Sockeye Salmon Restoration in the Okanagan Watershed: In the Salmon Opera, It's Not over till the Fat Lady Sings

A multi-decadal decline of Okanagan sockeye salmon culminated in fewer than 10,000 adult returns in 4 of 6 years from 1994-1999. Risk assessments have generally supported the view of a decline driven by cumulative, anthropogenic degradation of freshwater habitat in the Columbia basin. However, record returns averaging more than 200,000 adults from 2008-2014 indicate surprising resilience. Review of recent stock management and restoration efforts focused on Okanagan sockeye within a historic context has enabled us to identify the main factors associated with this spectacular increase. Our results indicate that a combination of intentional management actions and fortuitous events have enabled Okanagan sockeye to rebound to exceed historic maxima. The actions and events involved include: rejection of historic escapement objectives that underutilized the carrying capacity of spawning and rearing environments; development and  deployment of a decision support system to facilitate “fish friendly” water storage and release decisions influencing losses of sockeye eggs or fry to density-independent events; flood-induced improvements in incubation gravel quality; a small contribution (<10% of total production) from hatchery-fry reintroductions into Skaha Lake; improvements in juvenile fish-passage in the Columbia River and a coincidental return to survival-favourable conditions for southern sockeye stocks in coastal marine waters.