Prodissoconch growth of oysters Crassostrea Sacco, 1897 (Bivalvia, Ostreidae)

Abstract

Larval growth of three species of Crassostrea oysters was studied in laboratory conditions. Crassostrea rhizophorae and Crassostrea brasiliana are native species of the Paraná coast and are commercialized at local market. Crassostrea gigas, the Japanese oyster, is an exotic species and was introduced in Brazilian waters for aquaculture. Due to morphological and size similarities among Crassostrea larval shells, larvae identification in plankton samples are extremely difficult. In this paper we analyze prodissoconch modifications during larval growth. Samples collected from hatchery tanks were preserved in 70% ethanol. Larval dimension (height and length), duration of larval period, and prodissoconch growth in larval stages: D, umbo and pediveliger were studied. Results showed similarities in larval growth patterns between C. brasiliana and C. gigas. The longest larval growth period, from fertilization to metamorphosis, and the smallest larvae dimensions were observed in C. rhizophorae.