Data Shows Humans as Leading Cause of Whale Deaths


Collisions with ships can be deadly for right whales.

An analysis of four decades worth of data indicates that most whale deaths in the oceans are caused by humans and that attempts to prevent this have not had a demonstrable impact.

There are only 460 North Atlantic right whales (Eubalaena glacialis) in the waters of Canada and the USA. Both countries have implemented measures to protect these whales from becoming entangled in fishing gear or being hit by ships in certain areas. The US ‘ship strike rule’ that limits vessel speeds in certain areas, came into effect in 2008 and is set to expire in 2013.

The scientists published their analysis of all known deaths of eight species of large whales in the northwest Atlantic between 1970 and 2009 in the journal Conservation Biology.

During this period, 122 right whales, 473 humpbacks (Megaptera novaeangliae), 257 fin whales (Balaenoptera physalus), and scores of other whale species perished. In 67% of the cases, the scientists were able to assign human interaction as the cause of death. The entanglement in fishing gear remains the main cause of death in this category.

While the overall protection measures seemed to have no impact on whale deaths, several of the rules were only implemented towards the end of the study period and the analysis of the data suggests that future conservation efforts should be focused on vessel strikes around Cape Hatteras, north of Morehead City, North Carolina. Almost no measures have been implemented on this region to reduce whale deaths, so a focus on preventing vessel strikes here could have a significant impact.


Compliance with the strike ship rule is difficult to evaluate, but it has been noted that the overall compliance has improved recently. A report calls for speed restrictions to be continued and to be applied to smaller ships.

The North Atlantic right whale population appears to be growing, but more efforts need to be made to ensure its continued survival.

Reference: “Assessment of Management to Mitigate Anthropogenic Effects on Large Whales” by Julie M. Van Der Hoop, Michael J. Moore, Susan G. Barco, Timothy V.N. Cole, Pierre-Yves Daoust, Allison G. Henry, Donald F. McAlpine, William A. McLellan, Tonya Wimmer and Andrew R. Solow, 1 October 2012, Conservation Biology.
DOI: 10.1111/j.1523-1739.2012.01934.x

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