Two big Yangtze sturgeon, an endangered species known as "younger brother" of the Chinese sturgeon, arrived in the city last night from Sichuan Province's Yibin City, a city in the upper reaches of the Yangtze River.

The two Yangtze sturgeon, under the strictest state protection, will be displayed in the World Wildlife Fund Pavilion during the World Expo with 30 other kinds of precious aquatic animals.

Yangtze sturgeon, also called Dabry's sturgeon, is one of the three native sturgeons in the Yangtze River.

The other two are Chinese sturgeon, known as a living fossil for its long history, and white sturgeon, which disappeared some 50 years ago.

Different from the migratory Chinese sturgeon that swim into the sea to spawn, Yangtze sturgeon live in the Yangtze River, usually the upper reaches, all their lives.

The two Yangtze sturgeon - a 1.05-meter male and a 0.95-meter female - were selected from hundreds raised by Yibin Research Institute of Rare Aquatic and Terrestrial Wildlife.

They will be put into a grand fish globe, named "the ball of life," in the World Wildlife Fund Pavilion together with a 300-plus-kilogram Chinese sturgeon rescued by local experts.

They'll join more than 30 other rare species of animals living in the Yangtze River, including Chinese suckers, rock carp and knife fish.