While whale-watching can be a wonderful way for humans to engage with nature and to promote marine conservation, the noise from the boats can adversely affect our flippered friends. Researchers observed mother and calf short-finned pilot whales (Globicephala macrorhynchus) as whale-watching vessels with differing engines (electric vs. petrol) approached the whales from 60 meters away (slightly longer than half of a football field).
The noise from the petrol-engine vessel (noise between 139-151dB) decreased the whales’ resting time by 29% and decreased nursing behaviors by 81% compared to when the researchers observed behaviors from a stationary boat 300 meters away (slightly less than 3 football fields). In comparison, quieter electric engines (noise between 136-140dB) did not significantly affect the mom and calf behaviors.
Short-finned pilot whales hunt for food at deep depths during the day, so resting is important for recovering from those long dives. Additionally, whale calves need a significant amount of nutrition from nursing to grow and thrive, so reductions in this behavior could be detrimental to their health and survival. So, if you are going whale watching, consider asking the organization what type of engine they use on their vessels, and opt for a tour with a quieter electric engine so you can see these majestic creatures without disturbing them!
Sketch and fact contributed by Karli Chudeau.
Arranz, P., Glarou, M. & Sprogis, K.R. (2021). Decreased resting and nursing in short-finned pilot whales when exposed to louder petrol engine noise of a hybrid whale-watch vessel. Scientific Reports, 11,21195. https://doi.org/10.1038/s41598-021-00487-0