Studies on the bioaccumulation and effect of environmental stress on the green mussel, Perna viridis (Linnaeus, 1758).

Varshney, Rajat Kumar (2003) Studies on the bioaccumulation and effect of environmental stress on the green mussel, Perna viridis (Linnaeus, 1758). Masters thesis, Central Institute of Fisheries Education.

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    Environmental stress, particularly stress due to salinity variation and desiccation is encountered in mussel mariculture systems especially in the initial phase of stocking in the farms. The survivorship of mussel seed on conditioning and direct stocking in different salinities, under controlled conditions was studied. The LCso value for large (25 to 40 mm) and small size seed (10 to 25 mm) were estimated as 14 and 21 ppt respectively indicating the sturdiness of larger seed. The larger sized seed were less tolerant to lower salinities (LC50 = 32 ppt) when exposed directly without conditioning in ambient salinity. The condition indices of the surviving seed were comparable to that of the control. Stress related to desiccation was studied by exposing the seed for various durations and the survivorship in the recovery period was evaluated. In seed exposed for 12 and 24 hours of desiccation, mortality ranged between 6 and 26% during the recovery period at the end of 30 hours and was stabilized thereafter. Desiccation for 26 to 30 hours resulted in very high mortality ranging from 42 to 96% at the end of 30 hours of the recovery time while, above 30 hours and up to 48 hours of desiccation, none of the seed survived, Considering the significance of bioaccumulation and quality of the mussels marketed, the levels of heavy metals such as zinc, cadmium, lead and copper in farmed and naturally occurring mussels were analysed and compared. The order of magnitude of bioaccumulation of the trace metals was Zn>Cu>Pb>Cd in the mussel collected from the natural bed while in the mussel cultured in the off bottom system in bay and estuarine pond were Zn>Pb>Cd>Cu and Zn>Pb>Cu>Cd respectively. Positive correlation with size was observed in the accumulation of zinc (R^ = 0 .7869) and lead (R^ = 0 .7266) in the natural bed mussels, while in the off bottom farms the accumulation of Zn, Cd, Pb and Cu were negatively related to size with very low to nil values of Cd and Cu in harvestable size (> 60 mm) mussels. Gender based bioaccumulation of heavy metals was inconsistent indifferent size groups of mussels collected from the natural bed and in farmed systems.

    Item Type: Thesis (Masters)
    Uncontrolled Keywords: Bioaccumulation; Environmental stress; Green mussel, Perna viridis
    Subjects: Dissertations
    Molluscan Fisheries
    Divisions: CMFRI-Kochi > Mariculture Division
    Subject Area > CMFRI > CMFRI-Kochi > Mariculture Division
    CMFRI-Kochi > Mariculture Division
    Subject Area > CMFRI-Kochi > Mariculture Division
    Depositing User: Users 17220 not found.
    Date Deposited: 17 Sep 2016 04:38
    Last Modified: 06 Oct 2016 10:44

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