Sharma, A.P.Rathor, Prerna2020-06-252020-06-252019-08http://krishikosh.egranth.ac.in/handle/1/5810147995The present study was designed to evaluate the physico-chemical factors and their effect on primary productivity in fish ponds. The experiment was conducted in three ponds viz. duckhouse pond and broodstock pond and nursery pond; having area of 0.1 ha, 0.2 ha and 0.05 ha, respectively which were situated at coordinates 28o58’N, 79o25’ E and at an altitude of 252 m above mean sea level, in Uttarakhand. Three sites in all the three experimental ponds viz. duckhouse pond (S1, S2 and S3), broodstock pond (S1', S2' and S3') and nursery pond (S1'', S2'' and S3'') were randomly selected and sampling was done fortnightly for the duration of six months i.e. from December-18 to May-19. In physical parameters water temperature, water transparency, electrical conductivity and total dissolved solids were found in the range of 15.9 to 32.5 oC, 28.0 to 54.8 cm, 201.0 to 587.0 μScm-1, and 138.5 to 424.5 mgL-1, respectively. In chemical parameters pH, total alkalinity, dissolved oxygen, free carbon dioxide, nitratenitrogen, phosphate-phosphorus, ammonia-nitrogen and silicate were recorded in the range of 7.6 to 8.4, 114.3 to 177.3 mgL-1, 4.9 to 8.5 mgL-1, 0 to 2 mgL-1, 0.32 to 0.51 mgL-1, 0.018 to 0.057 mgL-1, 0.09 to 0.35 mgL-1 and 2.56 to 5.09 mgL-1, respectively. The mean values of GPP, NPP and CR in experimental ponds were in the range of 2701.44 to 9506.88 mgCm-3d-1, 1287.36 to 4042.56 mgCm-3d-1 and 972.00 to 7874.88 mgCm-3d-1, respectively. The net production efficiency and chlorophyll a concentration in the study ponds was recorded in the range of 10.3 to 31.7% and 1.12 to 9.12 mgm-3, respectively. Phytoplankton composition of the experimental ponds consisted a total number of 24 different taxa belonging to 4 different classes namely Bacillariophyceae (12), Chlorophyceae (6), Cyanophyceae (4) and Euglenophyceae (2). The phytoplankton density ranged from 19350 to 69170 cellsL-1. Group wise distribution of phytoplankton density revealed that Bacillariophyceae was most dominant group in the experimental ponds. The maximum diversity was found in the month of May followed by April and December.ennullThesis