As part of the Broodstock Program monitoring, Sea Grant biologists operate funnel net traps on Mill, Green Valley and Willow creeks each spring to monitor the downstream migration of coho smolts as they make their way to the ocean. Sonoma Water also operates a smolt trap on Dutch Bill Creek (among other streams). Data collected during smolt trapping efforts support estimates of smolt abundance, overwinter survival and growth.
The following figures show estimated abundance of smolts emigrating from these four streams between 2005 and 2018. Estimates include coho young-of-the-year released into streams the previous spring and fall, and spring releases of one-year-old smolts. For more information on our recent smolt trapping efforts, see our Spring 2018 Monitoring Report.