Volume 76, Issue 3, 2024

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https://hdl.handle.net/10524/77236

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Morphological variation of endemic Gymnocypris chilianensis (Cyprinidae) collected from three inland water systems in Qilian Mountains, China
(2024) Liu, Biyuan; Lou, Zhongyu; Peng, Di; Wang, Tai; Song, Dan; Cheng, Qiqun
To explore the morphological differences among different geographic populations of Gymnocypris chilianensis, 29 measurable traits and 13 landmarks on 191 individuals of 10 geographic populations were collected from three different inland water systems, i.e., Shiyang River, Heihe River, and Shule River, in Qilian Mountains, China. Multivariate statistical methods were used to compare morphological differences among the populations, such as principal component analysis, cluster analysis, discriminant analysis, and visual analysis of landmark data. The results showed that: (1) There were significant morphological differences between groups of G. chilianensis. The Shiyang River basin differs significantly from populations in the other two basins. (2) The inter-population differences were mainly reflected in the length of the trunk and tail, and the difference between trunk and caudal fin had the most obvious characteristics, proving the tail being the main direction of variation. This research provides an effective theoretical basis for the fine management and accurate protection of G. chilianensis germplasm resources.
Biological characteristics of Moolgarda cunnesius (Valenciennes, 1836) in Thua Thien Hue, Vietnam
(2024) Thi Hao, Nguyen; Hoang Nhat Minh, Nguyen; Hoi, Truong Cong; Phong, Bui Anh; Ty, Nguyen; Thanh, Pham; Huy, Nguyen Xuan; Giang, Tran Van
Moolgarda cunnesius (Valenciennes, 1836) is a species of the Mugilidae family, commonly known as a delicious fish with high nutritional and economic value, making it very promising. Zoological research methods and DNA barcoding are used to study this fish. Morphological Characteristics: The Leaf mullet has 62 to 75 gill rakers on the lower limb of the first gill arch. The upper jaw is slightly curved downward, and the anterior margin of the anterior alveolar is slightly concave. The body has 37 to 43 scales. The first dorsal fin has 4 spines, while the second dorsal fin is smaller and starts behind the anal fin. Pectoral Fins: These fins are 2/3 of the head length. Anal and Pelvic Fins: These fins are small. The second dorsal and anal fins have few scales, with scales only on the anterior and basal parts. The dorsal surface is green, the flanks and abdomen are iridescent silver, and the fins are slightly dull. There is a difference in the measurement criteria between the study areas, but there is no difference between male and female groups. Mahalanobis distance analysis showed no conformational difference between male and female groups of M. cunnesius and no similarity between sexes. Nutritional biological characteristics: The food composition includes a variety of zooplankton phytoplankton benthic animals, and organic detritus. Organic humus has the highest occurrence, followed by dinoflagellates, blue-green algae, diatoms, and the lowest is arthropods. This diverse food composition illustrates that M. cunnesius is an omnivorous species. Genetic Characteristics: COI gene DNA barcoding was used to study the genetic diversity of M. cunnesius in two regions of the North and the South of Tam Giang lagoon. Amplified and sequenced 10 samples of the COI gene of M. cunnesius in Tam Giang lagoon recorded a size of 650 bp. The rate of difference in COI sequences of the 2 samples is low compared to previous studies. The similarity coefficient of M. cunnesius in the two areas of Tam Giang lagoon is very high (0.9953).
Research progress on the application of Clostridium butyricum in shrimp aquaculture
(2024) Li, Jingyan; Wang, Jieyi; Kong, Dewei; Zhou, Falin; Shi, Jianzhi; Hu, Xiaojuan; Xu, Chuangwen; Jiang, Kui; Hong, Minna; Yang, Keng; Jiang, Song
In recent years, with the continuous expansion of aquaculture and the vigorous development of the aquaculture industry, the breeding environment and diseases have become increasingly prominent, and the quality and output of aquaculture products have been affected to a certain extent, which has become one of the important factors restricting the development of aquaculture industry. Clostridium butyricum is a kind of clostridium bacillus, a gram-positive bacterium, strictly anaerobic, which can form spores and produce short-chain fatty acids, biofuel compounds, and biomaterial precursors such as H~2~, butanol, and 1,3-propanediol in the process of fermenting carbohydrates and sugars. This article reviews the isolation, identification, main biological functions, and mechanism of C. butyricum in the gastrointestinal tract of aquatic animals and summarizes the role of C. butyricum in improving the growth performance, digestibility, survival, immune response, disease resistance, and intestinal structure, as well as regulating the intestinal symbiotic microbiota and metabolic disorders of aquatic animals. To provide insights into the key research directions of C. butyricum in shrimp aquaculture in the future, including research on the relationship between C. butyricum and the host immune system and the possibility of using C. butyricum as an antibiotic substitute for disease prevention and treatment, this study aims to provide a reference for the comprehensive utilization of C. butyricum in shrimp aquaculture and promote the high-quality development of the shrimp aquaculture industry.
Deformities in Litopenaeus vannamei caused by infectious hypodermal and hematopoietic necrosis viral (IHHNV) infection in intensive grow-out ponds of South east coast of India
(2024) Zhao, Caiyuan; Dewangan, Naresh Kumar; Gopalakrishnan, Ayyaru; Sravani, Savva; John, Anisha Shafni; Singh, Ramakrishna Rajkumar; Xu, Wenyan; Guo, Guojun; Xia, Silei; Tiwari, Sonu; Li, Xudong; Qin, Gaixiao; Hou, Jianan
Infectious hypodermal and hematopoietic necrosis virus (IHHNV) is a harmful virus that is responsible for the remarkable economic loss of Litopenaeus vannamei culture. IHHNV was first observed in shrimps, which were characterized by light microscopy, SEM, and TEM. The infected shrimps showed severe morphological deformity, including reduced body size, bent rostrum, shrunken and twisted antenna, rough cuticles, shrunken eyes, and rigid muscles. The antennal segments of the infected shrimps were fused together, puffy, dented, bent, and rough, as observed under a scanning electron microscope. The affected shrimps also showed tumor-like growth (hyperplasia) at the lateral position of the carapace in which the gastrofrontal sulcus was bent. This hyperplasia was found to be soft. In addition, the connective tissue of the diseased shrimp was in a degraded state, and the muscle fibers were despoiled. The nucleus of the cells from the infected gill cells of the shrimps was almost occupied by viral icosahedral particles, which TEM revealed. These viral particles were also found in the cytoplasm in a scattered manner within the same cells and were identified as IHHNV, as confirmed by polymerase chain reaction.
Observation on embryonic development of Gymnodiptychus dybowskii (Kessler, 1874) in Manas River, Xinjiang, China
(2024) Wang, Chengxin; Song, Yong; Li, Jiangling; Hu, Linghui; Serekbol, Gulden; Chen, Shengao
To protect the germplasm resources of Gymnodiptychus dybowskii (Kessler, 1874), a species endemic to Xinjiang, the key stages of embryonic development of G. dybowskii were studied. From May to July 2021, the artificial breeding of G. dybowskii was carried out at the fish breeding station of the Kenswart Water Conservancy Project. The embryos and early larvae were obtained using temperature promotion, water stimulation, hormone induction, and dry insemination techniques. their development process was observed, and morphological characteristics of each developmental stage were recorded. The results showed that the mature oocyte was round, heavy, and light yellow, with an egg diameter of (2.32 ± 0.21) mm. The fertilized egg was slightly viscous, and the viscosity disappeared after water absorption. Under the temperature of 15.6-17.7 ℃ (16.23 ± 0.52) ℃, the embryonic development of G. dybowskii lasted for 142 h and 33 min and went through 7 stages of fertilization, cleavage, blastula, gastrula, neurula embryo, organ formation, and membrane hatching, with a total of 26 periods. The membrane broke after 2376.724 ℃·h. The embryonic development of G. dybowskii follows the rule of freshwater bony fish, but it differs from other Schizothorax species in the muscular effect period and membrane emergence mode. In addition, differences in hatching water temperature among different geographic populations lead to differences in embryo development duration and accumulated temperature, which further proves that G. dybowskii is highly adaptive to the ecological environment of its habitat water, and these characteristics together constitute its survival and reproduction strategy in the natural environment. In this study, through the artificial breeding experiment of G. dybowskii, the characteristics of its embryonic development were explored, which laid the foundation for the cultivation of unique fish seedlings, enriched the early life history data of G. dybowskii, and further provided basic data for its resource protection.
Isolation and identification of Acinetobacter lwoffii from the Chinese Giant Salamander (Andrias davidianus)
(2024) Mao, Pan; Xie, Yixing; Wang, Cheng; Deng, Zhiyong; Yuan, Huayan; Tian, Mingzhu; Wei, Ying; Zhou, Yong
This study aimed to identify the primary pathogenic bacteria responsible for the mortality of the Chinese giant salamander (Andriasd davidianus). A pathogenic bacterium was isolated from a diseased Chinese giant salamander exhibiting typical symptoms under aseptic conditions and then identified by morphological examinations, biochemical analysis, and the sequence analysis of bacterial 16S rRNA. Artificial infection testing was then conducted to determine the pathogenicity of the isolated bacteria strain. Drug susceptibility tests were conducted using the agar diffusion method. The isolated pathogenic bacteria, named DN-2, was successfully identified as Acinetobacter lwoffii. The artificial infection showed that the typical symptoms of the disease could be replicated as the ones originally occurred, and this bacterium exhibited high pathogenicity to the Chinese giant salamander. In the Chinese giant salamander, the median lethal dosage (LD50) of A. lwoffii DN-2 for A. davidianus was determined to be 4.63×104 CFU/g. Drug sensitivity testing showed that these bacteria were highly sensitive to erythromycin, gentamicin, neomycin, streptomycin, midecamycin, ciprofloxacin, piperacillin, florfenicol, doxycycline, carbenicillin, and sulfanilamide. In summary, A. lwoffii was identified as the primary pathogen responsible for the demise of A. davidianus. Our study first presents how these bacteria harm Chinese giant salamanders.
Screening of sex-special genes in common long-arm octopus Octopus minor based on gonadal transcriptome sequencing
(2024) He, Jiabei; Wang, He; Liu, Chao; Chen, Siqing; Zhao, Qiang; Ge, Jianlong; Liu, Yongsheng
The common long-arm octopus (Octopus minor) is a commercially important aquaculture species in East Asia, and the male octopus grows faster than the female ones, while the information about sex-regulating mechanisms in octopuses is limited. Therefore, gonadal transcriptome sequencing was performed in O. minor to reveal the molecular mechanisms of sex regulation in cephalopods. Based on the sexuality and gonad development stage, 4 groups of 12 gonad tissues were sampled, and 11 libraries were retained for bioinformatics analysis. A total of 263,749,727 clean reads were obtained. The percentage of clean reads mapped to the O. minor reference genome ranged from 77.20% to 90.59%. A total of 3936 differentially expressed genes (DEGs) were obtained between ovarian and testicular libraries by Venn diagram analysis, including 855 ovarian up-regulated and 3081 testicular up-regulated genes. Four unigenes (transcription factor Sox-8, fermentation-1, forkhead box protein L2, and ribosomal protein large 24) and one pathway (ECM-receptor interaction) were screened to be candidate molecular markers for sex determination. The reliability and accuracy of our analysis were validated via quantitative real-time PCR in 10 randomly selected DEGs. The results of our study enhanced our understanding of the molecular mechanism underlying sex determination and potentially helped to screen the bio-markers for O. minor in different sexes.
Study on Maximum Power Limitation of Gillnet Fishing Vessels Based on EEXI
(2024) Lyu, Chao; Zhu, Shanshan; Liu, Shuang
To address issues such as insufficient fishing vessel data records, low energy efficiency, and high emissions, this study constructs and validates a predictive model for the maximum power limitation of fishing vessels. Using gillnet fishing vessels as a case study, the Energy Efficiency Existing Ship Index (EEXI) reference line formula for gillnet fishing vessels is fitted using the nonlinear least squares method. Sensitivity analysis reveals power's impact on fishing vessels' energy efficiency. The maximum power calculation method for fishing vessels is derived by combining the EEXI calculation formula, the reference line formula, and the power-speed relationship. Three regression prediction models—Decision Tree, Random Forest, and Gradient Boosting—are used to construct prediction models with gross tonnage, length between perpendiculars, and gross tonnage and length between perpendiculars as inputs, respectively. Results show that power significantly impacts the energy efficiency of fishing vessels. The EEXI reference line formula for gillnet fishing vessels has MAE, MSE, MAPE, RMSE, and R^2 values of 13.3518, 369.5200, 18%, 19.2229, and 0.6366, respectively. The Random Forest regression model with gross tonnage as input performs best in predicting the maximum power limitation of gillnet fishing vessels, with MAE, MSE, MAPE, RMSE, and R^2 values of 5.61423, 6152.40982, 1.90888%, 78.43730, and 0.633062393, respectively. This paper provides a reliable calculation method and prediction model for the maximum power limitation of fishing vessels, offering systematic technical support and decision-making references for limiting the maximum power of fishing vessels.
The Thermal Effects of Coastal Nuclear Power Plant Thermal Discharge on Two Fish Species Based on the Probabilistic Frequency of Temperature Increment
(2024) Li, Lei; Shao, Chenshan; Cai, Jiaying; Tang, Baojun; Su, Weiwei; Zou, Weiyi; Jiang, Mei
This study selected Trachinotus ovatus and Nibea albiflora as the focal subjects to investigate the impacts of probabilistic frequency of temperature increment through laboratory simulations that mimicked the seasonal water elevated temperature adjacent to two coastal nuclear power plants. This research was underpinned by the probabilistic analysis of temperature increase frequencies, aiming to evaluate the thermal tolerance of these species across different seasonal contexts. Results demonstrated that the T. ovatus did not exhibit mortality in the spring, autumn, and winter. Mortality in T. ovatus occurred only during the summer in temperature-duration probability experimental groups subjected to 8.5ºC above ambient temperature with exposure probabilities of 50%, 75%, and 100%. The average survival rates were (93.3±3.3) %, (93.3±5.1) %, and (86.7±2.9) % respectively. The N. albiflora experienced mortality in spring, summer, autumn, and winter, with the highest mortality rate in summer. Compared to N. albiflora, T. ovatus exhibited significantly higher thermal tolerance across all seasons. As the experimental temperature increased and the duration probability rose, the mortality rates of both fish species showed an upward trend. There was an interaction between elevated temperature and duration probability, with the duration of different elevated temperature amplitudes significantly impacting the fish's survival rates.
On the impact of government employment services on the quality of re-employment of unemployed fishermen in Yangtze River --A case study in Xiantao City of Hubei Province, China
(2024) Chen, Linsheng; Hu, Yawen; Zhang, Siyuan; Xu, Shiwei; Ren, Yilei; Li, Fei; Wu, Dan; Liu, Zifei
In the transition period of the Yangtze River fishing ban policy, the retrenched fishermen are in an inferior position in the employment market due to the lack of their own employment capital, and it has become a problem to switch to employment. Based on the study of employment quality and employment capital theory, this paper uses the PLS-SEM model to process the questionnaire data on the effect of government employment services on the quality of fishermen's re-employment based on the establishment of government employment services-quality analysis system and questionnaire design and collection. The total effect of government employment services on re-employment quality was 0.685. The indirect effect of government employment services on the quality of re-employment through the mediating variable of employment conditions was smaller than the direct effect of government employment services on the quality of employment. This research may provide a basis for solving the problems of high-quality re-employment for unemployed fishermen and sustainable livelihoods for fishermen.
Swordtail (Xiphophorous helleri) growth promoting activity and antibacterial property of pineapple (Ananas comosus) peel oil
(2024) Loganathan, Thanushanthahi; Gayani Yasodara, Liyanage; Manage, Pathmalal; Idroos, Fathima Sumaiya
The use of phytogenics that are low-cost and highly available has the potential to address some environmental, social, and economic issues in fish culture. The present study was conducted to evaluate the effects of the dietary application of pineapple (Ananas comosus) peel oil (PPO) on the growth performance of Swordtail (Xiphophorous helleri) and the antibacterial effect against pathogenic bacteria. PPO was incorporated in the diet of Swordtail (initial average weight ± SD of 0.12±0.07g and average length± SD of1.15±0.25 cm) to analyze the effect on growth performance. Two triplicate groups (each tank stocked with 15 fish) were fed with control and experimental diet for 10 weeks. The results showed significantly enhanced growth performance of fish fed with an experimental diet. The average weight gain (282.0±35.0%), relative growth rate (2.82±0.35), specific growth rate (1.92±0.12 %day-1), and condition factor (0.42±0.02%) were all higher, and feed conversion ratio (0.0219 ±0.040) is lower in fish fed the experimental diet. The carbohydrate content (60.05±0.050 %) in the control feed was higher (p≤0.05), whereas moisture (11.35±0.11 %) and ash (13.77±0.03%) contents were higher (p≤0.05) in experimental feed. The disc-diffusion method was used to test the antibacterial activity of the crude PPO against A. hydrophila and Pseudomonas spp. The inhibition zones were 2.37±0.13 51 cm and 2.06±0.08 cm, respectively. Conclusively, the present study recommends using PPO, which has a potential antibacterial effect against bacterial pathogens, as a potential feed additive to improve the growth performance of swordtail.
Toxic effects of multi-walled carbon nanotubes and ZnO nanoparticle exposure on pathology and apoptosis on the liver of Cyprinus carpio
(2024) Wang, Yashuai; Niu, Xuehan; Huang, Yong; Ren, Hongtao; Chen, Jiayong; Xu, Ruiyi; Gao, Xiaochan
ZnO nanoparticles (ZnONPs) and carbon nanotubes (CNTs) are frequently used nanoparticles with unique features. Aquatic organisms are exposed to a combination of contaminants in natural water systems, so the combination effect of two or more nanomaterials has caused much concern. In this study, the toxicity to the liver of common carp was explored under four weeks of exposure to single ZnONPs or in combination with multi-walled CNTs (MWCNTs). The results demonstrated that ZnONPs induced pathological changes and apoptosis in the liver. In combination, decreased pathological changes were observed in the LSC-ZnONPs group (50 mg L-1 ZnONPs and 0.25 mg L-1 MWCNTs) at the microscopic level and ultrastructural level, and increased pathological changes in the HSC-ZnONPs group (50 mg L-1 ZnONPs and 2.5 mg L-1 MWCNTs). A 52% reduction in the percentage of TUNEL-positive nuclei in the LSC-ZnONPs group and a 33% increase in the HSC-ZnONPs group were observed compared to the ZnONPs group. The mRNA expression of apoptosis-related genes, including caspase3, BAX, and XBP1, were significantly up-regulated in the exposure groups, confirming the occurrence of apoptosis. Significantly decreased caspase 3 and BAX mRNA levels in the co-exposure groups were detected compared to the ZnONPs group. Nevertheless, the XBP1 mRNA level was significantly upregulated in the LSC-ZnONPs group, but downregulated in the HSC-ZnONPs group, indicating multiple signal pathways involved in the apoptosis. In conclusion, a low concentration of MWCNTs (0.25 mg L-1) decreased the toxic effect of ZnONPs on common carp, but a high concentration of MWCNTs (2.5 mg L-1) enhanced it. This study will contribute to developing future risk assessment and management strategies for nanomaterials.
Development Dilemma of Litopenaeus vannamei Industry in China, Current Countermeasures Taken and Its Implications for the World Shrimp Aquaculture Industry
(2024) Tian, Jiteng; Wu, Wei; Li, Jiawei; Wan, Xiaoyuao; Zhao, Zhuming; Xi, Rui; Hu, Xili; Pan, Mingchao; Xue, Yueguang; Yu, Wensong
This study focuses on the Litopenaeus vannamei shrimp, exploring its development, dilemmas, and challenges in China's industry alongside countermeasures implemented by Chinese authorities and agencies. Since its introduction to China in 1988, L. vannamei, known for its high economic value and adaptability, has become China's leading mariculture shrimp species and one of the most significant globally. The thriving L. vannamei industry has boosted economic gains and job creation in China's marine fisheries, supplied high-quality protein to consumers, and fostered socio-economic growth. Additionally, China's experiences and lessons in the L. vannamei industry serve as valuable references for other shrimp-farming nations, promoting global industry health. Despite its success, the industry faces challenges, including germplasm resource scarcity, feed ingredient shortages, disease management, and wastewater treatment. To address these issues, China has initiated various strategies, including germplasm resource conservation, the development of low-fishmeal protein feeds, disease monitoring, and wastewater management, aiming for the industry's green and sustainable evolution. This paper asserts that China's initiatives in advancing the L. vannamei industry offer significant inspiration globally, particularly in two main areas: Firstly, through effective policy support, China has fostered research and development of new shrimp varieties suited to its aquaculture conditions, enhancing germplasm quality and breeding efficiency. Secondly, China has actively disseminated its innovations, outcomes, and experiences globally, hosting various aquaculture training sessions and seminars. These initiatives offer technical support and platforms for international dialogue, fostering cooperation and exchange among shrimp farming nations. Moreover, China's dedication to advancing artificial culture technology for L. vannamei---through collaborative and continuous research across breeding, nutrition, disease management, and sustainability---has led to significant industry advancements. These contributions not only extend the industry chain but also position China as a leader and model for global shrimp aquaculture innovation. Through this study, we aim to offer insights and practical advice by analyzing the challenges and responses within China's L. vannamei industry. We hope these findings will serve as valuable references for enhancing the global shrimp aquaculture industry and aid other nations in their aquaculture endeavors.
Effects of different temperatures on growth and gonad development related indexes of the ridgetail white shrimp, Exopalaemon carinicauda
(2024) Zhao, Zhenhui; Pang, Zhiyu; Deng, Deng; Li, Jianhong; Wang, Ning; Gao, Huan; Yan, Binlun; Deng, Kangyu
To explore the optimal growth and reproduction temperature of Exopalaemon carinicauda, this study tested five temperature gradients (16℃, 20℃, 24℃, 28℃, 32℃) to determine the effects of different temperatures on the growth, digestive enzyme activity, ovarian development performance, ovarian nutrient concentration, vitellogenin, and sex hormone levels of E. carinicauda. The results showed that (1) Between 20℃ and 32℃, the survival rate gradually decreased with the increase of temperature. As the temperature increases, the final body weight and specific growth rate first increase and then decrease (P\<0.05), with the fastest growth at 28℃; (2) The lipase activity first increases and then decreases with the increase of temperature (P\<0.05), reaching a maximum value of 1.22 ± 0.09 U/gprot at 28℃. The trypsin activity increased with the increase of temperature and reached a maximum value of 1695.45 ± 163.42 U/gprot at 32℃; (3) the gonadosomatic index and ovarian maturation rate increased with increasing temperature; the concentrations of total protein, total cholesterol, and triglycerides generally increased with temperature; the vitellogenin showed a trend of first increasing, then decreasing, and then increasing with the increase of temperature (P\<0.05); and (4) at temperatures of 24℃ and 28℃, the concentrations of gonadotropin-releasing hormone were relatively high and close. The highest estradiol concentration was 26.62 ± 1.49 ng/L at temperatures of 28℃. These findings indicate that 28℃ is a suitable temperature for promoting the maturation of the parent shrimp of E. carinicauda and may be recommended for a commercialized culture of this species.
Isolation, identification, and evaluation of the characteristics of Streptomyces sp. as the probiotic strains applied in aquaculture
(2024) Pham Thi, Tam; Nguyen Thi Thu, Hien; Vu Thi Bich, Huyen; Le Thi Tuyet, Mai; Le Minh, Hai; Ta Thi, Binh; Dao Thi Hong, Van; Vo Hong, Phuong; Vu Kim, Thoa; Dinh Thi Thu, Le; Man Hong, Phuoc
The present study was conducted to select Streptomyces strains that exhibited characteristics of probiotics for application in aquaculture. Streptomyces were isolated from soil and sediment samples collected from various habitats such as riverside, shrimp ponds, pangasius ponds, mangrove forests, or estuaries along the coast of Vietnam. Two strains of Streptomyces (AG12.2 and ND10.1) were selected due to (1) their potent antimicrobial activity against common pathogens that cause serious diseases in shrimp and pangasius such as E. ictaluri, A. hydophila, V. harveyi, V. parahaemolyticus, and (2) their superior ability to produce several extracellular enzymes that strongly hydrolyze organic compounds such as starch, CMC, and skimmed milk, compared to other strains. AG12.2 and ND10.1 can tolerate salinity from 0 ppt to 5 ppt and pH from 3 to 8; however, their growth is most vigorous at salt concentrations and pH between 0 ppt to 2 ppt, and 7.2 to 8, respectively. In vivo evaluation on L. vannamei in this study shows that shrimp that were fed with diets containing AG12.2 and ND10.1 had WG (%) increasing by 1.59 times and 1.61 times respectively, DGW (g/day) increasing by 1.64 times, and FCR decreasing by 1.30 times and 1.35 times respectively. The shrimp treated with AG12.2 and ND10.1 were then challenged with V. parahaemolyticus, resulting in a survival rate increase of 3.9 times and 3.71 times, respectively. Phylogenetic analysis revealed that strains AG12.2 and ND10.1 belong to Streptomyces kunmingensis and Streptomyces angustmyceticus, respectively. The findings of the present study led to the conclusion that Streptomyces kunmingensis AG12.2 and Streptomyces angustmyceticus ND10.1 are excellent candidates for producing beneficial probiotics for aquaculture.
The effects of exogenous additives on the vitality of Chinese pearl oyster (Pinctada fucata) sperm under different conditions
(2024) Li, Minghao; Fu, Zhengyi; Yang, Rui; Yu, Gang; Zhou, Wenli; Ma, Zhenhua
During the artificial breeding process of Chinese pearl oysters, the quality and vitality of sperm and eggs are pivotal in determining the success rate of fertilization. This study delves into the impact of externally added fructose, glucose, and ammoniated water on sperm vitality and lifespan under varying temperature conditions. The results indicate that the addition of exogenous energy sources and cell protectants, specifically monosaccharide energy substances, significantly improves sperm vitality. Moreover, under 4°C conditions, adding 2.8 mmol/L fructose, glucose, and 2 mmol/L ammoniated water to sperm samples significantly enhances sperm vitality and prolongs their lifespan. This provides strong evidence for the feasibility of short-term preservation and vitality enhancement strategies for Chinese pearl oyster sperm and also offers important scientific support for optimizing the artificial reproduction techniques of Chinese pearl oysters.
Exploring Multiple Paths to Improve Fishery Financial Performance from a Configuration Perspective: A Study Based on the fsQCA Method
(2024) Zhang, Siyuan; Xu, Shiwei; Huang, Xuping; Wang, Yiqi
Improving the financial performance of fishery enterprises is an inevitable choice to promote the development of fishery economy. In this paper, 102 observation samples are selected, and the necessary and sufficient conditions for high financial performance of fishery listed companies are analyzed by using collocation perspective and qualitative comparative analysis (QCA). Research has found that the formation of high financial performance is a complex causal relationship with multiple concurrent factors, which is the result of the combined effect of multiple conditions, and the effect of each condition is not equal; Moreover, there is no unique optimal model, and 6 different conditional configurations (paths or models) can achieve the same results. The conclusion of this study is helpful to enriching the research on the factors affecting the financial performance of fishery enterprises from the perspective of system integration, and is of great theoretical and practical significance to reveal the factor combination mode produced by the research tendency of fishery enterprise 'performance.
Evaluation of the efficacy of implementing Ecosystem-Based Management (EBM) strategies within fisheries across the middle and lower Yangtze River basin lakes in China
(2024) Liu, Chen; Chai, Yuan; Guo, Weichen; Gao, Jian
To mitigate the decline of fishery resources and the exacerbation of water pollution in Chinese lakes and to enhance the potential and sustainable use of lake fisheries, the Chinese government has actively implemented principles and models of ecosystem-based lake fishery management. This includes promoting ecological aquaculture techniques and the "retiring pens to restore lakes" policy. To assess the effects of ecosystem-based management on Chinese lake fisheries, data from 2007 to 2020 were collected for the Qiandao Lake, Tai Lake, Hongze Lake, Luoma Lake, and Gaobao Lake in the middle and lower reaches of the Yangtze River. The study employed Data Envelopment Analysis (DEA) to assess fishing efficiency through a static input-output efficiency model. Additionally, the Malmquist index and distance functions were used for a dynamic comparison of total factor productivity (TFP) across the five lake management models. The results indicate that trends in technological progress, scale efficiency, and TFP were consistent across the lakes from 2013 to 2020. Qiandao Lake, Tai Lake, and Hongze Lake showed a positive average annual growth rate in TFP, with Qiandao Lake having the highest average annual growth rate of 13.2%. In contrast, Gaobao and Luoma Lakes experienced a negative growth rate in TFP. Furthermore, Qiandao Lake exhibited significantly higher technical efficiency than the other four lakes, effectively achieving an efficient state, followed by Hongze Lake. The study demonstrates that technological progress and variations in scale efficiency are the primary factors driving the increase in TFP in fisheries. Promoting ecosystem-based "fishing for water conservation" aquaculture techniques and restricting aquaculture scale through the "retiring pens to restore lakes" policy contribute to enhancing TFP in ecological fisheries.
Effects of emodin on the physiological responses and antioxidant gene expression of Wuchang bream infected with Aeromonas hydrophila
(2024) Zhang, Yuanyuan; Lu, Hong; Ke, Han; Cheng, Hui-zhong; Zhu, Yong-an; Song, Li-ping; Tian, Hong-yan; Huang, Wen-wen
This experiment aimed to investigate the effects of emodin on the physiological responses and antioxidant gene expression of Wuchang bream infected with Aeromonas hydrophila. The experimental diets were prepared with supplementing 0, 30, 100 and 150 mg kg−1 emodin to basal (control) diet respectively, and fed to fish with initial weight of 50.4 ± 2.35 g. All ﬁsh were divided into five experimental groups: uninfected fish fed with basal control diet (negative control, NC), infected fish fed with the diet supplemented with 0 (positive control group, PC), 30, 100, and 150 mg kg-1 emodin. The fish were reared for 14 days, sampled at different time points and then analyzed. The results showed that the physiological responses and related antioxidant gene expression of infected Wuchang bream were significantly influenced by the dosage of added emodin and the feeding duration (P < 0.05). Comparing to the positive control group, emodin could inhibit the levels of cortisol (COR), triiodothyronine (T3), and thyroxine (T4) in infected Wuchang bream, with hormone levels reaching equilibrium in the shortest time at 30 and 100 mg kg-1 emodin supplementation. Meanwhile, emodin significantly affected alkaline phosphatase (AKP) activity, glucose (Glu) and triglyceride (TG) contents, and related antioxidant gene expression in infected Wuchang bream (P < 0.05), with the best effect observed at 100 mg kg-1 emodin supplementation in the diet. In conclusion, the supplementation of 100 mg/kg emodin to diet can enhance the resistance of Wuchang bream to A. hydrophila infection via promoting physiological metabolism and antioxidant capacity.
Characteristics of surface flow field and substrate in the spawning ground of Schizothorax grahami
(2024) Xu, Li; Zhou, Yang; Cui, Weijie; Lu, Qun; Liu, Jianhu; Duan, Cong; He, Tao
The Spawning ground is a crucial habitat for fish, and the physical characteristics of the habitat are important for fish life history. In this paper, Large-Scale Particle Image Velocimetry (LSPIV) was used to measure the surface flow field and the substrate (particle size and mineral composition) in the spawning ground of Schizothorax grahami. Based on the literature and consideration of experimental feasibility, two spawning grounds in the source of the Chishui River were selected—Erlongqiangbao (located in the mainstream) and Bamaoba (located in the tributary), two and three cross sections of each river section were analyzed respectively. The results show that Erlongqiangbao first flows in the direction of "southeast-northwest" and then "southwest—northeast" after crossing the bridge; the maximum velocity of the reach is 3.374m/s. The size of the substrate is mainly less than 1mm in the upstream section of Erlongqiangbao, both 25-50mm in the middle and downstream, and the substrate type mainly is quartz and calcite; Gushangtian flows in the direction of "southwest-northeast," the maximum velocity of the reach is 1.537m/s, the size of the substrate is mainly greater than 50mm in the upstream, and 25-50mm in the middle and downstream, the substrate type mainly is quartz, calcite, and dolomite. The mineral compositions of the two spawning sites were analyzed by principal component analysis. Quartz and anorthose are more than 1 in composite scores, respectively ranked first and second, indicating that they play a dominant role in the mineral composition. This study could provide basic data and ideas for restoring S. grahami spawning ground.

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