[A-CG42] Science in the Arctic Region

[ACG42-14] Long-term hydroacoustic monitoring of ice dynamics and animals in glacial fjords, NW Greenland

*Evgeny A. Podolskiy¹, Mayuko Otsuki², Kohei Hasegawa³, Shin Sugiyama⁴ (1.Arctic Research Center, Hokkaido University, 2.Graduate School of Fisheries Sciences, Hokkaido University, 3.Department of Marine Environmental Science, Hokkaido University, 4.Institute of Low Temperature Science, Hokkaido University)

Keywords:hydroacoustic, Greenland, ice, whale, Arctic

Listening in the ocean continuously and over a long-term opens many unique interdisciplinary opportunities in research and wildlife conservation. In remote arctic seas, high-resolution records of environmental, anthropogenic, and animal sounds (called geophony, anthrophony, and biophony, respectively) are particularly valuable. Despite the harsh conditions of the frozen sea and polar night, acoustic records can inform us about endemic animals' biodiversity, ice dynamics, and human activities.

Since August 2022, we have initiated continuous hydroacoustic monitoring in Inglefield Bredning Fjord, Northwest Greenland. This fjord is a key summering ground for endemic arctic whales (narwhals) filled with giant icebergs discharged by several fast-flowing maritime glaciers. We deployed five moorings to depths ~200-400 m, three of which could be successfully retrieved and redeployed in August 2023. These moorings included high-frequency hydrophones (Soundtraps ST 600 sampling at 64 kHz) and other oceanographic sensors (such as a CTD and a current meter), yielding more than 2 Tb of data.

All stations showed frequent bursts of noise due to icebergs, a dramatic overall reduction of noise in winter, persistent sound of ice melt, and an acoustic presence of narwhals in summer and fall. Here, we present our ongoing monitoring effort, show examples of this unique dataset, and discuss the challenges of data collection and signal analysis in some of the noisiest environments of the ocean.