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Ali Tahar

  • Biodiversity Journal, 7 (2): 229-232

    Souheila Ouamane, Lyamine Mezedjri & Ali Tahar
    Quality of swimming waters in the Gulf of Skikda (Algeria)

    ABSTRACT
    The purpose of this study is to determine the bacteriological and physico-chemical quality of swimming waters in the region of Skikda (Algeria), a popular tourist area known for its many beaches, through the water analysis of ten sites. This monitoring program was carried out for a period of five months.

  • Biodiversity Journal, 4 (2): 269-274

    Lyamine Mezedjri, Ahmed Kerfouf & Ali Tahar
    Reproductive cycle of the European anchovy Engraulis encrasicolus (Linnaeus, 1758) (Clupeiformes Engraulidae) in the gulf of Skikda (Algerian East coasts)

    ABSTRACT
    A study on the sexual cycle of the European anchovy, the pelagic fish Engraulis encrasicolus (Linnaeus, 1758) (Clupeiformes Engraulidae), was carried out in Algerian East coasts over a year (July 2008-June 2009). Annual sex-ratio (SR) showed that females dominate with an average male sex-ratio of 39.35%. The European anchovy spawning period ranges from April to October with peaks in the warmest months, strictly dependent on temperature. The gonado-somatic index was updated monthly which allowed us to divide the entire cycle into four successive phases: (i) a phase of slow maturation which occurs between the end of winter and the beginning of spring; (ii) a phase of significant sexual activity; (iii) a phase of emission of the sexual products which corresponds to the warmest months; and, finally, (iv) a phase of sexual rest occurring in the coldest months. Monthly variation of either hepato-somatic index or mesenteric fat reserves informed us about the origin of the energetic deposits, particularly important for the development of the gonads. In both sexes, the first sexual maturity is reached at a fish total length (Lt) of 12.5 cm.