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Volume :30 Issue : 1 2003
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Histology of ovarian development and maturity stages in the yellowfin seabream, Acanthopagrus latus (Teleostei: Sparidae) (Hottuyn, 1782) reared in cages
Auther : F. ABOU-SEEDO, S. DADZIE* AND K. A. AL-KANAAN
Department of Biological Sciences, Kuwait University, P.O.Box 5969, Safat 13060, Kuwait
ABSTRACT
Histological changes during the annual reproductive cycle and the stages of maturity of the ovary of Acanthopagrus latus (Hottuyn, 1782), locally called Sheim, reared in cages in Kuwait Bay, are described. The process of development is classified into four major phases: (i) primary growth phase, during which germ cells (oogonia) proliferate through mitotic division giving rise to perinucleolar oocytes, (ii) secondary growth phase, characterized by the elaboration of yolk in the oocytes, (iii) oocyte maturation/ovulation phase, when the eggs attain maximum size and are released from the follicle and (iv) oocyte atresia phase, when ripe eggs which do not ovulate undergo resorption. The first two phases break into a series of sub-phases referred to as stages. Seven maturity stages of the ovary are delineated. Observations on seasonal maturity stages indicate that the species has a prolonged spawning period extending from December to April. However, an earlier report based on quantitative study indicates that the level of spawning in December is too low to be of significance in terms of management. Data on the relationship of maturity stages to season and age of individuals reveal a lack of synchronization in the rhythm of ovarian development in fish of the same generation.