Reintroduction of Spring Chinook Salmon into Lookingglass Creek, Oregon

We compared natural production between an endemic spring Chinook salmon (Oncorhynchus tshawytscha) population that is locally extinct with two different supplementation stocks used in Lookingglass Creek, a tributary of the Grande Ronde River located in northeast Oregon.  Habitat in Lookingglass Creek has been relatively unaltered over this 3-stock study period from the 1960’s to present.  Spring Chinook salmon were once abundant in Lookingglass Creek and supported significant tribal and sport fisheries.  Intensive monitoring of natural production occurred throughout the 1960’s which provided the base-case endemic stock productivity data for this study.  Dam construction on the Columbia and Lower Snake Rivers was probably a major factor in the decline of the native Lookingglass stock in the late 1970’s.  The construction of Lookingglass Hatchery and weir in 1982 caused further stock reduction and final extirpation.    From 1992 to 1999, a non-endemic Rapid River (Idaho) stock was introduced to re-establish a spring Chinook population.  The weir at the hatchery and outmigrant traps allowed for precise monitoring of fish in and fish out for this comparison study.   Rapid River stock showed results similar to the endemic stock across all metrics evaluated (redd distribution, spawn timing, adults per redd, outmigrants per redd, outmigration timing and survival, and parent/progeny ratios).  A switch to a local Grande Ronde Basin stock (Catherine Creek captive broodstock progeny) began with juvenile releases in 2001 and returning adults placed above the weir beginning in 2004.  Marked (hatchery-origin) and unmarked (natural-origin) adults have returned to Lookingglass Creek and are successfully reproducing upstream of the hatchery.  As was the case with comparison of the first two stocks, the current Catherine Creek stock is also beginning to show similar or increased productivity and survival results across the same metrics.  Results indicate striking potential for hatchery reintroduction/supplementation success for spring Chinook salmon. Continued work will evaluate the productivity of progeny from captive Catherine Creek broodstock that spawn naturally versus those that are subjected to another “hatchery cycle” and used for broodstock in the Lookingglass Creek reintroduction project.