TheGoldenSpruce

In University, I wrote a paper focused on the impacts of increased selenium levels in the Elk River Valley. I tried to prove that increased selenium concentration has a negative impact on Elk River Valley Cutthroat. To be honest, I had a very hard time. I can't find my old paper, but I found this bit of research interesting. 'Despite these elevated egg Se concentrations, there was no significant effect on fertilization; time to hatch; percent hatch; or egg, larvae, and fry deformities or mortalities. Reproductive failure and embryonic terata have been reported at much lower egg Se concentrations in other fish species. The lack of any toxic response in this study may be due to an evolved tolerance to higher tissue Se concentrations in a population of fish living in a seleniferous river system.' Essentially, the fish population in the Elk River system have adapted to increased selenium concentrations. The studies did not state a specific threshold value for toxic selenium concentrations for the Elk River Valley Cutthroat population, nor was there a study on the long term impacts of increased selenium concentrations.

According to the scholarly article linked below, 'the spread of hybridization may be constrained more by demographic than by environmental factors'. So natural species may not be as well adapted to survive in our local stream. http://www.nrcresearchpress.com/doi/abs/10.1139/f03-125#.VrJ3B7IrLIU In contrast; according to the following article, climate change is significant factor responsible for the increase in hybridization between the species. http://www.npr.org/2014/05/27/316316952/hybrid-trout-threaten-montanas-native-cutthroats Protection of our headwaters is important, but that alone will not lead to rebound of these threatened species. Some finer point management may be required.

Not to downplay the importance of protecting critical habitat, but another significant threat to the native cutthroat is the introduction of invasive species; mainly the rainbow trout. I'm unfamiliar with the population dynamics in the Castle wilderness area but I am certain that competition and hybridization between native and invasive species contributes to the west-slopes being listed as threatened.