2020 Kitwanga River Salmon Smolt Assessment
|Author||Gitanyow Fisheries Authority|
|Related Species||coho, sockeye|
|Location||Kitwanga River, British Columbia|
|Subjects||smolt assessment, DNA, species abundance|
|Download File||Download lib_514.pdf, 3.9 MB|
In 2020, the Gitanyow Fisheries Authority (GFA) operated the Kitwanga River Smolt Enumeration Facility (KsF) for the 13th consecutive year since initiating the program in 2008. The purpose of the program is to enumerate sockeye and coho salmon smolts, and other resident trout and char species migrating out of Gitanyow Lake and the upper Kitwanga Watershed. In 2020, the facility was operated from April 14th to July 7th.
The sockeye smolt emigration was estimated at 23,753 fish in 2020, which is the highest count through the KsF since 2014 (n=33,423). Through scale analysis, it was determined that almost all of the smolts were 1-year-old fish (99.8%), which is similar to previous years. Average smolt length and weights were 107.4mm and 12.4g respectively, which were higher than the long term average of 106.8mm and 11.9g. Production estimates for Gitanyow Lake sockeye in 2020 was 83 smolts per female spawner (most originating from the 2018 broodyear). Almost all (99%) of the sockeye smolts migrated through the weir between April 30th – May 13th, 2020 with a peak count of 8,471 on the night of May the 6th. This was in line with previous years when peak runs generally occur in the 1st or 2nd week of May.
Coho smolt captures in 2020 totaled 8,194 fish by the time the KsF was decommissioned for the year on July 7th. GFA staff successfully sampled, fin clipped, and coded wire tagged (CWT) 95 % of the coho captured in 2020. Scales from 296 coho smolts were submitted to DFO for age analysis. The 2020 coho smolt age results were not available for inclusion in this report. Overall, GFA is confident that the entire sockeye and coho smolt run were captured through the KsF in 2020.
Cutthroat trout, bull trout/Dolly Varden (BT/DV) and rainbow trout were also enumerated and sampled for lengths through the KsF in 2020. DNA samples were also taken from BT/DV in 2020 to help determine species, but the results were not available in time for this report. Abundance by species was lower in comparison to previous year’s totals.