California Coast & Ocean

Shifting Lanes
Global shipping routes often pass through sensitive marine-life habitat, such as feeding and breeding grounds and migratory routes along the coast. Thousands of ships follow the North Pacific Great Circle Route each year, traversing the Aleutian Islands’ Alaska Maritime Wildlife Refuge as they travel between the U.S. West Coast and East Asia. Higher volumes of shipping are expected in many coastal waters as “short sea” shipping--the transport of freight for short distances along coasts and inland waterways--expands in response to congestion on roads and railways. Many countries are already eyeing new shipping lanes through sensitive Arctic waters as global warming melts the polar ice for longer periods each year. Such increases alarm marine conservationists. “We need to be rerouting these shipping lanes away from sensitive habitats,” Steiner said.

Rerouting lanes is uncommon, but it has been done. The IMO, which has some regulatory authority over shipping, has approved route changes and larger voluntary buffer zones off the central California coast and the Olympic coast of Washington, primarily to avoid oil spills and other catastrophic accidents in protected marine areas. In 2003, Canada shifted the shipping routes in the Bay of Fundy to reduce the risk of vessel strikes on critically endangered North Atlantic right whales, and in July 2007 ship traffic lanes in Boston Harbor were shifted and narrowed to try to reduce collisions with right whales in the area around Stellwagen Bank National Marine Sanctuary.

Moving vessels farther offshore may also make these sensitive nearshore areas a little quieter. However, Southall said that some scientists fear such shifts could also affect how shipping-lane noise is reflected into deep ocean basins, possibly making the situation worse there.

Regardless, moving shipping lanes is “incredibly complicated and controversial to do,” said Southall, pointing out that the Boston Harbor lane shift required many years and the efforts of many entities, including NOAA and the U.S. Coast Guard. If more shipping lanes are shifted in the future to protect marine mammals, “I think it’s more likely to be connected to mitigation for another issue,” such as vessel strikes or oil spills.

NOAA has also been trying to set speed limits for ships traveling along the eastern seaboard, varying by location and time of year--again, to try to reduce the risk of vessel collisions with whales. Slowing ships down also reduces propeller cavitation, so this strategy could reduce the impacts of shipping noise along busy coastal routes as well. NOAA’s proposed speed limits have been held up by the White House Office of Management and Budget and the Council of Economic Advisors since October 2006. The shipping industry opposes the limits, arguing that they would increase their costs.

Although Southall affirmed that “if you want to quiet ships down, one clear conclusion in many cases is to simply slow them down,” he isn’t sure how practical that is. “Everything in the industry is going in the other direction, to speed things up and make them bigger--and likely noisier,” he said. “We’re pursuing different voluntary measures at this point, together with forward-thinking members of the industry.” Metcalf agreed that slowing ships down might not be feasible, pointing out that “there’s a point at which, when you slow the ship down, it becomes unsafe to maneuver, especially in a narrow shipping channel--the limit is in the 10-to-14-knot range, depending on the size of the vessel and environmental conditions, including current and wind. And if you just reduce speed a little, how much will that help?”

Michael Jasny, a senior policy analyst with the Natural Resources Defense Council (NRDC), is more optimistic. “It may not be as economically disadvantageous as people have thought,” he said. “Sometimes ships go fast just to sit in port, so there would be nothing to lose by slowing down. You reduce carbon emissions, reduce marine noise, and reduce ship strikes on marine mammals--it’s a win for everyone.” The NRDC is also working to keep shipping lanes as narrow as possible to minimize the territory affected, said Jasny. Methods for achieving this include better enforcement that would keep ships from wandering, and combining multiple lanes.