a sturgeon swims gracefully in a calm river at sunset, showcasing its unique features

sturgeon river water fish nature wildlife aquatic swimming sunset environment habitat scales fins ecosystem tranquility biodiversity reflection surface predator prehistoric species conservation marine riverbank calm serene flora fauna aquaticlife elegance movement beauty natural wild swimmingfish freshwater ecosystemhealth underwater wildlifephotography riverlife speciesdiversity aquaticecosystem fishspecies naturalhabitat environmentalscience conservationefforts