Abstract:

In order to study the effect of climate change on gonad development of the blood clam of Yueqing Bay. The reproductive cycle of the blood clam from the pond culture of Yueqing Bay was studied from March 2010 to February 2011 in relation to environmental factors. The results indicated that gonad development of the blood clam could be divided into five stages: (1) proliferating stage; (2) growing stage; (3) maturing stage; (4) spawning stage; (5) resting stage. Histological analysis indicated that the gametogenesis of the blood clam began in March when water temperature was 16.6℃. Most of the blood clam matured in June to July and a massive spawning occurred after July when the temperature and chlorophyll a concentration decreased gradually. The blood clam from the pond culture of Yueqing Bay was a kind of animal of gonochorism, the mean oocyte diameter showed significant differences among months. It increased from (8.87±2.4) μm in March, reached a maximum value of (48.47±9.51) μm in July, decreased sharply after spawning, and attained a minimum value of (18.57±2.77) μm in August. Temperature and available food played an important role in the gametogenesis of the blood clam. The relationship between the size of oocyte and reproductive cycle demonstrated that oocyte diameter was a good indicator for identifying the gonadal maturity of the blood clam.