Evaluation of Remote Site Incubators to Incubate Wild‐ and Hatchery‐Origin Westslope Cutthroat Trout Embryos

Fish managers must weigh trade‐offs among cost, speed, efficiency, and ecological adaptation when deciding how to translocate native salmonids to either establish or genetically augment populations. Remote site incubators (RSIs) appear to be a reasonable strategy, but large‐scale evaluations of this method have been limited. We used 129 RSIs to incubate >35,700 eyed embryos of Westslope Cutthroat Trout Oncorhynchus clarkii lewisi at eight sites within the upper 30 km of the Cherry Creek basin (Madison River, Montana) from 2007 to 2010, after using piscicides to remove all fish. We obtained gametes from 258 parental‐pair crosses (164 females and 258 males) from four wild populations and two hatchery broods. All embryos were incubated to the eyed stage in two hatcheries prior to placing them in RSIs. Green‐to‐eyed egg survivals were higher for progeny of wild‐spawned adults (median, 91.0%; 95% CI, 88.7–93.7%) than for progeny of hatchery‐spawned adults (median, 81.7%; 95% CI, 74.9–88.4%), and this difference was highly significant (P