Course manual: National training on cage culture of seabass, 14 - 23 December 2009

Aquaculture aims at producing aquatic organisms of nutritional, ornamental, therapeutic and industrial value. Cage culture is one avenue where immense scope is there for all these. Cage culture is impressive to adopt in the fact that it provides ownership in public water with less cost of construction and reduced capital investment, safety from predators and competitors and ultimately high yield of fish with good economic returns

Eastward propagating MJO during boreal summer and Indian monsoon droughts

Improved understanding of underlying mechanism responsible for Indian summer monsoon (ISM) droughts is important due to their profound socio-economic impact over the region. While some droughts are associated with 'external forcing' such as the El-Nino and Southern Oscillation (ENSO), many ISM droughts are not related to any known 'external forcing'. Here, we unravel a fundamental dynamic process responsible for droughts arising not only from external forcing but also those associated with internal dynamics. We show that most ISM droughts are associated with at least one very long break (VLB; breaks with duration of more than 10 days) and that the processes responsible for VLBs may also be the mechanism responsible for ISM droughts. Our analysis also reveals that all extended monsoon breaks (whether co-occurred with El-Nino or not) are associated with an eastward propagating Madden-Julian Oscillation (MJO) in the equatorial Indian Ocean and western Pacific extending to the dateline and westward propagating Rossby waves between 10° and 25°N. The divergent Rossby wave associated with the dry phase of equatorial convection propagates westward towards Indian land, couple with the northward propagating dry phase and leads to the sustenance of breaks. Thus, the propensity of eastward propagating MJO during boreal summer is largely the cause of monsoon droughts. While short breaks are not accompanied by westerly wind events (WWE) over equatorial western Pacific favorable for initiating air-sea interaction, all VLBs are accompanied by sustained WWE. The WWEs associated with all VLB during 1975-2005 initiate air-sea interaction on intraseasonal time scale, extend the warm pool eastward allowing the convectively coupled MJO to propagate further eastward and thereby sustaining the divergent circulation over India and the monsoon break. The ocean-atmosphere coupling on interannual time scale (such as El-Nino) can also produce VLB, but not necessary

Boreal summer intraseasonal oscillations and seasonal Indian monsoon prediction in DEMETER coupled models

Even though multi-model prediction systems may have better skill in predicting the interannual variability (IAV) of Indian summer monsoon (ISM), the overall performance of the system is limited by the skill of individual models (single model ensembles). The DEMETER project aimed at seasonal-to-interannual prediction is not an exception to this case. The reasons for the poor skill of the DEMETER individual models in predicting the IAV of monsoon is examined in the context of the influence of external and internal components and the interaction between intraseasonal variability (ISV) and IAV. Recently it has been shown that the ISV influences the IAV through very long breaks (VLBs; breaks with duration of more than 10 days) by generating droughts. Further, all VLBs are associated with an eastward propagating Madden-Julian Oscillation (MJO) in the equatorial region, facilitated by air-sea interaction on intraseasonal timescales. This VLB-drought-MJO relationship is analyzed here in detail in the DEMETER models. Analyses indicate that the VLB-drought relationship is poorly captured by almost all the models. VLBs in observations are generated through air-sea interaction on intraseasonal time scale and the models' inability to simulate VLB-drought relationship is shown to be linked to the models' inability to represent the air-sea interaction on intraseasonal time scale. Identification of this particular deficiency of the models provides a direction for improvement of the model for monsoon prediction

Isolation and characteriation of extreme halophiles Halomonas aquamarina and Halomonas marina from trigger fish, Abalistes stellaris (Bloch & Schneider, 1801)

Screening of bacteria from the skin, gills and gut of the marine triggerfish, Abalistes stellaris (Bloch & Schneider, 1801), collected from Vizhinjam, Kerala, India, led to the isolation of 8 halophilic bacterial strains. The isolates were able to grow optimally in culture media with 5-15% salt content. Of these, 3 extremely halophilic bacterial isolates that grew in 20-25% of salt were selected for genotypic characterisation. Bacterial strain, IJ1, isolated from skin, and strains, IJ5 and IJ6, isolated from gut of A. stellaris grew optimally at pH 7.0 and 5-15% NaCl at 35 °C. The cells were Gram negative short rods. According to the phenotypic characteristics and comparative partial 16SrRNA sequence analysis, the strain IJ1 was identified as Halomonas marina strain DSM 4741 (GenBank Accession Number: KC599209) and strains IJ5 and IJ6 as Halomonas aquamarina (GenBank Accession Numbers: KC620376 and KC599210 respectively). H. aquamarina has been reported for the first time from any environment in India and both the strains have been deposited in the microbial repository of National Bureau of Agriculturally Important Microorganisms (NBAIM), Mau, India

Survey on functionally diverse bacterial strains from marine finfishes and crustaceans

Prokaryotic microorganisms compromise a large portion of the organic biomass of the world’s ocean and play an important role in the biogeochemical cycles and food webs of this ecosystem. Surface colonization by microorganisms is ubiquitous in marine systems with a large proportion of microbes occurring as complex communities. Despite their importance, comparatively little is known about the phylogenetic composition of this complex microbial population and the functional roles of their members. Living surfaces are ideal to explore colonization by microorganisms because eukaryotes are subject to a constant bombardment from the millions of microbial cells typically found in a millilitre of seawater

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Not AvailableIn the present study, screening of bacteria from gut of Indian oil sardine Sardinella longiceps collected from Kanyakumari coast, Tamil Nadu, India, has led to the isolation of a yellow pigmented strain SR-G1. Cell morphology, motility and the occurrence of spores were examined by phase contrast microscopy. The isolate was Gram-positive, with irregular rods, nonmotile branched cocci with colonies on nutrient agar yellow, opaque, glistening, circular and low convex with entire margin. The pH of the medium and incubation temperature were found to be limiting factors in growth of the bacterial strain. The optimum temperature for growth was 28 degree celsius. Key biochemical reactions include positive for catalase and negative for oxidase. The strain was H 2S-producing, starch and gelatinhydrolyzing and alkali-tolerant. The isolate grew well in minimal media containing glucose, fructose and sucrose. The strain SR-G1 was identified as Microbacterium esteraromaticum based on the phenotypic characteristics and 16S rRNA sequence analysis. Extraction and separation of the bacterial carotenoid was carried out by a one step methanol of hexane extraction. The coloured supernatant in hexane solvent was analyzed by using UV- Visible Spectrophotometer from 350-550 nm range for detecting the lambda max . The bacterial pigment was identified using a combination of UV/visible spectral data and HPLC retention time as Neoxanthin. Neoxanthin is one of the major xanthophylls which are reported to be directly associated with reduction in the risk of cancers, cardiovascular disease, agerelated macular degeneration, and cataract formation. Hence, the potential of microbial producers as an alternative to chemical synthesis of xanthophylls could be further examined.Not Availabl

Occurrence of fluorescent bacterium Pseudomonas aeruginosa a putative biocontrol agent in Indian pompano Trachinotus mookalee Cuvier, 1832

Bacterial diversity studies in healthy marine finfish Trachinotus mookalee Cuvier, 1832 have lead to the isolation of six strains of Pseudomonas spp. The bacteria were isolated from the skin, gills and intestine of live and healthy fish collected from Karwar, Karnataka, India (N- 13°, 05.722‘; E- 079°, 48.658‘). Among the strains three were non-fluorescent and others were fluorescent Pseudomonas strains. Fluorescent strains are known to secrete pyoverdine, a yellow-green siderophore which has wide application in agriculture and allied sectors. Fluorescent strains were further characterized by 16S rDNA sequencing and were identified as Pseudomonas aeruginosa strain TRG1 (Genbank Accession No. KC109784)

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Not AvailableScreening of bacteria from the skin, gills and gut of the marine triggerfish, Abalistes stellaris (Bloch & Schneider, 1801), collected from Vizhinjam, Kerala, India, led to the isolation of 8 halophilic bacterial strains. The isolates were able to grow optimally in culture media with 5-15% salt content. Of these, 3 extremely halophilic bacterial isolates that grew in 20-25% of salt were selected for genotypic characterisation. Bacterial strain, IJ1, isolated from skin, and strains, IJ5 and IJ6, isolated from gut of A. stellaris grew optimally at pH 7.0 and 5-15% NaCl at 35 °C. The cells were Gram negative short rods. According to the phenotypic characteristics and comparative partial 16SrRNA sequence analysis, the strain IJ1 was identified as Halomonas marina strain DSM 4741 (GenBank Accession Number: KC599209) and strains IJ5 and IJ6 as Halomonas aquamarina (GenBank Accession Numbers: KC620376 and KC599210 respectively). H. aquamarina has been reported for the first time from any environment in India and both the strains have been deposited in the microbial repository of National Bureau of Agriculturally Important Microorganisms (NBAIM), Mau, India.Not Availabl