Modelling population abundance and future trajectories for Arctic marine mammals to inform Canadian sustainable fisheries management

• Main Author: Biddlecombe, Brooke
• Other Authors: Ferguson, Steven (Biological Sciences), Muthukamarana, Saman (Statistics), Mills Flemming, Joanna (Dalhousie University), Wheeler (Watt), Cortney, Gillis, Darren
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: 2023
• Subjects: population dynamics; Arctic; cetaceans; harvest; stock status; abundance estimation; wildlife management; Arctic marine mammals; Balaena mysticetus; Beluga; Beluga*; bowhead whale; Climate change; Cumberland Sound; Delphinapterus leucas; Greenland; Hudson Bay; Monodon monoceros; narwhal*
• Online Access: http://hdl.handle.net/1993/37773

Arctic cetacean species, beluga whales (Delphinapterus leucas), narwhals (Monodon monoceros), and bowhead whales (Balaena mysticetus), have a long history of subsistence harvest by northern communities, as well as various levels of exploitation from historical commercial whaling. To achieve sustainable subsistence harvest, Arctic cetacean populations must be monitored to inform management decisions. Three populations: Northern Hudson Bay (NHB) narwhal, Cumberland Sound (CS) beluga, and Eastern Canada-West Greenland (EC-WG) bowhead whales, all pose various challenges associated with building population dynamics models for management. The NHB narwhal population presents challenges surrounding inconsistent abundance estimates which limit their ability to be included into a model, this was addressed by comparing abundance estimate methodologies and calculating correction factors to adjust older estimates accordingly. The CS beluga population is endangered and is assumed to be affected by the effects of climate change, thus, the challenge of incorporating environmental variables into a population dynamics model was addressed with this population. The EC-WG bowhead whales present a challenge with achieving an abundance estimate, as their vast range makes aerial surveys, the typical method for marine mammal abundance estimation, difficult. Instead, genetic mark-recapture analyses using biopsy samples were used to estimate EC-WG bowhead whale abundance. To model population dynamics of EC-WG bowhead whales the challenge of underestimated abundance from insufficient aerial survey coverage was addressed by using telemetry data in a utilization distribution map to extrapolate abundance. Challenges associated with determining population dynamics of Arctic cetaceans can be addressed with creative problem solving, considering the types of data available and specific management goals associated with each population of focus. February 2024 Fisheries and Oceans Canada