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It has long been known that ship strikes involving large vessels pose one of the greatest threats to North Atlantic right whales, whose slow movements and tendency to stay close to the water’s surface make them vulnerable to such deadly collisions.

New research at Dalhousie University shows that the endangered animals can also suffer fatal injuries if struck by small boats or by large vessels travelling at slow speeds.

Scientists in the Department of Oceanography used information about right whale anatomy and Newtonian mechanics to construct simple biophysical models that predict the stresses whales experience during collisions.

The team, led by Dan Kelley and Sean Brillant, determined the magnitude of stress from a collision that would likely cause lethal injuries to large whales. The study focused particularly on North Atlantic right whales, whose population has recently dropped to about 350 worldwide, but the model is applicable to 10 species of large whales. The model revealed that vessels of all sizes can cause stresses higher than the critical (lethal) level, and that large vessels produce stresses much larger than this even when travelling at reduced speeds.

Users can input a ship’s speed and mass, as well as a whale’s blubber, bone and skin thickness, weight, species and length into the model to determine the probability of a strike’s lethality.

The researchers looked at 40 ship strikes where they knew the speed and size of the vessel and found that many of the whales did not have broken bones. Instead, they suffered from massive internal hemorrhaging, a finding that suggests that collisions can be fatal even if they don’t break bones but disrupt the blood system on the whale’s back.

Dr. Brillant is available to explain the implications of the research, which was recently published in Marine Mammal Science, and how the model may be used as a tool for shipping managers, policy makers, researchers, veterinarians and students.

The paper is available upon request.

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Media Contact:
Alison Auld
Senior Research Reporter
Dalhousie University
Cell: 902-220-0491
Email: Alison.auld@dal.ca