The pallid sturgeon (Scaphirhynchus albus) is an endangered species of ray-finned fish, endemic to the waters of the Missouri and lower Mississippi River basins of the United States. Named for its pale coloration, it is related to the much smaller shovelnose sturgeon (S. platorhynchus). When mature at 15 years, individuals average 85 pounds (39 kg) and 30 to 60 inches long (76 to 152 cm). The fish spawns infrequently over its lifespan of up to a century. This sturgeon species has remained virtually unchanged since it coexisted with the Cretaceous dinosaurs 70 million years ago. In 1990, the pallid sturgeon became the first Missouri River basin fish on the U.S. Fish and Wildlife Service's endangered species list, after sightings had greatly diminished. Loss of habitat is thought to be responsible for its decline; much of the Missouri River drainage system has been channeled and dammed, reducing the gravel deposits and slow-moving side channels that are its favored spawning areas. In an effort to save the species from extinction, pallid sturgeon are being raised in a dozen hatcheries and released back into the wild. (Full article...)