This work was planned to study the population dynamic parameters, economic evaluation of crayfish Procambarus clarkii (Girard, 1852) besides value-added products extracted from its shells. A total of 4682 crayfish specimens were collected from the Nile River from September 2021 to July 2022.
Results of the length-weight relationships of P. clarkii showed an isometric growth (b= 2.99). Total and natural mortality coefficients were recorded at 4.64 yr-1 and 1.41 yr-1, respectively. Consequently, the fishing mortality was estimated as 3.23 yr-1 and the present level of exploitation rate of P. clarkii was 0.70. For management purposes, the exploitation rate should be reduced from 0.70 to 0.38 or (32 %) to maintain the spawning stock biomass. An economic fishery evaluation of crayfish population size showed that crayfish production from the studied region of Nile River was recorded by GAFRD during the period from 2015 to 2020. Beni-Suef was considered the most productive governorate (with an average of 3337 tons or 43.4% of the total catch). The seasonal factor of crayfish was recorded at 2.8.
Concerning value-added products extracted from wet and dried crayfish shells; the values of vitamin A, lutein, β-carotene, Chlorophyll A, Chlorophyll B, and total carotenoids were recorded in wet shells; it sharply reduced in dried shells as affected by the drying process. Chitosan extracted from dried shells has good properties and antioxidant activity however, extracted from wet shells showed a good antimicrobial activity. The dominant essential amino acids (EAAs) of dried shells were lysine (312.98µg/g) followed by tyrosine (238.16µg/g).