A new study says that changing shipping lanes may help prevent the injury or death of blue whales that accidentally collide with commercial ships in popular feeding areas.
In a 15-year study published in the journal PLOS ONE, marine biologists at Oregon State University’s Marine Mammal Institute studied the migration patterns of 171 blue whales using satellite technology. About one-quarter of the world’s 10,000 blue whales migrate in the Pacific Ocean off the West Coast.
To learn more, scientists attached satellite tags to the whales from 1993 to 2008. They discovered two areas off Los Angeles’ Channel Islands and San Francisco’s Gulf of the Farollones where whales and ships were likely to collide. The two “high-risk” areas are home to krill, or small shrimp-like food that blue whales depend on for their diet, as well as major shipping lanes.
“While the whales in this study generally occupied a wide region, most of the areas of highest concentration were close to large human population centers and busy port terminals,” the study said.
In September 2007, the National Oceanic Atmospheric Administration (NOAA) reported that ships had struck and killed three blue whales in the Santa Barbara Channel off the coast of Southern California.
Despite protections put in place by the International Whaling Commission in 1966, the report said the number of blue whales were not increasing at a significant enough rate for the species to sustain itself.
According to the report, “…the lack of evidence of substantial population growth during the past decades may indicate their recovery is being impeded, possibly by human impacts either indirectly through food chain interactions, or directly from physical interactions such as noise, or ship strikes.”
To reduce the likelihood of ship strikes, scientists suggest moving shipping routes southward, particularly during heavy feeding months from July to October. One suggestion included closing the northern shipping lane in and out of the ports in San Francisco Bay from August to November.
In 2003, Canadian authorities changed shipping lanes off of Nova Scotia, which led to a 90 percent reduction in collisions between the North Atlantic right whale and ships. In 2007, NOAA and the U.S. Coast Guard worked to enact the first regulations on shipping lanes in U.S. history, in order to protect the animal in waters around Boston Harbor.