THE EFFECTS OF TEMPERATURE AND SALINITY ON THE INCUBATION OF CYCLINA SINENSIS AND SURVIVAL, GROWTH AND METAMORPHOSIS OF C. SINENSIS LARVAE AND JUVENILES

The C. sinensis (Gmelin)belongs to the Lamellibranchia, Heterodonta, Veneroida and Veneroidae, is a familiar and economic seashell along sea in China. The reproductive season of this seashell is at 7-9months yearly, and it have entered now the large-scale artificial productive stage of seedling. In 2002-2003 years in the Leqing, Fenghua, et al, Zhe Jiang province, Author utilized the seedling facilities of the Te-gillarca granosa to engage in the seedling growth of C. sinensis, and investigated an influence of temperature and salinity on existing, growth regulations of the C. sinensis in different development stage. All these works will provide theoretical basis for increasing and steadying yield of the C. sinensis in seedling from now on. This experiments chooses to use with the parent clam 2-3 mature in ages, long specification in hull 3.0-4.5cm. At nine tempe-rature gradient (10-34℃)and under ten kinds of salinity(3-50) ,the effects of temperature and salinity on the incubation of C. sinensis and survival, growth and metamorphosis of C. sinensis larvae and juveniles are studied. The period experiment of floating to swim proceed totally 5d, after adhering to juveniles the experiment proceed 18d. The results show that suitable temperature is 24-32℃ for incubation and growth of larvae, and the most suitable temperature is all to 26-30℃. The suitable temperature is 22-32℃ for juveniles, and the best suitable temperature is 24-30℃. Under the most suitable temperature, the oosperm is changed to the D-shaped larva by 12-16h, and the metamorphosis rate amount to 80.7%-88.2% . The survival rate of the larvae and the juveniles distinguish for 86.2%-88.7% with 81.5%-84.0% ;Suitable salinity is 15-30 for incubation and growth of larvae, and 10%-35% for juveniles, the best suitable salinity is all to 20‰-25‰. Under the most suitable salinity; survival rate, metamorphosis rate and growth speed of the D-shaped larva are all tallest, attain 86.9% , 77.5% respectively with 9.38×11 .0μm/d. It need to spend average of 14-14.5d from the crawl larvae to the double, the live rate of the juveniles is 82.5%-85% to the double, the average growth in day amount to above 13. 1μm/d. The C. sinensis belongs to shellfish of a wide rang of temperature and salinity like most beach seashell, and the juveniles adaptability for the low salinity is stronger than the high salinity.