrea gigas and their expression during the larval shell formation period
    LI Jie, LIU Chang, NIU Jixiang, HE Muchun, ZENG Yuqing, QIAO Xue, WANG Lingling, SONG Linsheng
    Journal of Dalian Fisheries University. 2025, 40(4): 552-564. https://doi.org/10.16535/j.cnki.dlhyxb.2024-272
    Abstract (1183) PDF (380) HTML (0)   Knowledge map   Save
    We explored the composition of the chitin synthase (CHS) gene family members and their expression characteristics in Crassostrea gigas. The CHS genes of C. gigas were identified using a whole genome screening strategy, and the expressions of the CgCHS genes during the early larval development stage of C. gigas were analyzed using qRT-PCR.Two CHS gene subfamilies (CgCHS1 and CgCHS2) were identified in the genome of C. gigas, including one CgCHS1 and six CgCHS2 (1-6) members, which were unevenly distributed on chromosomes 2, 3, 4, and 7. All of the CgCHS genes encoding for proteins had conserved Chitin_synth_2 domains and multiple transmembrane domains, including 10 similar motifs (motif 1-10). Instability coefficient analysis showed that the CgCHS proteins were unstable except for the CgCHS1 protein. Furthermore, all of the members except CgCHS2 2 were hydrophilic proteins.Phylogenetic analysis showed that the CHS gene family of C. gigas clustered into one clade with CHS from G. aegis, O. bimaculatus, H. rubra, C. virginica and M. yessoensis.The qRT-PCR showed that the expression levels of CgCHS2 2-5 increased significantly during the critical stage of shell formation in trochophore and D-type larvae, and might be involved in the transformation of the chitin shell into the calcareous shell. The expression levels of CgCHS1 and CgCHS2 1 were up-regulated mainly in the blastocyst stage, which we speculated was due to the formation of shell glands. In summary, the CHS gene family was conserved in C. gigas, and the expression levels of CgCHS increased significantly during the critical period of larval shell formation. This result provides a solid foundation for the elucidation of the action of CgCHS in regulating larval development, especially during the transformation of the chitin shell into a calcareous shell in C. gigas.
  • Isolation, identification, and drug susceptibility of Vibrio parahaemolyticusfrom Litopenaeus vannamei
    LI Wei, ZHANG Yuanhao, SUN Yixiang, JI Xinyao, ZHANG Yongan, YUAN Yongchao, LI Jie
    Journal of Dalian Fisheries University. 2026, 41(1): 58-66. https://doi.org/10.16535/j.cnki.dlhyxb.2025-054
    Abstract (1177) PDF (259) HTML (0)   Knowledge map   Save
    To explore the pathogenicity of marine bacterium Vibrio parahaemolyticus originating from whiteleg shrimp (Litopenaeus vannamei) towards freshwater crayfish (Procambarus clarkii) and to establish the basis for diseased prevention and control, a dominant pathogenic strain(LJVP21) was isolated from the hepatopancreas of diseased shrimp during an outbreak of mass mortality in a L. vannamei farming area in Zhangzhou, Fujian Province. The strain was identified as V. parahaemolyticus. Subsequent artificial challenge experiments demonstrated that this strain is pathogenic to crayfish cultured in freshwater, with a median lethal dose (LD50) of 3.16×106 CFU/mL. Infected individuals exhibited symptoms such as hepatopancreas swelling and tissues discoloration (grey, with some appearing diffuse), swollen and reddened gill filaments, and atrophied intestines without contents. The bacterium was also successfully isolated from the hepatopancreas of infected crayfish. Antimicrobial susceptibility testing revealed that the strain was sensitive to eight agents-including florfenicol, moderately sensitive to ciprofloxacin and tobramycin, and resistant to six agents-including enrofloxacin. These results indicate that marine V. parahaemolyticus may pose a threat to freshwater aquaculture industries, and they provide a scientific reference for the prevention and control of related diseases.
  • Relationship between phytoplankton functional groups and environmental factors in Zhuweizi Reservoir and the surrounding tributaries of the Zhuanghe River
    CHEN Yaqiang, CHEN Huixia, HUANG Shengnan, ZAN Yangyang, WANG Zihan, CHU Chen
    Journal of Dalian Fisheries University. 2025, 40(5): 854-863. https://doi.org/10.16535/j.cnki.dlhyxb.2024-146
    Abstract (1167) PDF (114) HTML (0)   Knowledge map   Save
    To explore the important roles of phytoplankton in aquatic ecosystem of the Zhuweizi Reservoir and its upstream rivers, we used multivariate statistical methods, including variance analysis, Pearson correlation analysis, Mantel tests, and redundancy analysis (RDA), to elucidate the relationships between phytoplankton community structure and environmental factors. The results revealed the presence of 83 phytoplankton species across eight phyla in the reservoir and its upstream rivers, with diatoms and chlorophytes being predominant. Nine dominant functional groups were identified were D, J, L0, P, MP, TB, X1, X2, and X3. Statistically significant differences (P<0.05) in water temperature (WT), pH, chemical oxygen demand (COD), total nitrogen (TN), ammonium width=342,height=17,dpi=110 chlorophyll a (Chl-a), dissolved oxygen (DO), and chloride (Cl-) were observed between the reservoir and river areas. Furthermore, significant correlations (P<0.05) were found among the above ten environmental factors . Mantel tests indicated that pH, TN, and width=55,height=17,dpi=110 were the primary environmental factors influencing diversity of functional groups in the reservoir,and that permanganate index width=105,height=17,dpi=110 and DO were the main factors affecting diversity of functional groups in the river area.The RDA results showed the strong correlations between the functional group TB and TN, between functionalgroups D, P, X1, X2 and width=346,height=17,dpi=110 WT, pH. These results highlight significant correlations (P<0.05) among water temperature, pH, and nitrogen sources. Thee environmental factors, WT, pH, nitrogen sources, and DO, play an important role in shaping phytoplankton functional group diversity and structure.
  • Three-dimensional numerical simulation of the impact of artificial reef deployment on the marine environment in the Changshan Archipelago
    ZHAI Shichen, TIAN Jie, SONG Jun, LI Ming, ZHOU Jiale, YANG Minghao, FU Xiaomeng
    Journal of Dalian Fisheries University. 2025, 40(5): 831-842. https://doi.org/10.16535/j.cnki.dlhyxb.2025-035
    Abstract (1160) PDF (358) HTML (0)   Knowledge map   Save
    To investigate the regulatory mechanisms of artificial reefs on environmental factors in a particular area of the North Yellow Sea, a three-dimensional hydrodynamic-thermohaline coupled numerical model for the Changshan Archipelagic waters was established based on the Finite-Volume Coastal Ocean Model(FVCOM). By comparing multi-physical field simulation results before and after artificial reef placement, we systematically revealed the regulatory mechanisms of artificial reefs on the marine environmental factors of this North Yellow Sea area. The results demonstrated that artificial reefs significantly alter the local three-dimensional flow field structure. Surface flow velocities above the reef area were generally decreased (decrease of 0.02-0.06 m/s), whereas bottom velocities increased (increase of 0.08-0.15 m/s) as a result of enhanced vertical kinetic energy transfer. A turbulent dissipation zone induced by Kármán vortex streets formed on the upstream side, while a downstream acceleration zone with a velocity increase of up to 5.72% was observed on the lee side.Responses of the temperature and salinity fields exhibited vertical stratification characteristics: surface water temperature decreased by 0.04 ℃-0.14 ℃ due to upwelling-driven mixing and cooling, while the magnitude of bottom cooling (0.02 ℃-0.09 ℃) and salinity changes (ΔS≤0.02) were significantly smaller than those at the surface, indicating depth-dependent regulation of the thermohaline structure. Spatial heterogeneity analysis revealed that salinity decreased (ΔS≤0.02 ) at southern stations (A2, A3) due to sediment resuspension, whereas slight salinity increases occurred at northern stations (A1, A4) and were influenced by adjusted circulation patterns. Herein, we quantified the perturbations induced by artificial reefs on vertical thermohaline stratification in the North Yellow Sea.The findingsprovides a dynamic grounds for habitat optimization in marine ranching and may promote sustainable utilization of fishery resources.
  • Identification and functions of the Pm-SATB2 gene and its alternative splicing isoform in the pearl oyster (Pinctada fucata martensii)
    CHEN Zhihao, LIANG Xueru, JIAO Yu, WANG Qingheng, DU Xiaodong, DENG Yuewen
    Journal of Dalian Fisheries University. 2026, 41(1): 40-40. https://doi.org/10.16535/j.cnki.dlhyxb.2025-166
    Abstract (1132) PDF (286) HTML (0)   Knowledge map   Save
    To identify the special AT-rich sequence-binding protein Pm-SATB2 gene and its alternative splicing isoforms in the pearl oyster (Pinctada fucata martensii) and explore their functions in immune responses, we used bioinformatics, PCR, and fluorescence in situ hybridization (FISH) to analyze the sequence, isoform identification,expression changes, and cellular localization of Pm-SATB2. The results showed that Pm-SATB2 exhibits high sequence conservation and shares the highest homology with SATB2 from the Pacific oyster (Crassostrea gigas). Its fourth exon undergoes alternative splicing to form the isoform Pm-SATB2_1. Both Pm-SATB2 and Pm-SATB2_1 contain the ULD domain，CUTL domain，and homeodomain functional domains. Pm-SATB2 has two additional homeodomain domains compared to Pm-SATB2_1，suggesting potential functional differences between them. Quantitative PCR revealed high expression of both genes in hepatopancreas，gills，and gonads，with significant differential expression among hepatopancreas，gills，gonads，hemocyte mantle，muscle，and foot tissues (P<0.05). Lipopolysaccharide(LPS) stimulation induced significant upregulation of both genes at 6 h，whereas nucleus implantation caused downregulation from 6 h to 24 h. This finding suggests that Pm-SATB2 and its alternatively spliced isoform may play a role in executing related immune functions as LPS and nucleus implantation stimulated. The result of FISH showed that Pm-SATB2_1 was located predominantly in lymphoid cells，whereas Pm-SATB2 occurred mainly in granulocytes. In conclusion，Pm-SATB2 and Pm-SATB2_1 share similar expression patterns but have distinct cellular distributions，which suggests functional divergence and provides insights into their immunoregulatory mechanisms.
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Editor-in-Chief: SONG Linsheng
Deputy Editor-in-Chief:
ZHANG Guochen
LI Zhijun
LIU Ying
ZHANG Dongdong (executive)
Sponsor: Dalian Ocean University
Supervisor: Education Department of Liaoning Province
Address: No. 52,Heishijiao street, Shahekou District, Dalian, Liaoning Province, China
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