Acute toxicity of mercury to the fingerlings of Indian major carps (catla, rohu and mrigal) in relation to water hardness and temperature

 

Ashwani Kumar and Ashok Kumar Gupta

Department of Aquaculture, College of Fisheries

Maharana Pratap University of Agriculture & Technology, Udaipur-313 001, India

 

(Received: 1 March, 2004 ; Accepted: 29 September, 2004)

 

Abstract: In the present study short-term (96 hr) toxicity of mercury in relation to water hardness (270 and 560 mg/l) and temperature (16?C and? 35?C) to the fingerlings of Indian major carps, i.e. catla, rohu and mrigal has been evaluated using static bioassay.? The LC₅₀ indicates that both water hardness and temperature played significant role in mercury toxicity.? The test fishes were found most resistant with water hardness of 560 mg/l at 16?C as compared to that of water hardness of 560 mg/l at 35?C and water hardness of 270 mg/l at both the temperatures, i.e. 35 and 16?C.? Whereas the order of relative sensitivities of these fishes for mercury ions were recorded as catla>rohu>mrigal.? The safe concentrations of mercury were ranged in between 12.133 to 19.689 mg/l for catla; 64.039 to 82.555 mg/l for rohu and 73.510 to 89.585 mg/l for mrigal for both the water hardness and temperature.

 

Key words: Acute toxicity, Mercury, Catla, Rohu, Mrigal, Water hardness, Temperature.

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