Effects of osmotic pressure, temperature and stocking density on survival and sexual reproduction of Craspedacusta sowerbii

• Published in: Dōngwùxué yánjiū 2016-03, Vol.37 (2), p.90-95
• Main Authors: Zhang, Yuan-Wei, Pan, Xiao-Fu, Wang, Xiao-Ai, Jiang, Wan-Sheng, Liu, Qian, Yang, Jun-Xing
• Format: Article
• Language: English
• Subjects: Animal behavior; Animal reproduction; Animals; Density; Female; Hydrozoa - growth & development; Hydrozoa - physiology; Male; Osmotic Pressure; Reproduction; Survival Analysis; Temperature; 放养密度; 桃花水母; 渗透压; 温度; 生存时间; 繁殖密度; 非线性关系; 饲养密度
• ISSN: 0254-5853
• DOI: 10.13918/j.issn.2095-8137.2016.2.90

The effects of osmotic pressure, temperature and stocking density on medusae survival of Craspedacusta sowerbii were examined. The medusae were shown to be sensitive to the variations of osmotic pressure. And the survival time was 〈90 h at 34 mOsm/L and it declined rapidly with rising osmotic pressure. The peak survival time of 〉200 h was recorded at 0.2 mOsm/L. Comparing with 27℃ and 32 ℃ treatments, 23 ℃ treatment yielded lower activities at a range of 8-13/min. However, there was a longer survival time. A non-linear relationship existed between survival time and stocking density. Lower density resulted in larger body size. And sexual reproduction resumed after breeding for 〉22 days. Newly-formed polyps and medusae appeared subsequently but only in the higher-density groups of 10, 14 and 18 ind./L. It suggested that the number of newly-formed polyps and medusae was highly dependent on stocking density. That is, a higher stocking density produced more organisms. However, newly-formed medusae died within one month and none grew a diameter of 〉5 mm.