Abstract

For several years now, passive acoustics have been used extensively to monitor cetaceans, particularly humpback whales, which are very vocal during the breeding season. From January to June, humpback whales frequent the waters of the Caribbean and Martinique to breed and give birth. During this period, two stereophonic acoustic antennae were installed to the north west of Martinique (Bay of Saint Pierre) in order to detect and locate the humpback whales frequenting these waters. By recording 1 minute every 5 minutes, with a sampling frequency of 128kHz, over 1TB of data was recorded and analyzed. A neural network (CNN) was used to automatically detect humpback whale vocalizations, and animal passages were defined. The stereophony of the acoustic antennas enabled us to calculate the signal arrival delay times (TDoAs), and thus to define the azimuth of the source. In total, 3 passages were detected on the antenna to the North of Saint Pierre Bay, and 10 to the south, lasting from 2 to 16 hours. Most of these passages were in the same direction: from South to North, which shows that Martinique is indeed a stopover for humpback whales during their breeding season, and that they do not stay in the area for more than 16 hours. These antennae could be installed in future seasons to compare the acoustic presence of humpback whales in Martinique over several consecutive years