Supplementary material from "Use of glacial fronts by Narwhals ( Monodon monoceros ) in West Greenland"

• Main Authors: Laidre, Kristin L., Moon, Twila, Hauser, Donna, McGovern, Richard, Heide-Jørgensen, Mads Peter, Dietz, Rune, Hudson, Ben
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Figshare 2016
• Subjects: Ecology; FOS Biological sciences; 60801 Animal Behaviour; Arctic; Greenland; glacier; Iceberg*; Monodon monoceros; narwhal*
• Online Access: https://dx.doi.org/10.6084/m9.figshare.c.3518946.v1; https://figshare.com/collections/Supplementary_material_from_Use_of_glacial_fronts_by_Narwhals_i_Monodon_monoceros_i_in_West_Greenland_/3518946/1

Glacial fronts are important summer habitat for narwhals ( Monodon monoceros ), however, no studies have quantified which glacial properties attract whales. We investigated the importance of glacial habitats using telemetry data from n = 15 whales in September 1993 - 1994 and 2006 - 2007 in Melville Bay, West Greenland. For 41 marine-terminating glaciers, we estimated (i) narwhal presence/absence, (ii) number of 24h periods spent at glaciers and (iii) the fraction of narwhals that visited each glacier (at 5, 7 and 10km) in autumn. We also compiled data on glacier width, ice thickness, ice velocity, front advance/retreat, area and extent of iceberg discharge, bathymetry, subglacial freshwater run-off and sediment flux. Narwhal use of glacial habitats expanded in the 2000s probably due to reduced summer fast ice and later autumn freeze-up. Using a generalized multivariate framework, glacier ice front thickness (vertical height in the water column) was a significant covariate in all models. A negative relationship with glacier velocity was included in several models and glacier front width was a significant predictor in the 2000s. Results suggest narwhals prefer glaciers with potential for higher ambient freshwater melt over glaciers with silt-laden discharge. This may represent a preference for summer freshwater habitat, similar to other Arctic monodontids.