Classifying and combining herd surface activities and individual dive profiles to identify summer behaviours of beluga from the St. Lawrence Estuary, Canada

• Main Authors: Lemieux Lefebvre, Sébastien, Lesage, Veronique, Michaud, Robert, Humphries, Murray
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: NRC Research Press (a division of Canadian Science Publishing) 2017
• Subjects: Canada; Beluga; Beluga*; Delphinapterus leucas
• Online Access: http://hdl.handle.net/1807/87411; http://www.nrcresearchpress.com/doi/abs/10.1139/cjz-2017-0015

Studies of the behaviour of diving animals usually focus on either individual dives or surface group activities, but these complementary observations are seldom combined in the same study. We here study the summer (June-October) behaviour of St. Lawrence Estuary belugas (Delphinapterus leucas (Pallas, 1776)) by combining fine-scale individual diving data from 27 time-depth-speed recorder deployments (conducted in 2002-2005) with surface activity data from 1413 focal herd follows (conducted in1991-2012). We classified 6312 dives into seven dive types based on shape and swim speed. Dives were then combined into five bout types, including three pelagic, one benthic and one near-surface. We classified surface activities of herds into six clusters, differentiated primarily by their associated movement patterns (milling or directional) and further by herd structure and dispersion and occurrence of acrobatic surface events. Finally, we used herd focal follows conducted while tracking an individual beluga, to relate dive and bout types to surface activities. Results indicate that milling at the surface was more frequently related to benthic dives and potentially associated with behaviours such as benthic foraging, resting, socializing, and care of young. Directional surface movements were more frequently associated with pelagic dives likely used during pelagic foraging, exploration and travelling. The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author.