Showing papers by "Ruma Pal published in 2010"

Phytoplankton and nutrient dynamics of shallow coastal stations at Bay of Bengal, Eastern Indian coast

Abstract: Phytoplankton dynamics of Eastern Indian coast was studied from surface water for a period of 24 months (April 2005–March 2007) in relation to environmental variables like, temperature, pH, dissolved oxygen, biochemical oxygen demand (BOD), salinity and nutrient contents—including nitrate, phosphate and silicate. Total 43 taxa were recorded during the study period. Phytoplankton density ranged from approximately 350–3,000 cells/ml and showed complete dominance of diatom genera namely, Asterionella japonica in winter and Odontella rhombus in summer. Other frequently occurring diatoms were Coscinodiscus perforatus, Actinocyclus normanii f. subsala, Thalassiothrix fraunfeldii, Ditylum brightwelli, Stephanodiscus hantzschoides, Cyclotella meneghiniana, Thalassionema nitzschoides etc. Seasonal changes in abundance and diversity of phytoplankton significantly differed showing maximum diversity in autumn with high diversity index (2.76-Oct, 05) and minimum in winter (0.326-January, 06). The species evenness varied from 0.137 (January 06) to 0.991 (August 06), which signifies minimum variation in percentage contribution of individual species to total phytoplankton population in monsoon and maximum in winter. Correlation studies of total cell count to physicochemical variables indicated significant positive relation with dissolved oxygen, salinity and pH but negative relation with nitrate, silicate and BOD of the water body. Multivariate procedures like ordination by principal component analysis and multi dimensional scaling of phytoplankton population based on their occurrence data and magnitude of abundance indicated that some genera (Biddulphia heteroceros, B. dubia, Odontella aurita, Gyrosigma acuminatum, Coscinodiscus granii, Paralia sulcata, etc.) have specific preference for water temperature and salinity and flourished maximally in particular season(s). While other genera (A. japonica, C. meneghiniana, C. perforatus, D. brightwelli, S. hantzschoides, etc.) appeared in wide range of temperature and salinity gradient.

Evaluation of algae based feed in Goldfish ( Carassius auratus ) nutrition

Abstract: A short term laboratory feeding trial was conducted to evaluate the importance of algae based value added feed for the popular ornamental fish Carassius auratus (Gold fish). The feed was tested against Daphnia — the conventional feed used for Goldfish. Fresh algal biomass of Nostoc ellipsosporum and Navicula minima were mixed with daphnia to formulate the value added feed and proximate composition of feeds were analyzed. The experimental feed showed significantly higher protein (71.24% ±0.3), lipid (33.47%±0.2), and carotenoid (6.41%±0.13) (Pd″0.05), and increased level of amino acids (4.2%±0.1) and carbohydrate (14.72%±0.2) content than the control feed. Similarly the fishes fed with experimental feed showed 2 fold increase in protein, glycogen and carotenoid level as compared to the control fishes. Morphometric study also showed significant Body weight Gain (3.52%±1.2) and Specific growth rate (0.87±0.41) together with high Protein Productive value (0.051±0.14), Protein effficiency ratio (0.074±0.05) and low Feed conversion ratio (0.024±0.03) in experimental fishes which signifies better utilization of feed by the fishes. The VAF (Value added feed) fed fishes showed positive results in both morphometry and carcass proximate composition. Differences in body weight gain and Feed conversion ratio together with increased protein, glycogen and carotenoid levels were significant than the control fishes. The colouration of the gold fishes induced by algal carotenoids was more bright and vibrant indicating high market value.