Spatial Variations in The Length-Weight Relationship and Relative Condition Factor of The Introduced Freshwater Crayfish, Procambarus clarkii, (Girard, 1852) from the River Nile and Its Tributaries, Egypt

Document Type : Original Article


1 National Institute of and Oceanography and Fisheries, Al Kanater.

2 Faculty of Science (Boys), Al-AzharUniversity, Cairo, Egypt

3 Faculty of Science (Girls), Al-Azhar University, Cairo, Egypt.

4 National Institute of and Oceanography and Fisheries, Al Kanater


The biometric relationships for the freshwater crayfish, Procambarus clarkii (Girard, 1852) collected from four different sites of the River Nile and its tributaries (Helwan, El Warraq, El Rahawy and El Rayah El Menoufy) had calculated during the present study. The size of these individuals varied from 6.6 to 14.3 cm in total length, and from 3.6 to 80.8 g in total body weight. There was an obvious gradual increase in average weight, varied from 26.81 ±14.47g at Helwan to 27.46±18.6 g and, 27.52 ±17.22 g at El Warraq and El Rayah El Mounofy, respectively, reaching the highest average of 34.48±22.5 g at El Rahawy. The relationship < /span> between the total length and total body weight for the whole population (sexes combined) showed curvilinear relation at all sites, with positive allometric regression coefficient "b" higher than an isometric value ‘3”, recorded 3.169, 3.301 and 3.228 at Helwan, El Warraq and El Rahawy, respectively, but declined to negative allometry of 2.576 at El Rayah El Mounofy. The values of “b” were also higher in males than females at all between sexes (P> 0.05). The values of relative condition factor "Kn" (wellbeing) for this species was generally higher than ‘1” at most sites and averaged 1.14 ± 0.20, 0.96± 0.18, 1.12± 0.14 and 1.11+0.27 at Helwan, El Warraq, El Rahawy and El Rayah El Mounofy, respectively. It was also relatively higher in small and medium-sized individuals than the larger sizes.