Shell color polymorphism and metabolic activity in hatchery-reared juveniles of silver-lip pearl oyster, Pinctada maxima

This study describes the shell color polymorphism and its correspondent metabolic activities in hatchery-reared Pinctada maxima juveniles. Analysis of color distances assessed the similarities among the different phenotypes (Ph); from the most common Ph-1 (gray), Ph-2 (bronze), Ph-3 (white), Ph-4 (brown), Ph-5 (green), Ph-6 (purple), and Ph-7 (yellow). Yellow-colored shells (Ph-7) were found less unrelated to the other colored shells and also exhibited higher enzymatic activity; particularly in enzymes that have been linked to yellow or golden shell color in different bivalves. By contrast, green-colored shells (Ph-5) exhibited comparatively higher levels of enzymes (e.g. tyrosinase, superoxide dismutase) known to promote fast growth in various organisms, which is consistent considering that green-colored shells also exhibited the largest biometric values. These findings open the possibility to use shell color as a reliable indicator to breed high-quality P. maxima pearl oysters.