Surival of remote set seed of the clam Paphia malabarica : Effect of continued submergence and short term exposures to salinity variations

Globally clam mariculture is a very popular aquaculture activity. The seed for farming to a great extent comes from the natural bed but in many countries the hatchery produced clam seed is farmed. Most farmers also have adopted the convenient technique of remote setting the seed. Remote setting is the technique of setting the pediveliger larvae produced in hatcheries at sites away from the hatchery usually near the farm site. Paphia malabarica commonly known as the yellow foot clam or textile clam is an important resource and supports a commercial fishery in their places of occurrence. In the present experiment pediveliger larvae of P. malabarica produced in the hatchery of CMFRI at Tuticorin were remote set at the Calicut Marine hatchery complex after a transit period of 26 hrs. They were reared in the hatchery and before transferring these clams to the field two sets of experiments mainly to i) evaluate the effect of continued exposure to different salinities ranging from 0 to 35 ppt and ii) evaluate 10,15,20, and 25 ppt and subsequent revival in ambient salinity of 35 ppt were conducted to understand their tolerance to variations in salinity

Acid-base properties of Cu<SUB>1-x</SUB>Co<SUB>x</SUB>Fe<SUB>2</SUB>O<SUB>4</SUB> ferrospinels: FTIR investigations

Systematic IR spectroscopic studies were undertaken to investigate the acid-base properties of Cu-Co ferrospinels Cu1-xCoxFe2O4 (x=0 to 1) employed in phenol methylation to produce 2,6-xylenol. The IR spectra of the ferrospinels reveal that Fe3+ and Co2+ ions are mainly responsible for the various hydroxy groups on the surface. Temperature dependent IR studies of pyridine adsorbed on spinels and on the spinel phase with deliberately added metal oxide exemplify the contribution of the metal ions and their coordination state towards Lewis acidity. IR studies of the spinel surface with adsorbed CO2 and adsorption studies of electron acceptors such as 7,7,8,8-tetracyanoquinodimethane, 2,3,5,6-tetrachloro-1-4-benzoquinone and p-dinitrobenzene were carried out to evaluate the nature of the basic sites and the strength and distribution of the electron donor sites present on the spinel surface. It was found that the acidity (basicity) of the Cu1-xCoxFe2O4 spinel system increases (decreases) from x=0 to 1. A correlation between acidity, basicity and catalytic performance reveals that an intermediate acid-base character enhances the phenol methylation activity

Enhancing CO2 plasma conversion using metal grid catalysts

The synergy between catalysis and plasma chemistry often enhances the yield of chemical reactions in plasma-driven reactors. In the case of CO2 splitting into CO and O2, no positive synergistic effect was observed in earlier studies with plasma reactors, except for dielectric barrier discharges, that do not have a high yield and a high efficiency. Here, we demonstrate that introducing metal meshes into radio frequency-driven plasma reactors increases the relative reaction yield by 20%–50%, while supported metal oxide catalysts in the same setups have no effect. We attribute this to the double role of the metal mesh, which acts both as a catalyst for direct CO2 dissociation as well as for oxygen recombination.</p

Stock assessment of Bombayduck Harpadon nehereus (Hamilton, 1822) from Gujarat coast using non-equilibrium production model

Bombayduck Harpadon nehereus, harvested mainly by dol nets (stationary bag nets), has been a prolific fishery in the northern region of Arabian Sea and Bay of Bengal. Biomass and maximum sustainable yield (MSY) estimates for the Bombayduck stock in the Saurashtra region were obtained from a non-equilibrium surplus production model approach utilising catch per unit effort (CPUE) time series derived from fish landing data. Fox model was found to be the most appropriate defining model and the results demonstrated that the stock is currently being overexploited

Relating minimum legal size with optimum exploitation pattern in Uroteuthis (Photololigo) duvaucelii a along eastern Arabian seaRelating minimum legal size with optimum exploitation pattern in Uroteuthis (Photololigo) duvaucelii a along eastern Arabian sea

C ephalopods comprising of squids, cuttlefishes and octopus account for nearly 6% of marine fish landings in India. Squids with annual yields fluctuating between 77,241 and 1,00,014 t (2010-15) are mainly caught by trawlers along the eastern Arabian sea, bordering the west coast of India. The lndian squid, Uroteuthis (Photololigo) duvaucelii distributed in the shelf waters support the largest squid fishery in the country. Juvenile Indian squid predominantly under the minimum legal size (MLS) of 8 cm are landed in trawl seasonally. The length-cohort analysis was carried out in this study to assess the stock and mortality rates of U. (P.) duvaucelii population along west coast of India

Oxidative Dehydrogenation of n-​Butane: Activity and Kinetics Over VOx​/Al2O3 Catalysts

The catalytic activity of a VOx/Al2O3 catalyst for the oxidative dehydrogenation of n-​butane is investigated. The effects of reaction temp., oxygen to n-​butane ratio and GHSV on the catalytic performance are examd. and optimized. Interestingly, this simple catalyst gives good conversion and selectivity. Butane was 22-​24 %, and the selectivity to C4 alkenes was 56 %, of which 20-​22 % to 1,​3-​butadiene. Moreover, the catalyst is stable for at least 72 h on stream. Kinetic studies show that the activation barriers for the formation of (butene + butadiene)​, CO and CO2 amt. to 70.2, 65 and 81.3 kJ​/mol resp