Development of live feed enrichment product for marine fish larviculture

Phytoplankton cultures of Nanochloropsis oculata, Isochrysis galbana, Pavlova viridis and Dicrateria inornata, were scaled up and analysed for fatty acids. I. galbana proved to be the richest source of docosahexaenoic acid (DHA). P. viridis and D. inornata are rich in eicosapentaenoic acid (EPA). N. oculata is rich in EPA and arachidonic acid (ARA). When rotifers were enriched with I. galbana and analysed for fatty acids at specific time intervals, DHA content increased till 30 h with a maximum DHA level of 1.13% obtained in enriched rotifers. Subsequently, development of enriched emulsions using sardine oil (90%) and fish roe (10%) as the major ingredients yielded a DHA content of 39% and EPA content of 17% and was used to enrich rotifers. The resultant enrichment level was 8.76% DHA and 2.35% EPA at six hours after which, a decline in the polyunsaturated fatty acid (PUFA) content was observed. The enrichment formulation holds promise as an import substitute

Heterotrophic bacteria from the continental slope sediments of arabian sea

The marine environment is indubitably the largest contiguous habitat on Earth. Because of its vast volume and area, the influence of the world ocean on global climate is profound and plays an important role in human welfare and destiny. The marine environment encompasses several habitats, from the sea surface layer down through the bulk water column, which extends >10,000 meters depth, and further down to the habitats on and under the sea floor. Compared to surface habitats, which have relatively high kinetic energy, deep-ocean circulation is very sluggish. By comparison, life in the deep sea is characterized by a relatively constant physical and chemical environment. Deep water occupying the world ocean basin is a potential natural resource based on its properties such as low temperature, high pressure and relatively unexplored properties. So, a judicious assessment of the marine resources and its management are essential to ensure sustainable development of the country’s ocean resources. Marine sediments are complex environments that are affected by both physiological and biological factors, water movements and burrowing animals. They encompass a large extent of aggregates falling from the surface waters. In aquatic ecosystems, the flux of organic matter to the bottom sediments depend on primary productivity at the ocean surface and water depth. Over 50% of the earth’s surface is covered by deep-sea sediments that are primarily formed through the continual deposition of particles from the productive pelagic waters (Vetriani et al., 1999). These aggregates are regarded as ‘hot spots’ of microbial activity in the ocean (Simon et al., 2002). This represents a good nutritional substrate for heterotrophic bacteria and favours bacterial growthCochin University of Science And TechnologySchool of Marine Sciences, Cochin University of Science And Technolog

Biogeochemistry of the shelf sediments of south eastern Arabian sea: Effect on benthic bacterial heterotrophs

The composition and variability of heterotrophic bacteria along the shelf sediments of south west coast of India and its relationship with the sediment biogeochemistry was investigated. The bacterial abundance ranged from 1.12 x 103 – 1.88 x 106 CFU g-1 dry wt. of sediment. The population showed significant positive correlation with silt (r = 0.529, p< 0.05), organic carbon (OC) (r = 0.679, p< 0.05), total nitrogen (TN) (r = 0.638, p< 0.05), total protein (TPRT) (r = 0.615, p< 0.05) and total carbohydrate (TCHO) (r = 0.675, p< 0.05) and significant negative correlation with sand (r = -0.488, p< 0.05). Community was mainly composed of Bacillus, Alteromonas, Vibrio, Coryneforms, Micrococcus, Planococcus, Staphylococcus, Moraxella, Alcaligenes, Enterobacteriaceae, Pseudomonas, Acinetobacter, Flavobacterium and Aeromonas. BIOENV analysis explained the best possible environmental parameters i.e., carbohydrate, total nitrogen, temperature, pH and sand at 50m depth and organic matter, BPC, protein, lipid and temperature at 200m depth controlling the distribution pattern of heterotrophic bacterial population in shelf sediments. The Principal Component Analysis (PCA) of the environmental variables showed that the first and second principal component accounted for 65% and 30.6% of the data variance respectively. Canonical Correspondence Analysis (CCA) revealed a strong correspondence between bacterial distribution and environmental variables in the study area. Moreover, non-metric MDS (Multidimensional Scaling) analysis demarcated the northern and southern latitudes of the study area based on the bioavailable organic matterCochin University of Science and TechnologyAdvances in Applied Science Research, 2013, 4(3):315-32

Antagonistic effect of Pseudomonas aeruginosa isolates from various ecological niches on Vibrio species pathogenic to crustaceans

This is a valuable research work in which authors have demonstrated the antagonistic effects of pseudomonas on the growth of vibrioCochin University of Science and TechnologyJournal of Coastal Life Medicine 2014; 2(1): 76-8