|Jellyplankton outbreaks (massive occurrences of medusae and other gelatinous planktonic organisms) are an increasing threat for some key economic activities in coastal areas, such as fisheries, aquaculture and recreation
Through a broad joint effort among 10 partners we will define the basic biological and ecological factors that govern reproduction, growth, and survival for a number of different species, commonly occurring in high abundance. Five different habitats are appointed as model environments, all characterised by their seasonal or permanent mass occurrence of jellyplankton, but otherwise quite divergent. These study sites are investigated with the aim of defining and quantifying the importance of each target species, and especially its ability to affect fish production, and are backed up by other field- and experimental studies. The results are put into a historical perspective by reviewing previous documentation of fisheries and jellyplankton biomass. Literature and new data will be used in a mathematical model, to define the competitive ability between the targeted jellyplankton species and visual predators like fish, and this will help in understanding in which biological and environmental conditions one or the other of the two types of competitors will dominate. We will also design and use a particle-tracking model that will improve the possibility of giving prognoses for mass-occurrence due to advective transport. As a more specific approach towards the aquaculture industry we will study acute and chronic effects on fish of jellyfish stings. The main findings of relevance to the society will be reported and recommendations of actions being made.