Environmental DNA metabarcoding reveals seasonal and spatial variation in the vertebrate fauna of Ilulissat Icefjord, Greenland

Sascha Schiøtt*, Mads Reinholdt Jensen, Eva Egelyng Sigsgaard, Peter Rask Møller, Marcelo de Paula Avila, Philip Francis Thomsen, Søren Rysgaard

*Corresponding author for this work

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaperJournal articleResearchpeer-review

Abstract

Ilulissat Icefjord in Greenland is experiencing the effects of climate change, with the
Sermeq Kujalleq glacier being one of the fastest-moving and most productive ice streams in
Greenland. This is likely affecting the distribution of species in the fjord, including those impor-
tant to local fisheries. Due to heavy ice conditions, few studies on environmental and ecological
conditions exist from the fjord. However, new techniques such as environmental DNA (eDNA)
meta

barcoding now allow deeper insight into the fjord system. Here, we combine local ecological
knowledge with data on hydrographic conditions, stable isotopes (δ18O), and eDNA metabarcod-
ing to investigate the spatial and seasonal distribution of marine fish and mammals inside Ilulissat
Icefjord. Our eDNA results support local observations that Arctic char migrate to the southern
fjord during summer, harp seals forage in large herds in the fjord system, polar cod is the domi-
nant prey fish in the area, and Greenland shark likely does not reside in the fjord system. Lower
predation pressure in the Icefjord, due to the absence of Greenland shark and polar bears as well
as limited fishing/hunting, is presumably one of the reasons why ringed seals and Greenland hal-
ibut are larger in the Icefjord. Furthermore, our results indicate that in summer, the southern
branch of the fjord system has a more diverse community of vertebrates and different water
masses than the northern branch and main fjord, indicating a time lag between inflows to the dif-
ferent branches of the fjord system. Our approach highlights the value of combining local ecolog-
ical knowledge with scientific research and represents a potential starting point for monitoring
biological responses in Ilulissat Icefjord associated with climate-induced changes.
Original languageEnglish
JournalMarine Ecology Progress Series
Volume706
Pages (from-to)91-108
Number of pages17
ISSN0171-8630
DOIs
Publication statusPublished - Feb 2023

Keywords

  • Indigenous knowledge
  • Jakobshavn Icefjord
  • Marine-terminating glacier
  • Oceanography
  • eDNA

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