Quantifying spatial dynamics and stock structure of Atlantic halibut within the Gulf of St. Lawrence to improve sustainable exploitation and management

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Atlantic halibut (Hippoglossus hippoglossus) supports the most valuable groundfish fishery per-unit-weight in Atlantic Canada. Despite high socio-economic importance for 5 Canadian provinces, the stock in the Gulf of St. Lawrence (GSL) is currently managed under limited scientific knowledge, making the fishery vulnerable to changing ecosystem conditions. This research aims to generate new knowledge to improve the assessment and management of GSL Atlantic halibut. The main objective is to facilitate the optimal and sustainable exploitation of the resource by informing the design of a dedicated survey for the stock. This will be achieved through five specific objectives: (1) assess spatio-temporal variability in depth and temperature associations within the whole management unit through satellite tagging of adult fish; (2) reveal distribution and seasonal migration patterns using a geolocation model that relies on daily changes in depth and temperature recorded by satellite tags; (3) identify the timing and location of key behaviours such as spawning and feeding activity, which have implications for stock assessment and survey design; (4) locate potential nursery areas using a circulation model with the combined knowledge of spawning location, and egg and larval incubation period; and (5) assess connectivity among different sectors of the Gulf by quantifying movements through life history using otolith chemistry. In the short term, results from this program will facilitate the design of a new survey and provide a basis for improved management of the fishery including fishing quotas based on abundance of the resource. In the mid-term, the program will provide scientific information necessary for future choices by industry related to eco-certification, which typically gives access to premium markets and higher landed value. In the longer term, the students and postdoctoral fellow trained as part of this program will take key academic, government and industry positions in a sector where a severe shortage has been identified at the national level.