Pacific Underwater: The great grey migration | Healthy Oceans | David Suzuki Foundation
Photo: Pacific Underwater: The great grey migration

Grey whales can be identified by their heart-shaped blow, and are often mistaken for rocks due to their barnacle-encrusted skin. (Credit: Chrisweger via Flickr)

By Kat Middleton, Western Region Science & Policy Intern

Every March, thousands of eastern Pacific grey whales repeatedly dive, surface and blow plumes of water vapor during their migration north along North America's west coast. After wintering in tropical waters off the Baja peninsula, most travel over 10,000 kilometers to summer feeding grounds in the Bering Sea. But some "summer residents" end their migration right here along British Columbia's coast.

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Even though they can grow longer than your average school bus (up to 15 metres), these barnacle-covered leviathans lack a dorsal fin and so can be difficult to spot. Luckily, grey whales enjoy feeding in shallow waters, so they're frequently seen from shore, identified by their heart-shaped blow. Every March, the Pacific Rim Whale Festival in Tofino and Ucluelet celebrates the greys' return. Locals and travellers alike embrace the ocean giants' migration through education, art, food, song and dance.

But these whales are not only seen in remote parts of B.C.'s coastline: In 2010, one swam right into Vancouver's False Creek!

Greys are the only bottom-feeding whale. They swallow over 1,000 kilograms of shrimp, worms and fish every day by sucking up the sea floor and filtering a murky mix of seawater and mud with their baleen plates. They tend to favour one side while scraping the ocean bottom, which often leads to scarring and loss of eyesight from the steady onslaught of debris. Perhaps they choose one side to avoid going completely blind.

Killer whales are the greys' only non-human predator, collectively hunting grey whales and their calves. But we're the biggest threat to these massive marine mammals. Once hunted for their meat and oil to near extinction by commercial whalers, grey whales have rebounded to at least 18,000 individuals thanks to international conservation efforts.

Although no longer hunted, a variety of human activities still threaten grey whales. Shipping and boating noise disturbs communication and navigation. Collisions with ships cause serious injuries—some individuals bear prominent propeller scars. Poorly located industrial development and fishing gear entanglement are also significant, preventable threats.

B.C.'s grey whales are a "species of concern" under federal law, requiring protection to ensure their population continues to rebound. It's time Canada did more to protect important feeding grounds, reduce ocean pollution and underwater noise, and control vessel traffic. Please urge decision makers to support ecosystem-based management for the B.C. coast.

If you're passionate about the ocean and want to help us work to protect it, join our team of Ocean Keepers.

Help us protect the coast by becoming an Ocean Keeper »

March 26, 2014
http://www.davidsuzuki.org/blogs/healthy-oceans-blog/2014/03/pacific-underwater-the-great-grey-migration/

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