Recovery of a Restored Native Cutthroat Trout Population After Watershed Renovation

The Turner organization, in collaboration with state and federal partners, has implemented an initiative to restore native cutthroat trout (Oncorhynchus clarki spp.) to hundreds of km of stream on private and neighboring public lands in MT and NM.  Of interest to practitioners and the angling public are how restored native populations compare to the pre-treatment non-native trout community and how quickly the recovery occurs.  We examined the recovery of Rio Grande cutthroat in Costilla Creek, NM, following two separate rotenone treatments (2002 and 2008) and different restocking strategies.  Only young of year fish were stocked following the 2002 rotenone treatment, while mixed aged fish were used after the 2008 treatment.  Population data were collected over the period 2001-2013 with multi-pass electrofishing at four monitoring sites.  Preliminary results show the restored population was comparable in density, biomass, condition, and length frequency to pre-treatment numbers within three years post-treatment using either stocking strategy. However, the biomass and mean length of the population derived from mixed age class stocking were slightly lower than the population derived from young-of-year fish.  These results indicate that recovery of restored cutthroat trout populations can occur relatively quickly under multiple stocking scenarios and will compare favorably to the pretreatment population.