Ecology of American Shad

American shad is an introduced, invasive species in the rivers of the Western U.S. The annual adult shad migrations in the Columbia River typically include millions of fish, but the effects of this abundant species on native fish populations are poorly understood. We have studied American shad behavior and survival using PIT- and radio-telemetry. We have also evaluated a variety of life history characteristics, including sex ratios, repeat spawning rates and migration distance relationships with fish traits. We have used genetic information as well as scale and otolith analyses to help understand the ecology of the Columbia River population.

Study topics include:

• Adult shad behavior at dams
• Upriver migration rates
• Repeat spawning rates
• Effects of river environment on behavior, survival and distribution