Buoyant balaenids: the ups and downs of buoyancy in right whales

D P Nowacek, Mark Johnson, P L Tyack, K A Shorter, W A McLellan, D A Pabst

Research output: Contribution to journalArticlepeer-review

97 Citations (Scopus)


A variety of marine mammal species have been shown to conserve energy by using negative buoyancy to power prolonged descent glides during dives. A new non-invasive tag attached to North Atlantic right whales recorded swim stroke from changes in pitch angle derived from a three-axis accelerometer. These results show that right whales are positively buoyant near the surface, a finding that has significant implications for both energetics and management. Some of the most powerful fluke strokes observed in tagged right whales occur as they counteract this buoyancy as they start a dive. By contrast, right whales use positive buoyancy to power glides during ascent. Right whales appear to use their positive buoyancy for more efficient swimming and diving. However, this buoyancy may pose added risks of vessel collision. Such collisions are the primary source of anthropogenic mortality for North Atlantic right whales, whose population is critically endangered and declining. Buoyancy may impede diving responses to oncoming vessels and right whales may have a reduced ability to manoeuvre during free ascents. These risk factors can inform efforts to avoid collisions.

Original languageEnglish
Pages (from-to)1811-1816
Number of pages6
JournalProceedings of the Royal Society B: Biological Sciences
Issue number1478
Publication statusPublished - 7 Sept 2001


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