Establishing baselines for cetaceans using passive acoustic monitoring off west Africa

Abstract

Knowledge of cetacean presence in west African waters is sparse due to the remote and logistically challenging nature of working in these waters. Exploration and Production (EP therefore, collecting baseline information on species distribution is important. Previous research is limited although a number of species listed as vulnerable or data deficient by the IUCN red list have been documented. In 2012/2013, we deployed an array of eight Marine Autonomous Recording Units (MARUs) in a series of three deployments, off Northern Angola, targeting Mysticetes (2 kHz SR, continuous) during winter/spring and Odontocetes (32 kHz SR, 20% duty cycled) during summer/autumn. Preliminary results are presented on the temporal and spatial distribution of species identified from automated and manual detection methods. Humpback whales were frequently detected from August through December, with peaks during September/October. During the deployment period, sperm whales and Balaenopterid and Odontocete calls were also detected and possible species will be discussed. Species detections will be used to identify temporal hotspots for cetacean presence and any potential overlap with E&P activities. We recommend that future research efforts include visual and acoustic vessel surveys to increase the utility of passive acoustics for monitoring these populations.