Fecundity reproductive cycle of a local population of Gammarus Pulex in Sepidan (Fars Province, Iran)

Gammarus pulex reproductive was studied in Komehr spring, in Komehr village Fars province, South of Iran. Specimens were collected using a net with 1 mm mesh size. Water temperature, DO, PH, No2, No, Po4, Ec, K, Mg, Total hardens and TDS were measured. Biological parameters including length and wet weight of males and females, number of female having eggs, number of eggs presented in moraspum sac of female, sex ratio, egg size, fecundity and reproductive effort was studied. Mean length of both sex and mean wet weight of males increased in autumn, decreased in spring and increased again in summer. Number of eggs in marsopium sac, femaleʹs wet weight, fecundity, and reproductive effort increased from autumn toward summer and egg volume increased in autumn and winter and reduces a little with increasing in eggʹs number in spring and summer. All reproductive factors showed significant differences throughout the year