Baseline fish health metrics in at-risk habitats critical for pallid sturgeon (Scaphirhynchus albus) in the Upper Missouri River Basin and bull trout (Salvelinus confluentus) in the Flathead River, Montana, 2017-18

Baseline fish health information on pallid sturgeon and bull trout or appropriate surrogate species (shovelnose sturgeon, cutthroat trout, mountain whitefish) in critical habitats with elevated risks of oil spills. Shovelnose sturgeon (Scaphirhynchus platorynchus) were collected in three locations near the confluence of the Missouri and Yellowstone Rivers and cutthroat trout (Oncorhynchus clarki lewisi) and mountain whitefish (Prosopium williamsoni) were collected from critical bull trout habitat along the Middle Fork of the Flathead River. Fish health metrics evaluated included gene expression/enzyme induction in various tissues, differential changes in white blood cells, polycyclic aromatic hydrocarbon bile metabolites, histological changes in gills, metabolic oxidative stress, immune dysfunction, and disruption of endocrine signaling pathways.