Intertidal zonation and recruitment of oysters in the upstream of Jiantiao Bay, Sanmen County, Zhejiang Province

Abstract

This study aims to explore the intertidal zonation pattern of oysters and examine the effect of breeding site and spat collector on oyster recruitment in the upstream of Jiantiao Bay, which is essential to understand the biology, ecology and resource conservation of oysters. The quantitative field observations identified Kumamoto oyster <italic>Crassostrea sikamea</italic>, Sumonie oyster <italic>C</italic>. <italic>ariakensis</italic> and Hongkong oyster <italic>C</italic>. <italic>hongkongensis</italic> by using the morphological and molecular methods. <italic>C</italic>. <italic>hongkongensis</italic> was first recorded on the coast of Zhejiang Province. <italic>Crasssostrea sikamea</italic> was present at all five tidal zones (1.4 m, 2.2 m, 3.0 m, 3.8m, 4.6 m above the standard level in Jiantao Bay hydraulic station), and its densities gradually declined along a decreasing tidal elevation gradient. The densities of <italic>C</italic>. <italic>sikamea</italic> were the highest at the 4.6 m tidal zone and were significantly greater than those at the 1.4 m and 2.2 m tidal zones (<italic>P</italic><0.05). <italic>Crassostrea ariakensis</italic> and <italic>C</italic>. <italic>hongkongensis</italic> were only present at the deepest two tidal zones (1.4 m and 2.2 m). Results from the oyster recruitment experiments indicated that both recruitment site and spat collector significantly affected the densities and shell height of oyster spat. There were high oyster recruitment in the Jiantiao Bay. The study conlcuded that concrete tiles were better spat collector than plastic ring. In general, the upstream site (S1) should be recommended as the suitable breeding ground for <italic>C</italic>. <italic>sikamea</italic>.