17 September 2026, Volume 41 Issue 3

    

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  Early developmental characteristics of cyprinid fish (Acrossocheilus fasciatus) and environmental factors affecting its development and growth in the Changyuan River, China

  ZAN Zhongjie, DING Yu, WEN Lujie, JIANG Min, LIU Kai

  Journal of Dalian Fisheries University. 2026, 41(3): 361-374. https://doi.org/10.16535/j.cnki.dlhyxb.2025-236

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  In this study, we used artificial induction and fertilization methods to assess the embryonic development and growth process of larvae and juveniles of the cyprinid fish (Acrossocheilus fasciatus) exposed to different water temperatures and flow rates. The results showed that the fertilized eggs of A. fasciatus had a diameter of 2.36 mm ± 0.04 mm and were dull, slightly sticky, round in shape, and bright yellow in color. At water temperature of 23.3 ℃ ± 0.7 ℃, the embryo incubation time varied from 44 h 31 min to 54 h 35 min (average, 50 h 7 min ± 72 min). The embryos successively went through cleavage, blastocyst, gastrula, neurula, and organ formation stages, followed by the hatching period. The effective accumulated temperature throughout the process was 1 243.02 ℃·h. Under water temperature of 25.0 ℃ ± 1.4 ℃, newly hatched larvae (total length, 6.745 mm ± 0.034 mm) developed to the early larval stage (total length, 10.433 mm ± 0.057 mm) within 7 days post hatching (dph); they developed to the late larval stage (total length, 12.350 mm ± 0.083 mm) within 7 dph; and they developed to the juvenile stage (total length, 16.460 mm ± 0.115 mm) within 22 dph. During the development of juvenile fish, the first, second, sixth, and eighth melanin stripes formed on the sides of the body first, followed by the appearance of the third and fourth transverse stripes and finally the fifth and seventh transverse stripes. Under laboratory rearing conditions, the total length of juveniles was logarithmically correlated with their age, with the following fitting equation: L= 7.158 ln(t + 16.296) - 12.217 (R2= 0.988 5). The growth rate of the total length of early juvenile fish was the fastest. The length of the swim bladder was logarithmically correlated with the total length following the equation: B = 2.243 + 0.159 ln(L - 9.712)(R20.982 4). These results can be applied to improve artificial breeding and natural resource enhancement and protection of A. fasciatus.
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  Behavioral and physiological responses of Juvenile broadbanded velvetchin (Hapalogenys analis) under different salinity conditions

  ZOU Jinghua, PING Hongling, ZHANG Tao, SHI Huilai, ZHAO Yuxuan, ZHOU Qun

  Journal of Dalian Fisheries University. 2026, 41(3): 375-385. https://doi.org/10.16535/j.cnki.dlhyxb.2025-241

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  To explore influence of acute salinity stress on juvenile broadbanded velvetchin (Hapalogenys analis), we established three experimental groups with salinity of 5, 15 and 35, and a control group at 25 based on the optimal salinity range (24-26) for fish farming. The changes of fish behaviour were observed in a period of 0 to 108 h, and physiological indicators (serum cortisol level, branchial Na+/K+-ATPase activity, and hepatic superoxide dismutase (SOD) and catalase (CAT) activities) were determined. Additionally, histological alterations in the gills, liver, and kidneys were analyzed. We found that H. analis exhibited distinct physiological and pathological responses to varying salinities. Behaviorally, the control group remained normal and the 15 group adapted rapidly, whereas the 5 (low salinity) and 35 (high salinity) groups displayed suppressed activity and intense stress responses, respectively. Physiologically, serum cortisol concentrations in all groups showed an upward trend over time, with a significant increase observed in the high-salinity group. The interaction between salinity and exposure time significantly interfered with branchial Na+/K+-ATPase activity and induced a fluctuating pattern in hepatic SOD and CAT activities, which was characterized by initial inhibition followed by a compensatory increase. Histologically, deviations from the optimal salinity led to homeostatic imbalance. Low salinity primarily caused an increase in branchial mucous cells, hepatic nuclear swelling, and renal tubular dilation, whereas high salinity resulted in branchial epithelial damage, hepatic vacuolation, and renal tubular atrophy. These findings suggest that although H. analis possesses a degree of salinity adaptability, salinities outside the optimal range disrupt physiological functions and tissue homeostasis. This study provides a scientific reference for salinity regulation in the large-scale aquaculture of H. analis.
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  Recombinant expression of cyprinid herpesvirus 2 ORF4 protein in Escherichia coli and preparation of anti-ORF4 monoclonal antibodies

  ZHANG Jialin, LONG Xingyu, SHI Wei, LIU Miaoling, ZHANG Mingming, QIAO Guo

  Journal of Dalian Fisheries University. 2026, 41(3): 386-393. https://doi.org/10.16535/j.cnki.dlhyxb.2026-014

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  To prepare monoclonal antibodies (mAbs) against the open reading frame 4 (ORF4) protein of cyprinid herpesvirus 2 (CyHV-2), the recombinant protein was expressed using an Escherichia coli expression system. Using the recombinant ORF4 protein as an immunogen, two hybridoma cell lines stably secreting anti-ORF4 mAbs were obtained via hybridoma technology and screening. An indirect immunofluorescence antibody test confirmed that the mAbs specifically bound to ORF4 protein in CyHV2-infected RyuF cells, with fluorescence signals predominantly localized in the nucleus. When we investigated the tissue distribution and expression profile of ORF4 during CyHV-2 infection in Gibel carp (Carassius auratus gibelio), we detected a distinct target protein band at approximately 45 kDa in SDS-PAGE analysis. Immunofluorescence assays using the anti-ORF4 mAbs showed that ORF4 was highly expressed in the liver, spleen, and kidney of CyHV2-infected fish, while expression in the heart was relatively low. Positive ORF4 expression was detected in the spleen at 12 h post-infection, it peaked at 72 h, and then it gradually declined, demonstrating that the prepared mAbs can be used for the specific detection and tracing of ORF4 protein. In conclusion, the anti-ORF4 mAbs generated in this study are a valuable tool for further investigating the regulatory roles of ORF4 during CyHV2 infection.
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  Effect of different dietary wheat starch contents on the growth,intestinal health and serum biochemistry of juvenile grass carp (Ctenopharyngodon idella)

  LIU Wenshuo, LIAO Yuhong, ZHANG Yazhou, LI Shuyao, ZHANG Chongqiu, CHEN Shukai, WANG Zirui

  Journal of Dalian Fisheries University. 2026, 41(3): 394-403. https://doi.org/10.16535/j.cnki.dlhyxb.2026-018

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  We used a single-factor gradient experimental design to investigate the effects of different dietary wheat starch levels on the growth performance, intestinal health, and serum biochemical indices of juvenile grass carp (Ctenopharyngodon idella). A total of 450 juvenile grass carp with an initial average weight of 12.00 g±0.30 g were randomly divided into five groups, with three replicates per group containing 30 fish each. Five isonitrogenous and isolipidic diets were formulated with varying wheat starch levels: SC1 (11.6%), SC2 (14.6%), SC3 (17.6%), SC4 (20.6%), and SC5 (23.6%). The feeding experiment lasted for 56 days. The results showed that moderate levels of dietary wheat starch significantly improved growth performance. The fish weight gain rate and specific growth rate peaked were highest in the SC2 group (P<0.05). The SC1 group had the highest moisture and crude protein contents in the fish body, but the crude lipid content was highest in the SC2 group (P<0.05). With increasing starch levels, the activities of serum alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase followed a “decrease then increase” trend, and the SC3 group had the lowest values (P<0.05). High starch levels in the SC4 and SC5 groups led to a significant increase in blood glucose levels in the fish in these groups compared with the fish in the control group (P<0.05). Appropriate starch levels also improved intestinal morphology and digestive capacity. The intestinal villus heigth was greatest in the SC2 group (P<0.05), and intestinal trypsin activity and serum urea nitrogen level were highest in the SC3 group (P<0.05). Based on a comprehensive analysis of growth performance, intestinal health, and serum biochemical indices, the optimal dietary wheat starch level for juvenile grass carp was 14.6%-17.6%. Based on quadratic regression analysis of specific growth rate, the growth performance was optimized at a 16.02% dietary wheat starch, while liver function and intestinal digestive enzyme activities were best at 17.6%. The finding of the study provided scientific reference to scientifically formulated diet for juvenile grass carp.
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  Effects of acute alkalinity stress on the liver of Gymnocypris przewalskii based on a metabolomics approach

  HUANG Shuchen, LI Zhaonan, YANG Ying, LIANG Tianxiu, ZHANG Jingjing, CAI Rencuo, LI Changzhong, CHEN Yanxia

  Journal of Dalian Fisheries University. 2026, 41(3): 404-414. https://doi.org/10.16535/j.cnki.dlhyxb.2025-207

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  The mechanisms underlying the effects on the hepatic metabolic network of Gymnocypris przewalskii caused by acute carbonate alkalinity stress were investigated to analyze the molecular basis of alkalinity adaptation strategies in this plateau fish. A seven day stress test was conducted using an acutely alkaline 64 mmol/L carbonate NaHCO3：Na2CO3 mixture (9∶1). Liver metabolite changes were analyzed using LC-MS based untargeted metabolomics. Metabolic profile differences were assessed using principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA). Differential metabolites were screened based on VIP>1, P<0.05, and fold change FC≥2 or FC≤0.5. Key response pathways were identified using KEGG pathway enrichment analysis. The results indicated that the hepatic metabolic profile of the acute alkalinity stress group (AL64) was significantly altered compared with the control group (SAC), with a clear separation between the two groups demonstrated by the PCA and PLS-DA models. A total of 2 587 metabolites were identified, from which 617 significant differential metabolites were screened (383 in positive ion mode: 241 upregulated; 234 in negative ion mode: 120 upregulated). KEGG enrichment analysis revealed that in the positive ion mode, differential metabolites were significantly enriched in the alpha-linolenic acid metabolism pathway, with key metabolites such as alpha-linolenic acid, heptadecatrienal, and stearidonic acid being significantly upregulated. In the negative ion mode, significant enrichment was observed in the vitamin digestion and absorption pathway, with the key metabolites D-biotin and flavin mononucleotide (FMN) being significantly upregulated. This study shows that acute alkalinity stress affects the hepatic metabolic network of G. przewalskii, to create a dual adaptation strategy centered on “enhanced defense and optimized metabolism”. On the one hand, the upregulation of key lipid molecules in the alpha-linolenic acid metabolism pathway establishes a robust anti-inflammatory and antioxidant defense system. On the other hand, the activation of vitamin metabolism pathways optimizes the maintenance of the species’ energy metabolism and cellular homeostasis. This study reveals the molecular mechanisms underlying the tolerance of G. przewalskii to high-alkalinity environments from a metabolomic perspective, providing a theoretical basis for the conservation of fisheries resources in saline-alkaline waters and the breeding of stress-resistant varieties.
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  Comparative analysis of nutritional components of fast-growing bay scallop (Argopecten irradians) strains with different shell colors

  XIE Minghang, WANG Xubo, LI Lei, MAO Junxia, TIAN Ying, HAO Zhenlin, SONG Jian, YIN Donghong, CHANG Yaqing

  Journal of Dalian Fisheries University. 2026, 41(3): 415-424. https://doi.org/10.16535/j.cnki.dlhyxb.2025-239

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  To explore the relationship between shell color and nutritional quality in the fast-growing strains of bay scallop (Argopecten irradians), the nutritional components of adductor muscle were compared among the fast-growing red shell strain (RS), the fast-growing black shell strain (BS), and a common commercial population (CC). Proximate analysis indicated that the crude protein content of RS and BS strains exceeded that of the CC population, and that the BS strain exhibited significantly higher protein levels than that of the CC population. Although the total amino acid composition was similar across groups, the RS strain contained significantly higher glycine levels compared to the BS strain, suggesting a potentially superior flavor profile. Furthermore, the RS strain exhibited a higher proportion of EPA+DHA relative to total polyunsaturated fatty acids (85.33%) compared with the BS strain (82.85%). These findings demonstrate a correlation between shell color phenotypes and nutritional quality in A. irradians and suggest that red shell phenotype may serve as a viable genetic marker for breeding scallops with enhanced nutritional value and favorable fatty acid profiles.
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  Reproductive cycle and early growth and development of clam Mya japonica in Jiaozhou Bay

  WANG Tinghao, DU Meirong, WANG Hua, FENG Jialin, JIANG Zengjie, ZENG Huili, XU Xiaoyan, BI Mingyong, LIANG Yucai

  Journal of Dalian Fisheries University. 2026, 41(3): 425-435. https://doi.org/10.16535/j.cnki.dlhyxb.2026-027

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  To investigate the reproductive cycle and early growth and development of clam Mya japonica in Jiaozhou Bay for artificial seed rearing, annual gonadal histological sectioning and seedling cultivation experiments were conducted to observe the reproductive cycle and early developmental morphology. The results showed that the annual gonadal development of M. japonica in Jiaozhou Bay went through the following stages: proliferative, growth, mature, spawning, and resting. The gonadosomatic index, condition index, and fatness increased with rising water temperature. There were two peak spawning periods per year in Jiaozhou Bay, namely April-May and September. Seedling rearing of M. japonica was carried out based on this reproductive pattern. Under conditions of water temperature 20 ℃-22 ℃, salinity 28-30, and pH 8.0-8.2, fertilized eggs hatched into D-shaped larvae after 22 h (mean shell length 101.86 ± 3.60 μm). By day 25, the gill filaments became distinct, and the larvae entered the settlement and metamorphosis stage. They attached to substrate via a boot-shaped foot by secreting byssus, formed a secondary shell, and showed the initial rudiment of a siphon. The short membranous siphon emerged externally and performed rhythmic movements as the juveniles crawled. By day 40, the siphon elongated and could extend out of the secondary shell, and the membranous tube grew longer. At this stage, the juveniles crawled among sand grains using the boot-shaped foot, and the secondary shell around the siphon area grew rapidly, giving the shell an elongated boat-shaped appearance. After 61 days of rearing, the juveniles developed into young clams (mean shell length 3.31 ± 0.93 mm). When juveniles were subjected to intermediate cultivation in sea-based or hatchery-based systems, the survival rate of larvae in the indoor hatchery was significantly higher than that in the sea-based cultivation system (P< 0.05). Daily growth rate, however, was significantly lower in the hatchery compared to sea-based system (P< 0.05). Further research is needed to explore other intermediate rearing modes that achieve both high survival rate and good growth performance. The results of this study provide a theoretical basis for artificial seed rearing technology for M. japonica and lay a foundation for commercial seedling production and sea ranching stock enhancement of this species.
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  Effect of dietary kelp fucoxanthin on growth performance, antioxidant capacity, and non-specific immunity of juvenile abalone (Haliotis discus hannai)

  ZHANG Ruibiao

  Journal of Dalian Fisheries University. 2026, 41(3): 436-443. https://doi.org/10.16535/j.cnki.dlhyxb.2025-235

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  The study was to investigate the effect of dietary supplementation with kelp fucoxanthin (FX) on growth performance, antioxidant capacity, and non-specific immune function of juvenile abalone (Haliotis discus hannai). Six types of experimental diets were formulated by supplementing 0 (control), 0.20%, 0.40%, 0.60%, 0.80%, or 1.00% kelp FX. Abalone (six groups, three replicates per group, 300 individuals per replicate) with an initial shell length of 12.45 ± 0.86 mm and body weight of 0.19 ± 0.05 g were fed the experimental diets for 60 days. The results indicated that dietary supplementation with 0.20% to 1.00% kelp FX promoted growth and survival and enhanced antioxidant capacity and non-specific immunity of juvenile abalone. The 0.60% supplementation group brought about the optimal effect. The maximum specific growth rate of shell length (LsGR), specific growth rate of body weight, and 60-day survival rate were 0.93%·d-1, 3.02%·d-1(P<0.05), and 98.67% (P<0.05), respectively. Although no significant difference in LsGR was observed among the 0.40% to 1.00% groups, all values were significantly higher than those in the 0.20% group and the control group (P<0.05). The 0.60% group had the maximum activities of antioxidant enzymes superoxide dismutase(77.59 U·mL-1), catalase(1.99 U·mL-1), glutathione peroxidase (49.38 U·mL-1), and, and the minimum contents of malondialdehyde (3.13 μmol·mL-1). The catalase activity did not differ significantly between the 0.60% and 0.80% groups, but the values were significantly higher than those in other groups (P<0.05). The activities of non-specific immune enzymes acid phosphatase, alkaline phosphatase, lysozyme, and phenoloxidase in the 0.60% group were 16.67 King’s·100 mL-1, 7.81 King’s·100 mL-1, 4.12 U·mL-1, and 3.83 U·mL-1, respectively, all significantly higher than those in the other groups (P<0.05). These results demonstrate that dietary supplementation with an appropriate kelp FX benefits the growth, survival, antioxidant capacity, and non-specific immune function of juvenile abalone. 0.60% kelp FX was the optimal level. These findings provide a scientific basis and support for development and application of algal FX as a functional feed additive for abalone.
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  Effect of synergistic bacteria-algae regulation on the water environment of photovoltaic aquaculture pond and growth performance and physiological indices of Chinese mitten crabs (Eriocheir sinensis)

  LI Jiayi, JIN Wei, LU Cheng, YANG Xiwei, ZHU Haojun, GAO Jiancao, GAO Jun, YAO Yu, XU Gangchun, ZHENG Yao

  Journal of Dalian Fisheries University. 2026, 41(3): 444-454. https://doi.org/10.16535/j.cnki.dlhyxb.2025-245

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  To investigate the effect of effective microorganisms (bacteria) and Chlorella vulgaris to aquaculture water on the culture environment, growth performance, and physiological indicators of Chinese mitten crab (Eriocheir sinensis) in an integrated photovoltaic aquaculture system, we established a photovoltaic aquaculture group (FPI), a photovoltaic aquaculture group with bacterial-algal regulation (FP-BA), and a traditional pond group (TAC). Dynamic monitoring of the pond water environment, crab growth performance, and activities of antioxidant enzymes and non-specific immune enzymes was conducted at 0 (August 1), 30 (September 1), 60 (October 1), and 90 days (November 1). In terms of the water environment, the FP-BA group consistently and significantly had reduced levels of total nitrogen and total phosphorus (P<0.05), significantly decreased ammonia nitrogen and nitrite nitrogen during the mid-to-late culture period (60 and 90 days), suppressed proliferation of cyanobacteria and green algae, and a higher level of dissolved oxygen compared to the FPI and TAC groups. Regarding the physiology and growth, females crabs in the FP-BA group showed significantly enhanced activities of superoxide dismutase and amylase (P<0.05), and male crabs had higher SOD activity during the later culture period. Additionally, the final body weight, carapace length, carapace width, and other growth indicators of crabs in the FP-BA group were superior to those in the FPI and TAC groups. In conclusion, the introduction of bacterial-algal regulation into the integrated photovoltaic aquaculture system can effectively mitigate the ecological constraints caused by photovoltaic shading through the synergistic effects of optimizing water quality and enhancing the physiological functions of the crabs.
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  Effects of common carp (Cyprinus carpio) stocking density on the growth of water spinach (Ipomoea aquatica) and the capacity to purify effluent from the aquaponics systems

  HAN Yu, PEI Qingbao, ZHU Jijun, LI Liang, LUO Taiyou, SONG Yixin

  Journal of Dalian Fisheries University. 2026, 41(3): 455-462. https://doi.org/10.16535/j.cnki.dlhyxb.2025-224

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  To investigate the effect of common carp (Cyprinus carpio) stocking density on the growth of water spinach (Ipomoea aquatica) in a aquaponics system and purification capacity of this system for nitrogen compounds in aquaculture effluent, we adopted an experimental design with three groups of the different carp stocking densities (12, 10, 8 kg/m3), one no fish control group (CK) and a uniform water spinach planting density of 26 stalks/m2. Variations in water quality parameters, water spinach growth indices, nitrogen compound removal rates, and the correlations among them were systematically analyzed. The results showed that water spinach height, their fresh weight, crude protein content, and other growth indices of water spinach in all three groups were significantly higher than those in the control group (P<0.05), with plants in the high-density carp group (12 kg/m3) demonstrating the optimal comprehensive growth performance. Extremely significant positive correlations were found between the increment of water spinach plant height and the removal rates of ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen (r=0.651-0.719) and among the removal rates of the three nitrogen forms (r= 0.744-0.950). Plants in the low-density carp group (8 kg/m3) achieved the highest average removal rates of nitrogen compounds, 80.27% for ammonia nitrogen, 85.37% for nitrite nitrogen, and 70.92% for nitrate nitrogen. These results indicate that high carp stocking density (12 kg/m3) is most conducive to the accumulation of biomass and nitrogen-phosphorus nutrients in water spinach, while low carp stocking density (8 kg/m3) is most beneficial to the removal of nitrogen compounds from aquaculture tail water. These findings provide a scientific basis for the optimization of carp stocking density in practical aquaponics system.
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  Selectivity of diamond and T90 mesh codends of the stow net in the South China Sea

  YAN Lei, LI Jie, XING Binbin, YANG Bingzhong, WANG Teng, CHEN Zuozhi, ZHANG Peng

  Journal of Dalian Fisheries University. 2026, 41(3): 463-472. https://doi.org/10.16535/j.cnki.dlhyxb.2025-249

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  To investigate the selectivity of the two-stake stow net codends with different mesh structures for the main catch species in the coastal fishery of South China Sea, we conducted an experiment using the method of cover net to compare the selectivities of diamond mesh codend (D35) and T90 mesh codend (T35). Selectivity curves were fitted using Logistic and Richards models, and selectivity parameters were estimated by maximum likelihood. The results showed significant differences in selectivity between the two types of codend for four indicator species: the anchovy Coilia mystus, the sardine Harengula nymphaea, and the shrimps Parapenaeopsis hungerfordi and Metapenaeus joyneri. The T90 codend demonstrated markedly improved selectivity for shrimp compared with the diamond mesh codend. Specifically, the 50% retention length (L50) values of P. hungerfordi and M. joyneri increased by 24.8% and 30.5%, respectively, while the selection range (SR) values decreased by 46.9% and 8.67%. These results indicate enhanced retention of larger individuals and improved escape probability of juveniles under the T90 configuration. But, the selectivity improvement for laterally flat fish species was limited. Although the L50 of C. mystus increased in the T90 codend, its SR expanded by approximately 152.1%, indicating that it reduced size-selective precision. For H. nymphaea, the L50 decreased by 4.0% and the SR increased by 74%, suggesting that the T90 mesh structure did not effectively enhance size selectivity for this body shape. Overall, the T90 mesh structure has improved mesh geometric stability and can enhance the overall selectivity of stow net, particularly for elongated or demersal species. However, further optimization is required to improve juvenile release efficiency for laterally flat fish species. This study provides a scientific basis for codend structural improvement and minimum mesh size determination in stow net fishery in the South China Sea.
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  Study on the working efficiency of an improved jet fish pump with the shunt pipe

  GUAN Changxiu, WEI Ruishuai, ZHANG Liwei, PAN Lanlan

  Journal of Dalian Fisheries University. 2026, 41(3): 473-480. https://doi.org/10.16535/j.cnki.dlhyxb.2024-113

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  To improve the working efficiency of jet fish pump, a method combining theoretical calculation, numerical simulation, and experimental research was adopted to study the fluid parameters and efficiency of pump. We added a shunt pipe between the end of fish suction pipe and the inlet of working pump and adding a valve in the inlet pipe of the working pump to throttle the flow of the working water resulted in increased flow of the fish suction pipe. The minimum closing angle of valve and the working efficiency of the jet pump under different closing angles were calculated based on the principles of fluid mechanics. The computation fluid dynamics numerical simulation method was employed to analyze the flow rate, pressure, and efficiency of fish pump. The theoretical calculations and numerical simulation results were verified through physical model experiments, and all results were consistent. The results showed that the efficiency of the improved jet pump is linearly related to the closing angle of valve and that the flow rate of the diverting pipe is also related to the closing angle of valve: The larger the closing angle of valve (the smaller the opening of the valve), the larger the flow rate of the fish suction pipe and the higher the working efficiency of the jet pump. When the ratio of fish to water is 1∶1, the efficiency limit of the jet is 33%. At the same time, the internal flow field of the improved jet pump is stable and continuous. Both the axial and radial pressure difference in the throat is less than 10 kPa, suggesting that the improved jet fish pump is suitable for transporting live fish.
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  Study on the target detection model for ark shell (Scapharca broughtonii) based on improved YOLOv11n

  WANG Zhaowei, CAI Weiguo, GUO Shenghan, SHEN Xudong, YUE Wenhao, LI Donglin, CHEN Hao

  Journal of Dalian Fisheries University. 2026, 41(3): 481-492. https://doi.org/10.16535/j.cnki.dlhyxb.2026-021

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  To address the challenges of high parameter complexity and low detection accuracy in intelligent sorting of the ark shell (Scapharca broughtonii) caused by overlapping and mixed shellfish, we developed an improved YOLOv11-based detection method. We first integrated depth-wise separable convolution (DSConv) into the backbone and neck networks to reduce computational overhead. Second, SCConv was introduced into the backbone network to optimize the bottleneck structure of the feature extraction module, forming a feature extraction module termed SCC3k2 to enhance feature representation. Third, we redesigned the detection head using dynamic convolution, which resulted in a novel detection head (DCHead) that improves recognition accuracy. Finally, the original loss function was replaced with Wise-IoU to accelerate convergence. Experimental results demonstrated that the improved model achieved precision, recall, and mean average precision values of 89.6%, 87.5%, and 93.2%, respectively, representing improvements of 2.0%, 3.3%, and 2.6% over the baseline. Compared to the original YOLOv11n, the modified model reduced parameters, GFLOPs, and model size by 28.0%, 32.8%, and 27.3%, respectively, while increasing inference speed by 36.2%. Deployment on edge devices achieved 30 frames per second, which validated its practicality. The DSDC-YOLOv11n model mitigated false positives, missed detections, and redundant detections in shellfish sorting, and provided a reference framework for intelligent bivalve sorting systems.
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  Detection method of the Underwater organisms in marine ranching based on the improved YOLOv13

  LI Longwei, YUAN Hongchun, WANG Dexing, ZHANG Tianjiao

  Journal of Dalian Fisheries University. 2026, 41(3): 493-504. https://doi.org/10.16535/j.cnki.dlhyxb.2026-013

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  To address the problems of low detection accuracy and slow inference speed of existing detection methods in the complex underwater environment of marine ranches, we developed YOLO-DEA, an underwater biological object detection model based on an improved YOLOv13 architecture. By introducing dynamic convolution (DynamicConv), constructing the EMCA attention mechanism, and designing the ATFL loss function, this model effectively improves the system's detection of underwater biological targets. The results show that the mAP@0.5 values of YOLO-DEA on the RUOD and URPC2020 datasets are 87.4% and 73.7%, respectively, 2.5% and 2.9% higher than those from YOLOv13n. The model requires 6.2 GFLOPs, has a size of 5.4 MB, and achieves 106.5 FPS. The results indicate that YOLO-DEA achieves a balance between detection accuracy and detection speed. This new system offers visual technical support for real-time monitoring and resource assessment of underwater organisms in marine ranches, and results of this study provide a useful reference for the intelligent and automated development of marine ranches.
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  Research progress in antibiotic resistance genetic pollution in aquaculture environment and removal technology

  ZHOU Dandan, LI Fugui, WANG Runping, ZENG Xianliang, ZHONG Yunlin, LIN Xinguo, FU Hong, MENG Haohao, LIANG Ximei

  Journal of Dalian Fisheries University. 2026, 41(3): 505-515. https://doi.org/10.16535/j.cnki.dlhyxb.2025-191

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  Antibiotics have contributed significantly to the advancement of aquaculture. However, prolonged or excessive use of antibiotics not only results in drug residues but also induces emergence and dissemination of antibiotic resistance genes (ARGs). ARGs are widely detected in aquaculture environment and spread through multiple pathways. The potential threat of ARGs to human and animal health is a global concern. The paper reviews systematically the sources,pollution status,and transfer mechanisms of the ARGs in aquaculture environment, explores deeply into the existing technologies to remove the ARGs from aquatic environment,and analyzes briefly the prospects of technological advancement in the future. It aims to provide a reference for the effective prevention and control of ARGs pollution in aquaculture environments.
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  Research progress and prospects for machine learning in flow field prediction of aquaculture tank

  XU Hengming, WANG Yifan, CHENG Liangguang, REN Xiaozhong, FENG Qianyu, ZHANG Mingsen

  Journal of Dalian Fisheries University. 2026, 41(3): 516-526. https://doi.org/10.16535/j.cnki.dlhyxb.2025-237

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  Recirculating aquaculture systems (RAS) reveal a pivotal direction in the development of modern aquaculture industry. The hydrodynamic characteristics of the RAS directly determine key performance metrics—including flow uniformity, feed dispersion, waste removal efficiency, and dissolved oxygen distribution—thereby exerting a critical influence on environmental stability and healthy growth of organism. The flow field of a culture tank is governed by the combined effects of tank geometry, inlet structures, and outlet configurations. However, the complex multi-physics nature of flow field results in the high cost of traditional computational fluid dynamics (CFD) simulations computationally expensive and poor real-time performance. To overcome these limitations, machine learning (ML) techniques have recently been integrated into fluid dynamics modeling, enabling rapid flow prediction and optimization through data-driven models. We review research progress in culture tank flow fields, the application of ML in general flow prediction, and the specific potential of ML methods for aquaculture flow forecasting. We also summarize the current challenges and limitations of applying ML to RAS flow field prediction and explore perspectives on future research directions. Currently, ML-driven prediction technologies are propelling a paradigm shift in aquaculture hydrodynamic research, moving from traditional CFD simulations toward intelligent, data-driven, and real-time approaches. This transition provides new technical pathways for flow field optimization, energy-efficient operation, and the construction of digital twins, ultimately supporting the optimal design, precise regulation, and real-time control of RAS flow fields.
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  CRISPR/Cas9 genome editing technology and its application in exact breeding of fish

  HUANG Zhenqi, FAN Peng, HUANG Tianqing, LIU Enhui, GU Wei, WANG Gaochao, GE Kaibo, SUN Yunchao, LI Datian, XU Gefeng

  Journal of Dalian Fisheries University. 2026, 41(3): 527. https://doi.org/10.16535/j.cnki.dlhyxb.2025-246

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  The CRISPR/Cas9 system is a third generation gene editing technology and a significant breakthrough in modern biotechnology with high efficiency, precision, and programmability. We systematically review the CRISPR/Cas9 gene editing technology and its applications in fish Breeding. First, starting from the system’s origin and composition, we outline the classification and functions of CRISPR/Cas9. Based on the protein structure of Cas9, we clarify the working principle of Cas9 in achieving double-stranded DNA editing from aspects such as protospacer adjacent motif(PAM) recognition, cleavage by HNH/RuvC nuclease domains, and double-strand break-induced repair. Second, we describe the applications of the CRISPR/Cas9 system in trait improvement of fish, such as promoting growth and enhancing disease resistance. Finally, we summarize the technical advantages, challenges faced, and future development directions of CRISPR/Cas9 to provide a reference for improved application of CRISPR/Cas9 technology in fish breeding.