Zholdasova and Guseva, 1987


Zholdasova, I.M. and Guseva, L.N. (1987) Oogenesis and cyclic changes in the gonads of male and female catfish, Silurus glanis , in the lower Amudar'ya basin. Journal of Ichthyology, pp. 1-8

Associated characteristics

Species Development state Trait Primary Data Secondary Data
Silurus glanis Egg Oocyte diameter 1.65-2.3 [Diameter of ovulated egg cells] 1.97 mm
Silurus glanis Egg Egg adhesiveness Adhesive [This adhesive membrane ensures the development of the released eggs attached to substrate] Adhesive
Silurus glanis Female Age at sexual maturity 4 [Mass maturation in 5-6 years] 5.5 year
Silurus glanis Female Length at sexual maturity 63.5 63.5 cm
Silurus glanis Female Weight at sexual maturity 2.6 2.6 kg
Silurus glanis Female Oocyte development Asynchronous development of sex cells Asynchronous
Silurus glanis Female Onset of oogenesis Yolk accumulation in the oocytes of the old generation begins in autumn, and continues for 7-8 months ['October', 'November', 'December']
Silurus glanis Female Maximum GSI value 7.5% [Maturation coefficient, measured prior to spawning] 7.5 percent
Silurus glanis Female Oogenesis duration 7-8 months 7.5 months
Silurus glanis Female Resting period July, August: 0.42-0.81% 3.0 months
Silurus glanis Male Age at sexual maturity 3 [Mass maturation at 4-5] 4.5 years
Silurus glanis Male Length at sexual maturity 70.5 70.5 cm
Silurus glanis Male Weight at sexual maturity 2.2 2.2 kg
Silurus glanis Male Onset of spermatogenesis End of July-August ['July', 'August']
Silurus glanis Male Main spermatogenesis activity September ['September']
Silurus glanis Male Maximum GSI value May reach 0.94%, but mean is 0.38% 0.94 percent
Silurus glanis Male Spermatogenesis duration 2 months [July to September] 2.0 months
Silurus glanis Male Resting period 0.12-0.25% at the end of July [June-July] 3.0 months
Silurus glanis Spawning conditions Spawning season Second half of May ['May']
Silurus glanis Spawning conditions Spawning period duration 3-4 [Begins at the end of June and ends in Mid-July] 3.5 weeks
Silurus glanis Spawning conditions Spawning temperature 18-19°C 18.5 °C
Silurus glanis Spawning conditions Spawning water type Spawn in Amudar'ya River, its backwaters and lakes adjacent to the river Stagnant water
Silurus glanis Spawning conditions Spawning release Spawns intermittently [Most female spawns two batches of eggs] Multiple
Silurus glanis Spawning conditions Parity Alternate year spawning by some females No category