Genetic Analysis of Shape in Trout using image analysis

Abstract Text: We used digital images of rainbow trout (lateral view) to fit an ellipse around the circumference of the fish. The values for L and H, obtained from the ellipse, were used to calculate ellipticity as (L-H)/(L+H), and the surface area of the fish as π*1/2 L*1/2H. Heritability of ellipticity and surface area at age 8 months was 0.23 and 0.21. Surface area had near-unity genetic correlation with body weight at same age. Genetic correlations of ellipticity with body weight and surface area were -0.55 and -0.56. Genetic correlation of ellipticity with harvest weight at 14 months was -0.49. Estimates of ellipticity are comparable with those of Nile tilapia and common sole. We conclude that when shape is important, ellipticity should be included in the breeding goal, with a weight that reflects the desired direction of change in shape.

Keywords:

fish

shape

genetics