Anil Mohapatra

Elemental composition in mud crab Scylla serrata from Mahanadi estuary, India: in situ irradiation analysis by external PIXE.

During the present study concentration of nine elements (K, Ca, Mn, Fe, Cu, Zn, Se, Br and Pb) in different tissues of mud crab Scylla serrata from Mahanadi estuary, India were determined by the external PIXE set up at Institute of Physics, Bhubaneswar, India. The study demonstrates the effectiveness of the technique in analyzing both soft and hard tissue samples from marine organisms and opens the door for non-destructive, multi-elemental analysis of tissue samples with a very little sample preparation by direct irradiation. This technique can be well utilized for analyzing the tissue samples for environmental, toxicological and nutritional purposes. The study also demonstrates the elemental concentrations from tissue samples of any crustaceans from Mahanadi estuary for the first time. Sex based difference in the elemental concentration of the mud crabs were marked, which may be related to the growth rate and other biological activities. No significant difference in the concentration of elements (Ca, Mn, Fe, Cu and Zn) in the tissues of juveniles and adults of respective sex is observed, which indicated the active regulation of these elements by S. serrata.

Eco-Restoration Impact on Fishery Biodiversity and Population Structure in Chilika Lake

Chilika lake is not only the largest coastal wetland and a much focused Ramsar Site of international importance but also a unique fragile brackishwater ecosystem of distinction being regarded as the store house of rich living aquatic resources and hot spot of biodiversity (Fig. 1). With unique ecological Open image in new window Figure 1: Map of Chilka lake showing four ecological sectors, hydrological connections, hydrological intervention and fish landing sampling centres. characters resulting mostly from two antagonistic hydrological processes (freshwater inflow and sea water influx), Chilika has no parallel in the tropical world. The economic valuations of Chilika ecosystem has clearly established the importance of fisheries resources which accounts for more than 71% of the total valuation of the lake ecosystem (Ritesh Kumar, 2003), apart from providing food and livelihood securities to nearly 0.20 million people depending on lake fisheries. Fisheries of Chilika lake has been supporting the state economy and contributing to the earning of valuable foreign exchange to the extent of about 200 million rupees. However, fisheries of the lake suffered the most during the critical eco-degradation phase (last two decades) both in terms of yield and biodiversity status due to continued natural changes and unabated anthropogenic pressure.

Trace element-based food value evaluation in soft and hard shelled mud crabs

Concentrations of 10 elements were studied from the pre-moult hard shelled and newly moulted (soft shelled) crabs (Scylla serrata) by the (Energy Dispersive X-ray Fluorescence) EDXRF technique. The study evaluated the composition of all 10 elements from the body tissues and the exuvium of soft shelled and the carapace of pre-moulted hard-shelled crabs in order to evaluate the food value from nutritional and safety point of view for human consumption. The essential elements like K, Ca, Mn, Cu, etc., get reabsorbed from the carapace to the body tissues in order to meet the further requirement in the soft shelled crabs and are also utilized to some extent during the formation of new carapace, toxic element like Pb gets excreted during exuviation and element like Zn gets regulated, as and when become higher in bioavailable form. This study gives evidence that, the freshly moulted soft shelled crabs are more safe and nutritious than the hard-shelled crabs.