Abstract Habitat complexity can enhance the resilience of wetlands against environmental stressors such as extreme weather events, pollution, and habitat loss. The introduction of artificial induced complexity (AIC) can play a significant role in reshaping the macroinvertebrate communities within wetland ecosystems by enhancing habitat quality in protected areas. Therefore, this study was designed to examine the variation of macroinvertebrates community structure in artificially induced complex sanctuary site (SS), partially protected (PP) and open sites (OS) from July 2019-April 2020. AIC in the sanctuary sites was established through the installation of cemented hexapods and ring pipes. Over the study period, a total of 665 macroinvertebrates were gathered, with 55.55% originating from SS, 31.14% from PP, and 18.21% from OS sites. The community consists mainly of Lymnaea acuminatatea and Tubifex tubifex, with the most abundant species being Limnodrillus hoffmeisteri and Branchiura sowerbyi . A notable positive impact of AIC was evident in the increased total abundance and diversity indices of macroinvertebrate communities. The Analysis of Similarity (ANOSIM) revealed significant distinctions in community structures among various intervention types, which was further corroborated by a non-metric multidimensional scaling (nMDS) plot. Similarity of Percentage Analysis (SIMPER) highlighted that Limnodrillus hoffmeisteri made the most significant contribution to the dissimilarity observed among the different intervention types. Canonical Correspondence Analysis (CCA) revealed a close association between the structure of the macroinvertebrate community and three key ecological factors: periphyton biomass, macrophyte cover, and sediment properties. These findings could offer a more effective approach for managers and policymakers engaged in the conservation of macroinvertebrates and the sustainable management of fisheries resources within wetland ecosystems.
Increased temperature, decreased water level and reduced culture period of the ponds with lack of guidelines in selecting appropriate stocking size, density and combination of species are major constraints for safe production of fattening based carps in drought prone barind area of Bangladesh. In order to address these problems, an experiment was conducted during July-December, 2018 to determine the suitable species combination for fattening ponds of overwintered carps in Tanore upazila (sub district) of Rajshahi district, Bangladesh. Three different combinations of surface (G. catla and H. molitrix), column (L. rohita) and bottom (C. cirrhosus and C. carpio var. specularis) feeding carp species were tested under 3 treatments (T1, T2 and T3), each with 3 replications: T1 (Surface-30%, column-40%, and bottom-30%), T2 (Surface-40%, column-30%, and bottom-30%) and T3 (Surface-35%, column-35%, and bottom-30%). Application of good aquaculture practices in the studied ponds was found to improve the environmental conditions of pond. Significantly (P< 0.05) highest fish yield was obtained from treatment T2 which was 21.47% and 11.89% higher than T1 and T3, respectively. Significantly (P<0.05) highest cost benefit ratio was recorded with treatment T2 (0.42±0.02) followed by T3 (0.31±0.01) and T1 (0.21±0.01), respectively. Inclusion of appropriate number of fishes at different water layers of pond favoured the yield and economics of carp fattening. The study also suggests focusing on optimal stocking density together with the formulation of low cost feed for carp fattening in ponds under barind area of Bangladesh.
In this research an Integrated Photovoltaic Power Management System (IPPMS) has been designed to support the continuous power flow at household by integrating Instant Power Supply (IPS) and solar PV, which will also ensure the surplus electrical power to flow to grid. In this system, if solar power is available and loads are active, then power is supplied from solar to load but when the battery is not fully charged then power is supplied to the battery as well as loads from solar panels. During the unavailability of solar energy, and when the battery is not fully charged, then loads and battery collect power from the grid. Additionally, the generated excess electricity from solar panel can be served to grid at no load and fully charged battery condition. However, the analysis of the IPPMS shows that it costs lower than the grid electricity over a long run (5+ year period).
Suitable stocking density of Gulsa tengra (Mystus cavasius) was observed by measuring growth performance, production, and survival in nylon net cages for 120 days in Chalan Beel floodplain ecosystem. Fry of Gulsha tengra (5.55 ± 0.49 g in weight) were stocked into 6 × 3 × 2-m (36 m3) floating net cages with treatments: T1-50, T2-100, T3-150, and T4-200 fry/m3 (in triplicates). The stocked fry was fed twice daily with commercial floating pellet containing 32 % protein at the rate of 5 % /fish body weight during the first 2 months and then reduced to 3 % for the next 2 months. The highest weight gain was observed in the lowest density treatment, T1 (18.70 ± 1.37 g) and the lowest (8.66 ± 0.99 g) in highest density treatment, T4 (all tests for significance were performed at a 5 % level). The rate of survival varied from 86.6 % and 95.8 %, with T1 resulting in the significantly highest survival. A better feed conversion ratio was also observed in T1 (1.75 ± 0.26). Significantly higher protein (16.86 ± 0.36) and fat (2.78 ± 0.02) contents were recorded in the fish body composition in T1. Water quality parameters (temperature: 26.0 ± 1.0 °C, pH: 7.2 ± 0.2, DO: 6.4 ± 0.1 mg/l, NH3-N: 0.002 ± 0.001) recorded throughout the study period were within the suitable range for fish culture. The highest red (119.0 ± 4.85 ×106 µl) and white blood cell (233.2 ± 16.02 ×103 µl), hemoglobin (5.65 ± 0.30 g/dl), total protein (5.50 ± 0.03 g/dl), albumin (1.82 ± 0.06 g/dl), and globulin (3.65 ± 0.15 g/dl) were also observed in T1 indicating optimum condition. Total and net production per cage were the highest in T1 with approximately 50 % increase (88.31 ± 6.72 and 59.27 ± 5.79 kg, respectively) compared to T4. The net income and benefit–cost ratio was increased by approximately 42 % and 30 %, respectively, in T1. Thus, this study recommended an optimal stocking density of 50 fish/m3 for Gulsha tengra to achieve a profitable and robust yield in cage culture.
Data were collected from 50 fish farmers through questionnaire interview and Focus Group Discussion (FDG) in Paba upazila, Rajshahi district of Bangladesh during the period of October, 2015 to May, 2016 to evaluate the present status of traditional aquaculture and socio-economic condition of fish farmers. In the study area, average pond size was 0.83 ha (2-7 feet depth) and 80% of the ponds were characterized with loamy soil. Ground water was the main source for 70% of the ponds where about 90% of the fish farmers were engaged in polyculture of carp species. Majority of fish farmers were in the age group of 41-50 years with fish farming experience of 16 years (44%). Activities of DoF were minimum regarding fish farming of the fish farmers. In the present study, 80% of the respondents were related to fish culture as their principal occupation and majority of the fish farmers (50%) have the annual income of BDT 51,000 to 100,000. 30% of the respondents were educated up to secondary level of education. Health and sanitary status are in good condition than before. 94% of fish farmers have improved their socio-economic condition through fish farming. Therefore, proper training on fish farming and advanced technical knowledge are necessary to improve high pond productivity.Res. Agric., Livest. Fish.5(2): 269-277, August 2018
Sustainability in aquaculture or agriculture production is depended on its successive use of natural resources that can ensure economic increment and sustainability of the livelihood of people. The objective of the study was to find out suitable combination of rice-fish-vegetable to be cultured in rainfed rice field. Two experiments were conducted for 4 months under rainfed condition. Two rice varieties (BRRI-51 and BRRI-52), three different fish species. i.e., Cyprinus carpio var. communis, Barbonymus gonionotus and Oreochromis niloticus and two combinations of vegetables (Red amaranth + Indian spinach and Cucumber + Water spinach) were selected for these experiments. Significantly higher growth and production performance of fish, B. gonionotus were recorded in both of the experiments. Furthermore, between the rice varieties, BRRI-52 showed significantly higher grain yield, biological yield and harvest index. However, vegetable combination did not show any significant difference between the experiment. Finally, considering economic performance, integration of BRRI-52, B. gonionotus and Cucumber-spinach combinations was provided significantly higher net benefit and benefit-cost ratio (BCR). Therefore, combination of rice-fish-vegetable BRRI-52, B. gonionotus and Cucumber-spinach is recommended to improve food security and sustainability for resource-limited farmers in rainfed rice field. Rice-fish-vegetable integrated culture could address the sustainable development goals (SDG) and therefore policy implications should be considered for institutional support, technical facilities and extension services to increase the knowledge of farmers and to uplift the productivity and profitability.
The electron affinity difference Delta Ec= chi 2- chi 1, in CdS-Cu2S solar cells fabricated by four different processes has been measured from observations of the variations of open-circuit voltages with temperature. For CdS-Cu2S cells, the values of Delta Ec lie between 0.25 and 0.35 eV and are found to be independent of the process of cell fabrication. The use of ZnxCd1-xS in place of CdS reduces the value of Delta Ec to somewhat less than 0.1 eV. The method used for the measurement of Delta Ec is very simple. The values of the saturation current I0 for the different type of cells have been estimated from the slopes of qVoc versus kT plots and compared with those obtained from ln I versus V curves. The values of Io found for each cell by the two methods are in substantial agreement.
Padma is one of the largest rivers of Bangladesh, which has huge potential for fishery resources. Microbial pollution status of this riverine ecosystem has not been evaluated yet. Therefore, the present study was conducted to find out the bacterial pollution in sediment of this river. Four distinctive study locations were evaluated for three respective seasons in 2016. Enumeration of total heterotrophic bacteria (THB), total coliform (TC), fecal coliform (FC) and Vibrio cholerae were done by standard plate count technique from surface layer of sediment samples. Results revealed that all the samples were contaminated with THB, TC, FC and Vibrio cholerae with a range of 20.60×106±1.41 cfu/g (Site-2 Padma Garden) to 3.46×106±0.47 cfu/g (Site-4 Talaimari), 140.00×104±22.63 cfu/g (Site-2 Padma Garden) to 2.88×104±0.97 cfu/g (Site-1 T-Dam), 5.98×103±0.36 cfu/g (Site-2 Padma Garden) to 1.04×103±0.08 (Site-4 Talaimari) and 3.85×104±0.26 cfu/g (Site-3 I-Dam) to 0.91×104±0.07 cfu/g (Site-4 Talaimari), respectively. The bacterial density data had seasonality showing very high density during summer and winter seasons and the lowest in monsoon season. During the study period, it was observed that Site-2 (Padma Garden) and Site-3 (I-Dam) was comparatively more polluted with bacteria then other two sites. As per the criteria of sediment quality evaluation, the sediment of Padma River can be categorized as moderate to moderately high polluted with total heterotrophic bacteria, while very little polluted with fecal coliform bacteria. Therefore, the present study suggests a regular monitoring and assessment for reducing the bacterial load into the Padma River ecosystem through appropriate measures.
Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter Facebook Reddit LinkedIn Tools Icon Tools Reprints and Permissions Cite Icon Cite Search Site Citation C. C. Havener, M. A. Haque, A. C. H. Smith, X. Urbain, P. A. Zeijlmans van Emmichoven; Low‐energy measurements of electron capture by multicharged ions from excited hydrogen atoms. AIP Conf. Proc. 5 June 1993; 274 (1): 43–52. https://doi.org/10.1063/1.43757 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAIP Publishing PortfolioAIP Conference Proceedings Search Advanced Search |Citation Search
Freshwater pearl farming is an emerging sector of aquaculture in Bangladesh which plays a growing role at major jewelry markets. With some improved techniques, high quality image or designer pearls are now produced from freshwater mussels Lamellidens marginalis. Yet it is difficult to reach in conclusion as the quantities produced, culture techniques used, and the upgrading of the existing culture technique are not well documented. Furthermore, many obstacles such as proper dissemination of culture technologies among the interested peoples, optimization of the culture environment and culture methods, standardization of breeding protocol and so on need to be addressed by the scientific community. This review article reports for the first time about the status of freshwater pearl culture in Bangladesh highlighting the fundamentals of pearl production, culture techniques used in farms, challenges, and prospects for upgradation of current culture principles in Bangladesh.
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