Gualala River Steelhead--Large 2009 Spawning Population Dip
August 2009

The 2009 surveys of adult steelhead returning to the Wheatfield Fork of the river to spawn began in late December (2008) and were completed in mid-April (2009). These surveys were initiated with much anticipation and apprehension.

After a record return of spawners (estimated 4,000-5,800 fish) in 2008, what would Mother Nature reveal the following season? Would another large spawning run appear and provide hope of a sustained, “real” population uptick? Or would another average or below-average return of adult fish swim home, thus dashing any such hopes and the “feel-good” memories of 2008?

With 2009 survey results now compiled and analyzed, the answer, unfortunately, is not encouraging. The estimated (see Methods in the 2007 Annual Report) 2009 spawning return to the Wheatfield Fork was a meager 369 adult fish–the lowest annual value in 8 years. This low value is less than 10% of the estimated 2008 spawning return and more than 100 fewer fish than the previous low annual estimate of 486 spawners in 2004.

During five surveys of the Index Reach in 2009, the paucity of spawners was clear, with only 126 total fish recorded. This compares with 1,402 adult fish recorded during six surveys in 2008. Moreover, most (82=65%) fish in the 2009 season were recorded on the first survey in late December 2008. Counts plummeted dramatically during four subsequent surveys conducted through the end of the spawning season. In fact, during the two surveys conducted in March 2009, typically a peak-count month, only 19 adult fish were recorded. In contrast, 750 adults were tallied during two March surveys in the record 2008 spawning season.

The low return of spawners in 2009 leads to an important question: Was it a Gualala River or more widespread phenomenon? Apparently, it was widespread. Low steelhead spawner returns, including the hatchery-supported runs on the nearby Russian River, were recorded up and down the California coast in 2009. This suggests that the culprit in the steelhead downturns was likely poor conditions and survival at sea. Adding fuel to this thought is the fact that returns of Pacific lamprey (another anadromous species) to the Gualala in 2009 were also dismally low. Poor ocean conditions are already suspected as a major causative factor in the sharp downturns of Sacramento Valley salmon runs the past 2 years.

And poor ocean conditions are a worrisome backdrop to the other instream problems facing Gualala River steelhead, especially given the more profound ocean changes which may be on the horizon, as a result of global climate changes.



go to Related Links
go to Contact Author