MEPS 591:7-27 (2018)  -  DOI: https://doi.org/10.3354/meps12213

ABSTRACT: Historically, jellyfish have been little studied relative to fishes, and they have been considered to be nuisances to humans and of little ecological importance. Research in the last 3 decades on Aequorea spp. hydromedusae highlights how important jellyfish are, how little is known, and the many needs and opportunities for studies on jellyfish. The family Aequoreidae contains about 30 recognized species worldwide; however, discrimination among those species is difficult and needs clarification by molecular genetics. As for most cnidarians with a swimming medusa stage, Aequorea spp. also have an attached stage that probably is key to bloom formation but whose extent and ecology are not known. Because of their large sizes, they are reported from citizen science programs and caught in fishing trawls; therefore, abundance data for Aequorea spp. exist from commercial fishing areas. Dietary data for Aequorea victoria show it is an important predator of fish eggs, fish larvae, and crustacean zooplankton, indicating that the medusae are potentially important as predators and competitors of fish. Although their potential importance seems obvious, Aequorea spp. have been understudied globally. New chemical methods may increase knowledge about feeding by Aequorea spp. and other species. Large-scale feeding effects could be estimated from metabolic and biomass data, which is important for ecosystem models and fisheries management. As pelagic cnidarians and ctenophores and opportunities to study them increase, new technology and methods will provide new insights into their biology.

KEY WORDS: Review · Bloom · Fish · Aquaculture · Gelatinous · Trophic · Predation · Reproduction · Zooplankton