• Maria R Menezes

      Articles written in Proceedings – Animal Sciences

    • Determination of acute toxicity levels of mercury to the fishTilapia mossambica (Peters)

      Maria R Menezes S Z Qasim

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      Toxicity of inorganic mercury to the freshwater fishTilapia mossambica was demonstrated by static bioassays. Statistical analysis was used for calculating 48 hr median tolerance limit, 95% confidence limits and the slope function (S). No mortality was observed within 48 hr in mercuric chloride concentration of 0.7 mgl−1 although the swimming activity of the fish decreased and the rate of opercular movement increased significantly. Concentrations of 0.9 mgl−1 and higher proved lethal. Symptoms of mercury poisoning and safe concentrations of mercury have been discussed.

    • Use of electrophoresis and immunoelectrophoresis in taxonomic and pollution studies

      Maria R Menezes S Z Qasim

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      Studies were conducted on the electrophoresis of blood serum and eye lens proteins of 5 fishes and immunoelectrophoresis of the soluble lens proteins of 10 fishes. The effects of a toxic pollutant (mercury) on the electrophoretic patterns of the serum, haemoglobin and eye lens proteins of a euryhaline fishTilapia mossambica (Peters) has also been studied. The use of fish blood morphology as a biological index of water quality has been indicated.

    • Genetic and morphological variations in the Indian mackerelRastrelUger kanagurta (Cuvier 1817) from the Goa region

      Maria R Menezes Sandeep Naik Maria Martins

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      The population structure ofRastrelliger kanagurta (Cuvier 1817) from two localities off Goa (Arabian sea) was assessed from genetic and morphological characters. Seventeen loci were examined from 8 enzymes, sarcoplasmic proteins and hemoglobins. The allele frequencies were not significantly different between the two localities. Nei’s genetic distance value was 0-0017. The proportion of polymorphic loci at the 1% level was 47-1 and 52–9%. The level of genetic variation, estimated by average observed heterozygosity, was 5–8 and 6–6%. The sarcoplasmic protein-2 locus was found to be highly polymorphic. Significant (P< 0-001) departures from Hardy-Weinberg expectations were observed at this locus. About 67–89% of the variation in meristic characters was found to be within the groups.

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