Impact of mobile offshore drilling units on Odontocetes (PDF)

Martin, S.B., K.A. Kowarski, and J.J.-Y. Delarue

The Effects of Noise on Aquatic Life (2023)

DOI: 10.1007/978-3-031-10417-6_103-1

Anthropogenic sounds can negatively impact marine mammals, limiting their ability to effectively forage or communicate, displacing them from a portion of their range, or causing physical harm. To date, potential impacts of sounds associated with mobile offshore drilling units (MODUs) on cetaceans have not been investigated. Acoustic recordings were collected at 1–2 km and 20–40 km from three MODUs to investigate variation in the acoustic occurrence of odontocetes with distance from the MODUs.

The West Aquarius MODU, West Hercules MODU, and Stena Forth MODU acoustic measurements lasted for at least 2 months each and included at least 1 min in 20 with high enough sampling rates to record the echolocation clicks of delphinids, beaked whales, and sperm whales. Recordings in the general area of the operations from previous years were also available. A comparison of the odontocete acoustic presence near the operations to the acoustic presence at longer distances showed a substantial difference in acoustic occurrence for dolphins, pilot whales, and beaked whales that could not be attributed to masking of detections by sounds from the operations.