Expeditions:Gray Whale Migration Route

Each year, gray whales embark upon the longest annual migration of any mammal on Earth, traveling 10,000 – 20,000 miles each year. During the 17th-20th century, the whaling industry brought these magnificent gray whales to the brink of extinction. After being granted protection in 1949, gray whale populations have begun to increase, while the eastern population has become a conservation success story due to their recovery. However, gray whales continue to face many natural and human-made obstacles as they make their yearly migration across the Pacific Ocean.

Beginning in the Bering and Chukchi seas, the eastern population of gray whales begins their journey down the North American coastline towards the warm water lagoons of Mexico’s Baja California. Here, adult gray whales engage in courtships and mating, while pregnant mothers give birth in the protected shallow lagoons. Once the baby is strong enough, mother’s and their calves make the long journey back towards the Arctic in order to find their main food source in the nutrient rich cold waters of the North.

Along this journey, gray whales face many threats. Natural predators like orcas occasionally hunt gray whale calves, and may kill up to one-third of all new calves. Unfortunately, increasing human activities along their migration route poses even greater challenges to gray whales. Shipping, military sonar, and oil exploration projects add increasing noise pollution in the oceans, which disrupt gray whales primary sense: sound. Furthermore, entanglements in fishing gear and boat collisions are responsible for many gray whale deaths each year. Yet an even greater obstacle comes from the danger of climate change, which can greatly affect their main food source in the Arctic.

State of Gray Whales

• Over the last three decades, global warming has caused a 30% loss of gray whale’s main food supply in the Bering Sea.
• 1/3 of the population died from 1999 – 2000 because of starvation.
• Noise pollution is a growing threat to gray whales and all other marine mammal who use acoustic sound as their primary sense to communicate, navigate, and feed.

The Gray Whale Migration Route Expedition Team

Learn more about our work with Gray Whales

• Watch our PBS documentary series Jean-Michel Cousteau’s Ocean Adventures – Gray Whale Obstacle Course
• Jean-Michel Cousteau personally met with then-president of Mexico Ernesto Zedillo and with the help of the NRDC, convinced the Mexican government to abandon their plans to build a massive salt plant in southern Baja California near gray whale nursery grounds.
• Explore Jean-Michel Cousteau’s Global Alliance to Save the Whales.

Quick Facts

• Gray whales are bottom feeders that filter crustaceans from sediments in the seafloor. Surprisingly, most gray whales feed primarily from their right side!
• In 1994 gray whales were taken off the endangered species list and are currently protected by international law.
• Gray whales are considered one of the “friendliest” whales, as they will commonly approach boats alongside their calves.

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