الفهرس 
Family mugilidaeOnly 14 pages are availabe for public view
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Abstract
Mugilids have an economic importance in Egypt and in several parts of the world. Much work has be done to induce mugilids for artificial I spawning to supply the increasing numbers of fish farms. Meanwhle the mullet fry were severaly decreased in natural sources . Several studies were achieved ; - Biweekly samples were collected from lake Edku . - Determination of the age by using fish scales . - Determination of GSI . - Fecundity of Mrrgil cnyito . - Histological studies for gonads . - Histological studies for the pituitary gland and its different cells . Studying the relation of gonad maturation and the hypophysis, especially gonadotroph cells (GTH) . Reliable results were obtained and sulninarized as follows The average length of blclgil ctrpito varied from 1 0.5-32.5 cm for females and 1 0.5-34.5 cm for males.The total average length measured 26.5~111c orresponding to ayc group I11 The males IC.~ccgilcnpitom ature sexually at a smallcr size than females. Females and males ripe during their third year at 26.5 cm . Age group 1 was observed in Februa~y-March and April at 16.3% of the total samples,\vl~ile age groups 11 and III constituted 3 1.4% and 42.6% respectively of the total samples.Fishes in age group IV were also identified in October only at 61.1 % of the total samples.The age group V constituting 11.5% and were determined in December. The third age group was frequency dominate 42.6%.This dominance may be due to the fish selection of the used gears . Length-weight relationsl~ipw as expresed by the following equation: Log W = -1.9582+2.8909 Log L . Applying the calculations of the condition factor, it was less than one. Female growth was slightly higher than that of male.The correlation between gonadic weight and fish body weight (gonadosornatic index GS1)was used to describe the gonad’s state.There was a positive correlation between the absolute and relative fecundities and fkh length, weight and age.The egg diameter increased with increasing fish length .The histological study of the gonads elucidated that , the ovaries pass through two periods of maturation: Protoplasmic and Trophoplasmic growth. Protoplasmic growth starts after mitotic division of’ the germ cclls.This period is furthcr divided into two stages of ~nnturation which are characterized by the increase in cell size due to increase of the protoplasmic mass . Trophoplasmic growth appears in females when yolk and fat droplets being deposited in the cytoplasm of oocytes. The oocytes enlarge during the thlrd, fourth stagcs of nmturatlon. The primary yolk globules are usually round in fonn and when the oocytes grow, secondary yolk globules begin to appear. The ovarian follicles comprise two main cell layers,an inner granulosa and an outer thecal layer, separated by a thick basement membrane. Zona-radiata consists of two layers an outer (externa) and inner layer (interna) which consist of many membranous reticular network lamellae. The unovulated unripe eggs of females were reabsorbed . This atresia occurs in oocytes of stage 111 and V not only involves the cytoplasm and the nucleus but also includes yolk and lipid globules . Testicular development passes through four distinguished stages, starting with spennatogonia which give the primary sperniatocytes developing to secondary sper~natocytes.Then smaller spermatids de\dop which give finally spermatozoa