Population Biology of Red Swamp Crayfish, Procambarus Clarkii (Girard, 1852) in the Guadalquivir River Marshes, Spain

Abstract

Observations on a Procambarus clarkii population were carried out in the rice fields of the Guadalquivir river marshes. From April through October, 1993, crayfish samples were collected in traps (nasa) for the determination of reproductive state and total length. Females outnumbered males throughout the entire harvesting period with an average sex ratio of 1.414 (females/males). Ripe eggs (peaking in September and in May) and mature males (peaking in June) were observed during the whole rice growing period.