Microsatellite and Sequence Data Reveal Population Structure in California Redband Trout, Oncorhynchus mykiss subspp.

The taxonomic and ecological status of interior rainbow trout in California have beena topic of research interest for over 200 years, though no consensus has been reached regarding appropriate groupings. We use 11 microsatellite loci, 12 nuclear intronic regions, and the control region sequence of the mitochondria to examine structure within and between major watersheds in northern California. Populatoin genetic analyses show a deep between Upper McCloud redband trout and other redband and rainbow trout populations, supporting previous proposals to designate Upper McCloud redband trout as a separate subspecies. Phylogenetic analyses show monophyletic groups for populations in the Upper McCloud, Upper Pit, and Feather River drainages, providing support for many current designations and previous genetic research. There was no support for monophyletic clades corresponding to all sampled individuals from the Lower McCloud or Warner Valley watersheds, although in the case of Warner Valley, limiting sampling to California portions of the watershed may have skewed the results.