Wallowa Stock Steelhead Autumn Line: An Evaluation of the Second Generation

A new line of early returning Wallowa stock hatchery steelhead (hereafter the autumn line; AL) was created from 2004 to 2007 to potentially reduce straying and provide increased angling opportunities in autumn fisheries.  The second generation (brood years 2008 to 2011) have returned  to the Wallowa River in northeast Oregon since 2011.  We compared adult return timing between the AL and our standard Wallowa stock adults (hereafter SL) for the second generation and found that the AL returned one week earlier than the SL at Bonneville, McNary, and Lower Granite dams.  By comparison, first generation AL returned one, two, and three weeks earlier than the SL at the same three dams.  Smolt-to-adult survival of the second generation AL was similar to the SL at Bonneville Dam (1.5% each), whereas survival of the AL from the first generation was higher at Bonneville (2.9%) compared to the SL (2.3%).  Other metrics examined include straying and contribution to fisheries.  Currently, the AL is being used to produce one-half of our smolt production for the Wallowa Stock steelhead program.  Several options are still being investigated to encourage an earlier AL run timing.