Rajeeb K. Mohanty

Performance evaluation of rice–fish integration system in rainfed medium land ecosystem

Abstract This study was carried out for three successive years during 1999–2001 to evaluate growth and yield performance of fish, prawn and paddy under rice–fish integration system in rainfed medium land ecosystem. Irrespective of stocking density, faster growth rate was recorded for Catla catla followed by Cyprinus carpio, Cirrhinus mrigala, Labeo rohita and Macrobrachium rosenbergii. C. carpio and C. mrigala performed better growth rate against that of L. rohita probably due to the fact that being bottom dwellers, C. carpio and C. mrigala are more tolerant to fluctuation of oxygen concentration. Productivity of fish and prawn was, however, higher (p

Feeding management and waste production in semi-intensive farming of penaeus monodon (fab.) at different stocking densities

Studies on waste production and feeding management of Penaeusmonodon in semi-intensive culture system were carried out for foursuccessive crops at a commercial farm (M/S Suryo Udyog Ltd.) at Chandipur Coastof Orissa, India, at six different stocking densities. The prescribed feedingprogramme of C.P. Group, Thailand (NOVO-shrimp feed) were adopted andstandardized during first two crops and the standardized feeding scheme wasevaluated in the last two crops. Influence of standardized feeding programme onaverage feed conversion ratio (FCR) of P. monodon washighlysignificant (p < 0.001) against that of manufacturers (NOVO-feed)prescribedfeeding programme. A feeding frequency of more than four times a day showed noimprovement in growth rate and there was no change in diurnal feeding habitprobably due to the fact that, in scientific farming, aquatic environment isartificially controlled. It was also observed that, as the age and weight ofshrimp increases, feed % decreases from 8.8 to 1.9% and lift net(LN)% increases from 2.4 to 4.3% for 1–40 gmeanbody weight of P. monodon respectively. The higher thestockingdensity, the higher was the FCR and sedimentation rate. In the presentexperiment,the sedimentation rate was estimated to be 49.5 m3 (dryvolume)/1000.0 kg of shrimp biomass. The average quantity of wastematter production was only 571.4 kg of organic matter, 10.21kg of nitrogen and 0.527 kg of phosphorus at anaverage FCR of 1.437 and stocking density of 22.5 pcs m-2 during the four crop experimental period.

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.

Ichthyofaunal diversity of Chilika Lake, Odisha, India: an inventory, assessment of biodiversity status and comprehensive systematic checklist (1916-2014)

Chilika Lake, an assemblage of marine, brackish and freshwater ecosystems, on the east coast of India is a designated Ramsar site and a biodiversity hotspot. Intensive ichthyofaunal inventories and biodiversity assessments were carried out during 2000–2014 and documented 317 species belonging to 207 genera, in 88 families and 23 orders, including two endemic (Gobiidae) and one exotic cichlid species ( Oreochromis mossambicus ). In total, 255 collections (178 collections of previously recorded species and 77 that represent newly recorded species) were made during a post-restoration survey accounting for 80.44% retrieval of historically documented species. This paper presents an updated and comprehensive checklist of the lake’s ichthyofauna (1916–2014), which is comprised of 278 food fishes, 271 (85.49%) migratory and 46 (14.51%) are resident species indicating that the lake fishery is largely migratory species-dependent. An account of faunal characteristics for 129 commercially important species is provided. The checklist also documents 48 threatened species and 103 species under different categories of conservation status.

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.

Secondary Storage Reservoir: A Potential Option for Rainwater Harvesting in Irrigated Command for Improved Irrigation and Agricultural Performance

Present study recommends an option to overcome the limited water availability in surface irrigation system through provision of secondary reservoirs in the command. The harvested water can be utilized for irrigation in the dry season, short duration fish culture, etc. Approximately 10% of the command area is required for the secondary reservoir with assumption of 50% capacity of the main reservoir will be available for irrigating dry season crops. The demonstration of use of water from the secondary reservoir in addition to the water from main reservoir has resulted in substantial crop and fish yield. The gross and net returns from various cropping patterns considered using irrigation water from main reservoir (MR) and from main and secondary reservoir (MR+SR). Among the cropping patterns considered, rice-tomato cropping pattern resulted in highest net return of INR 29,457/ha followed by rice-brinjal cropping pattern (INR 22,430/ha) with benefit cost ratio of 2.07 and 1.79, respectively. Highest benefit-cost ratio of 2.09 was obtained for rice-sunflower cropping system due to relatively lower cost of cultivation of sunflower. The highest incremental value of net returns of 3710 /ha was obtained with rice-tomato cropping system. The low input-based scientific fish culture in the secondary reservoir has enhanced the fish yield by three fold over traditional practice increasing the gross return from the system. The economic analysis also revealed that the intervention is economically viable.