Summer 2019 salmon and steelhead snorkel counts
Sea Grant and Sonoma Water biologists conduct snorkel surveys each summer in order to document the presence, distribution and minimum count of salmon and steelhead. Wild coho young-of-the-year (yoy) were observed in 22 of the 43 streams surveyed, with an expanded count of approximately 4,200. Steelhead yoy were seen in all surveyed streams and the expanded count was nearly 80,000--the highest since standardized counts began in 2013 (note: number and length of streams surveyed varied by year). It's likely that the disparity between the high number of returning hatchery coho salmon adults over the winter of 2018/19 and the relatively low number of juveniles observed could likely be explained by the large, intense winter storm events scouring out or burying fragile eggs and/or emergent fry. The highest flows were after the primary coho spawning window, while steelhead spawning occurred over a longer period of time and into late spring.
The table below lists the results by stream. Snorkel surveys were conducted in every second pool and expanded counts were generated by doubling the observed count.
See our annual Summer Monitoring Report for more information on methods and outcomes.
Number of pools snorkeled
Coho salmon yoy
Expanded count coho yoy1
Expanded count steelhead yoy1
|- Kidd Creek||29||14||28||14||28|
|- East Austin Creek||94||21||42||1,107||2,214|
|- - Black Rock Creek||32||3||6||532||1,064|
|- - Gilliam Creek||34||0||0||20||40|
|- - Thompson Creek||15||0||0||129||258|
|- - Gray Creek 2||244||689||689||3,778||3,778|
|- - Devil Creek||15||0||0||152||304|
|- Ward Creek||60||0||0||364||728|
|- Bearpen Creek||15||0||0||141||282|
|Dutch Bill Creek||105||32||64||1,258||2,516|
|- Perenne Creek||12||2||4||17||34|
|- Grub Creek||21||0||0||9||18|
|- Mission Creek||3||0||0||134||268|
|Green Valley Creek||95||311||622||857||1,714|
|- Sexton Creek (Atascadero)||4||0||0||0||0|
|- Redwood Creek (Atascadero)||30||0||0||96||192|
|- Purrington Creek||70||101||202||662||1,324|
|- Little Green Valley Creek||18||0||0||63||126|
|- Nutty Valley Creek||13||20||40||10||20|
|- Harrison Creek||3||0||0||6||12|
|Santa Rosa Creek||73||0||0||2,402||4,804|
|Mark West Creek 3||229||714||1,428||4,468||8,936|
|- Porter Creek (Mark West)||62||24||48||1,118||2,236|
|- Press Creek||9||0||0||8||16|
|- Felta Creek||97||74||148||748||1,496|
|- Wallace Creek||31||0||0||301||602|
|- Palmer Creek||52||0||0||343||686|
|- Wine Creek||36||0||0||287||574|
|- Woods Creek||81||106||212||700||1,400|
|- - Dead Coyote Creek||10||3||6||33||66|
|- Yellowjacket Creek||69||0||0||253||506|
1 Expanded count is the observed count multiplied by a factor of 2.
2 Snorkel counts include yoy released as part of an RSI trial. Every pool was snorkeled for RSI monitoring.
3 Snorkel surveys occurred after stocking so observed count likely consists primarily of stocked fish.