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ESR prepress abstract   -  DOI:

Inter-annual variability in acoustic detection of blue and fin whale calls in the Northeast Atlantic High Arctic between 2008 and 2018

Heidi Ahonen*, Kathleen M. Stafford, Christian Lydersen, Catherine L. Berchok, Sue E. Moore, Kit M. Kovacs

*Corresponding author:

ABSTRACT: Northern Hemisphere blue and fin whales are regular summer migrants to Arctic waters. Given the profound changes the Arctic is currently undergoing due to global warming, changes in habitat use and distribution of these migratory species are predicted. In this study, three passive acoustic recorders were used to investigate the spatial and temporal vocal occurrence of these species in the Northeast Atlantic High Arctic - two in Fram Strait about 95 km apart and one north of the Svalbard Archipelago (Atwain). Acoustic data were available for seven years for western Fram Strait (WFS), two and a half years for central Fram Strait (CFS) and three years for Atwain. At both Fram Strait locations, most blue whale call detections occurred from August through October, though recently (2015–2018) in WFS a clear increase in blue whale call rates was detected in June/July, suggesting an expansion of the seasonal occurrence of blue whale. In WFS, fin whale 20 Hz calls were detected intermittently, at low levels, almost year-round. In CFS, fin whale calls were more frequent but occurred mainly from July through December. At Atwain, blue whale detections commenced in July, both species were recorded in September/October and fin whale calls extended into November. Results from this study provide novel long-term baseline information for the occurrence of blue and fin whales at extreme northerly locations, where traditional ship-based survey methods are seasonally limited. Continued sampling will support the investigation of how environmental change influences cetacean distribution and habitat use.