Blue Behemoth Bounds Back

Abstract

They grow longer than two city buses and are powered by a taxicab-sized heart. These whales have blue-gray backs and sides and white bellies, but in colder waters, their bellies acquire coats of diatoms. The single-celled algae gives them a yellowish cast and has earned the big blues a second name: sulfur-bottom whales. In summer and fall, the blues bellow out their massive pleated throats and suck in up to 45 tons of water at a gulp, straining it through mouths full of 500 to 800 baleen (whale bone) plates to extract three to four tons of krill each day. The fast-swimming, spindle-shaped leviathan easily eluded sail-powered whaling ships for 300 years. Then, in the 1860s, an enterprising Norwegian captain combined a steam-powered ship with a cannon-fired harpoon. For the next century, whalers vigorously pursued the blue whale and depleted its populations, first in the North Atlantic, then the North Pacific, and finally in its region of greatest abundance, the southern oceans. There, perhaps 190,000 blue whales once had roamed. The hunt reached its peak in the