Morphometric comparisons were made among three isolated populations of pallid sturgeon Scaphirhynchus albus and shovelnose sturgeon S. platorynchus from the upper Missouri River. Six measurements were made on 89 pallid and 204 shovelnose sturgeons. Means of several morphometric characteristics were statistically different between populations of both species. Pallid sturgeon means showed proportional trends relative to location on the river. Toward the headwaters, relative head and interrostral lengths were progressively shorter and outer barbel length relatively longer. The only trend observed for the shovelnose sturgeon was that relative head length became longer upriver. This was the opposite of the trend observed for the pallid sturgeon. Morphometric ratios commonly used to differentiate the two species were useful measures for live fish from isolated populations of Missouri River sturgeon but not for the overall sturgeon population. The exclusivity of morphometric ratios currently used to distinguish between the two species did not hold for our larger fish and large sample size. A cumulative morphometric characteristic index is described to aid managers in comparing individual fish within a composite sturgeon population, and the finding of three possible hybrids is discussed.

John Fraley served as project manager and edited the drafts of this report. For their outstanding effort in collecting and analyzing samples, we'd like to thank our field crew

The distributions of most native trout species in western North America have been severely reduced, and conservation of many of these species will require translocation into vacant habitats following removal of nonnative species. A critical question managers have is “Does it matter which donor sources are used for these translocations?” We present a case study that addressed this question for a large native trout translocation project in Montana. We introduced embryos from five source populations of Westslope Cutthroat Trout Oncorhynchus clarkii lewisi to a large, fishless watershed in Montana following removal of nonnative fish with piscicides. Source populations providing embryos for translocations were three nearby (<120 km) wild populations, the state of Montana's captive Westslope Cutthroat Trout hatchery conservation population (initiated 32 years ago using fish from wild populations located >350 km from the translocation site), and a population in captivity for one generation comprised of individuals from the three wild populations used as single sources for this project, which were variably crossed (59% within populations and 41% between populations) to provide embryos. We used remote‐site incubators at six different sites to introduce approximately 35,000 embryos from 400 genotyped parents. We later resampled and genotyped 1,450 of these individuals at age 1 and age 2. Juvenile survival for the more genetically diverse Montana Westslope Cutthroat Trout conservation population was twice as high as for other source populations, even though these other source populations were geographically closer to the translocation site than populations used to make the Montana Westslope Cutthroat Trout conservation population. Body weight for progeny from the two captive populations was higher than for progeny from wild source populations, and some differences were observed in body condition among source populations. Continued monitoring over several generations will be necessary to determine the eventual contributions of each source population and the relevance of these initial findings. Received October 9, 2015; accepted February 27, 2016 Published online July 20, 2016

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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 < 0.01). Over 26,500 fry were counted leaving RSIs. Median embryo‐to‐fry survival was 75.6% (95% CI, 72.2–79.0%). Fry exited individual RSIs from 8 to 45 d after embryo translocation. Fry survivals differed among years and sites, and year was more important than site in explaining variation in survival. The success of RSI fry introductions was confirmed by annual monitoring of fish abundance, which indicated that abundances of Westslope Cutthroat Trout 5 to 9 years after RSI introductions were equal to or higher than abundances of nonnative salmonids prior to their removal using piscicides.