Effect of environmental of acidic pH on mortality studies in different stages of fish, Cyprinus carpio(Linnaeus)

Abstract

The data are presented in tables (1 and 2) showed that the tolerance time of fry and fingerling stages of Cyprinus Carpio on exposure to different acidic pH media were analyzed. The fish showed no mortality from pH 5.0 to 7.0. in both the stages of fish. 25% mortality was observed in pH 3.0 with in 5 min of exposure period. However, 50% mortality was observed on exposure of fry with in 10 min of time. The total 100% mortality was witnessed with in 15 min of exposure of fry in pre pH acidic media. However, when the fry was exposed to 3.5 pH media 50% mortality was observed after 20 min of exposure period. The total 100% mortality was witnessed with in 25 min time duration on exposure of fry at pH 3.5. Whereas the survival time was varied for fry stage of Cyprinus carpio on exposure to pH 4.0, 10% mortality was seen after 20 min of exposure followed by 50% mortality and 100% mortality was observed at 25 and 30 min of duration respectively. Whereas at pH 4.5 in acidic media the exposure of fry stage of Cyprinus carpio witnessed 10% mortality after 3 hrs of exposure followed by 50% mortality was observed after 3 hrs 30 min and the 100% mortality was observed after 4 hrs of exposure. It is evidenced that the sub lethal acidic pH was ranges from pH 6.5 to 5.0. Similarly the lethal pH in acidic media was between pH 4.5-3.0. The mortality rate of fingerling stage of Cyprinus carpio on exposure to different acidic pH media showed differential pattern when compared to fry stage. On exposure to pH 3.0 media, the fingerlings recorded 20% mortality with in 5 min of exposure. However, it is recorded 40% mortality with in 10 min of exposure followed by 75% mortality with in 15 min of exposure and 100% mortality with in 20 min of exposure. However in 3.5 pH media the fingerling exhibited 20% mortality with in 20 min of exposure followed by 50% mortality with in 25 min and 100% mortality with in 30 min of exposure. When fingerlings exposed to 4.0 pH media it was evidenced that 40% mortality was observed with in 25 min of exposure followed by 50% mortality with in 30 min of exposure and 100% mortality was observed with in 3 hrs of exposure. Whereas on exposure to pH 4.5 the fingerling showed 20% mortality after 3 hrs 30 min followed by 50% mortality after 4 hrs of exposure and 100% mortality after 4 hrs 30 min of exposure. It was observed that the survival time of 100% mortality of fingerling in different acidic media was less when compared to fry stage of Cyprinus carpio.