A STUDY ON GROWTH CO-EFFICIENT AND RELATIVE CONDITION FACTOR OF THE MAJOR CARP (CATLA CATLA) IN TWO LAKES DIFFERING IN WATER QUALITY

Abstract. Physico-chemical water quality parameters viz. temperature, pH, alkalinity, turbidity, total solids, DO, BOD, nitrite, nitrate, phosphate, ammonia, and hydrogen sulfide coupled with diversity and density of plankton were studied during different seasons (monsoon, winter, summer) for two consecutive calendar years in two lakes to find out whether differences in water quality are reflected in growth co-efficient and relative condition factor of the major carp, Catla catla. Significantly higher levels of nutrients (phosphate, nitrate, nitrite) and ammonia, low plankton diversity, and significantly higher density of cyanophyceae were found in Yennehole lake (YL) compared to Belikere lake (BL). In addition, desmids were conspicuous by their absence in YL in contrast to their presence in BL. Concomitantly, growth factor (b) and relative condition factor (Kn) of C.catla were < 3 and < 1 respectively in YL whereas they were close to 3 (or> 3) and>1 respectively in BL in all the seasons in during the study period. The contrasting b and Kn values of the same species in two lakes differing in water quality provide an evidence that deterioration in water quality though not enough to cause death of fish, doe