Preventing lethal vessel strikes to endangered right whales
Mammals
North Atlantic right whale mother and calf.The outlook for the endangered North Atlantic right whale may be improving thanks in part to conservation measures aimed at preventing collisions with oceangoing vessels. North Atlantic right whales (Eubalaena glacialis) are highly endangered, numbering just 350 individuals remaining on earth. Collisions with oceangoing vessels are the leading case of death for the species which migrates through some of the world's busiest shipping lanes.
Scientists have estimated that vessel strikes may kill up to 10 right whales per year - a critically high number given the small remaining population and the whale's low reproductive rate and long lifespan. A variety of conservation measures have been adopted to reduce vessel strikes. These include the designation of right whale conservation areas, mandatory ship-position reporting, traffic separation schemes and vessel speed restriction.
A North Atlantic right whale kiled after being struck by a boat propeller.One such measure has been the subject of recent study. In 2007, the International Maritime Organization adopted a voluntary 'Area to be Avoided,' on the Roseway Basin off the coast of Nova Scotia where right whales aggregate during summer and fall.
New research in the journal Conservation Biology has reviewed vessel navigation tracks in the area to estimate compliance levels for the voluntary measure. The researchers Angelia Vanderlaan and Christopher Taggart estimated that the compliance rate ranged from 57% to 87% and stabilized at 71% within the first 5 months of implementation. Based on these figures, the study authors calculated an 81% reduction in risk of a vessel strike with a right whale in the area.
The researchers conclude:
"The degree of compliance we observed is likely due to adoption of the 'Area to be Avoided' by the International Maritime Organization (of which Canada is a member state) simply because routing measures internationally sanctioned by the International Maritime Organization are more likely to be recognized and adhered to by national and international shipping interests."
--by Rob Goldstein
VANDERLAAN, A., & TAGGART, C. (2009). Efficacy of a Voluntary Area to Be Avoided to Reduce Risk of Lethal Vessel Strikes to Endangered Whales Conservation Biology DOI: 10.1111/j.1523-1739.2009.01329.x
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