Age and growth of wild Suminoe (Crassostrea ariakensis, Fugita 1913) and Pacific (C-gigas, Thunberg 1793) oysters from Laizhou Bay, China

Shell height at age estimates from Suminoe (Crassostrea ariakensis) and Pacific (C. gigas) oysters from a natural oyster reef in Laizhou Bay, China were compared with shell height at age estimates from triploid C. ariakensis of known age from the Rappahannock River, Virginia. C. ariakensis and C. gigas reach shell heights in excess of 76 mm (3 inches) within 2 years after settlement regardless of the source location. This fast growth appears to continue through at least we 4 or age 5 in wild individuals, because the growth trajectories for both specie, had not reached asymptotic height in (he oldest individuals collected. Estimates of the asymptotic maximum height (SHmax) from fitted Von Bertalanffy (VB) growth models were greatest for Chinese C. ariakensis (244.0 mm, standard error of the mean [SE] 30.4) and near the maximum shell height (227.0 mm) measured at the time of collection. Maximum shell heights measured on live Chinese C. gigas (173.0 mm) and Rappahannock C. ariakensis (190.0 mm) were also within the standard error estimates for the SHmax estimates from the fitted VB models for Chinese C. gigas (158.6 mm, SE 20.3) and Rappahannock C. ariakensis (183 mm, SE 19.1). Fitted VB growth curves were not significantly different between species within the same habitat, within species in different habitats or between species in different habitats. The ratio of shell height to shell width and shell height to shell inflation for triploid C. ariakensis was significantly less than similar ratios observed in wild C. ariakensis and C. gigas oysters.