Browsing by Author "Hagos, Mebrahtu T"

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    Effect of heavy metals on spawning and hatching of Penaeus indicus in KwaZulu-Natal (Amatikulu Prawn Farm)
    (2004) Hagos, Mebrahtu T; Griffiths, Charles L; Evans, Laurence
    Generally aquaculture continues to suffer from pollution and this has resulted in the decline of production. The effect of pollution can be directly on the organisations cultured causing immediate death or retarding their growth and making them vulnerable to a variety of diseases, or indirectly by reducing their reproductive capacity. This study was carried out to investigate the effect of zinc and lead on the hatched eggs, and zinc and copper on spawing and hatching of eggs from mature female Penaeus indicus. The experiment for each heavy metal was conducted separately. In the post-spawning experiment, hatched eggs were counted and exposed to 0.0, 0.1, 10., 10.0 and 100 ppm of zinc and lead to see the effect of the heavy metals on hatching of the eggs and survival of the hatched eggs. Concentrations of 0.0, 0.1 and 1.0 ppm of zinc and lead did not show signicant difference of hatch rate among each other but 10.0 and 100.0 ppm of zinc and lead gave significantly lower hatch rate as compared with the lower concentrations. Hatch rate completely failed at 100.0 ppm of both heavy metals.