Reproductive biology and histological studies of the grey mullet, liza ramada, (risso, 1826) in lake timsah, suez canal

Abstract

Reproductive characteristics of Liza ramada in Timsah Lake showed that the male reaches first sexual maturity smaller than the female at a total body length of 14 cm. and 16 cm., respectively. Overall sex ratio is 1: 1.7 for males to females. The gonado-somatic index of males was lower than that of females. Where, the maximum GSI values were recorded in November 5.03 % and 12.4 % for males and females, respectively. The maturity stages of male and female Liza ramada are morphologically separated according to the changes in shape, size and colour of the gonad in different successive stages. These stages are virgin, maturing virgin, developing, developed, gravid and spent stages. Histologically, the oocyte maturation showed the following phases; first growth phase which includes chromatin stage, early and late perinucleolus stages. Second growth phase includes vacuolization stage, yolk stages (primary, secondary and tertiary), mature stage and ripe stage. The testes maturation classified into spermatogonia, primary spermatocytes, secondary spermatocytes, spermatids and spermatozoa. Different points of view which take place in this work show that of the spawning season of Liza ramada in Timsah lake which may be extending from November to January.