Jellyfish on the menu: mtDNA assay reveals scyphozoan predation in the Irish Sea

• Main Authors: Philip D. Lamb, Ewan Hunter, John K. Pinnegar, Simon Creer, Richard G. Davies, Martin I. Taylor
• Format: Article
• Language: English
• Published: The Royal Society 2017-01-01
• Series: Royal Society Open Science
• Subjects: jellyfish; diet; gut content analysis; predation; 16s mtdna
• Online Access: https://royalsocietypublishing.org/doi/pdf/10.1098/rsos.171421

Localized outbreaks of jellyfish, known as blooms, cause a variety of adverse ecological and economic effects. However, fundamental aspects of their ecology remain unknown. Notably, there is scant information on the role jellyfish occupy in food webs: in many ecosystems, few or no predators are known. To identify jellyfish consumers in the Irish Sea, we conducted a molecular gut content assessment of 50 potential predators using cnidarian-specific mtDNA primers and sequencing. We show that jellyfish predation may be more common than previously acknowledged: uncovering many previously unknown jellyfish predators. A substantial proportion of herring and whiting were found to have consumed jellyfish. Rare ingestion was also detected in a variety of other species. Given the phenology of jellyfish in the region, we suggest that the predation was probably targeting juvenile stages of the jellyfish life cycle.