Jellyfish are one of the most conspicuous animals in our oceans and are renowned for their propensity to form spectacular blooms. The unique features of the biology and ecology of jellyfish that enable them to bloom also make them successful invasive species and, in a few places around the world, jellyfish have become problematic. As man increasingly populates the world’s coastlines, interactions between humans and jellyfish are rising, often to the detriment of coastal-based industries such as tourism, fishing and power generation. However we must not lose sight of the fact that jellyfish have been forming blooms in the oceans for at least 500 million years, and are an essential component of normal, healthy ocean ecosystems. Here many of the world’s leading jellyfish experts explore the science behind jellyfish blooms. We examine the unique features of jellyfish biology and ecology that cause populations to ‘bloom and bust’, and, using case studies, we show why jellyfish are important to coastal and ocean ecosystem function. We outline strategies coastal managers can use to mitigate the effects of blooms on coastal industries thereby enabling humans to coexist with these fascinating creatures. Finally we highlight how jellyfish benefit society; providing us with food and one of the most biomedically-important compounds discovered in the 20th century. ​

Jellyfish generally are considered to be nuisances because they interfere with human activities by stinging swimmers, clogging power plant intakes and nets of fishermen, killing fish in aquaculture pens, and being both predators and competitors of fish. There is concern that environmental changes such as global warming, eutrophication, over-fishing, and coastal construction may benefit jellyfish populations. During this past decade following the first Jellyfish Blooms volume, some species have bloomed more frequently, expanded their range, and caused more problems for humans. Mnemiopsis leidyi, the ctenophore that invaded the Black Sea in the 1980s and damaged fisheries, now also blooms in the North, Baltic, and Mediterranean seas. Nemopilema nomurai, a giant Asian jellyfish, has bloomed frequently during this decade, causing severe damage to the Japanese fishing industry. Jellyfish Blooms: Interactions with Humans and Fisheries is the fourth volume in this series. Syntheses and original research articles address the question if jellyfish have increased globally and what factors may have contributed to the abundance of jellyfish. This volume is the most extensive to date, containing papers from all continents (except Antarctica) on scyphozoans, hydrozoans, cubozoans, staurozoans, and ctenophores, and on the fate of jellyfish blooms. This is a key reference for students and professional marine biologists, oceanographers, and fishery scientists and managers. Previously published in Hydrobiologia, vol. 690, 2012​

`Jellyfish', a group that includes scyphomedusae, hydromedusae, siphonophores and ctenophores, are important zooplankton predators throughout the world's estuaries and oceans. These beautiful creatures have come to public attention as featured exhibits in aquaria and in news headlines as invaders and as providers of genes used in biomedical research. Nevertheless, jellyfish are generally considered to be nuisances because they interfere with human activities by stinging swimmers, clogging power plant intakes and nets of fishermen and fish farms, and competing with fish and eating fish eggs and larvae. There is concern that environmental changes such as global warming, eutrophication, and over-fishing may result in increased jellyfish populations. The literature reviews and research papers in this volume explore the interactions between jellyfish and humans. Papers cover the medical aspects of jellyfish stings, jellyfish as human food and jellyfish fisheries, interactions of jellyfish and fish, effects of environmental changes on jellyfish, effects of introduced ctenophores on the Black Sea ecosystem, factors causing increases or concentrations of jellyfish, and others aspects of jellyfish ecology. This is an important reference for students and professional marine biologists, oceanographers, fishery scientists, and aquarists.

It is clear that a new type of human approach to marine ecosystems is needed to confront phenomena such as jellyfish blooms. This document provides an updated overview of this phenomenon in the Mediterranean and Black Sea and illustrates how the problem is affecting societies. It reviews current knowledge on gelatinous plankton in the affected region, providing a framework for its inclusion into fisheries science and the management of human activities such as tourism and coastal development. Fact sheets on the most important gelatinous plankters of the Mediterranean and Black Seas are included as an appendix.