Reducing Whale Fatalities along the California Coast

Issue

Coastal California is home to four major shipping ports—San Diego, Long Beach, Los Angeles, and Oakland—so large container ships constantly travel through the region’s national marine sanctuary waters. The Cordell Bank, Gulf of the Farallones, Monterey Bay, and Channel Islands sanctuaries are important feeding and breeding grounds for several species of large whales, including gray whales and endangered blue, humpback, and fin whales. In the past decade, 10 whale fatalities have been reported along the California coast and others may have gone undetected. Coastal managers have been working to reduce ship strike fatalities.

Process

Partners in this effort include NOAA’s Office of National Marine Sanctuaries, the National Marine Fisheries Service, the U.S. Coast Guard, and the International Maritime Organization. National Marine Sanctuaries staff downloaded ship tracking, or Automatic Identification System (AIS), data provided through MarineCadastre.gov to identify the highest concentrations of ship traffic along the California coast and within sanctuary waters. AIS data, along with whale sighting data and whale probability modeling, were used to determine areas that whales might be more likely to frequent and, therefore, should be avoided by ships. The group was able to determine areas where shipping lanes could be altered to reduce the amount of whale and ship interaction.

Impact

These changes are increasing maritime safety in and around the national marine sanctuaries. In the San Francisco Bay area, narrowing the shipping lanes in and around sanctuary waters will limit areas where ships are permitted to pass, while extending the shipping lanes will help regulate shipping traffic and speed farther from sanctuary waters. In the Santa Barbara Channel, the inbound south shipping lane was shifted 1 nautical mile north. Removing ship traffic from these areas of higher whale concentration will help reduce collisions and fatalities.

Read this press release for more information.

MarineCadastre.gov National Viewer helps San Francisco Bay area to determine a way for whales and ships to safely co-exist along the California coast
The previous shipping lanes (left) have been narrowed (right) to reduce the area where whales and ships might interact.

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