Eco-biology and fisheries of the whelk, Babylonia spirata (Linnaeus, 1758) and Babylonia zeylanica (Bruguiere, 1789) along Kerala coast, India

Mohan, Anjana (2007) Eco-biology and fisheries of the whelk, Babylonia spirata (Linnaeus, 1758) and Babylonia zeylanica (Bruguiere, 1789) along Kerala coast, India. Doctoral thesis, Central Marine Fisheries Research Institute.

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Eco-biology_fisheries_whelk, Babylonia spirata_ Babylonia zeylanica_ along Kerala coast, India_Anjana Mohan_2007.pdf

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    Abstract

    The two species of whelks, B. spirata and B. zeylanica were never found to coexist. The hydrographic parameters like temperature, salinity, ammonia, nitrite and nitrate of surface and bottom water were similar between the sites of the two whelk beds. pH, dissolved oxygen, phosphate and total suspended solids of surface and bottom water showed significant variations among zones. Total organic carbon of sediment was analysed for all the stations and significant variations were observed between S; and S2 and N2 and S; Significant variation in sediment texture between B. spirata and B. zeylanica beds was observed. The sediment texture in the B. spirata bed was silt-loam at all stations, while in the B. zeylanica bed, it was sand-loam at S; (10-20 m) and sandy at S; (20-30 m). In the north zone, Babylonia spirata was present at both the sites N; and N2 and in the southern zone at S; at a low density and was absent in S; B. zeylanica was observed only at site S2 (2 no/l0m2). The density of B. spirata varied among sites and maximum density was observed at N2 (6 no/l0m2) and minimum at S1 (0.04 no/l0m2). The density of B. zeylanica was low compared to the density of B. spirata at the same depth in the north zones. Length composition of B. spirata population in the two zones was similar, dominated by adult whelks. Females dominated the population in north zone, while males dominated the population at S1_ B. zeylanica inhabited only the deeper regions of south zone and the population was dominated by adult whelks and females out numbered males. B. spirata abundance was high in areas with more silt and TOC, and showed negative relationship with sand composition. B. zeylanica density increased with sand and significant negative relationship observed with clay, silt and TOC.

    Item Type: Thesis (Doctoral)
    Uncontrolled Keywords: Eco-biology; fisheries; whelk; Babylonia spirata; Babylonia zeylanica; Kerala coast; India
    Subjects: Molluscan Fisheries > Gastropods
    Theses
    Divisions: CMFRI-Kochi > Marine Capture > Molluscan Fisheries
    Subject Area > CMFRI > CMFRI-Kochi > Marine Capture > Molluscan Fisheries
    CMFRI-Kochi > Marine Capture > Molluscan Fisheries
    Subject Area > CMFRI-Kochi > Marine Capture > Molluscan Fisheries
    Depositing User: Arun Surendran
    Date Deposited: 09 May 2016 05:19
    Last Modified: 10 May 2016 05:41
    URI: http://eprints.cmfri.org.in/id/eprint/10774

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