SI2023 – A-5 – Tracking the Movements, Migrations, and Seasonal Residency of Atlantic Halibut (Hippoglossus) in the Sable Gully – Elizabeth Bateman

The northeastern tip of Sable Gully, a large submarine canyon near Sable Island, is one of the few known juvenile Atlantic Halibut “hotspots” on the Scotian Shelf. The Atlantic Halibut Council, in collaboration with Fisheries and Oceans Canada, Acadia University, Dalhousie University, and the Ocean Tracking Network (OTN), has deployed an acoustic receiver array and is now monitoring 144 km2 of this hotspot. This is the first acoustic telemetry project for Atlantic Halibut in Canada and provides valuable baseline information on the seasonal residency and movements of both juvenile and adult halibut through three detection methods: fixed receiver detections, active glider tracking, and opportunistic detections on other receiver networks maintained by the Gully Marine Protected Area (MPA), OTN, and their extensive network of collaborators throughout the Northwest Atlantic. Since 2020, 245 halibut ranging from 50-141 cm fork length have been acoustically tagged. After nearly 2 years and over half a million detections, this project suggests three migratory contingents occurring within the Sable Gully region: resident halibut that occupy the area year-round, seasonal migrants that return to the area annually, and dispersive halibut that undergo long-distance migrations. Detections of halibut on the Gully MPA receiver array deeper into the canyon indicate extensive movement into and out of the protected region. Halibut is Atlantic Canada’s most valuable groundfish, so new information on the movements of both juvenile and adult halibut will improve our understanding of stock structure and enable more sustainable management of this recently recovered species.