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Cercariae from snails in rice fields and canal supplying water directly to <em>Trichopodus microlepis</em> fish cultured in earthen ponds in Binh Chanh district, Ho Chi Minh City, Vietnam.
Get PDFSnails are the first intermediate host in the life cycle of trematodes. Previous research found that Trichopodus microlepis fish, cultured in earthen ponds in Tan Nhut Commune, Binh Chanh District, Ho Chi Minh City, Vietnam had a high infection rate with metacercariae of Centrocestus formosanus and Procevorum sp. It is necessary to investigate whether habitats supplying water to the ponds may contribute to the transmission by carrying intermediate hosts and/or cercariae into these ponds or not. A study of cercariae and snail composition in rice fields and canal supplying water directly to these Trichopodus microlepis ponds was carried out with six samplings in the years 2022 and 2023. A total of 1,151 snails were collected, and nine snail species belonging to 8 genera and 6 families were identified. Three snail species in both rice fields and canal were infected with trematode (cercariae stage) including Bithynia siamensis, Lymnaea viridis and Indoplanorbis exustus. The overall prevalence in the dry season (25.9%) was significantly higher than in the wet season (10.6%) (PLymnaea viridis and Indoplanorbis exustus), and pleurolophocercous in Bithynia siamensis. This finding shows that Bithynia siamensis is one of the infected sources for Trichopodus microlepis fish cultured in ponds, as pleurolophocercous is also the cercariae in the family of Heterophyidae (including Centrocestus formosanus and Procevorum sp.). Further research should be done to clarify the transmission of fish-borne zoonotic diseases to cultured Trichopodus microlepis in other habitats including the actual fishponds, and sources of trematodes in order to produce Trichopodus microlepis free of metacercariae, contributing to clean aquaculture development and safe food for local people in the area
Evaluation of genetic parameters of growth traits in G2 selected generation of <em>Penaeus monodon</em>
Get PDFFifteen whole sib families of the second-generation Penaeus monodon were constructed using artificial mating design in 2020. After labeling the families with fluorescent markers, the growth traits and genetic parameters were evaluated in a cement pond for 56 days. The results showed that the coefficient of variation of growth traits was 11.52-47.53%, indicating a high genetic variation. The heritability range of growth traits of the G2 population of P. monodon was 0.25±0.03-0.41±0.13, which belonged to medium and high heritability, and the statistical test results were significant (PPP. monodon has high genetic improvement potential, and the combination of family selection and individual selection achieved better genetic gain. The growth traits were highly positively correlated. Body length and body weight could be selected as the key traits for fast growth line selection, while the other growth traits could be indirectly selected through positive genetic correlation
Copper toxicity in juvenile largemouth bass (<em>Micropterus salmoides</em>): acute toxicity bioassay and oxidative stress response in gut and kidney
Get PDFAquaculture intensification has resulted in serious disease outbreaks in largemouth bass production. Compounds containing copper (Cu) are widely used as therapeutic agents in aquaculture. Currently, Cu misuse has been a severe issue in largemouth bass farming. However, few investigations have been performed on Cu toxicity in largemouth bass so far. In this study, an acute and a chronic toxicity test was carried out to determine the toxicity and the recommended dose of waterborne Cu in largemouth bass. In the acute toxicity bioassay, fish (2.58 ± 0.03 g) were exposed to 0 (control), 3, 6, 9, 18, or 30 mg/L Cu, and the results showed that the 96-h LC~50~ of waterborne Cu was 12.78 mg/L. Then a 30-day chronic toxicity test containing six treatments (i.e., 0, 51.3, 164, 513, 1640, and 5130 μg/L Cu) was conducted to investigate the influence of Cu on intestinal and renal health in terms of oxidative stress in juvenile largemouth bass (2.69 ± 0.02 g). The results showed that Cu concentrations at and above 51.3 μg/L significantly increased the malondialdehyde contents (in the intestine) and simultaneously decreased total superoxide dismutase activity levels (in the intestine and kidney), glutathione peroxidase activity levels (in the kidney), and reduced glutathione contents (in the kidney), compared to control. In contrast to control, fish exposed to high Cu concentrations (at and above 1640 μg/L) demonstrated lower catalase activity levels in the intestine and kidney. Based on the findings in the study, waterborne Cu content for largemouth bass farming was recommended to be less than 51.3 μg/L
The Phonological History of Tai Nüa: Implications from the Sino-Baiyi Manual of Translation
Get PDFAlthough the phonological history of Tai Nüa can be roughly demonstrated through comparison of its modern dialects against their reconstructed ancestor, namely, Proto-Southwestern Tai, neither the chronology nor the pathway of the transformative sound changes can be established in detail with any certainty. This study demonstrates a more fine-grained understanding of both the chronology and pathway of the sound changes through the examination of the recently available Sino-Baiyi Manual of Translation, a Chinese-Tai Nüa section of bilingual glossary books produced for diplomatic use during the Ming Dynasty. By comparing the phonological inventory of Tai Nüa as attested in this manuscript against the pre-established list of all characterizing sound changes from Proto-Southwestern Tai to Modern Tai Nüa dialects, we chronologize all the sound changes into the pre-16th versus post-16th century changes. Employing the pre- & post-16th century changes as the demarcating criteria, we tentatively propose a tripartite chronological division of Tai Nüa into 1) Old Tai Nüa, 2) Early Modern Tai Nüa, and 3) Modern Tai Nüa dialects
Length-weight relationships and biometry analysis of saddled seabream, <em>Oblada melanurus</em> (Linnaeus, 1758) in İzmir Bay (Central Aegean Sea of Türkiye)
Get PDFThe present study presents length-weight, length-length, length-girth relationships, and biometry of male and female specimens of saddled seabream, Oblada melanurus(Linnaeus, 1758), in the Turkish Aegean Sea. The length-length and length-weight relationships were calculated by measuring 516 individuals. The total length values of all male and female O. melanurus specimens were in the range of 17.2-30.7 and 18.5-30.0 cm, respectively, and the mean values were 21.84±2.04 and 22.44±2.12 cm, respectively. The length-weight relationships were W=0.0110TL3.057 for males, W=0.0114TL3.043 for females, and W=0.0089TL3.122 for all the specimens. The results denoted a high correlation (r²=0.966; p<0.001) in the length-length relationships. Furthermore, 287 individuals (105 females and 182 males) were examined for length-girth relationships and biometric analyses. Ten morphometric characters were analyzed to analyze biometry. In conclusion, no statistically significant differences were determined in morphology between the sexes (p<0.05)
Legislative files: Other legislation: "Laws that Treat Hawaii Differently": Appendix: Joint travel regulations (3 of 3)
Get PDFLegislative files: Other legislation: "Laws that Treat Hawaii Differently": Federal responses to survey: General: Department of State
Get PDFEconomic Benefits and Improvement Strategies for Clam Marine Aquaculture in China: A Comparative Analysis of Zhejiang, Tianjin, and Shandong
Get PDFIn recent years, clam mariculture output in China has steadily increased. However, environmental pollution and high aquaculture intensity have led to frequent diseases and unstable economic benefits. This study analyzes field research data from clam farming in Zhejiang Province, Tianjin City, and Shandong Province, focusing on farming costs, revenue, break-even points, and net profit sensitivity. The findings reveal that (1) variable costs consistently exceeded fixed costs, particularly in seedling costs, labor, and water rental; (2) net profit and margins ranked highest in Zhejiang, followed by Tianjin and Shandong; (3) Zhejiang exhibited the lowest break-even operation rate and the largest price discrepancies; (4) sensitivity to selling prices was high across all regions, with Zhejiang showing the lowest sensitivity to variable costs. To enhance economic benefits and promote sustainable development, government authorities and industry stakeholders should focus on cultivating high-quality seeds, implementing scientific management, developing green aquaculture, and emphasizing brand development