How many Lake Billy Chinook kokanee spawned in the Metolius River during fall 2017?

 435,000 Kokanee!

This number is an estimate and may be plus or minus 27,000 kokanee.  We are 95% confident that the number of kokanee spawning during October 2017 was 408,000 to 462,000.

The chart below shows Metolius River kokanee population estimates from 2009 to 2017.  As you see, the 2017 estimate is the largest since our study began in 2009.  The Lake Billy Chinook kokanee population varies in abundance from year to year. Over the years, knowing trends in kokanee population abundance can help with fisheries management decisions.

For information on the kokanee forecasting, see this link.

This chart shows the estimated number of Lake Billy Chinook kokanee that have spawned in the Metolius River and its tributaries since 2009. Each year’s estimate was determined using the mark-recapture study method. As you see the numbers can vary a lot, which is common among kokanee populations everywhere. The error bar for each year’s estimate shows the 95% confidence interval for that estimate. In other words, we are 95% sure that the estimate is in the range of numbers represented by the error bar. For example, 2017 kokanee spawner chart estimate is 434,000 plus or minus 27,000 kokanee. Therefore, we estimate that 408,000 to 462,000 kokanee spawned in 2017.