PRIMARY RESEARCH PAPER Role of winds and tides in timing of beach strandings, occurrence, and significance of swarms of the jellyfish Crambione mastigophora Mass 1903 (Scyphozoa: Rhizostomeae: Catostylidae) in north-western Australia John K. Keesing . Lisa-Ann Gershwin . Tim Trew . Joanna Strzelecki . Douglas Bearham . Dongyan Liu . Yueqi Wang . Wolfgang Zeidler . Kimberley Onton . Dirk Slawinski Received: 20 May 2015 / Revised: 29 September 2015 / Accepted: 29 September 2015 Ó Springer International Publishing Switzerland 2015 Abstract Very large swarms of the red jellyfish Crambione mastigophora in north-western Australia disrupt swimming on tourist beaches causing eco- nomic impacts. In October 2012, jellyfish stranding on Cable Beach (density 2.20 ± 0.43 ind. m -2 ) was estimated at 52.8 million individuals or 14,172 t wet weight along 15 km of beach. Reports of strandings after this period and up to 250 km south of this location indicate even larger swarm biomass. Strandings of jellyfish were significantly associated with a 2-day lag in conditions of small tidal ranges ( \ 5 m). More than 90% of strandings occurred 2 days after winds were blowing onshore, but with the small number of days when satellite wind data were available during the study period, this result was not statistically significant. Dedicated instrument measurements of meteorological parameters, rather than the indirect measures used in this study (satellite winds and modelled currents) may improve the predictability of such events and help authorities to plan for and manage swimming activity on beaches. We also show a high incidence of predation by C. mastigophora on bivalve larvae which may have a significant impact on the reproductive output of pearl oyster broodstock in the region. Keywords Jellyfish Á Bloom Á Wind Á Tide Á Diet Á Bivalve larvae Introduction Jellyfish are a ubiquitous and readily observed com- ponent of marine plankton. They may exist in high Electronic supplementary material The online version of this article (doi:10.1007/s10750-015-2525-5) contains supple- mentary material, which is available to authorized users. Handling editor: Sigru ´n Huld Jo ´nasdo ´ttir J. K. Keesing (&) Á J. Strzelecki Á D. Bearham Á D. Slawinski CSIRO Oceans and Atmosphere, Private Bag 5, Wembley 6913, Australia e-mail: john.keesing@csiro.au L.-A. Gershwin CSIRO Oceans and Atmosphere, GPO Box 1538, Hobart 7001, Australia T. Trew Shire of Broome, PO Box 44, Broome 6725, Australia D. Liu Á Y. Wang Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, Shandong, People’s Republic of China W. Zeidler South Australian Museum, North Terrace, Adelaide 5000, Australia K. Onton Department of Parks and Wildlife, Pilbara Region, PO Box 835, Karratha 6714, Australia 123 Hydrobiologia DOI 10.1007/s10750-015-2525-5