More jellyfish (and less fish) in Tomorrow’s Arctic? Exploring jellyfish’ range shifts, their role in pelagic and benthic food webs and interactions with fish stocks

• Main Authors: Havermans, Charlotte, Murray, Ayla, Pantiukhin, Dmitrii, Friedrich, Madlen, Eschbach, Andrea, Verhaegen, Gerlien, Dischereit, Annkathrin
• Format: Conference Object
• Language: unknown
• Published: 2021
• Subjects: Arctic; Svalbard; Climate change; Kongsfjord*; Kongsfjorden
• Online Access: https://epic.awi.de/id/eprint/57226/; https://hdl.handle.net/10013/epic.d641c354-6722-4f98-ab29-043ccab4260b

Jellyfish (ctenophores and cnidarians) are known to be major drivers of ecosystem changes. Increases in biomass, referred to as “jellification”, have been observed in several marine ecosystems, causing, amongst others, the collapse of major fisheries. For the Arctic, comprehensive datasets on jellyfish are currently missing, impeding our ability to detect changes of a similar magnitude. The Helmholtz Young Investigator Group “ARJEL” aims to combine the most recent technologies in optics and environmental DNA analyses, to better understand the role of jellies in the Arctic seas. We apply species and community distribution models to a broad set of archived and newly obtained data to understand distribution patterns and to predict range and community shifts under future climate-change scenarios. The role of jellies in the Arctic food web, their seasonal and regional variation in feeding habits and their importance as prey for planktonic predators and fish is assessed with DNA metabarcoding and biomarker studies. We investigate the role of “jelly-falls” in sustaining the benthic food web. Experimental studies will determine jellyfish’ thermal windows and resilience. The outcomes of the models, trophic data, and insights into the connectivity and adaptability of jellyfish species, will allow us to improve food web and ecosystem models, currently neglecting jellyfish. An understanding of jellyfish-fish interactions, and how these will be impacted by climate-change driven range shifts, will shed light on the fate of commercially exploited Arctic fish stocks. We will present the project aims and first results, as well as our planned research activities during our stay at AWIPEV, Kongsfjorden, in January 2022. Our ongoing foci include: i) the comparison of jellyfish’ communities in Arctic vs. Atlantic-influenced Svalbard fjords to forecast the impact of the ongoing Atlantification; ii) the comparison between various methods for assessing jellyfish diversity; iii) the ecology of overwintering jellyfish in Kongsfjorden.