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Analysis of morphological differences in five large yellow croaker (<em>Larimichthys crocea</em>) populations
Get PDFTo explore the morphological and phenotypic characteristics and differences among different populations of Larimichthys crocea, traditional morphological measurements were carried out on three wild populations from Zhoushan, Xiamen and Zhanjiang and two farmed populations from Ningde and Wenzhou. Seven morphological parameters of five L. crocea populations were compared and analyzed. The results of one-way ANOVA showed significant differences in trunk and caudal stalk among the five populations. The contribution rates of the first five principal components to the total difference among different populations were 29.984%, 18.462%, 17.234%, 12.167%, and 9.904%, respectively, and the cumulative contribution rates were 87.751%. Trunk can be used to distinguish different geographic populations best. The cluster analysis results showed that the distance between wild populations was the closest, while the distance between farmed populations was far. The step discriminant method established the classification discriminant function of 5 populations. The discriminant accuracy P1 was 78.3%-92.7%, the discriminant accuracy P2 was 76.4%-96.5%, and the comprehensive recognition rate was 99.3%. The discriminant accuracy of this method was high, and it could provide a reference for the differentiation of different populations of L. crocea. This study provided basic morphological data for identifying a large yellow croaker population, protecting germplasm resources, and breeding improved varieties
Effects of estradiol on fatty acid composition and tissue structure of hepatopancreas in <em>Procambarus clarkii</em>
Get PDFThe hepatopancreas of Procambarus clarkii provides lipids and other nutrients for ovarian development and contains hormones such as estradiol related to ovarian development. During the development of the P. clarkii ovary, the hepatopancreas' tissue structure and fatty acid content undergo corresponding changes. A controlled indoor experiment was conducted to investigate the effects of exogenous estradiol injection on the tissue structure and fatty acid content in the hepatopancreas of P. clarkii. The experiment consists of three experimental groups and one control group. The P. clarkii in the experimental group were injected with 5, 0.5, and 0.05 μg/(g body weight) of estradiol once every 5 days for 5 times and with normal saline injection as the control. After 25 days, the content of fatty acids and changes in tissue structure in the hepatopancreas were measured. The results showed that the main fatty acids in P. clarkii hepatopancreas were C18:4n, C20:3n, and EPA, and polyunsaturated fatty acid (PUFA) content was 57.17%±4.76%. Injecting estradiol mainly affected the content of C16:0, C16:1n, C18:0, C18:1n9, C18:2n, C18:3n6, C18:3n6, C18:4n, C20:1n, C20:2n, C20:3n, C20:4n3, C20:5n3, C22:n (n=1-4), C22:5n, and C22:6n in the hepatopancreas. Injecting estradiol significantly reduced the total content of PUFA in hepatopancreas with the reduction of C18:3n6, C18:4n, C20:3n, C20:4n3, C20:5n3 C22: n (n=1-4) (P<0.05); Estradiol injection significantly increased the total content of monounsaturated fatty acid (MUFA) in hepatopancreas with the increase of C18:1n9, and C20:1n (P<0.05); Injection of estradiol (0.05 μg/g) significantly increased the total content of saturated fatty acids (SFA) in the hepatopancreas (P<0.05) with the increase of C16:0 and C18:0 (P<0.05). Injecting estradiol can increase the volume and quantity of hepatopancreatic B cells, and the 5 μg/g group had the most obvious changes
The Thermal Effects of Coastal Nuclear Power Plant Thermal Discharge on Two Fish Species Based on the Probabilistic Frequency of Temperature Increment
Get PDFThis 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
Isolation, identification, and evaluation of the characteristics of <em>Streptomyces</em> sp. as the probiotic strains applied in aquaculture
Get PDFThe 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
Evaluation of the efficacy of implementing Ecosystem-Based Management (EBM) strategies within fisheries across the middle and lower Yangtze River basin lakes in China
Get PDFTo 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
Gross Domestic Product 2005-2022
Get PDFThis statistical bulletin (1/2024) presents gross domestic product (GDP) estimates from 2005-2022 following from the previous bulletin with new estimates for 2021 and 2022. The Solomon Islands National Statistics Office (SINSO) have decided not to make revisions to past estimates at this time. The SINSO is also planning the implementation of the 2024/2025 Household Income and Expenditure Survey (HIES) and a National Enterprise Census in the third quarter of 2024. These exercises will establish new benchmarks for GDP and require substantial revisions to the time series. SINSO have decided to put through revisions to 2020 and past years arising from methodological improvements and the population census at this time. Any methodological changes made for the current measures have been chained on to the 2020 levels to avoid distorting growth rates. Revisions tables are therefore omitted
Legislative files: Other legislation: "Laws that Treat Hawaii Differently": Military and defense: Department of Defense (1 of 2)
Get PDFGenetic Diversity and Structure of the Darkfin hind (<em>Cephalopholis urodeta</em>) in the Spratly Islands, Vietnam
No full textThe darkfin hind, Cephalopholis urodeta, is a commercially valuable reef fish species inhabiting the ecologically important Spratly Islands. Understanding this species' genetic diversity and population structure is crucial for developing effective conservation strategies, particularly given the increasing pressures on coral reef ecosystems. This study investigated the genetic diversity and population structure of C. urodeta within the Spratly archipelago using mitochondrial COI and Cyt b gene markers. We analyzed 30 individuals for COI and Cyt b, revealing high levels of haplotype diversity (Hd=0.9563±0.0226 for COI; Hd=0.9402±0.0229 for Cyt b). However, despite this high overall diversity, our analyses also revealed significant genetic structuring within the archipelago, suggesting restricted gene flow among some populations. This structuring is likely influenced by the complex oceanographic currents in the region and the spatial distance between reefs, which can limit larval dispersal. These findings highlight the need for spatially explicit conservation and management strategies for C. urodeta in the Spratly Islands. Recognizing the genetic differentiation within the archipelago and implementing management measures tailored to specific zones will be crucial for preserving genetic diversity, maintaining connectivity, and ensuring the long-term sustainability of this important resource
Intensive white shrimp (<em>Litopenaeus vannamei</em>) culture integrated with green mussel (<em>Perna viridis</em>), seaweed (<em>Gracilariopsis bailiniae</em>), and tilapia (<em>Oreochromis mossambicus</em>): impacts on water quality and growth of the shrimp
No full textThe production of Litopenaeus vannamei has significantly intensified, and integrated multi-trophic aquaculture (IMTA) has emerged as an effective farming technique to sustain the shrimp industry. Integrated aquaculture reduces pollution while increasing aquaculture production. This production system could give both ecological and economic benefits. Its contribution to the reduced amount of nutrients from intensive shrimp farming effluents and to the improvement of water quality conditions and growth of white shrimp are significant. This study aimed to evaluate the impacts on water quality and growth performance of shrimp (L. vannamei) at the same time assess the viability of rearing shrimps integrated with either green mussel, Perna viridis (GM alone), GM+seaweed (Gracilariopsis bailiniae), GM+tilapia (Oreochromis mossambicus), or GM+seaweed+tilapia. Shrimps were cultured outdoors for 60 days in a recirculating system at an average water exchange rate of 6 L hr-1. Shrimps were stocked at 400 shrimp m-3 in shrimp tank while seaweed (2kg m-2), green mussels (50 individuals per meter line), and tilapia (350 grams m-3) were cultivated separately in plastic baskets inside the biofiltration tank. Shrimp effluents were recirculated from the shrimp tank to the biofiltration tank. After 60 days of culture, results showed that shrimps without integration had the lowest average body weight (ABW), survival, weight gain, specific growth rate (SGR), biomass gain, and high feed conversion ratio (FCR) compared to shrimps with integration. This experiment confirmed that shrimp can be cultured intensively with either green mussel (GM alone), GM+ seaweed, GM+tilapia, or GM+seaweed+tilapia without adversely affecting the water quality and its growth performance and could even result in better yield than the shrimp cultured without integration. This research demonstrated the benefits of integrated aquaculture and could be further verified using large-scale culture