Evaluation of body weight and color of cultured European catfish (Silurus glanis) and African catfish (Clarias gariepinus) using image analysis

Abstract

Two cultured catfish species (European catfish Silurus glanis, and African catfish Clarias gariepinus) were evaluated for their weight estimation and colors by image analysis. A total of 60 whole fish from each species were first weighed, and then their pictures taken by a digital camera in a light box. Length, weight and color of all fish were determined by image analysis and results were compared between the two fish. Fish weight ranged from 7.4 to 39.61 g and 25.71 to 93.91 g for European and African catfish, respectively. Weight (W) vs length (L) data were fitted linear (W = A + BL), power (W = A LB) and second order polynomial equations (W = C0 + C1 L + C2 L2). The R2 values ranged from 0.835 to 0.974. For the W vs view area (V) relationship, the same equations were used. The R2 values for these equations ranged from 0.927 to 0.972. No significant difference was found between the average color values according to the L*, a* and b* distributions for both fish species (P > .05). Image analysis can easily determine length, view area, and color of fish and help in developing W vs L, and W vs V relationships.