海洋生态与环境科学重点实验室知识库

Jellyfish blooms have occurred worldwide and caused severe damage to tourism, fisheries, coastal industries and even the marine ecosystem, thus it has attracted widely public attention. The life cycle of scyphozoan jellyfish comprises a pelagic medusa stage and a benthic polyp stage. The success of asexual reproduction of the polyps directly determine the number of medusa, indicating the polyp stage is the key to understanding the population dynamic of medusae. Nemopilema nomurai, Aurelia sp.1 and Rhopilema esculentum are three common scyphozoan jellyfish in Chinese coastal waters, but to date, only the polyps of Aurelia sp.1 have been found, detecting the polyps of N. nomurai and R. esculentum is still an important topic. The polyps of the three species are possible to encounter with each other. To deepen understanding the distribution pattern of polyps of the three species, a 2×2 factorial design considering the attachment sequence and the size relationship of calyx diameter was set to explore the intraguild predation of the polyps. The results showed that the polyps of Aurelia sp.1 preyed on almost all polyps of the other two species in all treatments, except when the polyps of R. esculentum was bigger. The polyps of R. esculentum only preyed on the polyps of N. nomurai when the polyps of R. esculentum attached first and were bigger than the polyps of N. nomurai. The colony of polyps of N. nomurai was almost impossible to form in the place where the polyps of Aurelia sp.1 inhabited. The polyps of Aurelia sp.1 inhabited at depth of less than 20 m along coastal sea. Consequently, we conjectured that the colony of polyps of N. nomurai might be located in the nature habitats at depth of more than 20 m, which was helpful to detect the polyps of N. nomurai and confirm the nursery ground of N. nomurai. The polyps of Aurelia sp.1 aggressively preyed on polyps of other species might be useful knowledge for other systems in the world as well.