Sperm Whales Shift Click Patterns When Ships Pass

Researchers from the nonprofit Project CETI analyzed acoustic tags from 13 sperm whales off the Caribbean island of Dominica. The tags recorded more than 10,000 codas between 2014 and 2016. When background recordings detected nearby shipping noise, the whales produced a higher proportion of “a-codas” than “i-codas” and shortened the time between clicks. The change was strong enough that the team could predict the presence of ships from the whales’ click patterns. The findings were published on June 18 in *Ecological Informatics*.

Smithsonian Magazine

Shipping noise has doubled each decade since the first measurements in 1960, according to the nonprofit Ocean Conservancy. Acoustic ecologists warn that such anthropogenic sound can cause hearing loss, stress responses, altered geographic ranges, and disruptions to feeding and breeding in marine species. The study’s difficulty in classifying codas amid ship noise suggests that sperm whales may struggle to hear one another, potentially impairing communication.

Smithsonian Magazine

David Gruber, founder and president of Project CETI, noted that the compressed inter-click intervals raise the question of whether whales are merely reacting to noise or actively discussing the vessels. Nathan Merchant, an underwater bioacoustics expert at the U.K. government’s Centre for Environment Fishers and Aquaculture, described the results as adding nuance to the broader story of noise impacts on cetaceans.

Smithsonian Magazine

• “It really adds another dimension of nuance to that story about how underwater noise can affect cetaceans,” — Nathan Merchant, an underwater bioacoustics expert at the U

Smithsonian Magazine