Diagnosis, Prognosis, and Management of Jellyfish Swarms

Jellyfish includes creatures that are mostly constituted by water and have a gelatinous consistency.In this chapter, after providing a biological description of these organisms, the scales of variability associated to their life cycle and framing their dynamics in the context of the climate change, I review the diverse initiatives and management of coastal jellyfish swarms.Jellyfish swarms have relevant social and economic implications; however, systematic and periodic data of jellyfish occurrences along beaches is sparse.This data would help us to understand the inter-annual variability of the episodes of high jellyfish abundances and its potential relation to variable environmental conditions.Joint strategies with tools available to scientist, administration, policymakers, and stakeholders can optimize the cost of gathering these in situ data and maximize the benefit obtained from its scientific analysis.Three case studies of jellyfish blooms are presented, from which we can infer the importance of co-creation with stakeholders emerges as a key issue to allow for a solid understanding of the episodes and the implementation of appropriate knowledge-based future mitigation actions. Jellyfish: Biological Description and Scales of Variability Associated to Their Life Cycleellyfish, as a general term, includes creatures that are mostly constituted by water and have a gelatinous consistency.As gelatinous zooplankton they include a broad taxonomy, including numerous groups such as Ctenophores, Cnidarians, salps, larvaceans, molluscs, and worms.This chapter focuses on two phyla, namely Ctenophora and Cnidaria, which are the most relevant due to their great impact on the ecosystem and economy. Biological description of jellyfishAmong the gelatinous zooplankton, there is a distinct group of carnivores in the pelagic environment, the Ctenophores (commonly known as comb jellies).Recently, a new hypothesis of animal evolution emerged indicating that all animal phyla originated from this group (Dunn et al., 2015;Jager and Manuel, 2016;Presnell et al., 2016;Shen et al., 2017), having regenerative capacities as adults (Martindale, 2016).They have been found to be important predators in the surface waters of the open sea in the North Atlantic and Indian Ocean (Harbison et al., 1978), in the