| Abstract/Description or Keywords |
The population of white sturgeon (Acipenser transmontanus) in the Nechako River has been in decline over much of the last century. The decline has been primarily associated with the damming of the river in the early 1950s. Prior to 1950, the population of sturgeon in the Nechako River was estimated to be over 5000 fish (Korman and Walters 2001), as of 2006 the estimated population of mature individuals had decreased to 305 (Wood et al 2007). The white sturgeon population in the Nechako River has been designated as “Endangered” under the Federal Species at Risk Act, and provincially is considered “Critically Imperiled” (BC Conservation Data Centre 2013). The BC Government (Ministry of Forest, Lands and Natural Resource Operations (FLNRO) and Ministry of Environment (MoE)) is the lead agency for the recovery process of the Nechako White Sturgeon. Flows in the Nechako River have been regulated since the completion of the Kenny Dam in 1952. The population of white sturgeon in the Nechako River has been experiencing decades of recruitment failure. Past studies link recruitment failure to the increased sediment inputs from the 1961 Cheslatta River avulsion, with notable and rapid decrease in recruitment occurring during the mid-1960s (Korman and Walters 2001, Northwest Hydraulics 2003). Chronic recruitment failure of Nechako white sturgeon has been ongoing since 1967 (McAdam et al. 2005). Although recruitment since approximately 1967 has remained very low, some limited recruitment continues to occur with the number of individuals varying from year to year. In the Terms of Reference for this project, FLNRO indicated that the study was to focus on sturgeon recruitment after 1967. As the cause of the recruitment failure is likely attributed to the effects of the Cheslatta River avulsion and changes to river hydrology, this study is intended to investigate environmental factors that have contributed to the survival and low level variation in recruitment of white sturgeon under altered habitat conditions since 1967. FLNRO has previously collected aging samples (fin rays) from Nechako white sturgeon of all age cohorts recruited since 1967. These aging structures represent an important opportunity to potentially identify environmental factors that influence the growth and recruitment of white sturgeon in the Nechako River. FLNRO has retained EDI Environmental Dynamics Inc. (EDI) to age a number of archived fin rays, confirm hatch year, and assess factors that may have enhanced the recruitment of white sturgeon over the past 45 years. |
