Image Analysis to Determine Length-Weight and Area-Weight Relationships, and Color Differences in Scaled Carp and Mirror Carp Grown in Fiberglass and Concrete Tanks

Sixty scaled carp Cyprinus carpio and sixty mirror carp Cyprinus carpio carpio were raised in fiberglass and concrete tanks. Fish pictures were taken by a digital camera in a lightbox. Image analysis was used to determine length-weight and view area-weight relationships. Length-weight data were fitted to a power equation: (Weight W) = A (Length L)(B). R-2 ranged from 0.838 to 0.959. Based on the B values, scaled and mirror carps reared in the fiberglass tank showed a negative allometric growth while this was positive for the fish in the concrete tank. For the view area (V)-weight relationship, linear (W = A + BV), and second order polynomial equations were used in addition to the power equation. The R-2 values for these equations ranged from 0.916 to 0.995. Skin color was measured by image analysis. Both scaled and mirror carp reared in concrete tanks had L*, a* and b* values significantly higher than those reared in fiberglass tanks (P < .05). Also, the fish reared in fiberglass tanks tended to have less weight for the same view area, compared to those reared in concrete tanks.