Currently, it is estimated that 571 White Sturgeon live within the Nechako River. This number is very low, contains far too few juvenile fish, and will not support a healthy, vibrant sturgeon population. Local biologists and scientists have predicted that within the next 40-50 years, if the current trend is not reversed, the Nechako White Sturgeon will be extinct. This means everyone needs to work together to help save the Nechako White Sturgeon!
Sometimes our activities can alter fish habitat to the point where fish’s survival or health is threatened.
Human activities that effect sturgeon habitat are:
Land Use – farming, logging
Road and Corridor Development
Regulation Of River Flow
In the case of the Nechako River , the development of the Kenney Dam in the late 1950s, and the subsequent alteration of the Nechako ’s flows, has likely had a negative effect on the sturgeon. White sturgeon populations in other regulated systems, including the Kootenay/Kootenai and Columbia rivers, have also experienced declines. The effect(s) of river regulation that impact white sturgeon survivability are not well understood.
The Nechako white sturgeon are different from the lower and mid Fraser River sturgeon populations. Nechako sturgeon are slower to grow and likely slower to mature. Fraser sturgeon mature and can spawn between the ages of 14 and 20, with males maturing at an earlier age than females. Once sturgeon reach the age of sexual maturation, they don’t spawn every year, but may spawn only 1 in 3-5 or more years, with females spawning less frequently than males. The late age of maturation and infrequent repeat spawning will hamper the survivability of Nechako sturgeon and potentially other sturgeon stocks.
Lack of Juveniles
The Nechako white sturgeon population, as can be seen from the graph above, does not have high numbers of juvenile fish in the 1 to 25 year old range. By comparision, the combined catches from the Fraser mainstem stocks indicate these populations are made up largely of young fish, which should be the case with any healthy population. The Nechako population seems to be comprised largely of fish 30 to 50 years of age. It seems that younger generations of fish are not surviving or “recruiting” to maturity. The graph below depicts ages of a sample of sturgeon collected from the early 1980s and a sample from the late 1990s. It is evident that the population is ageing with very few new juvenile fish “recruiting” into the population. This is a dangerous trend.
Age Distribution Chart
The failure of a population to produce juvenile fish at a rate that will replenish or maintain the adult or reproductive portion of the population, such as what has occurred in the Nechako white sturgeon population, is known as a “recruitment failure.” There are a number of scenarios that could be playing-out to cause a recruitment failure, but they generally result from an absence of spawning, unsuccessful spawning, or conditions that result in poor egg, larval or juvenile survival.