Living Fossils: Sturgeon of the San Francisco Estuary

Abstract

Sturgeon are fish that are considered living fossils. Their ancestors date back over 200 million years, to the same time as dinosaurs. These fish can grow taller than humans (over 2 m), weigh over 160 kg, and live as long as humans. Sturgeon species have special adaptations, such as a vacuum-like mouth and body armor called scutes. There are 27 species of sturgeon worldwide. Two species, green and white sturgeon, are native to California, USA, and are some of the largest animals in San Francisco Bay. Sturgeon populations have declined due to habitat loss, water management, overfishing, poaching, pollution, and climate change. Sturgeon cannot jump over barriers like salmon can, so structures like dams that block water also block sturgeon from reaching their natural spawning habitat farther upstream in the river. Scientists are using new technologies to monitor sturgeon populations and discover the unique behaviors of these dinosaur-era fish in California’s rivers and estuaries.