North Arm Kokanee Escapement/Fry Production Summary Report

Author: S. Arndt

An estimated 16,487 Kokanee ascended Meadow Creek in 2018, roughly three times the 2017 return and similar to 2016. Male and female kokanee length averaged 37.9 cm and 36.2 cm respectively, similar to the last three years. Average male weight was 726 g while females averaged 564 g. Average fecundity at 646 eggs/female was a slight decrease from the previous two years (778 in 2016, 724 in 2017), and egg retention was 5. The percentage of females in the channel was 51.8%. Three age classes of Kokanee were present in the 2018 run: age 2 (15%), 3 (77%) and 4 (8%; ages by Carol Lidstone, Birkenhead Scale Analyses, Lone Butte, BC).
The number of adults returning to Meadow Creek and the Lardeau River decreased significantly in 2013, followed by historic low returns for the last five consecutive years; escapement for the two locations in 2018 is more than double 2017 escapement but still the third lowest on record. All fish that reached the Meadow Creek spawning channel were passed into the channel for a total potential egg deposition of 3.92 million. Total Meadow Creek egg deposition including those enumerated below the channel was estimated to be 5.47 million (not including 4.24 million eyed eggs planted later in the fall).
Lardeau/Duncan River escapement was estimated at 12,853 kokanee. The combined Meadow Creek and Duncan/Lardeau River escapement was estimated at 29,340 fish.
Total channel fry production in 2018 measured at the enumeration fence was 6.35 million, based on 39 nights of sampling between March 30 and June 2, 2018. This includes naturally spawned fry from Kootenay Lake Kokanee, and fry from supplementary eggs planted into the channel (from sources outside Kootenay Lake). Fry movement out of the channel peaked on May 8 (1.09 M) and May 15 (1.42 M). The egg to fry survival rate was estimated at 75% for naturally-spawned eggs based on an average rate from previous years, however, there was some evidence in the data that the timing of fry movement at the bottom of the planted eggs (leg 6) was different from the timing at the bottom of the channel (regular enumeration fence). Since all temporal expansion numbers are based on previous sampling at the enumeration fence, the number of fry coming from the planted eggs may need to be re-estimated with additional data collected in fall 2019. Higher survival in recent years is least partly due to the electric fencing that was in place to protect spawning Kokanee in the channel from bear predation starting in Fall 2016.

An estimated 16,487 Kokanee ascended Meadow Creek in 2018, roughly three times the 2017 return and similar to 2016. Male and female kokanee length averaged 37.9 cm and 36.2 cm respectively, similar to the last three years. Average male weight was 726 g while females averaged 564 g. Average fecundity at 646 eggs/female was a slight decrease from the previous two years (778 in 2016, 724 in 2017), and egg retention was 5. The percentage of females in the channel was 51.8%. Three age classes of Kokanee were present in the 2018 run: age 2 (15%), 3 (77%) and 4 (8%; ages by Carol Lidstone, Birkenhead Scale Analyses, Lone Butte, BC).
The number of adults returning to Meadow Creek and the Lardeau River decreased significantly in 2013, followed by historic low returns for the last five consecutive years; escapement for the two locations in 2018 is more than double 2017 escapement but still the third lowest on record. All fish that reached the Meadow Creek spawning channel were passed into the channel for a total potential egg deposition of 3.92 million. Total Meadow Creek egg deposition including those enumerated below the channel was estimated to be 5.47 million (not including 4.24 million eyed eggs planted later in the fall).
Lardeau/Duncan River escapement was estimated at 12,853 kokanee. The combined Meadow Creek and Duncan/Lardeau River escapement was estimated at 29,340 fish.
Total channel fry production in 2018 measured at the enumeration fence was 6.35 million, based on 39 nights of sampling between March 30 and June 2, 2018. This includes naturally spawned fry from Kootenay Lake Kokanee, and fry from supplementary eggs planted into the channel (from sources outside Kootenay Lake). Fry movement out of the channel peaked on May 8 (1.09 M) and May 15 (1.42 M). The egg to fry survival rate was estimated at 75% for naturally-spawned eggs based on an average rate from previous years, however, there was some evidence in the data that the timing of fry movement at the bottom of the planted eggs (leg 6) was different from the timing at the bottom of the channel (regular enumeration fence). Since all temporal expansion numbers are based on previous sampling at the enumeration fence, the number of fry coming from the planted eggs may need to be re-estimated with additional data collected in fall 2019. Higher survival in recent years is least partly due to the electric fencing that was in place to protect spawning Kokanee in the channel from bear predation starting in Fall 2016.