A total of 1,690 individual narwhal nonecholocation sounds were recorded over 5 h in 2007 and 2009. Each sound was classified as either tonal (FM) or pulsed (amplitude modulated). Omnipresent in all the recordings were the songs of bearded seals, Erignathus barbatus, which were often so loud and numerous that the lower frequency ranges of narwhal sounds could not be distinguished.
Data extracted in the frame of a joint ICSTI/PANGAEA IPY effort, see http://doi.pangaea.de/10.1594/PANGAEA.150150
Supplement to: Stafford, Kathleen M; Laidre, Kristin L; Heide-Jørgensen, Mads Peter (2012): First acoustic recordings of narwhals (Monodon monoceros) in winter. Marine Mammal Science, 28(2), E197-E207