A publication for the faculty, staff, administrators, and friends of California State University, Chico
December 8, 2005 Volume 36 / Number 4


Salmon Spawn in Big Chico Creek

The week before Thanksgiving break, two fall-run Chinook salmon set up “house” on campus. The female made her nest, known as a redd, right below the mall bridge. This is the third year in a row that salmon have spawned at that site.

The salmon arrived the week before, but the rains had raised the water level too high to spawn. So they waited. Salmon prefer to spawn over golf-ball-size gravel in about eight to ten inches of water. By Monday, conditions were ideal. To make her redd, the female used her tail to sweep away any sediment so her eggs would fall down into the cracks and crevices between the gravel, safe from predators. You might still see the clean gravel if you look closely.

The female was building her redd for about three days, while the male waited under the tree. On the fourth day, the two of them started the mating dance. They spawned soon after. By Monday of break, they were gone. The eggs should hatch sometime in January, and the juvenile fish will migrate to the sea with the spring floods. The young will live in the ocean for three years. Those that survive will then begin the journey to spawn in their home creek.

Salmon are common in Big Chico Creek but have been greatly diminished in number. They are a great indicator of environmental quality because they travel through so many ecosystems on their journey between the ocean and their spawning grounds.

—Mark Stemens and Jim Pushnik