Stories From The Field

Reducing Whale Fatalities along the California Coast

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Issue

Coastal California is home to four major shipping ports—San Diego, Long Beach, Los Angeles, and Oakland—so large container ships travel constantly 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 the number of these fatalities from ship strikes.

Process

NOAA’s Office of National Marine Sanctuaries (ONMS) and the National Marine Fisheries Service worked with the U.S. Coast Guard and the International Maritime Organization (IMO) to determine a way for whales and ships to safely co-exist along the California coast. ONMS downloaded ship tracking, or Automatic Identification System (AIS), data provided through MarineCadastre.gov. The data helped 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. Working with several sanctuary offices, the U.S. Coast Guard and the IMO, ONMS was able to determine areas where shipping lanes in the San Francisco Bay Area and the Santa Barbara Channel could be altered to reduce the amount of whale and ship interaction.

Impact

These changes to the shipping lanes will help increase 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.

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The previous shipping lanes (left) have been narrowed (right) to reduce the area where whales and ships might interact.
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