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

• Published in: Marine Ecology Progress Series
• Main Authors: Schiøtt, Sascha, Jensen, Mads Reinholdt, Sigsgaard, Eva Egelyng, Møller, Peter Rask, de Paula Avila, Marcelo, Thomsen, Philip Francis, Rysgaard, Søren
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2023
• Subjects: Indigenous knowledge; Jakobshavn Icefjord; Marine-terminating glacier; Oceanography; eDNA; Arctic; Climate change; glacier; Greenland; Ilulissat; Jakobshavn; Kujalleq; polar cod; Sermeq Kujalleq
• Online Access: https://pure.au.dk/portal/da/publications/environmental-dna-metabarcoding-reveals-seasonal-and-spatial-variation-in-the-vertebrate-fauna-of-ilulissat-icefjord-greenland(5b691b4d-be2e-44e6-8f1c-3003da4be6c3).html; https://doi.org/10.3354/meps14250

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.