Environmental DNA Monitoring of Narwhal (Monodon monoceros) and Fish Biodiversity with Inuit Communities

Abstract

The Northern Hudson Bay (NHB) narwhal (Monodon monoceros) population is geographically and genetically distinct and represents a vital cultural and subsistence resource for Inuit communities in Nunavut. While aerial surveys provide abundance estimates for population models and sustainable harvest limits, complementary approaches are needed to expand spatial and temporal monitoring in the rapidly changing Arctic. Here, we demonstrate how Inuit community members can actively contribute to monitoring narwhals and co-occurring taxa using environmental DNA (eDNA). Opportunistic water samples collected by hunters during subsistence outings detected narwhal eDNA alongside multiple fish and marine mammal species, providing ecological information difficult to obtain from aerial surveys, particularly for smaller-bodied taxa such as fish that are rarely detectable from aircraft. We also compare two metabarcoding assays, 12S160 and MiFish-U, for detecting marine mammal and fish DNA. MiFish-U primarily detected narwhal in the hunting context, whereas 12S160 mainly detected fish. These findings highlight the potential to collect multi-taxa ecological data during traditional hunting activities using a minimally invasive method. Incorporating eDNA sampling into long-term monitoring in collaboration with Inuit communities can enhance biodiversity assessments and advance our understanding of narwhal ecology in Arctic marine ecosystems.