Blue Whales May be Heavily Impacted by Shipping Traffic Near California

Scientists have found a bit more about the movements of blue whales. They've discovered that these massive mammals have their feeding areas bisected by heavily used shipping lanes. The findings reveal that these creatures may be at risk for increased injury and mortality.

The new findings are part of the most comprehensive study of blue whale movements ever conducted. Researchers tracked the movements of blue whales off of the West Coast in order to identify important habitat areas. In addition, the researchers focused on the timing and presence of major ports and shipping traffic near these habitat areas.

The scientists attached transmitters to 171 blue whales off California at different times between 1993 and 2008. Then, they tracked the whales' movements via satellite.

"The main areas that attract blue whales are highly productive, strong upwelling zones that produce large amounts of krill-which is pretty much all that they eat," said Ladd Irvine, lead author of the new study, in a news release. "The whales have to maximize their food intake during the summer before they migrate south for the winter, typically starting in mid-October to mid-November. It appears that two of their main foraging areas are coincidentally crossed by shipping lanes."

In fact, during one year a total of five blue whales were hit off of southern California during just a seven-week period. This, in particular, reveals how dangerous it can be to have shipping lanes that cross these areas.

Moving the shipping lanes, though, could be an option. In the past, scientists brought concerns about right whale ship strikes in the Bay of Fundy to the attention of the International Maritime Organization. This caused the industry to modify the shipping lanes.

"It is not often that research results are so applicable to a policy decision," said Daniel Palacios, co-author of the new paper. "It's not really our place to make management decisions, but we can inform policy-makers and in this case it is pretty straightforward. You will eliminate many of the ship strikes on blue whales by moving the shipping lanes south of the northern Channel Islands."

The findings are published in the journal PLOS One.