The Yangtze sturgeon lived in its namesake river for 140 million years. Now it doesn’t. Nor does another behemoth it shared China’s longest waterway with for ages, the Chinese paddlefish. Updating its Red List of Threatened Species on Thursday for the first time in 13 years, the International Union for Conservation of Nature declared the two species, known as “the last giants of the Yangtze,” extinct.

Once the largest freshwater fish in the world, the Yangtze sturgeon, Acipenser dabryanus, could reach 26 feet in length and weigh 1,500 pounds. Its historic range extended throughout Asia, including Japan, Korea, and the Yellow River in China. Dubbed a “living fossil,” it sported a rounded snout, large pectoral fins, and rows of elevated ridges on its spine and flanks. Though there are still captive fish in breeding programs, authorities, despite many efforts, have failed to successfully reintroduce the fish to the river system, and now it considered extinct in the wild.

The Chinese paddlefish, Psephurus gladius, could reach 23 feet in length and weigh a half a ton. It had a long silver-gray body, poorly developed eyesight, and a swordlike snout that it used to locate prey by sensing electrical activity. According to National Geographic, no paddlefish exist in captivity and no living tissues of the fish have been preserved, so there is no hope for its future. 

Both fish declined precipitously after the construction of the Yangtze’s first dam, the Gzehouba Dam, in the late 1980s. The Yangtze sturgeon historically traveled 2,000 miles from the East China Sea to its spawning grounds above the dam. The last Chinese paddlefish ever seen was caught and tagged in 2003, the same year the Three Gorges Dam was built.

Both species were considered delicacies and were historically overfished. The paddlefish was once a favored food of ancient emperors, while the sturgeon’s caviar was highly valued. Pollution and ship travel likewise contributed to the fishes’ demise. The Yangtze sturgeon was particularly sensitive to noise and, according to National Geographic, scientists believed that industrial runoff may have caused some fish to change their sex from male to female.

The IUCN’s latest list of threatened species, stated that 100 percent of the world’s remaining 26 sturgeon species are now at risk of extinction, up from 85 percent in 2009.