For young salmon, the journey along the San Joaquin River in Central California is no small feat. Every spring and fall, thousands of these fish—each as long as a pinky finger— embark on a 350-mile race, swimming day and night and dodging predators along the way to reach the Pacific Ocean. But less than 5% survive the journey, and in some years, hardly any make it. Elevated water temperatures, dams and poor water quality all endanger the animal, but human-introduced predators, including striped and largemouth bass, kill most of them. In a new CU Boulder-led study, researchers reveal how these salmon learn to swim in different parts of the river at different times of day to avoid predators and conserve energy. 

Other salmon news:

• The Lookout (Chico, Calif.): Video: It’s not easy being a salmon in California’s Central Valley
• The Sacramento Bee: Salmon return to North Yuba River for first time in almost a century as restoration continues
• Active NorCal: Salmon return to North Yuba River for the first time in nearly a century