140 research outputs found

    Success in hatchery development of seabass and its potential for commercial cage culture in India

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    Brackishwater fish farming is considered as one of the potential areas not only as a source for fish production but also ensures the food security, livelihood for coastal community, business opportunity for entrepreneurs and also can earn foreign exchange. Coastal aquaculture has grown tremendously in early 1990s with farming of single species, the tiger shrimp Penaeus monodon. However, the shrimp farming faced severe set back due to outbreak of viral diseases coupled with social and other environmental issues. To overcome these issues, it is important to introduce some of the remedial measures in order to revive the aquaculture industry to achieve the sustainable production and one such measure clearly visible is the diversification of brackishwater aquaculture with fish species. It is evident that crop rotation can also decrease the risk of disease outbreak in the pond system

    Prediction and management of natural disasters through indigenous Technical Knowledge, with special reference to fisheries

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    Traditional Indigenous knowledge has over the years played a significant role in solving several major social-ecological problems including those related to climate change and variability. People living close to nature often observe the circumstances around them and are the often the first to identify and adapt to any changes. The appearance of certain birds, mating of certain animals and flowering of certain plants are all seen as important signals of change with respect to timing and seasonality of natural phenomena that are well understood in traditional knowledge systems. Indigenous and local peoples have relied on biodiversity as a buffer against environmental variation, change and catastrophe

    Status of Bioprospecting of Marine Molluscs in India

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    Continuous pressure on the environment arising inevitably or otherwise out of technological progress and human population growth has made it necessary to place a commodity value on biodiversity (Randall, 1991)

    Effect of vitamin C dietary supplementation on growth and survival of grey mullet, Mugil cephalus (linnaeus, 1758) fry

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    The present study was conducted to examine the effect of dietary supplementation of vitamin C on growth performance and survival of Mugil cephalus juveniles. Mullet juveniles of an average weight of 3.5 gm each were distributed into four treatment groups and were fed with one of the ten purified diets for 45 days. The growth performance and survival of the experimental animals were measured fortnightly. The experimental purified diets were formulated to contain with or without graded levels of vitamin C. The growth performance (absolute growth, percentage weight gain, SGR, PER, per day growth) were significantly higher in mullets fed with diet containing vitamin C supplementation than fed without vitamin supplementation. The vitamin had no significant effect on survival of the mullet juveniles and all the treatments were significantly similar to each other. These finding can be used for formulation of species specific feed for mullet fry for ensuring optimum growth

    Growth performance of goldfish, Carassius auratus and basil, Ocimum basilicum in media bed aquaponics

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    An experiment of 36 days duration was conducted to study growth performance of goldfish Carassius auratus and basil Ocimum basilicum reared in a media bed aquaponic system. Goldfish fry (3.32 ± 0.45 g and 4.20 ± 0.39 cm) were stocked in rectangular 75 l capacity (water volume of 50 l) plastic tanks at three different stocking densities viz., 500 m-3 (T1), 600 m-3 (T2) and 700 m-3 (T3), respectively and basil plants were planted at a density of 20 m-2, i.e., 10 plants 0.44 m-2 in the rectangular plastic tanks filled with crushed stone media. The goldfish fry were fed with artificial feed (33% protein) at 5% of body weight in equal proportions, two times a day. Control (C) group was set with only basil plants. Growth parameters of goldfish such as length gain (%), weight gain (%) and specific growth rate (% d-1) were significantly higher in T3 (p<0.05) as compared to T1 and T2. However, feed conversion ratio (FCR) and protein efficiency ratio (PER) did not differ between treatments. Similarly, basil plant growth in terms of height gain (%) and leaves yield (nos. plant-1) were found to be highest in T3 which was significantly different from T1, T2 and control (C). Throughout the experimental period, values of water parameters in all the treatments were found to be in favourable ranges. From the results of the present study, it could be concluded that for maintaining good water quality with highest production in media bed aquaponics, the optimum stocking density is 700 m-3 for goldfish fry and 10 plants per 0.44 m2 for basil plants

    Embryonic Development of Discus, Symphysodon aequifasciatus Pellegrin, 1904 in Indian Condition

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    The experiment was conducted to investigate the embryonic development of discus (Symphysodon aequifasiatus) and determine the time required for major egg developmental stages and hatching. Regular observations were made using optical microscope and the images were recorded using a digital camera attached to the microscope. Important water quality parameters were kept optimal for the hatching of discus eggs. Newly laid eggs were oval-shaped and yellow in colour with an average diameter of 1.37 ± 0.14 mm. The embryonic development of fertilized eggs was divided into 16 stages and the development of each stage was recorded in times lapse. The result revealed that cleavage occurred after 1hr after fertilization followed by development of blastula and gastrula at 20.5 hr and 24 hr after fertilization respectively. The period of organogenesis started with the formation of embryonic notochord from 37.5 hrs after fertilization. The appearance of a defined head and tail of the embryo with 19 somites was observed at 40.0 hrs after fertilization, whereas heart beat along with blood circulation appeared after 55.5 hrs after fertilization. The eggs hatched after 69.06 hr after fertilization

    Integrated Assessment of Heavy Metal Contamination in Sediments from a Coastal Industrial Basin, NE China

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    The purpose of this study is to investigate the current status of metal pollution of the sediments from urban-stream, estuary and Jinzhou Bay of the coastal industrial city, NE China. Forty surface sediment samples from river, estuary and bay and one sediment core from Jinzhou bay were collected and analyzed for heavy metal concentrations of Cu, Zn, Pb, Cd, Ni and Mn. The data reveals that there was a remarkable change in the contents of heavy metals among the sampling sediments, and all the mean values of heavy metal concentration were higher than the national guideline values of marine sediment quality of China (GB 18668-2002). This is one of the most polluted of the world’s impacted coastal systems. Both the correlation analyses and geostatistical analyses showed that Cu, Zn, Pb and Cd have a very similar spatial pattern and come from the industrial activities, and the concentration of Mn mainly caused by natural factors. The estuary is the most polluted area with extremely high potential ecological risk; however the contamination decreased with distance seaward of the river estuary. This study clearly highlights the urgent need to make great efforts to control the industrial emission and the exceptionally severe heavy metal pollution in the coastal area, and the immediate measures should be carried out to minimize the rate of contamination, and extent of future pollution problems

    Effects of anthropogenic activities on the heavy metal levels in the clams and sediments in a tropical river

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    The present study aimed to assess the effects of anthropogenic activities on the heavy metal levels in the Langat River by transplantation of Corbicula javanica. In addition, potential ecological risk indexes (PERI) of heavy metals in the surface sediments of the river were also investigated. The correlation analysis revealed that eight metals (As, Co, Cr, Fe, Mn, Ni, Pb and Zn) in total soft tissue (TST) while five metals (As, Cd, Cr, Fe and Mn) in shell have positively and significantly correlation with respective metal concentration in sediment, indicating the clams is a good biomonitor of the metal levels. Based on clustering patterns, the discharge of dam impoundment, agricultural activities and urban domestic waste were identified as three major contributors of the metals in Pangsun, Semenyih and Dusun Tua, and Kajang, respectively. Various geochemical indexes for a single metal pollutant (geoaccumulation index (I geo), enrichment factors (EF), contamination factor (C f) and ecological risk (Er)) all agreed that Cd, Co, Cr, Cu, Fe, Mn, Ni and Zn are not likely to cause adverse effect to the river ecosystem, but As and Pb could pose a potential ecological risk to the river ecosystem. All indexes (degree of contamination (C d), combined pollution index (CPI) and PERI) showed that overall metal concentrations in the tropical river are still within safe limit. River metal pollution was investigated. Anthropogenic activities were contributors of the metal pollution. Geochemical indexes showed that metals are within the safe limit

    Metal release from contaminated estuarine sediment under pH changes in the marine environment

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    The contaminant release from estuarine sediment due to pH changes was investigated using a modified CEN/TS 14429 pH-dependence leaching test. The test is performed in the range of pH values of 0-14 using deionised water and seawater as leaching solutions. The experimental conditions mimic different circumstances of the marine environment due to the global acidification, carbon dioxide (CO2) leakages from carbon capture and sequestration technologies, and accidental chemical spills in seawater. Leaching test results using seawater as leaching solution show a better neutralisation capacity giving slightly lower metal leaching concentrations than when using deionised water. The contaminated sediment shows a low base-neutralisation capacity (BNCpH 12 = -0.44 eq/kg for deionised water and BNCpH 12 = -1.38 eq/kg for seawater) but a high acid-neutralisation capacity when using deionised water (ANCpH 4 = 3.58 eq/ kg) and seawater (ANCpH 4 = 3.97 eq/kg). Experimental results are modelled with the Visual MINTEQ geochemical software to predict metal release from sediment using both leaching liquids. Surface adsorption to iron- and aluminium- (hydr)oxides was applied for all studied elements. The consideration of the metal-organic matter binding through the NICA-Donnan model and Stockholm Humic Model for lead and copper, respectively, improves the former metal release prediction. Modelled curves can be useful for the environmental impact assessment of seawater acidification due to its match with the experimental values.This work was supported by the Spanish Ministry of Economy and Competitiveness, Project No. CTM 2011-28437-C02-01, ERDF included. M. C. Martı´n-Torre was funded by the Spanish Ministry of Economy and Competitiveness by means of FPI. Fellowship No. BES-2012-053816

    From Cleanroom to Desktop: Emerging Micro-Nanofabrication Technology for Biomedical Applications

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    This review is motivated by the growing demand for low-cost, easy-to-use, compact-size yet powerful micro-nanofabrication technology to address emerging challenges of fundamental biology and translational medicine in regular laboratory settings. Recent advancements in the field benefit considerably from rapidly expanding material selections, ranging from inorganics to organics and from nanoparticles to self-assembled molecules. Meanwhile a great number of novel methodologies, employing off-the-shelf consumer electronics, intriguing interfacial phenomena, bottom-up self-assembly principles, etc., have been implemented to transit micro-nanofabrication from a cleanroom environment to a desktop setup. Furthermore, the latest application of micro-nanofabrication to emerging biomedical research will be presented in detail, which includes point-of-care diagnostics, on-chip cell culture as well as bio-manipulation. While significant progresses have been made in the rapidly growing field, both apparent and unrevealed roadblocks will need to be addressed in the future. We conclude this review by offering our perspectives on the current technical challenges and future research opportunities
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