Review of jellyfish trophic interactions in the Baltic Sea

ABSTRACT

Despite the diversity and oftentimes large biomass of jellyfish in marine systems, their ecological role remains poorly understood. We here provide the first systematic review of studies on jellyfish trophic ecology in the Baltic Sea (a regional marine system under strong multiple global and regional anthropogenic pressures). In total, we identified 57 peer-reviewed publications, with notable taxonomic bias towards two species (Aurelia aurita; non-indigenous Mnemiopsis leidyi) and spatial bias towards five areas (Bornholm Basin, Kiel Bight, Kertinge Nor, Lim- and Gullmarsfjord). The studies provide evidence for diverse trophic roles of jellyfish as predators and as competitors of other jellyfish, zooplankton and fish species. In combination, the studies also highlight potentially large impacts via top-down (grazing) and bottom-up (nutrient excretion) effects, but also, strong spatio-temporal variability in the magnitude of these effects, depending on the occurrence of jellyfish blooms. Studies on the role of jellyfish as prey for fish, seabirds or marine mammals, and for benthic systems via food-falls, were limited or lacking for the Baltic Sea, despite increasing focus on these topics globally. Improved understanding of the temporal (seasonal, inter-annual, long-term) and spatial variability of blooms and corresponding trophic effects, would provide more systematic understanding of the ecological role of jellyfish in the spatio-temporally variable Baltic Sea. A broader spatial coverage, inclusion of more jellyfish taxa and under-studied early life history stages, as well as the implementation and continuation of long-term data series would represent important steps towards this goal.

KEYWORDS:

• Food web
• predation
• competition
• zooplankton
• fish
• Aurelia aurita

Acknowledgement

The authors thank Susanne Landis @scienstration.com for providing professional illustrations.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

All authors received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 774499, project ‘GoJelly – a gelatinous solution to plastic pollution’. Jan Dierking received additional support from the BONUS XWEBS project, which is funded by BONUS (Art 185), funded jointly by the EU and the German Federal Ministry of Education and Research. Additionally the authors would like to thank the reviewers and editor for constructive comments on the manuscript.