Not all jellyfish are equal: isotopic evidence for inter- and intraspecific variation in jellyfish trophic ecology

Nicholas E C Fleming, Chris Harrod*, Jason Newton, Jonathan D R Houghton

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

37 Citations (Scopus)
276 Downloads (Pure)

Abstract

Jellyfish are highly topical within studies of pelagic food-webs and there is a growing realisation that their role is more complex than once thought. Efforts being made to include jellyfish within fisheries and ecosystem models are an important step forward, but our present understanding of their underlying trophic ecology can lead to their oversimplification in these models. Gelatinous zooplankton represent a polyphyletic assemblage spanning >2,000 species that inhabit coastal seas to the deep-ocean and employ a wide variety of foraging strategies. Despite this diversity, many contemporary modelling approaches include jellyfish as a single functional group feeding at one or two trophic levels at most. Recent reviews have drawn attention to this issue and highlighted the need for improved communication between biologists and theoreticians if this problem is to be overcome. We used stable isotopes to investigate the trophic ecology of three co-occurring scyphozoan jellyfish species (Aurelia aurita, Cyanea lamarckii and C. capillata) within a temperate, coastal food-web in the NE Atlantic. Using information on individual size, time of year and ;delta C-13 and delta N-15 stable isotope values, we examined: (1) whether all jellyfish could be considered as a single functional group, or showed distinct inter-specific differences in trophic ecology; (2) Were size-based shifts in trophic position, found previously in A. aurita, a common trait across species?; (3) When considered collectively, did the trophic position of three sympatric species remain constant over time? Differences in delta N-15 (trophic position) were evident between all three species, with size-based and temporal shifts in delta N-15 apparent in A. aurita and C. capillata. The isotopic niche width for all species combined increased throughout the season, reflecting temporal shifts in trophic position and seasonal succession in these gelatinous species. Taken together, these findings support previous assertions that jellyfish require more robust inclusion in marine fisheries or ecosystem models.
Original languageEnglish
Article numbere1110
Number of pages21
JournalPeerJ
Volume3
DOIs
Publication statusPublished - 21 Jul 2015

Keywords

  • Aurelia aurita
  • Bayesian statistics
  • Cyanea capillata
  • Cyanea lamarckii
  • Food web
  • Niche width
  • Scyphozoan jellyfish

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Medicine(all)
  • Neuroscience(all)

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