Annual changes in the ovarian activity of the freshwater teleost, <i>Barbus luteus</i> (Heckel) from Southern Iraq

Abstract

The present paper describes the morphology, histology, and annual cyclical changes in the ovaries of Barbus luteus (Heckel). The ovaries are paired structures, joined by short oviducts. The ovarian structure consists of a number of lamellae, which contain the germ cells in various phases of maturation—immature, maturing and mature. Two types of yolk have been reported in the oocyte. The endocrine function of the gonads has been attributed to the follicular cells forming the ‘pre‐ovulatory corpus luteum’ and ‘postovulatory corpus luteum’. The ovaries undergo a regular annual cycle which has been divided into five stages, based on various criteria, viz, ovarian size, colour, gonosomatic index, average ova‐diameter, histological composition, and the spawning activity.