• H K Vardia

      Articles written in Proceedings – Animal Sciences

    • Relative toxicity of phenoxy herbicides onLehistes (Poecilia) reticulatus (Peters)

      H K Vardia V S Durve

      More Details Abstract Fulltext PDF

      Phenoxy herbicides 2,4-D, its sodium and ethyl amine salts and ethyl esters, commonly used in aquatic weed eradication programmes, were tested by acute and static bioassay investigations on a cyprinid fishLebistes (Poecilia) reticulatus under laboratory conditions. The toxicities of these different formulations are compared and reported in relative toxicity ratings. ‘Safe application rate’ and ‘safe application factor’ equations were also calculated. Median lethal concentrations at various time intervals are also reported along with respective fiducial limits and regression equations. Comparative regressions are drawn for three time intervals, 24, 48 and 96 hr.

    • Effect of copper, cadmium and zinc on fish-food organisms,Daphnia lumholtzi andCypris subglobosa

      H K Vardia P S Rao V S Durve

      More Details Abstract Fulltext PDF

      The results of static and acute bioassay studies onDaphnia lumholtzi (Cladocera) andCypris subglobosa (Ostracoda) to the varying dosages of Cu, Cd and Zn were presented. The 96 h, LC50 values forDaphnia were found to be 0·009, 0·083, 0·437 and forCypris 0·25, 0·687, 8·3 mgl−1 for Cu, Cd and Zn respectively. This indicates thatDaphnia is very sensitive whileCypris has a good amount of resistance. The rank order for toxicity of 3 metals is Cu>Cd>Zn. The study indicates that the waters getting polluted by heavy metals even at low concentration would remove the population of fish-food organisms without directly effecting fish fauna, thus making water body unfit for fishery use.

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