| Abstract/Description or Keywords |
Hill Creek Spawning Channel (HCSC) was built as partial compensation for fish losses as a result of the construction and development of hydro-electric dams on the upper Columbia River. The HCSC compensation provides enhanced spawning habitat with controlled flow and increased survival rates for kokanee (Oncorhynchus nerka), a keystone species within Arrow Lakes Reservoir (ALR). The channel also provides important spawning and rearing habitat for adfluvial rainbow trout (Oncorhynchus mykiss). HCSC provides an important component of fry production for Arrow Lakes Reservoir and contributes to restoring kokanee abundance to historic pre-impoundment levels. Based on the 2005 kokanee brood year, total deposition was calculated to be 12,986,880 eggs deposited in the channel. Production was estimated at 4,660,360 fry emigrating from HCSC in 2006. Subsequent kokanee egg-to-fry survival was estimated to be 35.9% in 2006 which was appreciably higher than 2.8% in 2005 and close to the long term average. The peak of the fry out-migration occurred on May 15th and 16th when > 800,000 fry emigrated from the channel nightly. In summary, 2006 fry production at the HCSC indicated that the channel had recovered from the 2004 and 2005 production problems. Increased monitoring and maintenance probably contributed to the improved conditions for kokanee egg deposition, incubation and subsequent fry emigration at HCSC in 2006. Hill Creek Spawning Channel, Arrow Lakes Reservoir, kokanee, egg-to-fry survival, fry enumeration, migration, production. |
