Ship strikes have been a concern for a number of species of large whales along the US West Coast and there has been new research examining aspects of this threat as well as measures to reduce the incidence. The incidence of ship strikes as a cause of whale mortality has increased in recent decades based on examination of stranded marine mammals and appears to be the result of a combination of increased number and speed of ships and increasing whale numbers. Most of the research and management focus has been on the shipping routes leading to Los Angeles/Long Beach and the San Francisco Bay area, the two busiest ports along the US West Coast. In both areas working groups involving industry, environmental groups, managers, and researchers have identified ways to reduce this problem and research has identified areas of overlap between shipping lanes and areas of concentration of whales for feeding. Small changes to shipping lanes have been made in both areas to try and reduce the overlap between ship routes and whale concentrations. Research has been conducted by Cascadia Research and a number of other research groups to better identify reasons for ship strikes. Tags deployed on blue whales near shipping lanes off southern California revealed that this species is not very effective avoiding ships even in near-collision close encounters with ships. In the Pacific Northwest primary humpback whale feeding areas occur very near and in routes traversed by ships coming into ports in Washington State and British Columbia although this species does not seem as vulnerable to ship strikes as some of the larger whale species like blue and fin whales.
Citation:
Calambokidis, J., 2016. Whales and ship strikes, lessons from research and mitigation efforts on the US West Coast. Presentation at Salish Sea Ecosystem Conference, Vancouver, BC. 13-15 April 2016.