Characterizing the underwater soundscape at the site of a proposed port in northeast Iceland.

Finnafjörður is a small fjord in northeast Iceland, where the planned construction of a large port has the potential to meaningfully change the marine soundscape and ecosystem. In this study, we used one year (2021/22) of passive acoustic recordings to characterize the pre-construction soundscape, including broadband and decidecade sound pressure levels (SPL), frequency-weighted sound exposure levels, seasonal and diel variability and identified regular types of sound. Finnafjörður is relatively quiet with median decidecade levels centered between 25 Hz and 50 kHz of 74.5 to 86.3 dB re 1 μPa. Wind and rain dominate ambient SPL, while anthropogenic sources only occasionally contributed to the soundscape. Regular biological sound sources include humpback whales, toothed whales, and fish. This baseline soundscape description can be used for noise management during port construction, to monitor future changes in the region, and to act as a framework for comprehensive impact assessments as ports are developed globally.