The present study showed that Carassius auratus have a moderately long life span, with average of 6-7 years. The population was detected in the Hammar marsh throughout the year. The monthly catch was dominated by age group 3 and 4 years, which accounted for 60% of the catch. The seasonal pattern of the relative condition factor indicates that maximum value coincided with pre-spawning period. The growth rates of C. auratus in East Hammar differ from those expressed in other regions of its distribution. This may be related to either variations in the ecological conditions or to the applied method used in age estimation. Fully mature specimens (maturity stage 6 and 7) were defined as those that were ready to reproduce. They reached maturity in the second year of life .The monthly percentage of individuals in different maturity stages and direct observation of gonads of C. auratus population in Hammar Marsh revealed that spawning of this species took place in March to September suggesting that different individuals do not mature at the same time and that there is an extended spawning season. Moreover the presences of all maturity stages of C. auratus in the investigated area indicates that Hammar Marsh is the spawning ground of this species and that there is no evidence of spawning migration. Fecundity varied from a mean of 227,800 eggs per female at 110 mm in total length to a mean of 545916 eggs per female at 309mm. It was correlated significantly with age, fish length, body weight and gonad weight.

No abstract

No abstract

No abstract