Ecological and societal benefits of jellyfish

Jellyfish are often considered as stressors on marine ecosystems or as indicators of highly perturbed systems. Far less attention is given to the potential of such species to provide beneficial ecosystem services in their own right. In an attempt to redress this imbalance, we take the liberty of portraying jellyfish in a positive light and suggest that the story is not entirely one of doom and gloom. More specifically, we outline how gelatinous marine species contribute to the four categories of ecosystem services (regulating, supporting, provisioning and cultural) defined by the Millennium Ecosystem Assessment. This discussion ranges from the role of jellyfish in carbon capture and advection to the deep ocean through to the creation of microhabitat for developing fishes and the advancement of citizen science programmes. Attention is paid also to incorporation of gelatinous species into fisheries or ecosystem-level models and the mechanisms by which we can improve the transfer of information between jellyfish researchers and the wider non-specialist community.