This study compares the gonadosomatic index (GSI), oocyte growth (OG), gonadal histology, and plasma level concentrations of sex hormones (estradiol-17β (E2) and vitellogenin (V)) of twice-spawning (T-SP) and once-spawning (O-SP) females of rainbow trout throughout the additional and the normal reproductive cycle, respectively. In T-SP, the GSI values rapidly increase from May to November, in c...

  This study involves the investigation of Tinca tinca (L., 1758) living in Kapulukaya Reservoir in Turkey. It was observed that the fish reach sexual maturity at the age of III and the breeding period starts in May and ends in July. The mean monthly gonadosomatic indices varied from 1.38 ±0.06 (in October) to 8.01±1.03 (in May). According to monthly variations of the GSI, spawning of the tench...

A reproductive analysis of 1225 specimens of Poeciliopsis gracilis obtained through monthly samples from Coatetelco, a tropical shallow lake in Central Mexico, was made. There was an evident sexual dimorphism, including a difference in body size at the onset of reproduction. Sex ratio deviated significantly from unity. Monthly variations in gonadosomatic (GSI), hepatosomatic (HSI) indexes and o...

In the present study tissue cholesterol and serum cortisol changes during two reproductive phases have been correlated in the freshwater fish Notopterus notopterus. The reproductive cycle of N. notopterus has two phases such as breeding phase (April - August) and non breading phase (October - December). The cholesterol content of the ovary and liver increased during breeding phase. The serum co...

This study was aimed to observe the correlations among egg, larvae and maternal characteristics of Persian sturgeon. A total of 41 females were used and the variables including fertilization rate, incubation survival rate, larvae survival rate during yolk sac absorption (before feeding), and larvae survival rate after first feeding were determined. As a result, fertilization rate was positively...

This study was carried out with the aim of examining the seasonal reproductive cycle of the female crayfish Astacus leptodactylus from Aras Dam Lake, Western-Azerbaijan, Iran. Gonadosomatic index (GSI), and oocyte size were measured in females sampled seasonally in June, August, November(2011), January(2012). Development of the oocytes was categorized according to the diameter and the presenc...

This study was carried out with the aim of examining the seasonal reproductive cycle of the female crayfish Astacus leptodactylus from Aras Dam Lake, Western-Azerbaijan, Iran. Gonadosomatic index (GSI), and oocyte size were measured in females sampled seasonally in June, August, November(2011), January(2012). Development of the oocytes was categorized according to the diameter and the presenc...

ABSTRACT Anableps anableps is a viviparous teleost typical from Amazon Delta estuaries. It representative of this biome in Maracá, which offers potential for biomonitoring. The aim study to apply different biomarkers males and females species verify possible seasonal influences on their physiology. To collect fish, three expeditions were carried out the rainy season April 2018 February 2019. Bi...

Spatio-temporal patterns of the gonadosomatic index (GSI) and life cycle stages sea urchin Paracentrotus lividus were studied at two Corsican near sites which differ in terms protection status. The results highlighted an annual GSI with spring spawning (between May June) presumed lesser autumn (October or November). Spatial revealed homogeneity larval densities between whereas differences obser...