title: Effects of osmotic pressure, temperature and stocking density on survival and sexual reproduction of Craspedacusta sowerbii.
abstract: 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.
authors.affiliation: State Key Laboratory of Genetic Resources & Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Yuan-Wei
authors.initials: YW
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Genetic Resources & Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China.
authors.forename: Xiao-Fu
authors.initials: XF
authors.lastname: Pan
authors.affiliation: State Key Laboratory of Genetic Resources & Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China.
authors.forename: Xiao-Ai
authors.initials: XA
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Genetic Resources & Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China.
authors.forename: Wan-Sheng
authors.initials: WS
authors.lastname: Jiang
authors.affiliation: State Key Laboratory of Genetic Resources & Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Genetic Resources & Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China. yangjx@mail.kiz.ac.cn.
authors.forename: Jun-Xing
authors.initials: JX
authors.lastname: Yang
mesh_terms: D000818:Animals; D005260:Female; D037402:Hydrozoa / Q000254:growth & development / Q000502:physiology*; D008297:Male; D009997:Osmotic Pressure; D012098:Reproduction; D016019:Survival Analysis; D013696:Temperature
keywords: Craspedacusta sowerbii; Osmotic pressure; Stocking density; Temperature