A.T.RAMCHANDRANAIKKISHOR, C.,2023-12-202023-12-202019https://krishikosh.egranth.ac.in/handle/1/5810203995Four farm ponds of different agro-climatic regions viz, Dakshina Kannada and Shivamogga districts were selected for the study. The selected ponds were from designated as Coastal ponds from Dakshina Kannada (ponds P1 and P2) and Malnad ponds from Shivamogga (ponds P3 and P4). Physico-chemical and biological characteristics of water from selected farm ponds were assessed. The results showed variation in different water quality parameters. The water temperature ranged from 24.30 to 32.10 oC, pH from 5.60 to 9.35, Transparency from 7.1 to 30.40 cm, Dissolved oxygen from 3.1 to 11.34 mg/l, Alkalinity from 24 to 166 mg/l, Carbon dioxide from 1.11 to 13.74mg/l, Ammonianitrogen from 0.29 to 18.65 μg at./l and Phosphate-phosphorus from 0.21 to 5.34 μg at./l. A total of 3 genera of phytoplankton (Cyanophyta, Chlorophyta, and Bacillarophyta) were found dominant groups. The pond sediment characteristics such as temperature, pH, electrical conductivity, organic carbon, available phosphorus, available potassium, total nitrogen and textural compositions were within the range suited for freshwater farming. Quantitative and qualitative analyses of phytoplankton showed that plankton content was moderate. The gross primary productivity ranges from (14.45-184.45 mg C/m3/hr). Maximum net primary productivity (136.23 mg C/m3/hr) was recorded during March in pond P3 and Community respiration ranged from 0.31 to 127.94 mg C/m3/hr. Highest concentration of Chl-a (3.75 mg/l) was recorded in pond P4 in March while lowest was in pond P2 (0.19 mg/l) in January. Zooplankton abundance was belonging to 5 classes viz, Rotifera, Protozoa, Copepoda, Cladocera and Ostracod. Average numbers of zooplankton varied from farm ponds (P1&P2) was 176 to 10368 Cells/m3 and in (P3&P4) was 1579 to 21797 Cells/m3. Highest concentration of Chl-a (3.75 mg/l) was recorded in pond P4 in March while lowest was in pond P2 (0.19 mg/l) in January. Average growth rate and average body weight of three major carps such as Catla (Catla catla), Rohu (Labeo rohita) and Common carp (Cyprinus carpio) was recorded for 16 months. Maximum growth in terms of length and weight of catla, rohu and common carp was from pond P3 and P4 (52.75cm and 1080.71g, 44.40cm and 954.19g and 48.43cm and 1023.18g respectively). Key words: Farm ponds, Physico-chemical characteristics, Plankton diversity, Primary productivity, Chl-a, Indian major carps.Thesis