Evidence of Natural Production: O. nerka in the Sawtooth Valley Lakes, Idaho, USA

In November 1991, Snake River sockeye salmon Oncorhynchus nerka were listed as endangered.  As a result of the listing, the Redfish Lake sockeye salmon project was initiated to conserve and rebuild Snake River sockeye salmon populations in the Sawtooth Valley lakes.  The goal of the recovery project is to reinstate naturally produced salmon in the Sawtooth Valley Lakes.  To date, the recovery effort has focused on development of a captive brood-stock based on anadromous sockeye salmon and residual, non-anadromous sockeye salmon.  Redfish Lake stocks have been reintroduced into Redfish Lake and two other Sawtooth Valley sockeye salmon nursery lakes (Pettit and Alturas) using a variety of release strategies, including egg boxes and adult releases for volitional spawning that produce unmarked natural out-migrants.  In this paper, we present evidence that naturally produced sockeye salmon are present today and may play an important role in recovering Sawtooth Valley sockeye salmon.  We will present examples of smolt production from residual sockeye salmon in both Redfish and Pettit Lakes. The former likely stems from the native residual stock and the latter from Redfish Lake stock introduced to Pettit Lake which have residualized. In Alturas Lake, introduction of the Redfish sockeye salmon has not established any known residual sockeye salmon.  However, the Alturas Lake kokanee population produces smolts and adult returns in small, but perhaps biologically significant numbers.