Cetacean presence and ambient sound level analysis in Bermuda: A comparison to historical records

Abstract

Marine Protected Areas (MPAs) are established to conserve nature while also preserving ecosystem services and cultural values. Many ongoing MPA discussions are centered on offshore islands, including Bermuda, a British Overseas Territory in the North Atlantic Ocean, which is currently assessing a management plan to protect 20% of its EEZ. Marine mammals are essential targets to monitor as part of effective MPA management because they are keystone species. In addition, as human activities raise ocean noise levels worldwide, monitoring ambient sound levels is essential to evaluating impacts on marine ecosystems. We collected nine months of passive acoustic data (at 250 kHz sampling rate and with 24-bit resolution) between December 2021 and September 2022, approximately 24 nm south of Bermuda, close to a location where previous studies were conducted in 1966 and 2013–2014. The cetacean presence and ambient sound levels derived from our dataset will be compared to these historical datasets. Our comparative analysis focused on humpback whales (Megaptera novaeangliae), fin whales (Balaenoptera physalus), minke whales (Balaenoptera acutorostrata), blue whales (Balaenoptera musculus), sei whales (Balaenoptera borealis), and beaked whales (family Ziphiidae). Results will illustrate how Bermuda’s offshore underwater soundscape has changed over nearly six decades.