Age and growth of Chrysichthys auratus (Geoffroy 1809) (Family: Claroteidae) from Lake Nasser, Egypt

Abstract

Chrysichthys is a widely distributed catfish in all inland and coastal water bodies and is one of the important commercial catfish families in Lake Nasser, Egypt. A total of 1176 Chrysichthys auratus specimens were collected from Lake Nasser during monthly catches in 2019. Total length (TL) ranged from 13 to 31 cm (mean 22.0 ± 3.0 cm), and total weight ranged from 23.1 to 320.2 g (mean 133.5 ± 52.2 g). For males, females, and combined sexes, the length–weight relationship revealed negative allometric growth. The condition factor values were highest during May for males, females, and combined sexes, and all values were >1.0, indicating that the fish were in good condition. Three age groups were identified from the data, with mean TLs of 19.16, 23.18, and 26.21 cm, as determined using vertebral growth rings. The growth constants of von Bertalanffy were calculated as L_∞ = 35.43 cm TL, K = 0.41 y⁻¹, and t_o =  − 1.7. The growth performance index was 2.55, and longevity was 9 y. The using of vertebrae was validated to age determination of C. auratus. These findings will contribute to assess the fishery status and fisheries management of C. auratus in Lake Nasser.