Life, Death, and Data: The story of a salmon run in the Middle Fork Salmon River basin

What the Salmon Leave Behind

After spawning, Chinook salmon complete their life cycle and die naturally. While their journey has come to an end, their role in the ecosystem and in fisheries research, is far from over.

As crews walk streams throughout the MFSR basin, every salmon carcass becomes an opportunity to collect valuable biological information. Biologists record the fish's length, determine its sex, look for tags, and collect tissue samples for DNA analysis. Each piece of information helps build a more complete picture of the population.

These samples allow biologists to learn more than just how many fish returned to spawn. They provide insight into the age composition of the population and help track the genetic diversity and long-term health of Idaho's wild Chinook salmon. When combined with redd counts and other survey data collected each year, carcass sampling helps IDFG monitor population trends and make informed management decisions to conserve these fish for future generations.