Effects of some water quality parameters and some metals on osmoregulation of Oreochromis mossambicus in Bolgoda lake

Abstract

The present study was carried out in Bolgoda Lake at Attidiya, Borupona and Dampe from September2005 to January 2006 with the objective of studying the effect of some water quality & some heavymetals on Osmoregulation of Oreochromis mossambicus. Only the Dissolved Oxygen andTransparency showed significant difference among measured water quality parameter within 3 sites.The highest value of Dissolved Oxygen (9.40 ± 1.56 mg/l) was recorded at Attidiya & lowest fromBorupona (3.88 ± 1.1 mg/I). Dissolved Oxygen of Dampe was 6.44 ± 2.20 mg/I. OsmoregulatoryCapacity of three sites were significantly different. Maximum Osmoregulatory Capacity (240.90 ±2.01) was recorded in Borupona and minimum Osmoregulatory Capacity (126.30 ± 1.12) was recordedin Dampe station. Osmoregulatory Capacity of Attidiya was 168.70 ± 0.79. A significant negativecorrelation of Dissolved Oxygen was recorded with Osmoregulatory Capacity. Transparency alsomade great effect to the Osmoregulatory Capacity. Maximum Osmoregulatory Capacity value wasrecorded in Borupona that has high transparency (87 ± 1.1 ern) and with low Transparency (65 ±0.71cm) minimum Osmoregulatory Capacity value was recorded. That was in Dampe station.Transparency of Attidiya was 80 ± 0.79 ern

There was a significant difference (P<0.05) in the metal levels in a particular organs (gills, muscles)and between the three sites. Gi lis recorded highest values for all measured metals in three sites. Mostabundant metal in three sites was Fe. The Highest value was recorded in Attidiya (2940 ± 27.3flg/g).The lowest Fe value was recorded in Borupona (1290 ± 31.5 ug/g). Next most abundant metal wasZn. The highest value of Zn (805 ± 7.43 flg/g) was recorded in Dampe and lowest value was recordedin Borupona (382 ± 3 .59flg/g). Cu was found only in Attidiya site, but it was very low, relative to theother elements. A significant negative correlation with Osmoregulatory Capacity was observed for·Z'n in gills & muscles.