Sounds from airguns and fin whales recorded in the mid-Atlantic Ocean, 1999–2009

Abstract

Between 1999 and 2009, autonomous hydrophones were deployed to monitor seismic activity from 16° N to 50° N along the Mid-Atlantic Ridge. These data were examined for airgun sounds produced during offshore surveys for oil and gas deposits, as well as the 20 Hz pulse sounds from fin whales, which may be masked by airgun noise. An automatic detection algorithm was used to identify airgun sound patterns, and fin whale calling levels were summarized via long-term spectral analysis. Both airgun and fin whale sounds were recorded at all sites. Fin whale calling rates were higher at sites north of 32° N, increased during the late summer and fall months at all sites, and peaked during the winter months, a time when airgun noise was often prevalent. Seismic survey vessels were acoustically located off the coasts of three major areas: Newfoundland, northeast Brazil, and Senegal and Mauritania in West Africa. In some cases, airgun sounds were recorded almost 4000 km from the survey vessel in areas that are likely occupied by fin whales, and at some locations airgun sounds were recorded more than 80% days/month for more than 12 consecutive months.

Spatial and temporal distribution of cetaceans in the mid-Atlantic waters around the Azores

“…Here we show that B. physalus, B. borealis and B. musculus are frequently sighted every year, especially in spring and summer. Landbased observations indicate that these species also occur in the region in late autumn and winter, as has been recently shown for B. physalus using passive acoustic data (Silva et al 2011;Nieukirk et al 2012), and contradicting previous reports (Visser et al 2011). Baleen whales are thought to undertake annual migrations between low latitude wintering grounds and high latitude summer feeding areas.…”

Ocean ambient sound south of Bermuda and Panama Canal traffic

“…Much of the low frequency noise in the North Atlantic is driven by shipping and oil and gas exploration, both of which are prevalent across the basin (Ross, 2005;Klinck et al, 2012;Nieukirk et al, 2012). In this paper, we present recent (2013)(2014) monthly patterns in ocean ambient sound south of Bermuda and compare them to recordings collected at the same location in 1966 (Perrone, 1976).…”

Vocalization Source Level Distributions and Pulse Compression Gains of Diverse Baleen Whale Species in the Gulf of Maine

“…The fin whales are identified from their characteristic 20-Hz center frequency high intensity calls [5][6][7][8] that have been associated with communication among fin whale individuals [75] and also found to be uttered by males as breeding displays in their mating grounds [5,76] (Figure 1A). Instantaneous azimuthal bearing estimates of the selected 1410 fin whale vocalizations are associated into 20 distinct bearing-time trajectories (Figure 2).…”

“…The four baleen whale species analyzed here are fin whale (Balaenoptera physalus), sei whale (Balaenoptera borealis), minke whale (Balaenoptera acutorostrata) and an Unidentified Baleen Whale Species (UBWS) . Each baleen whale species was identified from its characteristic vocalization type: the fin whales were identified from their short duration 20-Hz center frequency calls [5][6][7][8]; the sei whales from their downsweep chirps occurring singly or as doublets with roughly a 4-s separation or sometimes as triplets [9][10][11]; and the minke whales were identified from their pulse trains [12][13][14] comprised of a series of click sequences (see Figure 1 here and also the Extended Data Figures 1-4 of [1]). The unidentified baleen whale species vocalized downsweep signals in the 30-60 Hz frequency range over a 2-3-second duration (see Figure 1J here and the Extended Data Figures 1B and 3A of [1]).…”