Current Issue
  
  • Select all
    |
  • YE Linchang , LIU Yun , LIU Yuan , GUO Jianlei , YIN Leiming
    2023, 50(6): 1.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to understand the effect of low-frequency vibration stimulation on the behavior and physiology of Larimichthys crocea, this study simulated the vibration of breeding cabin by self-made steel sink and actuator, and used the main frequency of underwater noise of traditional knocking operation to catch large yellow croaker. The frequency of 125 Hz ( 150 dB ) and 200 Hz ( 150 dB ) were used to conduct vibration stimulation experiments on 250 g and 500 g groups of large yellow croaker to determine the behavioral response and physiological and biochemical changes of large yellow croaker ( cortisol, epinephrine, thyroxine ). The results showed that : ( 1 ) In the early stage of acoustic stimulation, the behavioral responses of the two groups of test fish were characterized by random movement, cruising away after slow approach, free or around cruising. After adaptation, the test fish were basically in a regular or free cruising around the wall, cruising away after slow approach, or stagnant, and there was no obvious disturbance response. ( 2 ) In 250 g test group, the change of adrenaline at 125 Hz frequency ( about 40.93 % increase ) was the most significant ( P < 0.05 ). Under the condition of 200 Hz frequency, the change of thyroxine ( increased by about 41.08 % ) was the most significant ( P < 0.05 ). Except for increase of other blood indexes except epinephrine was higher than that of 125 Hz frequency group. Therefore, 250 g large yellow croaker was more sensitive to 200 Hz. In the 500 g test group, the change of thyroxine ( increased by about 28.68 % ) at 125 Hz frequency was the most significant ( P < 0.05 ), and other blood indexes decreased. Under the condition of 200 Hz frequency, the change of thyroxine ( increased by about 41.79 % ) was the most significant ( P < 0.05 ) and higher than that of 125 Hz frequency group, while other blood indexes increased in different degrees in 200 Hz frequency group. Therefore, the 250 g and 500 g groups were more sensitive to 200 Hz vibration stimulation. In this study, the effects of low-frequency vibration stimulation on the behavioral response and physiological and biochemical indexes of large yellow croaker were analyzed. The aim was to improve the growth rate, survival rate and quality of large yellow croaker during the breeding process of large yellow croaker, and to provide data support and reference.

  • CUI Jiaqin, ZHANG Haixin, LUO Guozhi, TAN Hongxin,
    2023, 50(6): 9.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To investigate the effect of different C/N on the accumulation of off flavor in biofloc reactor, different initial DOC/DIN(Dissolved organic carbon, DOC: Dissolved inorganic nitrogen, DIN)  gradients were set up for group A (no glucose added, C/N of 6), group B (C/N of 10) and group C (C/N of 20) by adding glucose to the bioflocs released from shrimp farming and a 7-day experiment was conducted.Water quality monitoring was carried out everyday. The concentrations of Geosmin (GSM) and 2-Methylisoborneol (2-MIB) in the BFT water were detected at the beginning and end of the experiment and the flocs were taken for nutrient index detection.The results showed that the accumulation of Geosmin (GSM) and 2-Methylisoborneol (2-MIB) was 22.41 ng/L and -0.19 ng/L at C/N of 10, which were significantly lower than those in the C/N of 6 group (76.4 ng/L and 4.43 ng/L) and C/N of 20 group (50.98 ng/L and 3.52 ng/L), respectively; the total ammonia nitrogen and nitrite nitrogen concentrations were lower than 0.10 mg/L and 0.15 mg/L, respectively, in all groups during the experiment; the crude protein content of bioflocs was highest at 31.64 %±0.22 % at C/N of 10. It was shown that the addition of glucose can effectively reduce the accumulation of GSM and 2-MIB production, and the most effective of reducing the accumulation of GSM and 2-MIB production was achieved when the C/N in the biofloc reactor was 10, as well as having water quality improvement effect.

  • LIU Zheng, HUANG Weiqing, ZHANG Yi, XU Kan, LI Tingting, SHAO Yizhen, LIN Peihua
    2023, 50(6): 17.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to solve the industrial bottlenecks of the traditional pond aquaculture of the Scylla paramamosain in the hole, such as mutual killing, serious losses caused by natural disasters, and cumbersome operation of the existing factory circulating aquaculture system of "Crab Apartment", the Scylla paramamosain in the hole was cultured in the "dragon boat" type factory circulating aquaculture system and the factory circulating aquaculture system of "Crab Apartment" designed in this experiment. The breeding cycle was 30 d. Compare the survival rate, aquaculture water environment, growth performance and nutritional quality. The results showed as follows: The survival rate of the Scylla paramamosain in the dragon-boat type factory circulating aquaculture system was (98.66±0.58) %, which was significantly higher than that in the crab apartment factory circulating aquaculture system (P < 0.05). In the "Dragon Boat" type industrial recirculating aquaculture system, the ammonia nitrogen content was 0.0625-0.0671 mg/L, the nitrite nitrogen content was 0.0213-0.0253 mg/L, and the active phosphate content was 0.0315~0.0346 mg/L, all of which were lower than that in the "Crab Apartment" industrial recirculating aquaculture system.The body weight specific growth rate of the Dragon-boat type factory recirculating aquaculture system was (3.43±0.50) %/d, the molting interval time was (20.4±0.25) d, and the growth performance was significantly higher than that of the "crab flat" factory recirculating aquaculture system (P < 0.05). The essential amino acid index (E) in muscle of the Scylla paramamosain cultured in the "Dragon Boat" type industrial recirculating aquaculture system was 67.35, which was higher than that in the "crab House" industrial recirculating aquaculture system; The fatty acid composition and quality safety of muscle were better than that of "Crab Apartment" industrial circulating aquaculture system. The results showed that the adoption of the "dragon boat" type industrial recycle aquaculture system could reduce water pollution, improve the survival rate and growth rate of the crab, improve muscle nutrition and reduce the content of heavy metals in the muscle, which could be used as a new model for the industrial culture of the crab.

  • HE Xi, SHI Tingyu, CHEN Fei, YU Qili, LUO Guozhi
    2023, 50(6): 25.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Biofloc technology (BFT) has been proven to perform closed, high-density aquaculture at a lower cost and has received much attention from aquaculturists in recent years. The two critical services of bioflocs in BFT aquaculture systems include removing ammonia nitrogen from feeding and providing nutrients for some cultured animals. The current experiment investigated the ammonia nitrogen removal efficiency and nutrient composition of bioflocs under the condition of two bioflocs concentrations (300 mg/L and 600 mg/L) and three Bacillus subtilis additions (104 CFU/mL, 105 CFU/mL and 106 CFU/mL) in the suspended growth reactors. The results showed that the bioflocs concentration had a significant effect (P < 0.05) on the removal rate of ammonia nitrogen. The highest ammonia nitrogen removal rate was (3.85 ± 0.27) mg N/h observed in the group with 600 mg/L bioflocs and 106 CFU/mL Bacillus subtilis, which was significantly higher than that in the 300 mg/L bioflocs groups. The bioflocs concentrations had a significant effect on the major nutrients (crude protein, crude ash, crude fat) and some amino acids in the bioflocs. There was no significant effect of bioflocs concentrations on the content of major nutrients (crude protein, crude ash, crude fat) and some amino acids in the bioflocs (P > 0.05). The crude protein content of the bioflocs was (27.22±0.47)% and (27.43±1.07)% for the 300 mg/L and 600 mg/L bioflocs groups with the Bacillus subtilis addition level of 106 CFU/mL, which was significantly higher than the other two bacteria addition levels. The copy numbers of four nitrification genes (ureC, amoA, nxrA, Hao) were higher in the groups at a concentration of 600 mg/L than in the 300 mg/L groups. The copy numbers of amoA, ureC and Hao genes in bioflocs increased with the addition of Bacillus subtilis. The results of the current study proved that the 600 mg/L bioflocs and 106 CFU/mL Bacillus subtilis were beneficial to improve the ammonia nitrogen removal rate and nutritional content of the bioflocs. 

  • ZHANG Shizhong, ZHANG Tianshi, WANG Xingxing, YUAN Shijia, YANG Bo, ZHAO Lei
    2023, 50(6): 33.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
     Aiming at the problem that the inclination angle is too large and easy to roll over when the sinking and floating aquaculture cages is sinking and floating. In this study, an automatic control and management system for sinking and floating aquaculture cages was developed. The automatic control system of sinking and floating aquaculture cages is mainly based on PID control technology. In order to realize automatic control of the inclination angle of cages, and the appropriate parameters of the PID control system are explored, which uses inclination angle signal and control algorithm to adjust the actuator. The corresponding management system for automatic control of sinking and floating aquaculture cages was developed. The main functions include: floating and sinking control, feeding control, cleaning cage, GPS positioning and camera cleaning, as well as underwater camera monitoring, water quality, flow rate, liquid level and pressure data monitoring, etc. After a series of experiments such as the buoyancy-gravity ratio of the cage, the water inlet diameter and diameter ratio of the adjusting buoy, the PID control, the suitable values of the buoyancy-gravity ratio of the cage is 1.2, the water inlet diameter and diameter ratio of the adjusting buoy is 0.03, and the PID parameters are P:100, I:1000, D:0. In this study, the control and information of each module of the sinking and floating aquaculture cages were integrated into a set of system, which improved the performance of the automatic control system of the deep-sea aquaculture cages. The system can control the output in a timely and stable manner, and achieve the stable sinking and floating of the aquaculture cages. The results of the research have certain theoretical and practical meaning. The automatic control system of deep-sea sinking and floating aquaculture cages is one of the important technical means to achieve the industrialization development of deep-sea aquaculture. The research methods and experimental results proposed in this paper provide important data reference and theoretical basis for the research and application of deep-sea sinking and floating aquaculture cages. 

  • YANG Longjiang, HAN Lulu, TANG Zhengxian, PENG Xiaoqian, MEI Huiqing, ZHAI Xuliang, XUE Yang, REN Chaoying, ZHU Chengke
    2023, 50(6): 41.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to explore the treatment capacity of an integrated wastewater treatment system for freshwater pond aquaculture wastewater, this study selected an aquaculture base with an integrated wastewater treatment system in Chongqing. According to the water quality evaluation indexes in "Requirement for Water Discharge from Freshwater Pond Aquaculture " (SC/T 9101-2007), the water quality of aquaculture wastewater and effluent from various treatment units was measured and analyzed. The results showed that the annual average suspended matter content (TSS), 5-day biochemical oxygen demand (BOD5), permanganate index (CODMn), total nitrogen (TN), and total phosphorus (TP) removal efficiencies were 67.30%, 77.13%, 39.31%, 48.39% and 52.62% in the comprehensive wastewater treatment system, and the removal effect was obvious. After the wastewater treatment system is used to treat the aquaculture wastewater, the treated aquaculture wastewater is all lower than the level 1 standard of "Requirement for Water Discharge from Freshwater Pond Aquaculture ", and the wastewater can be directly discharged or recycled. The research shows that the integrated wastewater treatment system has an obvious effect on the treatment of aquaculture wastewater, and can effectively control the pollution index of aquaculture wastewater, which has a positive significance for improving the aquaculture environment and reducing aquaculture pollution.

  • WANG Dinghong, YANG Xinting, PAN Liang, ZHU Wentao, JIAO Dongxiang, ZHOU Chao,
    2023, 50(6): 49.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In intensive aquaculture, real-time monitoring of fish feeding status is one of the important bases for developing scientific feeding strategies. In order to achieve temporal detection of fish feeding states , and to solve the problem of high error in detecting feeding state switching by existing methods, this paper proposes a fish state detection network BMN-Fish based on an improved BMN (Boundary Matching Network), which introduces an efficient depth module and consists of an Efficient Channel Attention Module Net (ECANet) and a Base Residual Module (BRM). Among them, the Efficient Channel Attention Module can expand the perceptual field of the temporal dimensional features, so as to improve the ability of the model to extract local information; the Base Residual Module enables the algorithm to focus on the regions of interest in the feature map, which can strengthen the global perception ability of the algorithm. The experimental results showed that the AUC and AR@100 of BMN-Fish were 93.32% and 95.28%, which were 2.17% and 1.95% higher than BMN, respectively. BMN-Fish could effectively detect the sequential feeding movements of fish, and provide important information for the formulation of intelligent feeding strategies for intensive aquaculture.

  • 2023, 50(6): 60.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    This study proposes a lightweight underwater image restoration method for obtaining high-quality underwater biological images and addressing issues such as color cast and low contrast. The method compensates for color distortion in underwater images through global averaging and max pooling, reducing the influence of irrelevant features in the input images and enhancing the model's focus on key features. It introduces ghost convolution to reduce redundancy in feature maps and model parameters. Additionally, dynamic convolution is used to adaptively adjust the brightness and contrast of images in three color spaces, overcoming the limitations of single-color restoration and enhancing the tone and brightness of the images based on RGB restoration. The results show that the proposed model outperforms contrast methods based on non-physical and physical models in terms of peak signal-to-noise ratio (PSNR) and structural similarity index (SSIM), with values of 24.298 and 0.891, respectively, on the Enhanced Underwater Vision Perception (EUVP) underwater scene dataset. Compared to the deep learning models Shallow-Uwnet and Water-Net on the EUVP underwater biological image dataset, the proposed model achieves computational efficiency of only 0.27% and 0.04%, respectively. The improved images show an SSIM improvement of 3.77% and 6.72%, compared to the two aforementioned models. By directly adjusting pixel values to restore underwater image colors, this model occupies only 41 KB of storage space, making it suitable for deployment on underwater robots. This study demonstrates that the proposed model effectively enhances underwater biological images, and due to its low computational load and storage requirements, it contributes to the accurate support of ocean data and promotes the development of marine resources.

  • YUAN Hongchun , SHI Jingwei
    2023, 50(6): 74.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Pelagic fishery is still faced with the problems of low automation and intelligence level.  As the traditional method of catch statistics is counting by people, which wastes time and energy, automatic catch statistics becomes one of hot spots in the study of pelagic fisheries. To solve this problem in the pelagic tuna fishery, this paper presents an automatic counting method based on DP-YOLO (DCNv2-PConv-YOLO) model combined with dynamic detection gate algorithm. Due to the lightweight nature of  YOLOv7-tiny, it is treated as a baseline model. Using deformable convolution DCNv2 can obtain more shape features. To alleviate the speed decrease caused by adopting DCNv2 and ensure that it can work on edge devices, partial convolution PConv is used to replace regular convolution to improve detection speed, reduce model computation and performance demands of the hardware.  Dynamic detection gate algorithm is designed to avoid repeated counting. Meanwhile, a new miscounting error index called ECE (Error Counting Error) is proposed to evaluate the counting method. To verify the influence of the module on YOLOv7-tiny, ablation test results show that DP-YOLO not only reduces 3.3% of parameters, 23.7% of calculation time and 2.1% of calculation time, but also increases the average accuracy by 5.3%.  The test results of automatic catch statistics show that the identification accuracy of this method is 95.8%, the counting accuracy achieves 97.9%, and ECE is only 2.1%, which is respectively 45.8% and 25% higher than the existing counting algorithms of YOLOv5s+Deepsort and YOLOv7-tiny+Deepsort. This algorithm provides a novel method of automatic counting catch for pelagic fishery. Therefore, the study can meet the catch statistics requirements of tuna longline fishery.
     
  • WANG Yuting, Xiao Naiyong, SHI Wenzheng,
    2023, 50(6): 84.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to realize the high-value utilization of low-value fish products, this study prepared the silver carp hydrolysate by enzymatic hydrolysis, and constructed the Maillard reaction (MR) system with xylose to study the effect of ultrasound-assisted MR on the flavor characteristics of the hydrolysate, and compared with the traditional wet MR and enzymatic hydrolysis. The results showed that the ultrasonic pretreatment could promote the generation of intermediates and the degree of browning and improve the rate of the MR; the fluorescence intensity of the hydrolysate decreased after the MR, indicating the introduction of hydroxyl groups. Compared with the hydrolysate, the bitter amino acids of the ultrasound-assisted Maillard reaction products (MRPs) were reduced by 18%, which was better than the un-sonicated group. The results of MMSE-GC-MS and electron tongue showed that the volatile compounds (benzaldehyde, furfural and 2-ethylfuran, etc.) of the ultrasound-assisted MRPs contributed to the aroma enhancement were higher in the products, and the bitterness and astringency were lower than those of the hydrolysate and the MRPs. The above results indicate that the ultrasonic treatment can effectively improve the flavor characteristics of the hydrolysate and provide a reference for the development of freshwater fish products.

  • MA Tiantian, OUYANG Jie, XIAO Zhefei, SHEN Jian,
    2023, 50(6): 93.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To study the hot air drying characteristics of Antarctic krill and establish a drying model. Methods: Using frozen Krill as raw material, the effects of different temperature and drying quantities on the drying time and drying rate of krill were studied, and the effective diffusion coefficient and drying activation energy of krill were analyzed under different drying conditions. Five drying models, Lewis, Henderson and Pabis, Page, Modified Page, Wang and Singh, were used to fit the test data. The optimal drying model was determined and validated with the determination coefficient R2, Chi-square test value X2, root mean square error M and error square sum S as the evaluation indexes of model fitting effect. Results: The drying time was shortened and the drying rate increased with the increase of temperature or the decrease of drying quantities. The influence of drying amount on drying time and drying rate was less than that of temperature. When the temperature was 50 - 100℃, the effective diffusion coefficient of water was 1.459×10-8 - 6.310×10-8, and the dry activation energy was 29.599 kJ/mol. When the drying amount was 0.5 - 3.0 kg, the effective diffusion coefficient of water was 4.63×10-9 - 3.533×10-8. By comparing the fitting effect evaluation indexes of the five models, it was found that the Page model had a high R2 value and a low X2, M and S value, which could better fit the test data of Antarctic krill. The predicted value of the model had a high coincidence degree with the test value, and it could accurately predict the change law of water ratio in the hot-air drying process of Antarctic krill. Conclusion: Increasing the temperature or decreasing the drying amount can shorten the drying time and increase the drying rate. Page model can accurately describe the hot-air drying process of Antarctic krill, and provide theoretical basis for the prediction and control of hot-air drying process of Antarctic krill.

  • XU Guoqiang, YU Baocun, ZHANG Hongliang, ZHOU Yongdong, ZHU Wenbin, XU Liuxiong
    2023, 50(6): 103.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to clarify the selectivity of beam shrimp trawl for Parapenaeopsis hardwickii and Solenocera melantho, the authers conducted the selectivity tests of different mesh sizes in December 2018 and March to April 2019, respectively. The results showed that: In December, the experiment mainly focused on catching Parapenaeopsis hardwickii, whose body length ranged from 35 to 100 mm,with an average body length of 66 mm; in the experiment from March to April, the main fishing was Solenocera melantho, whose body length ranged from 30 to 140 mm, with an average body length of 60 mm. with the increase of mesh size, the average body length of Parapenaeopsis hardwickii increased from 71 to 74 mm, and the average body length of Solenocera melantho increased from 64 to 74 mm. The mesh size had a significant effect on the body length of the two types of shrimp. When the mesh size for Parapenaeopsis hardwickii was 25mm、28 mm and 38 mm, its L50 was 55.334 mm、57.396 mm and 68.319 mm; when the mesh size for Solenocera melantho was 22 mm、25 mm、28 mm and 38 mm, its L50 was 54.919 mm、62.734 mm、72.807 mm and 74.819 mm. The equations for the relationships between mesh size of the codends and L50 for Parapenaeopsis hardwickii and Solenocera melantho, respectively, are as follows: L50=1.023m+29.331 (R2=0.995),L50=1.134m+34.280 (R2=0.724). As the mesh size of codends increased(25~38 mm, 22~38 mm), the selectivity curves of both Parapenaeopsis hardwickii and Solenocera melantho shifted sequentially to the right, and the selectivity curves both showed crossover phenomena, which were inseparable from the body shape characteristics of the shrimp. In order to release shrimps with body length less than 70 mm, it is recommended that the mesh size of codend should not be less than 39.75 mm during the main catch of Parapenaeopsis hardwickii; The mesh size of codend should not be less than 31.50 mm during the main catch of Solenocera melantho. The results of this study can provide reference for the management of beam shrimp trawl and the protection of two kinds of shrimp resources in the East China Sea.