سال انتشار: ۱۳۸۷

محل انتشار: اولین کنگره بین المللی مدیریت بهداشتی و بیماریهای آبزیان

تعداد صفحات: ۱

نویسنده(ها):

Peyman Mohammadzadeh – Azad University, Science and Research Branch. Tehran- Iran
Lalleh Ziaee microbiologist –
Sina Amiri –

چکیده:

Objective:Studies were conducted on the changes occurring in the ovaries of adult female Cichlosoma nigrofasciatum during a yearly cycle (between two spawning periods). The aims of this study were: (1) to confirm timing, frequency and duration of the spawning period, (2) to monitor changes in the gonado-somatic index, (3) to relate (GSI) the histological characteristics of the ovaries and (4) to describe the stages of oocyte and ovarian development.
Method & Materials: Gonadal samples were taken monthly from the females from septamber 2006 to July 2007. Gonad samples were stained with H & E Stain. Different stages of oocyte development (nucleus changes, oocyte diameter and forming of yolk vesicle, yolk granules and lipid droplets) were surveyed.
Results & Conclusion: According to the results gonad development of Cichlosoma nigrofasciatum was asynchronous. Each month, there were individuals with gonads at a range of developmental stages, and it is clear that not all females spawned at a same time. The GSI dramatically increased from September. A surge of GSI was observed in May. Results showed changes studied are not temperature-dependent and their course is similar, irrespective of whether the females had or had not spawned during the spawning season preceding the experimental period. Cichlasoma nigrofasciatum appropriate spawning habitat. Thus, the potential spawning season has been 6-7 months. spawning may occur whenever water temperature are >16° C for prolonged periods and there is appropriate spawning habitat. Thus, the potential spawning season has been 6-7 months.