Fisheries and Oceans Canada (DFO) seeks to continue marine ecosystem research and monitoring of the Eclipse Sound region, including Tremblay Sound and Milne Inlet. This field program consists of passive acoustic monitoring, remote biopsy and tagging of killer whales and photo identification of killer whales. Length: 8 weeks Time: August – September Research Questions: 1.What are the fine-scale movements of narwhals in the Eclipse Sound area, and how do these movements relate to prey availability, predator presence, shipping traffic and oceanographic parameters? 2.What are the temporal and spatial patterns of underwater sound (biological, wind, ice, shipping) in Tremblay Sound and Milne Inlet?3.What is the population size and structure of killer whales in the Eastern Canadian Arctic and what is their ecology (distribution, movement, diet)? 4.What is the fine-scale behaviour of killer whales and how do they interact with their prey species and influence the Arctic marine ecosystem? Project Objectives: 1.Assess narwhal and killer whale abundance, behaviour and distribution in Eclipse Sound. 2.Examine environmental noise and vocalizations of marine mammals in Tremblay Sound and other areas. 3.Continuation of community-based research teams for remote tagging of killer whales and narwhals. 4.Produce a catalogue of killer whale calls and associated behaviors to allow for passive acoustic monitoring (PAM) of presence and activity throughout the study area. Rationale: Killer whale presence and shipping traffic is increasing in Eclipse Sound and there is growing concern among Inuit that this will negatively impact marine mammals and food security. This project seeks to understand cumulative effects of shipping and killer whales on narwhals. Methods: Hydrophones and recorders will be attached to small bottom anchored moorings placed within Milne Inlet and Tremblay Sound to record ambient noise, shipping noise, and marine mammal vocalizations. Specific locations will be determined after consultation with local Hunters and Trappers Organizations (HTO), Parks Canada, and local communities. Recorder deployments in Milne Inlet will be retrieved in the fall and retrieved the following summer in Tremblay Sound. Biopsy collection and satellite tag deployment will be done remotely from a boat using either CO2 rifles or crossbows. For satellite tagging of killer whales, the whales will be slowly approached by boat, to within 10m, and Limpet model satellite tags will be deployed onto the dorsal fin with 6-cm metal darts that will anchor below the skin into the cartilage. Impacts: Researchers will be stationed out of Pond Inlet. Environmental impacts from the project are expected to be minimal. Impacts from remote tagging are expected to be minimal and will follow the required DFO animal use protocols to ensure that the methods meet the Canadian Council on Animal Care guidelines. Community Involvement and Data: Locally hired project participants have been previously trained and involved in narwhal and killer whale research program (moorings, drones, remote tagging). The 2021 field program and beyond will continue to hire, train and work with Inuit researchers. Data will be stored and managed using DFO protocols. Interim and final results will be shared with local communities and organizations including those from graduate students’ research. *** The previous NPC application included narwhal and killer whale research. Due to covid-19 travel restrictions DFO personnel will not travelling to Nunavut and will not be doing any narwhal tagging or skin biopsies. Only killer whale research included in this application will be conducted in the summer of 2021 and all research will be done by trained Inuit researchers. Researchers will no longer be based in field camps, instead will be based from their homes in Pond Inlet. This has results in changes in the Materials Used, Water Use and Waste components of the NIRB application compared to the NPC application. The NIRB application is up to date with changes based on the revised research program.