Abstract
The B″ subunit of lactate dehydrogenase from the liver tissue of wild populations of resident rainbow trout (Salmo gairdneri) from the Loon and Pennask Lake areas has been found in a frequency of 0.400–0.800. An electrophoretically identical subunit was found in similar proportions in anadromous steelhead trout from the Thompson River, and from the Coquihala River in considerably smaller proportions. Steelhead from some coastal streams in and near Vancouver and Vancouver Island, and other selected streams from the Fraser and Skeena river systems generally revealed a very low frequency of less than 0.1.