Hierarchical Classification of Narwhal Subpopulations Using Social Distance

• Published in: The Journal of Wildlife Management
• Main Authors: Charry, Bertrand, Marcoux, Marianne, Cardille, Jeffrey A., Giroux‐Bougard, Xavier, Humphries, Murray M.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2019
• Subjects: Arctic Archipelago; Baffin Bay; Baffin; Canadian Arctic Archipelago; Jones Sound; Monodon monoceros; narwhal*; Smith sound
• Online Access: http://dx.doi.org/10.1002/jwmg.21799; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fjwmg.21799; https://onlinelibrary.wiley.com/doi/pdf/10.1002/jwmg.21799; https://onlinelibrary.wiley.com/doi/full-xml/10.1002/jwmg.21799

ABSTRACT Effective wildlife management and conservation require knowledge of distribution, sex composition, and age structure of a population. We explored the distribution of the Baffin Bay narwhal ( Monodon monoceros ) population in August 2013 by documenting sex and age distribution across the Canadian Arctic Archipelago covering 2,317,152 km 2 . For 6,314 narwhals identified in 3,393 aerial images taken across the Eastern Canadian Arctic, we calculated a matrix of swimming distances between all individuals. We then used a quantitative clustering approach to partition our dataset (partitioning around the medoids). The clusters obtained from the analysis supported the delimitation of the 5 narwhal management stocks currently used by the Department of Fisheries and Oceans but did not support the hypothesized division of Jones Sound and Smith Sound stocks. Across the 5 clusters, male:female ratios varied between 0.72 and 1.44 and the proportion of newborns relative to the number of females varied between 0.07 and 0.18. As a highly detailed snapshot of narwhal distribution across a very large region, our study is a step toward better documentation of the basic population information required for stock assessment, sustainable harvest, and habitat protection of narwhals in an era of rapid Arctic change. © 2019 The Wildlife Society.