High Diversity of Killer Whale Populations Revealed by Passive Acoustic Monitoring in Gwaii Haanas, Haida Gwaii, Northern British Columbia, Canada, With Insights Into Seasonal Occurrence

ABSTRACT Marine waters of Gwaii Haanas National Park Reserve, National Marine Conservation Area Reserve, and Haida Heritage Site (Gwaii Haanas) in southern Haida Gwaii, Canada, provide habitat for several killer whale ( Orcinus orca ) populations that are culturally important to the indigenous Haida Nation and listed under Canada's Species at Risk Act. Detailed information about these populations in Gwaii Haanas is limited by the area's remoteness and challenging conditions for boat‐based surveys. We examined killer whale occurrence and seasonal presence inferred from distinctive vocalizations recorded during 14 year‐long deployments of underwater passive acoustic monitoring recorders at three sites during 2009–2024. Six populations from three ecotypes were detected: Bigg's (West Coast Transient and Gulf of Alaska), Resident (Northern, Southern, and Southern Alaska), and Offshore killer whales. Multiple detections of Southern Alaska Residents plus three independent visual encounters off Haida Gwaii provide the first documentation of this population in Canadian waters. A detection of Southern Resident killer whales is also notable, as this endangered population is rarely observed north of Vancouver Island. Passive acoustic monitoring in Gwaii Haanas revealed the highest killer whale population diversity of any such monitoring site in the northeastern Pacific, encompassing all populations known from Southeast Alaska to northern California.