Gray Whale Migration
by Jessica Taekman on February 06, 2009
Gray whale migrating through the Gulf of the Farallones.
Public domain image from NOAA.
Now is the time to see gray whales migrating along the California coast and maybe even appearing inside the Bay. The whales travel up to 6,000 miles each way between their breeding grounds in Baja California and their principal feeding areas in the North Pacific. They generally stay close to shore during their migration, preferring the relatively shallow waters along the coast. They can sometimes even be spotted from shore, especially at protruding points such as Point Reyes.
The whales’ southward migration occurs between December and February, and the northward return between March and April. They average approximately 80 miles per day. Gray whales occasionally enter San Francisco Bay; the peak number of sightings in the Bay has occurred in March through May, coinciding with the whale’s northbound migration.
Keep an eye out for a whale’s spout as it exhales. Gray whales exhale a heart-shaped plume of mist–generally blowing three to five times in 15- to 30-second intervals before raising their flukes and diving (or “sounding”). They’ll generally stay submerged for three to five minutes before breaking the surface to take more breaths. Another behavior to watch for is called “spy hopping”– the whale sticks its head just above the water. We don’t know why whales spy hop, but many scientists believe the whales are looking for landmarks to keep themselves oriented in relation to the shoreline.
The Eastern Pacific population of gray whales represents a conservation success story. In the late 1930s, they were driven to the brink of extinction by commercial whaling –their numbers may have dropped to as low as 1,000 individuals. The International Whaling Commission banned commercial hunting in the late 1940s, and that has enabled the population to recover to its pre-exploitation abundance, estimated at about 21,000 whales.