Benthic ecosystem determines jellyfish blooms by controlling the polyp colony development.

The harmful irregular jellyfish blooms in recent years are difficult to be deciphered by macro hydrographic condition changes. To fundamentally explain the dynamic of jellyfish populations, we shifted the focus to the polyp stage of jellyfish life cycle and local benthic ecosystems. We monitored the population dynamics of Aurelia coerulea polyps in Jiaozhou Bay and other benthic biofouling species in situ to explore the adaptive mechanism of polyps and interspecific interactions in the benthic microhabitat. Our results showed that as temperature increased, the polyps multiplied on the bare substrate, however, other benthic fouling organisms simultaneously invaded the polyp colony according to their different colonisation methods and physiological characteristics. In addition, the polyps were extremely tolerant to food scarcity in the natural environment at low temperatures. Our study indicated that it is necessary to consider the local benthic ecosystem and implement ecosystem-based management strategies to predict and manage problematic jellyfish blooms.