This year, Chinook salmon counts passing Bonneville Dam set new (modern day) records. On September 12, almost 64,000 Chinook passed the dam! That is great news, but it is important to remember that Chinook salmon return to the Columbia River in three different pulses: spring, summer, and fall. The fall-run is the pulse that smashed the record books. Most of these record-setting fish are returning to spawning areas and hatcheries downstream of the Upper Columbia and to the Snake River.
Here in the Upper Columbia, the summer and fall Chinook runs this year were higher than the 10-year average, while spring Chinook (the only ESA-listed Chinook run in the Upper Columbia) were below the 10-year average (see Table below). However, the number of spring Chinook “jacks” (fish that mature one-year earlier than most fish) are higher than the 10-year average, which suggests that next year there may be a good return of r endangered spring Chinook to the Upper Columbia. Another ESA-listed fish, the threatened steelhead, returned lower than half the 10-year average this year.
Cumulative counts for fall-run Chinook (up to October 8) at Bonneville and Rock Island dams from the Columbia Basin Research website can be viewed through this link: (http://www.cbr.washington.edu/dart/query/adult_daily).
So, why have the Chinook runs in the lower Columbia and Snake Rivers returned in record numbers? Most would agree that it is a combination of factors, including good survival conditions when the juveniles migrate to the ocean, and good conditions in the estuary and ocean. Exactly what does this mean? It is difficult to understand, but it does suggest that freshwater efforts (e.g., improving passage conditions at dams, improving habitat) are having a positive effect.
See more information in the CB Bulletin below: http://www.cbbulletin.com/428448.aspx
Thanks to Chuck Peven/RTT Chair